IM- PROVEMENTS IN OBTAINING CERTAIN COMPOUNDS OF MANGANESE FROM CHLORINE RESIDUES, AND IN MANUFACTURING CHLORINE BY MEANS THEREOF
Year: 1869

page_text: LETTERS PATENT to Walter Weldon, of Park, Villa, West Hill,
Highgate, in the County of Middlesex, for the Invention of "IM-
PROVEMENTS IN OBTAINING CERTAIN COMPOUNDS OF MANGANESE FROM
CHLORINE RESIDUES, AND IN MANUFACTURING CHLORINE BY MEANS THEREOF,
Scaled the 24th August 1869, and dated the 10th March 1869.
PROVISIONAL SPECIFICATION left by the said Walter Weldon at the
Office of the Commissioners of Patents, with his Petition, on the
10th March 1869.
I, WALTER WELDON, of Park Villa, West Hill, Highgate, in the
County of Middlesex, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN OBTAINING CERTAIN COMPOUNDS OF MANGANESE
PROM CHLORINE RESIDUES, AND IN MANUFACTURING CHLORINE BY MEANS THEREOF,
AND IN APPARATUS AND ARRANGEMENTS FOR THESE PURPOSES," to be as
follows:-.
I. This Invention relates chiefly to the regeneration or other pro-
duction in the wet way from residual products of the manufacture of
A

page_text: chlorine, of certain compounds containing manganese and oxygen, and to
the manufacture of chlorine by means of such compounds so regenerated
or produced.
II. For improvements relating to the objects thus recited four
Patents have already been granted to me, the said four Patents being
numbered and dated, respectively, as follows:-No. 1948, July 26th
1866; No. 133, January 18th 1867; No. 2501, September 4th 1867;
and No. 565, February 20th 1868. The present Invention consists in
certain further improvements which have been discovered or devised
in the course of my endeavours to bring into practical operation the
improvements for which the four Patents, bearing the numbers and
dates just enumerated have already been granted to me as aforesaid.
III. Of the further improvements which thus constitute the present
Invention, some relate to the mechanical means and modes of working
to be employed for the obtainment from chlorine residues in the wet
way of compounds of manganese suitable for use in manufacturing
operations for the liberation of chlorine from hydrochloric acid, some
depending on certain newly discovered chemical facts have for object
the proper regulation of the proportions and times of addition of one
of the chemical reagents employed in the production of those com-
pounds, or of certain of them; some consist in promoting the formation
of those compounds by a certain employment of certain other compounds
capable, in the circumstances, of acting as "carriers" of oxygen; some
relate to the preliminary purification and other treatment of the residual
liquors from which the compounds first mentioned are generated (or
regenerated, as the case may be); some refer to forms and dispositions
of apparatus, and to ways of proceeding, in and by which to effect the
reaction of the said compounds upon hydrochloric acid in such wise
as to secure the liberation therefrom of the utmost practicable pro-
portion of free chlorine; others refer to the utilization of one of the
constituents of the resulting residual liquor; others to the utilization
of a byc product of the decomposition of the principal constituent of
that liquor; and others to general arrangements and combinations of
apparatus, processes, and modes of proceedure in order to the systematic
manufacture of chlorine either wholly or partially by means of artificial
compounds of manganese obtained as aforesaid. One or two of the said
improvements, while referring primarily and mainly to the manufacture
of chlorine by means of the said artificial compounds of manganese,

page_text: are applicable also to other purposes, as will be more particularly pointed
out below.
IV. The compounds of manganese to which the improvements about
to be indicated refer may be compounds either simply of manganese and
oxygen, or of manganesc, oxygen, and a second metal. The process to
which the improvements in question mainly apply consists, essentially,
in decomposing chloride of manganese by a protoxide of other metal,
and then peroxidizing the resulting protoxide of manganese by treating
it in the wet way with either atmospheric air or some other suitable
gaseous oxidizing agent. One of the improvements for which the
Letters Patent of the number and date last mentioned in paragraph II.
were granted to me consists in adding to solution of chloride of t
manganese more lime than simply the quantity necessary to decompose
the chloride of manganese therein, and then treating with atmospheric
air or other suitable gaseous oxidizing agent the resulting mixture of
protoxide of manganese, free lime, and solution of chloride of calcium.
In the Specification describing those improvements I speak of the result
obtained by thus adding to a solution of chloride of manganese more
than an equivalent of lime and then treating the resulting mixture as
just indicated as consisting of solution of chloride of calcium holding
in suspension free lime and a more or less rich peroxide of manganese;
but I have now discovered that such result will scarcely ever contain
any free lime, unless the proportion of excess of lime used have been
very much greater than I recommended in that Specification, and that it
will never contain any free peroxide of manganese, but that either all
or the greater part (and most usually all) the lime in it will be combined
with peroxide of manganese, and that all the peroxide of manganese in
it will be combined either with lime or with protoxide of manganese.
V. This discovery that when protoxide of manganese associated with
lime is treated with air in the wet way the resulting peroxide of
manganese or a part of it combines with the lime, or with some of it,
forming therewith a salt in which MnO2 plays the part of an acid,
nakes much more intelligible than it was before the manner in which
the lime promotes the peroxidation of the oxide of manganese, but
at the same time makes evident that the directions which are given in
the final Specification of my Patent, No. 565, dated February 20th 1868,
with respect to, the proportions of excess of lime which it may be most
desirable to use under different circumstances, and the principle upon
2

page_text: which the proportions to be used are to be determined, are not sound
directions. In that Specification, proceeding upon the only theory of
the action of the lime, which at the date of that Specification I had as
yet been able to form, that is to say, upon the theory that the lime
acted in some way simply as a "carrier" of oxygen to the oxide of
manganese, which theory involved the conclusion that a small excess
of lime would secure as high a degree of peroxidation of the oxide of
manganese as could be obtained by means of a larger excess of lime,
provided only that when using the small excess of lime the treatment
with air or other gaseous oxidising agent were continued proportionably
longer than when using the larger excess of lime, I remark as follows:-
"The proportion of free lime which it will be desirable to have present
"with protoxide of manganese which has been recovered by means of
"lime and is to be peroxidized in the wet way will vary with circum-
"stances, depending chiefly in each case upon the nature of the par-
"ticular kind of economy which the manufacturer desires to realize,
"that is to say, more especially upon whether his object is to obtain
"from his supply of hydrochloric acid the very largest yield of chlorine,
"which oxides of manganese regenerated from chloride of manganese
"in the wet way by means of lime can possibly enable him to obtain
"therefrom, or whether while being content with some smaller yield of
"chlorine than this, he aims simply at obtaining such yield of chlorine
"with the utmost possible economy of time, labour, and apparatus.
"He will use lime more freely in the latter case than in the former,
"but will have to subject each charge of recovered oxide to the per-
oxidizing treatment for longer periods in the former case than in
"the latter. . . . . I incline to think that in all cases in which
the manufacturer of chlorine shall be content with obtaining in the
"free state one-third of the total quantity contained in the hydrochloric
"acid which he consumes in his manufacture thereof, the proportion of
"free lime which it will be found most advantageous to have associated
"with the oxide of manganese will be from one-half to three-fourths of
an equivalent. Manufacturers desiring to obtain in the free state by
"means of oxides of manganese regenerated from chloride of manganese
by means of lime in the wet way more than one-third of the total
"chlorine in their hydrochloric acid must use a smaller proportion of
"excess of lime than that just stated; and must subject their recovered
" oxide to the action of the peroxidizing blast for longer periods than it
"will be needful to subject it thereto when using such proportion of
"
66
68

page_text: "excess of lime as that indicated above." What I now believe, how-
ever, to be the true theory of the action of the excess of lime, in the
circumstances in question, does not admit of a small proportion of lime
although aided by however much longer a period of treatment with the
oxidizing agent, enabling as large a proportion of the oxide of manganese
operated upon to be raised to the state of MnO2 as can be raised to that
state by the aid of a larger proportion of lime, and does not admit,
indeed, of any proportions of lime increasing the quantity of MnO in
the final product to a greater extent than that of half an equivalent
of MnO for every equivalent of lime used.
VI. I believe that my recent observations and researches respecting
the peroxidation of hydrated MnO in the wet way and the influence
thereupon of the presence of lime have fully established the following
conclusions, among others:-Firstly, that MnO2 can be formed in the
wet way by direct combination between MnO and atmospheric oxygen
only in presence of some base with which the MnO2 can combine as it
forms; secondly, that when hydrated MnO, submitted to the action of
the air, has no other basic substance associated with it, a part of the MnO
itself acts as a base towards that part which is converted into. MnO³, the
result being either Mn2O³ (otherwise a compound of one equivalent of
MnO with one equivalent of MnO, which compound I regard as
manganite of manganese, and the correct formula of which I believe to
be either MnMnO³, or, as it will be herein-after written MnOMnO⁹,)
or MnO (otherwise a compound of one equivalent of MnO3 with two
equivalents of MnO, which compound may be regarded either as di-
manganous manganate, and be written as Mn2MnO', or as basic
manganite of manganese, and be written as MnOMnOMnO2), according
to temperature and other conditions; thirdly, that when CaO is present
with the hydrated MnO operated upon the resulting MnO tends to
combine to a certain extent and in certain ways varying with varying
conditions with CaO rather than with MnO, forming therewith,
according to circumstances, either a compound of one equivalent of
MnOs with one equivalent of CaO (which compound I regard as
manganite of calcium, and write either as CaMnO³, or as in this
Specification it will hereafter be written, as CaOMnO2), or a compound
of one equivalent of MnO3 with two equivalents of CaO (which com-
pound I regard either as di-calcic manganate, written Ca³MnO', or as
basic manganite of calcium, written CaO,CaOMnO³) or a compound

page_text: of one equivalent of MnO with more than two equivalents of CaO;
fourthly, that the condition which seems mainly to determine whether
MnO obtained by treating MnO with air in the wet way shall com-
bine with only one or with more than one equivalent of CaO is that
of the proportion of CaO in the presence of which the MnO is formed;
fifthly, that compounds of MnO3 with more than one equivalent of CaO
are slimy, gelatinous bodies, exceedingly indisposed to settle from the
solution in which they are produced; sixthly, that compounds of MnO
with more than one equivalent of CaO are capable of decomposing
chloride of manganese to the extent of the CaO in them in excess of the
quantity equivalent to the MnO2 in them, but that compounds of MnO2
with only one equivalent of CaO cannot act upon chloride of
manganese at all; seventhly, that some but not all of the compounds
of MnO2 with MnO can be decomposed, more or less completely, by
the joint action, in the wet way, of air and CaO, their MnO, or a part
of it, being obtained either as MnOMnO2, or as MnO,MnOMnO³,
or as MnO2 combined with CaO, or partly in one and partly in either
or both of the others of these states, according to the proportion of CaO
used and the temperature employed; eighthly, that some compounds of
MnO with MnO, produced in the wet way, can be decomposed, more
or less completely, by the joint action, in the wet way, of CaO and
atmospheric oxygen, a part or the whole of their MnO at the same
time undergoing peroxidation; and, ninthly, that some compounds
of MnO2 with MnO, as formed by treating hydrated MnO with air at
ordinary temperatures, can be further peroxidized, a part of their MnO
being converted into MnO, by further treatment with air, in the wet
way, aided by heat.
VII. It would thus appear that the true theory of the action of lime
in promoting the peroxidation of protoxide of manganese in the wet way
is, not that the lime acts as a "carrier" of oxygen to the oxide of
manganese, but that it acts in place of a part of the MnO itself, as a
base for MnO to combine with, thereby rendering free to undergo
peroxidation a portion of MnO which, but for the presence of the lime
would have got locked up in combination with MnO in a state in
which it would have been incapable of being peroxidized, at least by
the process in question. It follows that, as stated in the final sentence
of paragraph V., the utmost extent to which the presence of CaO can
increase the proportion of MnO which can be converted into MnO by

page_text: treatment with air in the wet way, is that of half an equivalent for each
equivalent of CaO used. This will be seen at once if it be considered
that, inasmuch as if two equivalents of MnO, not having any other
basic substance associated with it, be treated with air in the wet way, as
long as any peroxidation goes on, the result will consist of one equi-
valent of MnO combined with one equivalent of MnO (in other
words, of one equivalent of MnOMnO, or neutral manganite of
manganese), only one equivalent of MnO2 would be gained if two
equivalents of CaO were used and the result obtained by their aid was
two equivalents of MnO2 combined with two equivalents of CaO (that
is to say, two equivalents of CaOMnO2, or neutral manganite of
calcium). To get 2CaOMnO, however, instead MnOMnO is a
very important advantage, seeing that whereas only half the manganese
in the latter compound is in the state of peroxide, the whole of the
manganese in the former compound is in that state. Both compounds
consume the same quantity of hydrochloric acid per given yield of free
chlorine, but the compound the whole of whose manganese is in the
state of peroxide is nevertheless by much the more advantageous of the
two, for reasons which will be fully detailed in the final Specification
of the present improvements, and some of which, or what are sub-
stantially such, are set forth in paragraph 31 of the final Specification
of my former improvements aforesaid, the Letters Patent for which
are numbered 565 and dated the 20th February 1808.
VIII. It will usually be desirable then that as large a proportion as
possible of the product obtained by decomposing by means of lime the
chloride of manganese contained in the residues of the manufacture of
chlorine and treating the resulting mixture with either atmospheric air
or some other suitable gaseous oxidizing agent, in order thereby to
obtain a compound or compounds by means of which to manufacture
more chlorine, should be in the state of CaOMnO³. Now in the
former Specification just alluded to, in the passage which is quoted from
it above in paragraph IV., I recommend that MnO which it is desired
to convert by treatment with a gaseous oxidizing agent in the wet way
into a very rich peroxide, should have associated with it "from one-half
to three-fourths of an equivalent of lime," and from what has been said
in the present Specification with respect to the nature of the influence
of lime in promoting the peroxidation of protoxide of manganese in the
wet way, it might perhaps be expected that when working under the

page_text: said former Specification, and using half an equivalent of lime, half the
manganese would be obtained as CaOMnO and the other half as
MnOMnO2, the product being 2CaOMnO3+MnOMnO', and of the
total oxide of manganese in it (reckoned by itself, without taking
into account the CaO combined with a part of it) about 78 per cent.
being in the state of peroxide, and that when similarly working under
that Specification and using three-fourths of an equivalent of lime,
three-fourths of the manganese would be obtained in the state of
CaOMnO and only one-fourth as MnOMnO³, the product being
6CaOMnO3+MnOMnO3, and thus about 89 per cent. of the total
oxide of manganese in it being in the state of peroxide. There is
evidently, however, some important difference between the conditions
which prevail in manufacturing operations and the conditions under
which were performed the small experiments upon the results of which
were founded the statements made in the former Specification in
question with respect to the amount of peroxidation obtainable by
means of from half an equivalent to three-fourths of an equivalent of
CaO applied as therein directed, for while I have now no doubt that in
those experiments (although I was then unaware of the true nature of
the products they yielded) I really obtained mixtures of neutral man-
ganite of calcium with manganite of manganese, of the total oxide of
manganese in which mixtures from 70 to 90 per cent. was in the state
of peroxide, it has been found impossible to repeat those results on the
large scale, under the conditions which obtain in manufacturing
operations, when proceeding as in those experiments, and as is pre-
scribed in the Specification referred to. It has been found that under
the conditions which prevail in operations conducted on a practical
manufacturing scale, and dealing with actual chlorine residues, if any
very considerable excess of lime be used, and the whole of that excess
of lime be added, as the Specification in question directs, at the com-
mencement of the operation, the portions of MnO which are first
formed combine, not with one equivalent of lime only, but with two
equivalents thereof, and that although the basic manganite of calcium
thus formed at the earlier stages of the operation may sometimes,
under special circumstances, be decomposed at later stages of the
operation and be caused to give up its second equivalent of lime to
subsequently formed portions of MnO2, as a rule it remains undecom-
posed and constitutes part of the final product, rendering that product
incapable of settling satisfactorily, and causing such product by reason

page_text: both of its extreme bulkiness and of the second equivalent of lime
combined with a portion of its MnO3, to require for its solution an
excessive proportion of acid. It has thus been found that, in order to
secure the obtainment, under the conditions which have place in
industrial operations, of products rich in MnO3, but containing no (or
only very little) basic manganite of calcium, it is essential that the
excess of lime used be added otherwise than wholly at the commence.
ment of the operation.
IX. Experience has moreover shown that whenever any very con-
siderable portion of lime, not combined with MnO3, is allowed to be
present with such a mixture of solution of chloride of calcium with
oxide of manganese as is obtained by decomposing by means of lime,
the chloride of manganese in actual chlorine residues obtained in
manufacturing operations, which mixture is being treated with atmos-
pheric air, for the peroxidation of the protoxide of manganese in it,
there is apt to be formed a very curious; body which I take to be either
an oxychloride of calcium, or a compound of oxychloride of calcium with
oxide or oxides of manganese, or of oxychloride of calcium with both
oxide or oxides of manganese and combinations of CaO with MnO2, and
which is probably the one or the other according to the stage of the
operation at which it is formed, and that not only does the formation of
this body invariably cause the whole mixture to become very thick,
sometimes causing it actually to solidfy, but, moreover, the presence of
this body greatly retards the peroxidation of the proloxide of manga-
nese present, and not unfrequently prevents any peroxidation whatever
going on, however energetically the blast of air may be applied. This is
another reason why I now prefer, in most cases, to add such excess of
lime as may be used otherwise than as directed in my former Specifi-
cation above cited.
X. As regards the most advantageous proportion of excess of lime
to employ when it is desired, as it usually will be, to obtain a product
which shall settle with maximum readiness, and shall liberate the
largest practicable proportion of chlorine from the hydrochloric acid
required to dissolve it, I now believe that it will usually be best not to
use much, if any, more than half an equivalent of excess of lime, being
the quantity which, when so applied as to secure that the whole of it
shall enter into combination, but only in such wise as to form neutral
manganite, gives a product consisting of two equivalents of CaO MnO³,

page_text: mixed or combined with one equivalent of MnO MnO2. Three-fourths
of the manganesc in this mixture or compound is in the state of per-
oxide, about 78.6 per cent. of the total oxide of manganese in it being
in that state. Up to and perhaps a little beyond the limit of this
degree of richness in MnO it is easy to obtain products containing no
appreciable quantity of basic manganite of calcium, and which
accordingly settle well, and are economical in relation to acid; but, so
far as I can gather from such experience as I have had hitherto,
products more than 82 or 83 per cent. of the total oxide of manganese
in which is in the state of MnO2, rarely settle so well, and are not
nearly so easily obtained free from basic manganite as products the
proportion of MnO in the total oxide of manganese in which is under
or does not greatly exceed 80 per cent. On this point, however, I shall
be able to say more in the final Specification of the present improve-
ments. I need only add here that in some special cases it may be
worth while, when it is desired to convert the whole or nearly the whole
of the MnO into MnO2, and the formation of some portion of basic
manganite of calcium can be put up with, to apply to the last part of
the MnO more than an equivalent of lime.
XI. Those of the improvements collectively constituting the present
Invention to which the considerations above set forth refer, consist,
then, firstly, in producing from chlorine residues by means of lime and
atmospheric or other gaseous oxygen applied in the wet way, and in
manufacturing chlorine by means of such compounds of manganese,
oxygen, and calcium as are obtained when the excess of lime used is
half an equivalent, or any proportion less than half an equivalent, and
this excess is added, not all at once, but gradually, in such wise as to
be added by, or about, or a little before, or a little after that stage of
the operation at which one-third of the MnO operated upon has
been converted into MnO2; secondly, in producing, and similarly
applying such compounds of the said bodies as are obtained by the
same method of procedure when the proportion of excess of lime used
is as just mentioned, but its addition is made more gradually, in such wise
that the last of it shall not be added until at, or about, or a little before,
or a little after that stage of the operation at which one-half of the MnO
operated upon has been converted into MnO2; thirdly, in producing and
applying as aforesaid such compounds as are obtained when the excess of
lime used is three-quarters of an equivalent, or any proportion between

page_text: half an equivalent and three-quarters of an equivalent, and its addition
is made gradually at either of the two rates above mentioned; fourthly,
in producing and applying as aforesaid such compounds as are obtained
when the last stated proportions of excess of lime are used, but their
addition is made so gradually as not to be completed until after that
stage of the operation at which one-half of the MnO has been converted
into MnO; fifthly, in similarly producing and applying such
compounds as are obtained by the same methods of proceedure when
there is gradually added from three-quarters of an equivalent to an
equivalent and a quarter of excess of lime; sixthly, in combining with
the use of any of these proportions of excess of lime and rates of addition
of them, the plan of adding to the solution of chloride of manganese,
which forms the starting point of the process by which the compounds
in question are obtained, less in the first instance than enough lime
to completely decompose it, and treating with air or whatever other
gaseous oxidizing agent may be employed the resulting mixture of
protoxide of manganese with mixed solution of chloride of manganese
and chloride of calcium for some little time before adding more lime;
seventhly, in having no, or scarcely any, lime present with the oxide of
manganese until from one-fourth to one-half of it has become converted
into MnO2, and then adding a certain proportion of lime gradually
or otherwise and thereafter continuing the peroxidizing treatment as
long as peroxidation will go on; eighthly, in treating with solution of
chloride of manganese, and with either air or other gascous oxidizing
agent any product containing basic manganite of calcium, (whether
such product have been obtained by procceding according to any of
the methods above set forth, or by adding to the MnO at or before
the commencement of the peroxidizing treatment whatever excess of
lime was used in forming such product,) using as nearly as may be
such proportion of chloride of manganese as the second equivalent of
lime in the basic manganite contained in the said product can decompose;
ninthly, in stopping the addition of chloride of manganese in cases in
which the method of proceedure adopted is that of putting the lime.
first into the vessel in which the peroxidation is performed, and adding
the chloride of manganese thereto gradually (air or other gaseous
oxidizing agent being injected all the while) in time to leave undecom-
posed enough lime to form from five to twenty per. cent. of man-
ganite of calcium, and afterwards either adding more lime in such
wise as to form more manganite of calcium, or not, as may be

page_text: preferred; and tenthly, in treating with air or other gaseous oxidizing
agent under the influence of heat mixtures with solution of chloride
of calcium, of compounds which have been formed by treating therein
at temperatures not artificially raised either protoxide of manganese
alone or protoxide of manganese and lime. Each of the methods of
proceedure thus enumerated has its own special advantages, and each is
the best under the special set of circumstances to which it chiefly
applies, as will be pointed out in detail in the final Specification of
the present improvements.
.
XII. Some new points with respect to the lime used which I consider
to be of importance consist, firstly, in carefully grinding the lime with
water and arranging for the mud or milk of lime so obtained to flow
from the mill in which it is produced to the bottom of a vessel in
which it can deposit its coarser particles, or some of them, the finer milk
or mud overflowing from this vessel either into a second similar settling
vessel or into a reservoir, from which it can be pumped or otherwise
transferred into the vessel or vessels containing the chloride of
manganese which it is to decompose; secondly, in slaking the lime
before putting it into the mill in which it is to be ground into milk
or mud; thirdly, in also sieving the lime before putting it into the mill;
fourthly, in grinding the lime with solution of chloride of manganese
instead of with water, so as to avoid the increase of bulk which the
addition to the chloride of manganese liquor of mud or milk of lime
made with water would cause; fifthly, in passing the mud or milk
of lime through a fine sieve before adding it to the chloride of manganese
liquor; sixthly, in using the lime not in the state of milk or mud but
in that of dry hydrate of lime; and, seventhly, in putting the chloride
of manganese to the lime when the lime is thus employed as dry
hydrate instead of putting the lime to the chloride of manganese.
XIII. Another of the improvements which collectively constitute the
present Invention consists in promoting the peroxidation of low oxides
of maganese in the wet way by adding to the mixture containing such
oxides, either before the commencement of the treatment of such
mixture with air or other gaseous oxidizing agent or at some stage
during the progress of that treatment, any salt capable of imparting
oxygen to the oxide or oxides of manganese contained in the mixture
to which it is added, and of then absorbing oxygen, to replace that
with which it has thus parted from the air or other gaseous oxidizing

page_text: "
agent with which the mixture is treated, in such wise that a com-
paratively small quantity of such salt may carry" oxygen to a
comparatively large quantity of oxide of manganese. The salts most
suitable for use in this way are the hypochlorites, chlorites, perchlorates,
manganates, permanganates, and ferrates.
XIV. Another of the improvements constituting the present Inven-
tion consists in artificially cooling a mixture of hydrated oxide or
oxides of manganese with water or a saline solution, whether or not
containing other substances also, which mixture is being treated with
air or other gaseous oxidizing agent for the peroxidation of the oxide
of manganese in it, or of a part thereof, in order by such cooling to
diminish the chemical activity possessed by the resulting MnO2 at the
moment of its formation, and thereby to diminish the tendency of such
MnO to combine with such base or bases as may be present in the
mixture in which it is formed.
XV. Certain others of the improvements collectively constituting the
present Invention relate to the neutralization of the residual liquors
resulting from the digestion of hydrochloric acid with any compounds
of manganese capable of liberating chlorine therefrom, when such
liquors are not neutralized by any of the methods set forth below,
in paragraph XVII., and to the utilization of the free hydrochloric
acid in such cases contained in them. These of the said improvements
consist, firstly, in treating the said residual liquors for the neutralization
of the free acid in them, and the decomposition of any sesquichloride
of iron or sesquichloride of aluminium which they may contain, with
native or other carbonate of lime, not in lumps, but in the state of
more or less fine powder; secondly, in combining the neutralization of
residual liquors remaining in the cases above mentioned, after the
digestion together of hydrochloric acid and artificial compounds of
manganese produced in the wet way with the generation of carbonic
acid gas, for use in the manufacture of bicarbonates, or otherwise, such
neutralization being then effected in suitable closed vessels, from which
the carbonic acid gas set free by the reaction upon carbonate of lime
of the free hydrochloric acid in the liquors treated can be readily
collected and conveyed to the places at which it is to be used, and
thirdly, in combining the necessary neutralization of the free acid in
such residual liquors with the decomposition, in order to the obtainment
of free sulphur therefrom, of compounds produced in processes for

page_text: the recovery of sulphur from alkali makers' "tank waste." When
generating by the method just mentioned carbonic acid for actual use if
there be any danger (which, however, may be readily avoided) of the
carbonic acid being contaminated with chlorine, I wash it with solution
either of a protosalt of iron or of a protosalt of any other metal
which, when in solution as a protosalt, can be readily peroxidized by
free chlorine, with simultaneous conversion into hydrochloric acid of the
chlorine which occasions its peroxidation..
XVI. I have next to enumerate certain new methods of turning to
account the chloride of calcium produced by decomposing chloride of
manganese by means of lime. One of the said new methods consists
in adding magnesia to the chloride of calcium in solution, and then
treating the resulting mixture with carbonic acid gas, preferably under
pressure, so as to obtain carbonate of lime and solution of chloride of
magnesium, which last can be readily resolved by evaporation and
calcination at a low temperature into hydrochloric acid and magnesia
for use over again. The carbonic acid used in this operation may be
that contained in products of combustion, which products may be
applied just as they are obtained, the other gases associated with
the carbonic acid gas in such products escaping from the vessel
in which the operation is performed under pressure by lifting a
suitably loaded valve. Another of the said new methods consists in
treating a mixture of solution of chloride of calcium and magnesia with
sulphurous acid, so as to obtain sulphite of calcium and chloride of
magnesium, the latter to be decomposed as before, and a third consists
in decomposing the chloride of calcium in a furnace by the joint action
of silica and steam. These methods of treating chloride of calcium
are obviously applicable also to chloride of calcium produced otherwise
than by the decomposition of chloride of manganese by lime.
XVII. The improvements next to be set forth relate to the application
of artificial compounds of manganese, obtained in the wet way, to the
liberation of chlorine from hydrochloric acid. They consist in using for
the treatment of such compounds of manganese with hydrochloric acid
stone stills of greater depth than width; in filling up the corners of such
stills at the bottom, so that their bottoms may slope from all sides,
or if not from all sides from two sides, to the centre; in passing
artificial compounds of manganese into the stills in the state of fluid mud
admitted by means either simply of tubes and cocks, or of S tubes, or,

page_text: preferably, of liquid lutes, such as are in common use in nearly all
chemical works; in heating the mud before it goes into the stills; in
heating the mud either by passing the mud itself through tubes
heated externally, or by passing tubes heated internally through the
vessels containing the mud, or by applying heat externally to those
vessels themselves; in heating the acid before it goes into the stills; in
heating the acid either by passing the acid itself through tubes of either
platinum, earthenware, ebonite, or other suitable material, such tubes
having heat applied to them externally, or by passing tubes heated
internally through the vessels containing the acid, or in making those
vessels of stone and heating them externally either by steam or by means
of water baths, saline baths, or baths of heated pitch; in putting the acid
into the stills first, and running the mud in upon the acid; in sending
the mud into the stills first, in certain special cases, and running the acid
in upon the mud; in running the acid and mud into the stills simul-
taneously; in injecting steam into the stills for the purpose of heating
their contents; in injecting steam into them for the purpose of agitating
their contents; in heating the stills externally, by means either of
steam or of water baths, saline baths, sand baths, or pitch baths; in
obtaining nearly or quite neutral residual liquors by sending into the
stills an excess of mud, and then, instead of running off the total contents
of the stills, allowing the undissolved peroxide to settle in them and
drawing off only the supernatant liquor; in drawing off the whole
contents of the stills, when an excess of mud is used, and allowing the
undissolved peroxide to settle in other vessels; in either adding the
excess of mud at the beginning, or having an excess of acid at first, so
that the mud first added shall be dissolved completely, and then adding
more mud so as to neutralize the remainder of the acid either mainly or
exclusively with the CaO and MnO contained in such mud, leaving
its MnO, or some thereof, unacted upon; in using an excess of acid
in cases in which free acid in the residual liquor can be turned to
account, or in which the utmost economy of acid is not so important
as simplicity of mode of procedure and economy of labour and attention,
and thereby dissolving at each operation the whole of the mud which
goes into the stills, and having no undissolved peroxide in the residual
liquors; in neutralizing such residual liquors containing free acid, by
means of the CaO or MnO in artificial compounds containing those
bodies or either of them, not in the stills, but in separate vessels; in
allowing the impuritics contained in the residual liquors to settle with

page_text: the undissolved MnO2 contained in them, in cases in which the residual
liquors are mainly or completely neutralized by means of the CaO or
MnO (or both) in an excess of manganese mud, and in then dealing
with the deposit of MnO3 mixed with sundry impurities which is so
obtained by periodically dissolving it in special operations in which an
excess of mud is not used, but in which an excess of acid is employed,
the whole of the MnO being thereby dissolved, and an acid residual
liquor remaining, which acid residual liquor will carry away with it all
the impurities which were associated with the MnO%, and will after-
wards deposit them on being neutralized by carbonate of lime or other-
wise; and in following any of these methods of proceedure when using
in the manufacture of chlorine by means of artificial compounds of
manganese obtained in the wet way any such stills as are at present
employed in the manufacture of chlorine by means of native ores of
manganese, or any other kind of stills whatever. I have here stated,
as before, only the nature of the improvements in question, reserving
till my final Specification particular instructions as to how best to carry
them into effect, and as to the particular circumstances under which
each is most advantageously applicable.
XVIII. What I regard as a still more important improvement
relating to the modes and means of treating together hydrochloric acid
and such artificial compounds of manganese as the present Invention
chiefly refers to consists in using for their reaction upon each other
what I propose to call a "continuous still," being a series of vessels so
connected together and otherwise arranged that acid and manganese mud
may be continually being run into the first of them, and solution of
chloride of manganese, neutral or acid, as may be preferred, be con-
tinually running out of the last of them, while from the first vessel and
some of the succeeding vessels chlorine shall be continually being
evolved. Such a "continuous still" might be composed of any number
of vessels, not less than two, but a series of from four to six vessels will
probably be found to answer best. The principle upon which I propose
to arrange and connect together suitable vessels in suchwise that a series
of them shall constitute a "continuous still" is one which admits of
being embodied in a very great number of different forms, of which,
however, it will be sufficient to describe only one. Suppose six closed
vessels A, B, C, D, E, and F arranged, say, in a line, and each vessel,
beginning with A, connected with the next by a tube proceeding from

page_text: about the centre of its right side through the left side and down nearly
to the bottom of the interior of the next vessel, let A, B, C, and D
be provided with an exit tube for chlorine, and let A have adapted
to it two inlet tubes descending nearly to its bottom, and either D or E
be furnished with one similar inlet tube, while F is furnished with an
exit tube for liquor placed at a level a little below that of the upper
orifices of the tubes by which the six vessels are connected together.
The vessels being thus arranged it is obvious that if any liquid be run
continuously into the vessel A by means of either or both of the two
inlet tubes adapted to that vessel the liquor so run in will first rise up
in A till it reaches the orifice of the tube connecting A with B, will
then flow through that tube to the bottom of B, will then rise up in B
till it reaches the orifice of the tube connecting B with C, will then run
through that tube to the bottom of C, will then rise up in C till it
reaches the orifice of the tube connecting C with D, will proceed in
this way through D and E into F, and will finally flow off from F
through the exit tube provided for that purpose. Supposing that what
is run into A is hydrochloric acid, run in through one of the inlet
tubes, and peroxide of manganesc mud run in through the other, that
the whole series of vessels, or, if not the whole of them, all but the
first or so, are suitably heated, by being placed in a bath or otherwise,
that the proportions of acid and mud are properly adjusted, and that
the rate at which they are run in is in proper accordance with the size
of the vessels, it is clear that acid and mud may be kept constantly
running into A, chlorine constantly coming off from A, B, and C, and
perhaps D, and a liquor free from undissolved peroxide constantly
running off from F. When it is desired that the liquor running off from
F should not contain much free acid a further quantity of mud should
be run into either the vessel D or the vessel E, by the inlet pipe pro-
vided for that purpose, by which means the liquor issuing from F may
be rendered nearly or absolutely neutral, as may be preferred. In this
case the residual liquor issuing from F will usually have associated with
it more or less undissolved MnO', and must therefore be dealt with
by one of the methods set forth above in paragraph XVII.
XIX. I believe that stills constructed substantially on the principle
just indicated will be found to possess important advantages for use for
the generation of chlorine by means of artificial oxides of manganese
obtained in the wet way, and that they will be found very useful also for
other purposes. The method of connecting together the various vessels
B

page_text: constituting such a still (at least in one of its forms) need not be
exactly such as is described above, but the vessels may be connected by
tubes passing from the bottom of one to a point in the next at the level
to which liquor is to be allowed to rise in it, or by tubes from the
liquor level of one to the bottom of the next, or by tubes from the
bottom of one to the bottom of the next, and from the liquor level of
that to the liquor level of the succeeding one, and so on, or in any one'
of a great many other equivalent ways. The application of the
fundamental principle of such stills may moreover be extended by
placing within each closed vessel constituting a part of such a still a
smaller open vessel, and so arranging that whatever enters the closed
vessel shall go direct to the bottom of the inner open vessel, and shall be
obliged, before it can issue from the closed vessel to rise up to the top
of the inner open vessel to overflow into the space between that vessel
and the sides of the containing closed vessel, and then to pass down to
near the bottom of that space. I believe that the best way of turning
to account for the generation of chlorine by means of artificial oxides of
manganese obtained in the wet way the stills at present in use for the gene-
ration of chlorine by means of native oxides of manganese will probably
be found to be that of connecting a series of them together, sub-
stantially as above indicated, and so forming of a number of them one
"continuous still." It may be added, however, that a continuous still
need not necessarily be formed of a series of distinct vessels, but may
obviously be formed equally well by dividing a single vessel into
compartments, and providing suitable passages between the different
compartments thereof, and that a little obvious arrangement might
even enable so simple a thing as a long tube merely to act as a
continuous still. It may also be further suggested that it will some-
times be desirable to make the first vessel or compartment of a
continuous still of more or less considerably larger capacity than the
subsequent ones.
XX. I now come to some points of improvement in the form and con-
construction of the vessels in which the peroxidation of artificial oxides
of manganese in the wet way is performed when it is effected by
injection of a blast of air or other gas or gases, and in certain arrange-
ments connected therewith. I prefer to make these vessels either of
wrought iron or of cast iron, but they may also be made of either wood,
stone, or brickwork. When made of either of the three last-mentioned
materials they should preferably be lined with either metal or a suitable

page_text: cement. I consider that it is best that they should be of either square or
round horizontal section, and that their depth should be greater than
their width. When they have false bottoms, underneath which the
blast is injected, the holes in such false bottoms should preferably be
conical, with their narrowest extremity upwards. I prefer that the
real bottoms of the vessels should slope somewhat towards the centre.
At a certain distance below the tops of these vessels, being at or about
the level to which when in use they are filled with the mixture into
which the blast is injected, I like to adapt what may be spoken of as
perforated covers, but may conveniently consist simply in each case of
a row of planks, arranged an inch or two apart, and firmly secured to
ledges of angle iron or otherwise. These afford sufficient exit for the
excess of air, and at the same time prevent undue vibration of the
vessels being caused by the splashing of their contents against their
sides. Finally, I believe that it greatly economizes air if such vessels
be furnished with a number of perforated diaphragms, or other equi-
valent contrivances, fixed horizontally, at intervals of a foot or so, more
or less; the object of such diaphragms being to break up into thin
streams, and prevent collecting into large bubbles, the air which is
injected into such vessels at their lower part, and thereby caused to
rise up through their liquid contents. Instead, however, of actual
diaphragms, it is perhaps better to use rows of flat strips of metal, such
strips being placed at little intervals apart, and care being taken to
secure that the intervals between the strips in one row shall not be in a
perpendicular line with the intervals between the strips either in the
row immediately above or in the row immediately below. Instead of flat
strips of metal it might be well to use pieces bent somewhat after the
fashion of angle iron, and so having a more or less V-shaped transverse
section. These should be arranged with the point of the V, so to speak,
upwards, and perhaps closer together than when using flat strips, but
with the same regard as when using flat strips to the positions of the
intervals between them. When using simply flat strips of metal it
would perhaps be better to arrange them in lines or planes passing
diagonally instead of horizontally across the vessels..
XXI. An important modification of the plans prescribed in my
former Specification, No. 565, A.D. 1868, for the purification of the
residual liquors of the manufacture of chlorine, preliminarily to treating
them for the obtainment from them in the wet way of artificial com-

page_text: pounds of manganese for use again in that manufacture, consists in
placing the vessels in which these liquors, after neutralization, shall
deposit their impurities at a higher elevation than the vessels in which
the regeneration of oxides of manganese from these liquors is after-
wards effected. Having run these liquors from the stills into a well or
other receptacle placed below the stills, I therein neutralize them, if
they require neutralization, and then immediately pump them up into
settling tanks placed at such an elevation as I have just said. I prefer
to make these settling tanks either of wood or of cast iron. When the
liquors have deposited their impurities in these tanks I decant them into
the vessels in which the regeneration from them of peroxide of manganese
is to be effected, which vessels I prefer to place immediately under the
said settling tanks. Below the vessels in which the regeneration process
is performed I place tanks for the peroxidized mud to be run into and
be allowed to settle in, and I prefer that these should be at such an
elevation that the mud, after it has settled, and as much as possible of
its solution of chloride of calcium has been drawn off from it, shall be
able to run from them into the stills. The settling tanks for the per-
oxidized mud, the vessels in which the peroxidation is effected, and the
settling tanks for the chloride of manganese liquors may conveniently be
supported one above another in the order named by means either of stout
wooden "legs" or of iron pillars. When it is preferred to keep down
the height of the apparatus as much as possible, special settling vessels
for the peroxidized mud may be dispensed with by the vessels in which
the mud is peroxidized being used also for it to settle in. When the
lime employed to decompose the chloride of manganese is added thereto
as mud or milk, either a tank to be used as a reservoir of such mud or
milk of lime should be placed at such an elevation that such mud or
milk can readily run from it into the vessels in which the chloride of
manganese is decomposed, or if the reservoir of milk of lime is placed
at any lower level there should be duly adapted to it either a force
or lift pump or other appliance by means of which known quantities of
the mud or milk can be readily forced or lifted into the vessels in which
they are required. When the deposit which forms in the chloride of
manganese settlers contains no MnO2, it should be periodically re-
moved from those vessels and either thrown on to filter beds, so as to
permit all adherent chloride of manganese liquor to drain from it, or have
such adherent liquor separated from it by means of centrifugal hydro-
extractors, or have such liquor simply washed from it in any convenient.

page_text: way. When the said deposit does contain MnO3, it should be treated
as is indicated above in paragraph XVII.
XXII. Instead of dealing with mud containing manganite or man-
ganites of calcium produced in the wet way for the separation from it
of some of its solution of chloride of calcium, simply by leaving it to
settle and then drawing off such clear liquor as forms, such mud may be
either filtered or have the greater part of its solution of chloride of
calcium separated from it by means of centrifugal hydro-extractors.
I also claim the separation of associated solution from mud containing
any oxides of manganese formed in the wet way by means of filters
having either a vacuum applied to their under surface or either steam
or pneumatic pressure applied to their
upper surface.
XXIII. The artificial compounds of manganese to which those parts
of the present Invention refer which do not obviously relate to or involve
special methods of forming such compounds may be any compounds
formed by any method of applying either air or other gaseous oxidizing
agent to any mixtures of either oxide of manganese only, or of oxide of
manganese and lime or other substances with either water or solution of
chloride of calcium or other suitable saline solution. I wish, however,
to make here a special claim for the application of all such parts of the
present Invention to compounds produced by adding solution of chloride
of manganese gradually to milk of lime, and simultaneously injecting air
or other gaseous oxidizing agent into the resulting mixture, and special
claims also for the use of a blast engine for the production of such
compounds; for the production of them by means of air applied at the
temperature of the atmosphere; for the plan of running or otherwise
transferring such compounds from vessel to vessel in the state of mud,
and of sending them in that state into the stills in which they are to be
dissolved; for the separation of sulphates and other impurities from the
liquors from which they are formed; and for the use in their formation
of lime enough to yield products, the oxide of manganese in which,.
reckoned by itself, shall contain more than 60 per cent. of MnO2.
With the exception of that last mentioned I make the same special
claims also with respect to such compounds as are producible by
treating with air or other gascous oxidizing agent mixtures of previously
prepared hydrated oxides of manganese with water only.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Walter Weldon in the Great Seal Patent Office
on the 9th September 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WALTER
WELDON, of Park Villa, West Hill, Highgate, in the County of Mid-
dlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of March, in the year
of our Lord One thousand eight hundred and sixty-nine, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Walter Weldon, Her special licence
that I, the said Walter Weldon, my executors, administrators, and
assigns, or such others as I, the said Walter Weldon, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
OBTAINING CERTAIN COMPOUNDS OF MANGANESE FROM CHLORINE RESIDUES, AND
IN MANUFACTURING CHLORINE BY MEANS THEREOF, AND IN APPARATUS AND
ARRANGEMENTS FOR THESE PURPOSES," upon the condition (amongst others)
that I, the said Walter Weldon, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Walter Weldon, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
the following statement :-
I. This Invention relates chiefly to the regeneration or other pro-
duction in the wet way from residual products of the manufacture of
chlorine, of certain compounds containing peroxide of manganese, and
to the manufacture of chlorine by means of such compounds so re-
generated or produced.

page_text: II. For improvements relating to the objects thus indicated four
Patents have already been granted to me, the said four Patents being
numbered and dated respectively as follows:-No. 1948, July 26th
1866; No. 133, January 18th 1867; No. 2501, September 4th 1867;
and No. 565, February 20th 1868. The present Invention consists in
certain further improvements which have been discovered or devised in
the course of my endeavours to carry into practical operation the
improvements for which the four Patents bearing the numbers and
dates just enumerated have already been granted to me as aforesaid.
III. Of the further improvements which thus constitute the present
Invention some refer to the mechanical means, appliances, arrange-
ments, and modes of working to be employed for the obtainment from
chlorine residues in the wet way of compounds of manganese suitable
for use in manufacturing operations for the liberation of chlorine from
hydrochloric acid; some, depending on certain newly discovered chemical
facts, have for object the proper regulation of the proportions to be.
used of one of the reagents or materials necessary to the production
of one class of the said compounds; others relate to the manner and
time of addition of the said reagent or material, or of a portion of it;
others consist in promoting the formation of the said compounds, or
some of them, by the aid of bodies capable of acting in the circumstances
as "carriers" of oxygen; others relate to the purification and other
treatment of the residual liquors produced in the manufacture of chlorine
preliminary to the treatment of these liquors for the recovery from them
in the wet way of their manganese in a condition in which it can be
employed again in that manufacture; others refer to forms and dis-
positions of apparatus, and to ways of proceeding in and by which to
effect the required reaction between hydrochloric acid and artificial
compounds containing peroxide of manganese produced in the wet way;
others refer to the utilization of the free acid which is sometimes con-
tained in the resulting residual liquor; others have reference to the
utilization of a bye product of the decomposition of the essential
constituent of that liquor; and others to general arrangements and
combinations of apparatus, processes, and modes of procedure in order
to the systematic manufacture of chlorine, either wholly or partially by
means of artificial compounds containing peroxide of manganese, and
produced in the wet way as aforesaid.
TV What may be regarded as the tynical form of the process to

page_text: which all the improvements comprised in the present Invention have
reference, and is the form of it to which all these improvements most
specially apply, consists in decomposing by lime the chloride of
manganese contained in the residual liquors produced in the manu-
facture of chlorine, then treating with atmospheric air other suitable
gaseous oxidizing agent the resulting mixture of hydrated protoxide of
manganese and solution of chloride of calcium, and then after separating
from the resulting compound containing peroxide of manganese either
only a portion or the whole of the solution of chloride of calcium in
which it was thus formed, employing the said compound to liberate
chlorine from hydrochloric acid. One of the most important of the
improvements for which the Letters Patent of the number and date
last mentioned in paragraph II. were granted to me consists in adding
to solution of chloride of manganese more lime than simply the quantity
required to decompose the chloride of manganese therein, and then
treating with atmospheric air or other suitable gaseous oxidizing agent
the mixture of protoxide of manganese, lime, and solution of chloride
of calcium which is so obtained. In the Specification filed in pursuance
of the conditions of the said Letters Patent I speak of the result which
is got by thus adding to a solution of chloride of manganese more than
an equivalent of lime, and then treating the mixture as produced with
either air or some other suitable gaseous oxidizing agent, as consisting
of solution of chloride of calcium, holding in suspension free lime and
a more or less rich peroxide of manganese; but I have now discovered
that such result never contains any free lime, unless either the pro-
portion of lime used in excess of the quantity required to decompose the
chloride of manganese have been greater than is recommended in that
Specification, or the oxidizing treatment have not been sufficiently long
continued, and that it never contains any free peroxide of manganese,
but that all the lime in it, save in the cases mentioned, is combined
with peroxide of manganese, and that all the peroxide of manganese
in it is in all cases combined either with lime or with protoxide of
manganese.

page_text: "
"
68
acted simply as a "carrier," in some manner absorbing oxygen, and then
communicating the oxygen so absorbed to the protoxide of manganese.
This theory obviously involved the conclusion that a small proportion
of lime would secure as high a degree of peroxidation of the oxide of
manganese with which it was associated as could be obtained by means
of a larger proportion of lime, provided only that when using the smaller
proportion of lime the treatment with air or other gascous oxidizing
agent were continued sufficiently longer than when using the larger
proportion of lime. Hence in treating, in the Specification in question,
of the proportions of lime most desirable to have associated with re-
covered protoxide of manganese which is to be peroxidized by treatment
with air in the wet way, and of the principle upon which to determine
the proportion best to be employed in any particular case, I remark as
follows: "The proportion of free lime which it will be desirable to
"have present with protoxide of manganese which has been recovered
by means of lime, and is to be peroxidized in the wet way, will vary
"with circumstances, depending chiefly in each case upon the particular
"kind of economy which the manufacturer desires to realize, that is to
say, more especially upon whether his object is to obtain from his
supply of hydrochloric acid the very largest yield of chlorine which
"oxides of manganese regenerated from chloride of manganese in the
"wet way by means of lime can possibly enable him to obtain there-
"from; or whether while being content with some smaller yield of
"chlorine than this he aims simply at obtaining such yield of chlorine
"with the utmost possible economy of time, labor, and apparatus. He
"will use lime more freely in the latter case tlian in the former, but will
"have to subject each charge of recovered oxide to the peroxidizing treat-
"ment for longer periods in the former case than in the latter. . . . . .
"I incline to think that in all cases in which the manufacturer of
"chlorine shall be content with obtaining in the free state one-third
"of the total quantity contained in the hydrochloric acid which he
consumes in his manufacture thereof, the proportion of free lime
"which it will be found most advantageous to have associated with
"the oxide of manganese will be from one-half to three-fourths of an
"equivalent. Manufacturers desiring to obtain in the free state by
"means of oxides of manganese regencrated from chloride of manganese
by means of lime in the wet way, more than one-third of the total
"chlorine in their hydrochloric acid must use a smaller proportion of
"lime than that just stated, and must subject their recovered oxide to
66
"

page_text: "the action of the peroxidizing blast for longer periods than it will be
"needful to subject it thereto when using such proportion of lime as
"that indicated above." I have now found, however, that these are
not sound instructions, and that a small proportion of lime, although
aided by however much longer a treatment with the peroxidizing blast,
cannot enable so large a proportion of the protoxide of manganese with
which it may be associated to become converted MnO3 by treatment
with atmospheric or other gascous oxygen in the wet way, as a larger
quantity of lime will enable to be thereby raised to that state. I have
found, on the contrary, that in all cases in which MnO, which is treated
with atmospheric or other gascous oxygen in the wet way, has associated
with it a quantity of lime not too great for the whole of it to be of
service in promoting the peroxidation of the MnO, and this lime is
made to render the utmost advantage which it is capable of rendering
in the circumstances, the quantity of MnO' which is obtained over and
above the quantity which would have been obtained if no lime had been
used always bears a certain definite relation to the quantity of lime
employed, there being thus a maximum proportion in which gain of
MnO can be yielded by CaO, which proportion can in no case be
exceeded.
VI. I have ascertained certain facts which make it perfectly intelligible
how this happens. It would seem that the production of Mn O' by
direct combination in the wet way between hydrated MnO and atmos-
pheric or other gaseous oxygen absolutely requires the presence of a base
with which the MnOs can combine as it forms. When protoxide of
manganese, not having any other basic substance associated with it, is
treated with atmospheric or other gaseous oxygen in the wet way a part
of the protoxide itself has to act as the required base; and this is the
reason why in that case only a portion of the protoxide can become
peroxidized, the other portion being required to become as MnO with
the portion which becomes converted into MnO%. When, however, the
protoxide of manganese which is treated with atmospheric or other
gaseous oxygen in the wet way, has lime associated with it the MnO
which forms (or a part of it according to the proportion of lime present)
combines with CaO instead of with MnO, thus leaving free to undergo
peroxidation that part of the MnO which, but for the presence of
the CaO, this MnO2 must have combined with, and which would thus
have got locked up in a state in which it would have been incapable of

page_text: being peroxidized, at least in the wet way and by the process now in
question. It follows that the presence of enough lime to take the place
of that portion of the protoxide which, if no lime were present, would
have to go into combination as base, and also to supply the requisite base
for that portion itself to combine with after undergoing peroxidation,
will enable the whole of the MnO operated upon to be converted
into MnO2. The lime thus acting not as a "carrier" but simply by
substituting itself for that part of the protoxide which when protoxido
of manganese not having any other basic substance associated with it
is treated with atmospheric or other gaseous oxygen in the wet way
does not undergo peroxidation, and by further furnishing base for
the MnO formed by the peroxidation of that part of the Mnoo to com-
bine with, evidently each particle of it can act only once, and can thus
yield only a fixed and definite proportion of gain of MnO³.
VII. Two questions here arise. The first is as to the maximum
absolute amount of gain of MnO2 which can be effected in my process
by means of CaO; the second, as to the minimum amount of CaO which
can be made to yield a given amount of gain of MnO².
VIII. When hydrated MnO, having no other basic substance
associated with it, is treated with atmospheric or other gascous oxygen
in the wet way, under the circumstances the most favorable to its
peroxidation, only one-half of it becomes converted into MnO³, the
other half remains as MnO, and this half, playing the part of a base,
combines with the half which becomes converted into MnO2, and which
then plays the part of an acid, the two uniting to form the compound
which is ordinarily called "sesquioxide of manganese," and written
Mn2 Os, but which I prefer to call "neutral manganite of manganese,"
and to write either as MnOMnO2, or preferably as MnMnO%. If the
said treatment be performed at a temperature above a certain limit only
one-third of the MnO becomes converted into MnO%, and the MnO3
formed in this case combines with two equivalents of MnO, forming
therewith the compound which is commonly called "red oxide of man-
ganese,"
," and written Mn³ O', but which I prefer to call "basic manganite
of manganese,'
," and to write either as MnO, MnMnO³, or as MnO,
MnOMnO2, or as (MnO) 2MnO2. (Possibly, however, this compound
may be not a manganite but a basic manganate, and its correct
formula Mn MnO*.)

page_text: proportion of it that can be peroxidized by treatment with atmospheric
or other gaseous oxygen in the wet way when itself is the only basic
body present; whereas, as stated in paragraph VI., the presence of a
sufficient quantity of CaO enables the whole of the the MnO to be con-
verted into MnO2. Therefore, by the aid of CaO, the quantity of MnO
which can be obtained in my process, per given quantity of MnO
operated upon, can be just doubled. When MnO alone is treated with
atmospheric or other gaseous oxygen in the wet way there is obtained
only half an equivalent of MnO2 per equivalent of MnO operated upon,
but when the MnO has associated with it a sufficient quantity of CaO
there is obtained, per equivalent of MnO treated, a whole equivalent
of MnOº.
X. Such being the maximum amount of absolute gain of MnO2 which
can be effected by the use of CaO with the MnO treated in my process,
the next question is as to the minimum amount of CaO by means of
which the gain of a given amount of MnO2 can be accomplished. I
have found that two compounds of MnO2 with CaO can be formed in
my process. One of them contains only one equivalent of CaO per
equivalent of Mn0%, and may be regarded as sesquioxide of manganese,
or MnO (otherwise manganite of manganese, or MnMnO³), the
MnO of which is replaced by CaO. This compound I call "neutral
manganite of calcium," and I write it either as CaMnO³, or
as CaOMnO2. The other contains two equivalents of CaO per equi-
valent of MnO%, and I regard it as corresponding to red oxide of
manganese, or Mn³ O'. This compound I write either as CaO, CaMnO³,
or as CaO, CaOMnO³, or as (CaO) MnO³, and I call it "basic man-
ganite of calcium." (Possibly, however, like Mn³ O', it may be really a
basic manganate and its truc formula Ca³ MnO'.) Obviously, the
relation between the quantity of MnO2 gained in my process by means
of CaO and the quantity of CaO by which the gain thereof is effected
will depend upon whether this CaO goes to form neutral manganite or
to form basic manganite, the maximum gain of MnO2, per given quantity
of CaO used, taking place of course when the CaO forms neutral man-
ganite only. Let us suppose then two operations in which MnO is
treated with atmospheric or other gaseous oxygen in the wet way, and
let us suppose that in one of them CaO is not used, and the product
obtained is neutral manganite of manganese, being the richest product
which can be obtained when MnO by itself is so treated in the wet way,

page_text: while in the other CaO is used, and the product obtained consists
entirely of neutral manganite of calcium, being that one of the two
compounds of MnO2 with CaO which can be formed in my process
which contains the least quantity of CaO. For the sake of the simpler
llustration let us regard the MnO operated upon as being in each case
wo equivalents. The result of the one operation will be simply,-
while in the other CaO is used, and the product obtained consists
entirely of neutral manganite of calcium, being that one of the two
compounds of MnO2 with CaO which can be formed in my process
which contains the least quantity of CaO. For the sake of the simpler
llustration let us regard the MnO operated upon as being in each case
wo equivalents. The result of the one operation will be simply,--
MnO® + MnO,
or one equivalent of MnO2 combined with one equivalent of MnO; but
the result of the other operation will be,―
MnO® + Cao
MnO + CaO,
or two equivalents of MnO2, each of them combined with an equivalent
of CaO. In this last result there is an equivalent of MnO2 more than
in the result first represented, but there are also in it two equivalents of
combined CaO; whence we see that when CaO is employed to promote
the peroxidation of hydrated MnO by treatment with atmospheric or
other gaseous oxygen in the wet way, and all the CaO which is so
employed combines with MnO2 in such wise as to form therewith neutral
manganite of calcium, and therefore in such fashion as to yield gain
of MnO2 in the largest possible proportion, the ratio in which the CaO
yields gain of MnO2 is that of one equivalent of MnO2 gained per two
equivalents of CaO employed.
XI. The operator must not expect then, as my former Specification
above quoted authorizes him to do, to find that a small quantity of CaO
will promote the peroxidation of MnO by treatment with atmospheric
or other gaseous oxygen in the wet way to the same extent as a larger
quantity of CaO, if only, when using the smaller quantity of CaO, he
continues the oxidizing treatment for a sufficiently longer period than
when using the larger quantity. On the contrary he must expect to
gain MnO by means of CaO, within the limits within which CaO can
yield such gain, only in proportion to the quantity of the CaO which he
may so employ as to secure that it shall perform that function by the
performance of which by CaO associated with MnO which is treated with
atmospheric or other gaseous oxygen in the wet way, it is, as I have ex-
plained above, that the gain of MnO2 which is obtained by means of such
CaO is effected, and the maximum proportion in which he must expect
to gain MnO by means of CaO is that of one equivalent of MnO*
gained per two equivalents of CaO employed in gaining it. Thus, if he

page_text: desires to peroxidize sixty per cent. of the MnO which he may treat
with atmospheric or other gaseous oxygen in the wet way, being ten
per cent. of it more than he could peroxidize by so treating it by itself,
he must use with it not less than a fifth of an equivalent of CaO. If
he desire to peroxidize, by the same method seventy-five per cent. of
the MnO operated upon, being twenty-five per cent. of it more than
could be so peroxidized without the aid either of CaO or of some other
similar body, he must use with it not less than half an equivalent
of CaO. If he desire to peroxidize the whole of the MnO upon which
he operates, being fifty per cent. of it more than he could peroxidize by
treatment with atmospheric or other gascous oxygen in the wet way, in
the absence of any basic body other than itself, he must use with it not
less than a full equivalent of CaO; and similarly for all proportions of
his MnO above one-half, the conversion into MnO3, when MnO is
treated with atmospheric or other gaseous oxygen in the wet way, of any
portion of the MnO operated upon above the half of it which such treat-
ment would convert into MnO3 if no CaO were used with it, requiring, at
the least, for every per cent. of the MnO above fifty per cent. which is so
converted into MnO2, two per cent. of an equivalent (that is to say,
one-fiftieth of an equivalent) of CaO. The regulation by this law,
according to the proportion of the MnO operated upon which it is
intended shall become converted into MnO3 of the CaO employed to
promote the peroxidation of MnO by treatment with atmospheric or
other gaseous oxygen in the wet way, constitutes a very important part
of the present Invention.
XII. The part of the present Invention next to be treated of is the
gradual addition to the mixture containing the MnO which is to be
peroxidized in the wet way of the CaO employed to promote its peroxi-
dation when such mixture is that obtained by adding lime to the residual
liquors produced in the manufacture of chlorine. There are certain
conditions of the residual liquors of the chlorine manufacture which do
not allow of good results being got when decomposing by lime the
chloride of manganese in such liquors and then adding to the resulting
mixture, either before treating it with air or at some very early stage of
its treatment therewith, any considerable further quantity of lime. The
statements made in the Specification filed in pursuance of the conditions
of the Letters Patent numbered 565, and dated the 20th February 1868,
with respect to the extent to which the presence of certain proportions

page_text: of CaO with MnO treated with air in the wet' way would promote the
peroxidation of such MnO were based upon small laboratory experiments
in which I had found it quite easy, by adding to solution of chloride of
manganese from one equivalent and a half to one equivalent and three-
quarters of CaO and then treating with air the mixture so obtained,
to convert into MnO from seventy-five to nearly ninety per cent. of
the manganese operated upon. When I came however to work in the
same way on the large scale with actual residues of the manufacture of
chlorine I could not get satisfactory results. Whenever I proceeded by
adding to those residues at the commencement of the operation any
considerable proportion of lime in excess of the quantity required to
decompose the chloride of manganese in them (the lime so employed in
my process in excess of the quantity necessary to decompose the chloride
of manganese operated upon will hercin-after in most cases be spoken of
as "the excess of lime"), and so had some considerable quantity of CaO
present from the commencement of the peroxidizing operation in the
mixture treated with air, the portion of MnO3 which were first formed
combined with two equivalents of CaO forming therewith basic man-
ganite of calcium, which compound, although it was sometimes under
special circumstances decomposed at later stages of the operation, giving
up one of its equivalents of CaO to subsequently formed portions of
MnO2, usually remained undecomposed and constituted part of the final
product, rendering that product incapable of settling satisfactorily, and
causing it both to be unduly costly for lime and to consume when
applied to the manufacture of chlorine an excessive proportion of acid.
Morcover, when I proceeded by the manner in question there was nearly
always formed a curious yellow body which must have been a compound
either of oxychloride of calcium with oxide or oxides of manganese or of
oxychloride of calcium, oxide or oxides of manganese, and compounds
of MnO with CaO, and which caused the mixture being operated upon
to assume a very thick consistence, sometimes causing it to actually
solidify, and in this and other ways greatly retarded the peroxidation of
whatever uncombined MnO might still be present, not infrequently
preventing any further peroxidation whatever going on however encr-
getically the blast of air might be applied. From these experiences I
could not but conclude that there were conditions, necessarily obtaining
when my process was practised industrially, owing to which one could
not obtain on the large scale, when adding the whole of the excess of
lime used at the commencement of the operation, results corresponding

page_text: with those which I had so frequently obtained on the small scale when
so adding the excess of lime, and therefore that in order to secure the
obtainment in industrial operations of products rich in MnO2, but con-
taining no (or only very little) basic manganite of calcium, it was
essential that the excess of lime used should be added, not all at once,
but by degrees. My Provisional Specification of the present Invention
was drawn up under this conviction, which has not been in the least
shaken until within the last few days. The experiences above stated
have been constant aud invariable until quite recently; but within the
last few days, since beginning to write the present Specification, I have
found some reason to believe that those conditions of the residual liquors
of the chlorine manufacture which render it impossible to get good
results when treating such liquors by my process for the obtainment
from them in the wet way of compounds containing peroxide of man-
ganese, and using a considerable excess of lime, added wholly at or near
the commencement of the operation are not, as I had previously sup-
posed them to be, inevitable conditions, but are conditions which it is
practicable to avoid. It is possible, therefore, that in a subsequent
Specification I may be able to point out how to secure conditions under
which the whole of the excess of lime used, even though it should amount
to a full equivalent, may be added at once; but in the meantime it is
certain that in the absence of such conditions the evils which would be
experienced if a large excess of lime were added all at once may be
entirely avoided by adding the excess of lime by degrees.
XIII. As to the rate at which the excess of lime should be added,
when it is found that the conditions which obtain are such that the
addition of the whole of the excess of lime at the commencement of the
operation is not compatible with the realization of the best results, this
is a point depending so much upon the proportion of excess of lime used,
the constitution of the liquors with which the process is commenced,
and other circumstances, that only general instructions can be given
with respect to it. It will sufficiently guide the operator, however, to
say that when he finds it necessary or desirable to add his excess of lime
otherwise than all at once, and desires, as he usually will, both to obtain
as rich a result as possible and to obtain it as rapidly as possible, the
rate of addition of his excess of lime should be such as to secure on the
one hand up to the point to which it is required that the MnO' which
forms should combine with CaO instead of combining with MnO, that

page_text: no nascent MnO shall be constrained to combine with MnO by reason
of there not being any CaO present for it to combine with instead, and
on the other hand, that there shall never be present enough CaO as yet
uncombined with MnO either unduly to favour the formation of basic
manganite of calcium or to cause the mixture which is being operated
upon to assume a condition unfavorable to the peroxidation of this
uncombined MnO remaining in it. Hence some portion of the excess
of CaO should preferably be added at the commencement of the peroxi-
dizing operation; then before the whole of this portion has become
combined with MnO the next portion should be added, and so on until
the whole of the excess of CaO has been added. The number of portions
into which it will be best that the excess of CaO should be divided, and
the intervals at which it will be best that the portions into which it is
so divided should be respectively added, will vary so with circumstances
that the only rule of invariable application which can be laid down with
respect to these points is that the addition of the excess of CaO should
preferably be made with the utmost rapidity compatible with CaO not
yet combined with Mn O³, or combined therewith otherwise than as in
neutral manganite of calcium, never being present in such proportion as
to cause the mixture which is being operated upon to go prejudicially
thick, or otherwise to retard instead of promoting the peroxidation of
whatever uncombined Mn O may still be contained in it. By taking
from time to time a certain volume, say one or two cubic inches, of the
mixture which is being operated upon and testing it for MnO² the
operator may always readily learn at what rate peroxidation is going on;
and as his liquors will usually be of very nearly the same constitution
every time they are reproduced a very few operations in each of which
the addition of the excess of lime used is made with a different degree of
rapidity, and the rate at which peroxidation goes on is observed, will
enable him to ascertain once for all what rate of addition of his excess
of lime is best adapted to the constitution of his liquors, the rate at
which his engine supplies the peroxidizing blast, and the other circum-
stances of his particular case. He may perfectly well ascertain, however,
the maximum rate at which he may add his excess of lime without thus
actually testing the rates of peroxidation corresponding to various rates
of addition of it since he cannot add it too rapidly, provided only that he
does not add it so rapidly as to cause the mixture which is being operated
upon to assume the prejudicial condition which is above spoken of, anb
which he may recognize, not only by the thick consistence and more or

page_text: less yellow colour of the mixture when in that condition, but by the
circumstance that when in that condition the mixture does not froth.
When peroxidation is going on rapidly the mixture froths considerably,
especially at the earlier stages of the operation; but when it has got
into that state, due to the presence of too much lime, in which, although
there is still remaining in it much uncombined MnO, or at least MnO
not yet combined with MnO2, peroxidation is either stopped altogether or
goes on only very slowly, it ceases to froth at all. A quite sufficient rule
will therefore be that the operator shall add his excess of lime as rapidly
as he can consistently with his not causing the mixture to assume or
closely approach the condition in which it ceases to froth. The rate of
addition which will accord with this rule will be different in different
cases; but what it is in his own case cach operator will very readily find
by his first few operations.
XIV. In the Provisional Specification of the present Invention I
give certain examples of proportions of excess of CaO and rates of
adding them. These are, firstly, half an equivalent or any proportion
less than half an equivalent of excess of CaO, added gradually in
such wise that it shall all be added by, or about, or a little before, or a
little after that stage of the operation at which one-third of the MnO
operated upon has become converted into MnO2; secondly, half an
equivalent or any proportion less than half an equivalent of excess
of CaO, added gradually in such wise that the last of it shall not be
-added until at, or about, or a little before, or a little after that stage
of the operation at which one-half of the MnO operated upon has become
converted into MnO2; thirdly, three-fourths of an equivalent, or any
proportion between one-half and three-fourths of an equivalent of excess
of CaO, added gradually at either of the rates just mentioned; and
fourthly, three-fourths of an equivalent, or any proportion between one-
half and three-fourths of an eqvivalent, of excess of CaO, added more
gradually still. I also speak in that Specification of the gradual addition
of from three-quarters of an equivalent to an equivalent and a quarter
of excess of CaO. The further experience which I have had, however,
since the date of that Specification has convinced me that nothing can
be said with respect to particular proportions of excess of Caọ, and
particular rates of addition thereof which could guide the, operator
nearly so well or so soundly as the general considerations and instruc-
tions which are set forth above. The operator will prefer almost

page_text: invariably, to use as nearly a full equivalent of excess of CaO as he
may find that he can cause to go into combination as neutral manganite
of calcium; and for no proportion of excess of CaO would the rate of
addition of it which might be the best in one case be the best in every
case, while the instructions which are given above apply to all cases.
All that I can usefully add with respect to this part of the matter is,
firstly, that although, as stated in my Provisional Specification of the
present Invention, when proceeding in that part of the process to which
this Invention relates which consists in peroxidizing hydrated MnO
by treatment with atmospheric or other gaseous oxygen in the wet way
by the method of adding gradually the CaO which may be employed
to promote the peroxidation of such MnO, and which CaO is herein-
before and herein-after called the "excess of CaO, there is certainly
more risk of some part of such excess of CaO going to form only
basic manganite of calcium or else not acting at all, when such excess
of CaO amounts than when it does not amount to more than half an
equivalent, yet by sufficiently carefully observing the instructions given
above a full equivalent of excess of CaO may be used by the manner
in question without formation of of any basic manganite, the whole of
the MnO operated upon being in such case converted into MnO2, and
the product consisting solely of neutral manganite of calcium; secondly,
that, nevertheless, considering how greatly the risk just spoken of
increases the more nearly the excess of CaO used approaches a full
equivalent, it may perhaps be best as a rule especially where economy
of acid is of great importance, not to attempt to obtain a product
consisting solely of neutral manganite of calcium, but to be contcut
with a product containing some proportion of mangauite of manganese;
and thirdly, that there may be however certain special cases in which
it shall be very desirable, not only to convert the whole or very nearly
the whole of the MnO operated upon into MnO2, but to do this with
the utmost possible rapidity, while the formation of some portion of
basic manganite of calcium, or the presence otherwise in the product
of more CaO than the quantity necessary to form neutral manganite
of calcium with all the MnO2 in it can be put up with, in which cases
it will be well to use somewhat more than an equivalent of excess
of CaO.

page_text: in which although either less or not more than an equivalent of excess
of CaO have been used, some portion of the excess has either not
acted at all or has acted by forming basic manganite of calcium, it
will be well to add towards the end of the peroxidizing operation as
much chloride of manganese liquor as the mixture can decompose
continuing the peroxidizing treatment until the MnO resulting from
the decomposition of the MnCl so added shall have undergone all the
peroxidation possible to it in the circumstances. This expedient which
is equally applicable of course by whatever method the excess of CaO
employed be added will secure that the final product shall contain
neither free lime nor basic manganite of calcium, since basic manganite
of calcium to the extent of its second equivalent of CaO decomposes.
chloride of manganese, becoming thereby reduced to neutral manganite.
XVI. It will be convenient to speak next of those parts of my
present Invention which relate to the employment of compounds
containing peroxide of manganese produced in the wet way for the
liberation of chlorine from hydrochloric acid. They apply equally to
any and all compounds containing peroxide of manganese which have
been formed by treating with either atmospheric air or any other
gaseous oxidizing agent by whatever method or by means of whatever
mechanical appliances such treatment thereof may have been made,
any mixture with either water or a suitable solution either of oxide
or oxides of manganese only or of oxide or oxides of manganese
and other substance or substances. One of them, without which I doubt
whether the manufacture of chlorine by means of such compounds
could be rendered economically practicable, consists in passing such
compounds into the stills in the state of fluid mud (which will be
herein-after spoken of as "manganite mud") admitted thereinto either
simply by pipes and cocks, or by S or U tubes, or preferably by
hydraulic lutes; such mud preferably consisting of a mixture of such
compounds with a portion of the liquor in which they were produced.
XVII. There is no kind of chlorine still at present in use which could
not be employed for the generation of chlorine by means of manganite
mud, but the stills which answer best in one system of treating
together manganite mud and hydrochloric acid which is the only system
of treating them together of which I have as yet had actual experience
are stills of the same material and construction as the stone stills which
are at present ordinarily used by manufacturers of chlorine in this

page_text: country, and which are known to continental manufacturers as "vases
à chlore Anglais," but differing from such ordinary stills in being of
greater depth than width. I also prefer that they should be of much
greater capacity that the largest of the stone stills which have hitherto
been used by manufacturers of chlorine. I believe that with the
exception of the one in which all my experiments on the large scale
with respect to the manufacture of chlorine by means of the compounds
to which the present Invention relates have been performed, and a
second which has just been erected for my process, there are no chlorine
stills at present in existence which are appreciably more than four and
a half feet deep, while there are only very few which are much if any
more than three feet deep. Moreover so far as I know all the stone
chlorine stills in ordinary use are invariably either wider or longer or
both wider and longer than they are deep. I prefer to make them
when they are to be employed for the generation of chlorine by means
of manganite mud, but otherwise than on the "continuous " system
which will be described below either cubes of equal dimensions, or
what I consider to be by very much the best, of greater depth than either
width or length, and I like them to be at least six feet deep and
believe it best that they should be more nearly twice that depth. The
experimental still above referred to is ten feet deep and six feet and a
half by six feet and a half inside, and the recently erected still also
above spoken of is of the same depth but measures cight feet by eight
feet inside; and I think that stills for the generation of chlorine by
means of manganite mud, when such stills are not to be worked on
thic continuous plan which will be described presently might with
advantage be even larger than these.
XVIII. Of the many methods of bringing manganite mud suitably
into contact with the hydrochloric acid from which it is required to
generate chlorine which I have tried, what I consider to be the best,
when not working on the "continuous" system, consists in putting the
acid into the stills first, and then making the manganite mud run in
gradually upon the acid, regulating the rate of addition of the manganite
mud according to the rate at which it is desired that chlorine shall be
disengaged. If the contents of the stills worked on this plan be kept at a
suitable temperature, the manganite mud will dissolve with such extreme
rapidity that it will be possible in a still having a capacity of, say, six
hundred cubic feet, or so, to generate enough chlorine for the production.

page_text: of from a ton to a ton and a half of bleaching powder in one hour. In
fact, in the circumstances in question, until a certain proportion of the
acid has been neutralized, the manganite mud -dissolves as fast as it
enters the stills. By regulating the rate of addition of the manganite
mud one can thus regulate with the utmost nicety the rate of the
disengagement of chlorine. One can either neutralize a charge of acid
and so generate a charge of chlorine in one hour, or even less, or one
can extend the operation over any number of hours.
XIX. I have said that when the acid is put into the stills first, and
the contents of the stills are kept at a suitable temperature, the man-
ganite mud dissolves as fast as it enters, until a certain proportion of the
acid has been neutralized. This proportion will vary with the strength
of the acid, the density of the mud, and other circumstances, but it will
usually be considerably over eighty per cent., and I have known it
exceed ninety-five per cent. When such proportion of the acid has been
neutralized, be this proportion what it may in the particular case, the
remainder of the acid cannot dissolve MnO (or at least cannot do so
at all rapidly) but it can dissolve both MnO and CaO, and can moreover
abstract these bases from their compounds with MnO3; therefore by
addition in sufficient quantity of more manganite mud, after the said
proportion of the acid has been neutralized, one can readily neutralize
the whole remainder of the acid; having done which in the manner
mentioned, the residue of the operation will be a mixed solution of
MnCl and CaCl, containing suspended in it undissolved the MnO³ of
that part of the manganite mud, the MnO or CaO of which, one or both,
alone took part in the neutralization of the last portions of the acid.
When using in this way an excess of manganite mud I prefer to allow
such undissolved MnO to settle in the still before drawing off therefrom
any of the residual mixed solution aforesaid, and then when this MnO2
has suitably settled to draw off only as much or nearly so of the aforesaid
mixed solution as may have become clear and supernatant above the
deposited MnO, leaving behind in the still a residue containing the
MnO2 which has so been left undissolved, and has thus deposited. I
then run upon this residue the next charge of acid, from which point
I proceed as before, and so on continually.
XX. It will usually however be best when proceeding as just described
not to neutralize the acid before it leaves the still quite completely.
There will usually be in the hydrochloric acid employed more or less

page_text: sulphuric acid, which will form sulphate of calcium in the stills, in all
cases in which the manganite mud contains, as it most commonly will
do, cither CaO, free or combined, or CaCl; and this sulphate of calcium
would deposit with the undissolved MnO2, and so accumulate in the
stills until it at length choked them, if the acid were always completely
neutralized in the stills. Morcover with the lime used in my process
for the regeneration from chlorine residues of compounds containing
peroxide of manganese there will usually be appreciable quantities of
AFO, FeO', and Si'0', which also would accumulate in the stills when
working on the plan now in question, if enough excess of manganite
mud were always used therein to completely neutralize the acid and
decompose the acid sesquichlorides either originally existing in the
hydrochloric acid or formed in the stills by the reaction thereof upon the
two just mentioned sesquioxides. There should therefore be left, either
every time or once per given number of times, enough acid not
neutralized to hold in solution all Al, Fe, and CaSO', together with all
soluble SiO, which may be present.
XXI. When this is done the liquors drawn off from the stills will
contain four bodies, AlCl3, FeCl³, CaSO, and some free HCl, besides
possibly some little dissolved SiO3, which should all be got rid off before
commencing to treat these liquors for the recovery from them of their
manganese in a state suitable for use again in the manufacture of
chlorine. To this end having drawn off these liquors from the stills
into a suitable well or other receptacle, I treat them with carbonate of
lime in a somewhat fine state of division, whereby I decompose their
Al CP and FeCl³, and by neutralizing their HCl cause their CaSO* and
also their dissolved SiO³, if any, to go out of solution. If the liquors be
now left at rest for a few hours Al2O, FeO³, CaSO', and perhaps also
SiO, will deposit, the liquors thereby becoming quite clear and of
a beautiful pink color, and containing now only MnCl and CaCl.
To effect easily however this neutralization by carbonate of lime of acid
liquors from the stills the carbonate of lime employed must be somewhat
finely divided. I tried at first to use it in lumps, but in that state I
could not get it to neutralize the last portions of the acid with at all
satisfactory rapidity. I prefer that it should be as fine as not very
coarse sand.
XXII. When using in the stills an excess of manganite mud and thus

page_text: if one prefers that course, be caused to deposit instead of in the stills
themselves in separate vessels, so that the stills may be constantly
occupied in generating chlorine, except when being emptied or charged.
In such case the acid might usually be completely neutralized in the
stills, the deposit of MnO2 with sundry other bodies which would then
be obtained in the separate vessels in which the neutral residual liquors
thus formed in the stills were allowed to settle being dealt with by
periodically dissolving it in special operations, in which special operations
an excess of acid should be employed, and the MnO2 completely dissolved.
the residual liquors of these special operations being thus acid liquors
containing no undissolved MnO', but containing in solution the accu-
mulated impurities of a number of operations in which excess of mud
had been used, which impurities they would deposit on being neutralized
by carbonate of lime.
XXIII. I think it will be best, however, when desiring to keep the
stills constantly occupied in the performance of their especial function,
that of generating chlorine, to take means to sufficiently neutralize the
acid employed, without using for that purpose an excess of manganite
mud. The denser the manganite mud employed and the stronger the
acid used the more will this be possible; it will be the more possible
also if the contents of the stills be heated during the reaction upon each
other of the acid and the manganite mud otherwise than by the ordinary
method of injection of steam, so as to avoid the dilution of them, which
is caused by the condensation of the steam, or of some of it, when that
method is followed.
XXIII. There are two methods by which the contents of the stills
may be heated otherwise than by injection of steam; one consists in
applying heat externally to the stills themselves; the other, in heating
either the manganite mud, or the acid, or both before they enter the
stills.
The first of these methods is a little difficult in the case of stills
of the large size I have recommended above; it is more possible for
smaller stills, but in all cases, nevertheless, the latter method I incline to
think is the best. The manganite mud can be readily heated either by
applying heat externally to vessels containing it, or by placing within
such vessels suitable pipes through which steam, or hot water, or hot air,
or hot products of combustion, or other hot gases are made to pass; or
by making the mud run on its way to the stills through tubes or other
conduits heated from the outside. The acid also can be heated by means

page_text: of tubes in like manner, provided that such tubes be made of a material
which the acid cannot too readily corrode; but the acid can be heated
most conveniently, perhaps, in vessels of stone or earthenware, heated
exteriorly by means of either sand, water, or saline baths.
XXIV. When working with hot acid and hot manganite mud, or even
with hot manganite mud only, it is possible, even although the acid used
be so dilute as not to exceed 1.1 specific gravity, to neutralize as much as
or even more than ninety-eight per cent. of the acid employed without
using any excess of mud. It will usually be desirable, however, even
when thus working with hot mud, to provide means of injecting steam
into each still, so that, if necessary, one may be able to raise the tempe-
rature of the contents of the stills towards the end of each operation of
solution.
XXV. It will sometimes be the case that any free hydrochloric acid
which may be contained in the liquors from the stills can be utilized so
advantageously that there will be no need to endeavour to neutralize by
manganite mud more than a certain proportion of the acid employed. I
desire to indicate in especial two methods by which any free acid con-
tained in the liquors from the stills may be turned to useful account.
One of these methods consists in combining the necessary neutralization
of acid residual liquors from which compounds containing peroxide of
manganese are to be regenerated in the wet way with the decomposition
by means of the free acid in such liquors, of compounds produced in
processes for recovering sulphur from alkali waste; and the other
consists in combining the neutralization of such liquors with the manu-
facture of carbonic acid gas. In order to utilize by the method last-
mentioned the free acid in such liquors the said liquors should be run
into a suitable generator, in which they should find carbonate of lime,
preferably but not necessarily in a state of somewhat fine division, and
from which there should then pass off CO2 by one exit, and neutralized
liquor by another. To avoid all danger of the CO being contaminated
by chlorine it might be washed with a solution of a protosalt of iron, or
with a solution of a protosalt of any other metal solution of a protosalt
of which sufficiently readily absorbs chlorine.
XXVI. I have above recommended that, when manufacturing
chlorine by means of manganite mud, in stills not worked on the
"continuous" system, the acid should be put into the stills first; but
the reverse method, though I do not think it so advantageous, is by no

page_text: means impracticable. When following the plan of putting the manga-
nite mud into the stills before the acid, the rate at which chlorine is
given off will depend upon the rate at which the acid is run in upon the
mud. When working on this plan the first third of the acid may be
added with almost any degree of rapidity one chooses (especially if, by
injection of steam or otherwise, the contents of the still be well agitated
all the time), seeing that the first third or so of it will react only upon
CaO or MnO, or both, if both are present, and so no chlorine be dis-
engaged until a little more than that third has been added. After that
point chlorine will be generated at the rate at which more acid goes in.
When thus putting the manganite mud into the stills first the acid
employed cannot be neutralized to so high a degree without use of excess
of mud, as when the acid is put into the stills first, and to neutralize up
to a given point by means of excess of mud requires a larger excess of
mud than is required when working on the other plan. When putting
manganite mud into the stills before the acid it will usually be best to
add acid enough to completely dissolve the mud so put in before the
acid, and then, if it is desired to neutralize the acid pretty completely in
the still, to add more mud to the resulting acid liquor.
XXVII. A better plan is to make the acid and the manganite mud
run into the stills at the same time; preferably, however, in such
manner that the acid shall be a little in excess of the mud until near the
end of the operation, when, if it is desired to have as little free acid as
possible or nearly so in the resulting residual liquor, a suitable excess
of mud should be finally added after the addition of acid has been
stopped.
XXVIII. When the acid is put into the stills the first the manganite
mud which is added thereto need not necessarily be added by measure.
It will be sufficient to work by the acid, and to measure only that
running each time into each still a certain proper quantity of acid, and
then adding manganite mud until this acid is neutralized up to the point
desired. The operator will soon learn how to secure uniformly the same
degrees of neutralization. At a certain stage of the operation he must
begin to take from time to time samples of the contents of his still, and
he will soon become able to judge by the appearance of these samples,
and by how rapidly or otherwise their color when it has begun to
deepen lightens on stopping the flow of mud and injecting steam, at what
point the neutralization of his acid has arrived. If the temperature of

page_text: the contents of his still be kept, as it should be, at something above
180° F. (being the temperature spoken of above in paragraph XVIII. as
"a suitable temperature,") the first portions of mud which enter will
completely dissolve, and their equivalent of chlorine be liberated almost
instantaneously, and samples taken from the still during this stage will
be of a yellow color, differing little from that of common hydrochloric
acid. At a further stage they will have a brown color, which will
rapidly disappear if the flow of mud be stopped, especially if steam be
injected the while, and then, if more mud be added, they will become
darker and darker until, when the point has been reached at which no
more MnO2 will dissolve, and there is some undissolved MnO in sus-
pension, they will have a black color, which will not disappear on
further heating. The operation should finish by the temperature of the
contents of the still being raised to about 200° F., or even to their point
of ebullition, or nearly thereto.
XXIX. In the Sheet of Drawings which accompanies this Speci-
fication, Figure 1 indicates the general arrangement of apparatus which
I consider to be the best, in a general sense, for the performance of my
process as perfected by the present Invention. The various parts of this
apparatus, as represented in Figure 1, are as follows:-A, a stone still
about eight feet by eight feet square and ten feet deep; B, a well to
receive the liquors from the still; C and C', tanks into which these
liquors are lifted after neutralization by means of the the pump R and the
pipe K, and in which they are then allowed to deposit their impuritics;
E, a reservoir of milk of lime; D, the oxidizer, in which the salt of
manganese in the liquors from the tanks C and C¹ is decomposed, and
the resulting mixture of MnO with solution of CaCl treated either
with atmospheric air or some other gaseous oxidizing agent, or with such
gaseous oxidizing agent and CaO; J, a pipe, by means of which the
blast of air or other gaseous oxidizing agent is conducted from the
blowing engine to the bottom of the oxidizer; Q and Q', conduits,
by means of which the liquors which have deposited their impurities
in the tanks C and C₁ run therefrom into the oxidizer on opening the
cocks O, O; F, F, F, tanks in which what is produced in the oxidizer
is allowed to settle, and from which the deposited mud after the removal
of the clear solution of CaCl, which at length forms above it, is
eventually run into the still; M, a pipe suitably fitted with cocks or
valves, by means of which the contents of the oxidizer can be made to

page_text: run at will into either of the tanks F, F, F; N, a similar pipe, similarly
fitted with cocks or valves, by means of which manganite mud from
cither of the tanks F, F, F, can be run into the still; T, a hydraulic
lute, by means of which the manganite mud enters the still; S, S, plugs,
by lifting which the deposit which has formed in the tanks C and C¹ is
caused to run by the pipe L into the filtering or other vessel G; P, a
pipe, by which the liquor which drains from the mud in the vessel G
finds its way to the well B; U, entrance for acid; V, exit for chlorine;
and, lastly, H, H, H, and I, I, I, ladders and platforms to enable the
workmen to reach all parts of the apparatus.
XXX. With such an apparatus, my process, or rather that form of it which
I consider the most advantageous, or at any rate the most advantageous
in the present circumstances of the chlorine manufacture, is conducted
as follows-The liquors from the still are run into the well B, in which,
if they contain either HCl, Al Cl³, or Fe² Cl³, they are treated with
carbonate of lime, preferably in powder, until they have become neutral.
I prefer to agitate or stir them well during this treatment with carbonate
of lime. They are then pumped up into the cisterns C and C', or one
of them, where they are left at rest until they have deposited whatever
solid matters they may on first reaching these cisterns hold in sus-
pension. From the cisterns C and C', or one of them, a charge of clear
liquor is run into the oxidizer D, and upon this is run from the tank Ea
quantity of milk of lime containing the quantity of CaO, which is
equivalent to the quantity of MnCl in the charge of liquor, or
preferably a little more than that quantity of milk of lime. The
injection of the oxidizing blast is then commenced, more milk of lime
is gradually added, and at length, if needful, a little more liquor from
the tanks C and C', the blast being in any case preferably continued until
peroxidation ceases to advance, when the contents of the oxidizer are run
off into one of the tanks F. They are then allowed to remain at rest
until they have settled sufficiently; the portion which has become
clear, and which is simply solution of CaCl is then decanted, and the
remainder is then manganite mud, ready to be run into the still. With
the liquor which results from its treatment in the still the above
described round of operations is recommenced, and so on, time after
time continually.
XXXI. I believe that the arrangement of apparatus, and the method
fundum uil

page_text: this, arc by much the best; but many modifications of both are possible.
Thus the height of the apparatus might be diminished by allowing the
product of the peroxidizing operation to settle in the vessel or vessels in
which it was produced, instead of in distinct settling tanks. In this
case, instead of having one oxidizer in the position represented in the
Drawing and a row of settling tanks below it, one would have in the
position of the settling tanks F, F, F, a row of vessels, in cach of which
one would first produce, and then allow to settle the mixture of com-
pounds of MnO2 with solution of CaCl. Also instead of commencing
the operation in the oxidizer by making milk of lime run in upon
manganese liquor, one might commence it by making manganese liquor
run in upon milk of lime. Moreover, in place of performing the
operation of peroxidation by injecting air by means of a blowing
engine into the mixture operated upon, one might perform it by any
of the methods described in paragraph 29 of my Specification filed in
pursuance of the conditions of the Letters Patent, numbered 565, and
dated the 20th of Feb 1868. I greatly prefer however the general
disposition of apparatus, and the general mode of operating, which are
described above in paragraphs XXIX. and XXX.
XXXII. There is not shown in the Drawing above referred to
(Figure 1 in the accompanying Sheet of Drawings) any appliances for
supplying the tank E with milk of lime, for the reason that these may
be so extremely various. As for the preparation of the milk of lime, it
may be made by any method which will yield it sufficiently fine. Plans
which answer very well are those of carefully grinding the lime with
water, and arranging for the mud or milk of lime which is so obtained
to flow from the mill, in which it is produced, to the bottom of a vessel
in which it can deposit its coarser particles, or some of them, the fine
milk or mud which overflows from this vessel being afterwards made to
pass through other similar settling vessels, if need be, of slaking and
sieving the lime before grinding. it, and of passing the milk of lime itself
through a fine sieve before adding it to the chloride of manganese liquor.
In some cases, when it is desirable that the bulk of the liquor operated
upon should not be increased more than is unavoidable, the lime may
be ground with a portion of the chloride of manganese liquor itself
instead of with water. In some cases, too, the lime may be added instead
of as milk or mud as dry hydrate.
TTTTTY
A
Thuma
1

page_text: :
accompanying Sheet of Drawings) may be regarded as representing, on
the scale of a quarter of an inch to the foot, an apparatus suitable for
the treatment at one time, in that part of my process which relates
to the regeneration in the state of peroxide of the manganese contained
in the residual liquors of the manufacture of chlorine, of somewhere
between one thousand and twelve hundred cubic feet of such liquors.
According to the strength of the liquors treated, and the degree to
which the peroxidation of the MnO obtained from them is carried,
there will be produced, per operation, in such, a quantity of man-
ganite mud containing from about 2,000 to about 4,000 pounds of
actual MnO2. The time required per operation will depend chiefly
upon the size of the blowing engine, and the rate at which it is worked.
The only indication which I can at present give on this point is, that a
blast engine having an air cylinder two feet in diameter and a two and
a half feet stroke, double action, and worked at not less than 70 strokes
per minute, will certainly produce, when the excess of lime used is a
considerable one, 400 pounds of actual MnO
per hour.
XXXIV. The number of settling tanks for manganite mud,
marked F, F, F, in the Drawing, will usually require to be above three.
It must be according to the number of operations made per day, and
the rate at which the product produced in each particular case is found
to settle. The time required for settling will be from 10 or 12 to 36
hours, according to circumstances. The larger the proportion of Mn O'
in any product, and the more rapidly such product has been produced,
the more rapidly, as a general rule, will it settle.
XXXV. In the Drawing, the oxidizer is represented with its corners
cut off at the bottom. It may either have its corners thus cut off at the
bottom or not, as may be preferred; I do not know that there is any
appreciable advantage in the former plan. It may be either of square
horizontal section, like the oxidizer in the Drawing, or of circular hori-
zontal section; I believe the latter form is best. I prefer to make it
either of wrought iron or of cast iron; but it may also be made of either
wood, stone, or brickwork. When made of wood it should preferably
be lined, either with zinc, lead, or iron; and when made of stone or
brickwork, it should also preferably be lined either with wood or with
one of the metals mentioned, or with both wood and a metal, or with a
suitable cement.
VVVUT
13

page_text: blowing engine into the oxidizer is represented as terminating in a box
pierced with holes. However, the air may be distributed either by
that means, or by means of a false bottom, or simply by the pipe which
brings it terminating, near the bottom of the oxidizer, in a number of
radial arms, each arm being a tube, either perforated throughout its
length or simply open at its further extremity. When a false bottom is
used, the holes in it should preferably be conical, with their narrowest
diameter upwards. At a certain distance below the top of the oxidizer,
at or about the level to which, when at work, it is filled with the
mixture into which the blast is injected, I prefer to adapt what may be
spoken of as a perforated cover, but may conveniently consist simply of
a row of planks, arranged an inch or two apart, and fixed securely to
ledges of angle iron or otherwise. Such an arrangement of planks
affords sufficient exit for the spent blast, and at the same time prevents
injurious vibration of the oxidizer from the splashing of its contents
against its sides. Finally, I believe it would be well for the oxidizer
to be furnished with a number of false bottoms, or rather, perforated
diaphragms, or other equivalent contrivances, fixed horizontally, at
intervals of a foot or so apart, more or less, their object being to break
up into thin streams, or to prevent collecting into large bubbles the
air or other gascous oxidizing agent which is injected into the oxidizer
at its lower part and has to rise up through its contents. Instead of
actual diaphragms, one might use rows of flat strips of metal or wood,
the strips in each row being placed each at some little distance from
the next, and care being taken to secure that the intervals between the
strips in one row shall not be in a vertical line with the intervals
between the strips either in the row immediately above or in the row
immediately below. Instead of flat strips, strips beut after the fashion
of angle iron, more or less, and arranged with the point of the angle
upwards, might be used, and the rows of strips, instead of being
arranged in horizontal planes, might be arranged in planes passing
diagonally across the oxidizer.
XXXV. The cisterns marked C and C in the Drawing above
described should be made either of cast iron or of wood, or of wood
lined with either zinc or lead. They should not be made of wrought
iron as solution of MnCl acts very powerfully on that materially. When
they are not made of wood simply it will be well to clothe them
externally with wood in order to prevent the too great cooling of their

page_text: contents. The cisterns C and C' in the Drawing are really one cistern
divided by a partition into a large and a small compartment, the large
compartment being for the MnCl liquor which is required to be put
into the oxidizer at the beginning of an operation therein and the small
compartment for MnCl liquor to be added, if required, towards the end
of the operation. Obviously, however, this arrangement of the cistern
in question is by no means essential.
XXXVI. Only one still is represented in Figure 1. The number
of stills which the manufacturer will require will depend mainly upon
whether or not the mode of procedure which he follows includes the use
in the still at each operation of an excess of manganite mud. When
an excess of mud is used and the undissolved MnO is left to settle in
the still itself, it will be difficult to perform an operation in the still
in less than from three or four to six hours, but when an excess of
mud is not used an operation in the still may be performed with almost
any degree of rapidity, an operation per hour being perfectly possible,
given only sufficient facilities for rapidly emptying the still, for rapidly
adding acid and mud, and for rapidly taking the gas. The still repre-
sented in the Drawing is a large one of over 600 feet of cubic capacity.
With acid at 27° Twaddell and mud containing about four pounds of
actual MnO per cubic foot, there can be generated in such a still
at one charge chlorine enough for from 25. to 30 cwt. of bleaching
powder. As I have already said, however, the stills used in my process
need not necessarily be of such large size, on the contrary, they may
be of any size or kind whatever, but I prefer that they should not
be smaller than that represented in Figure 1 except when they are
used on that "continuous" system which I shall proceed to describe in
the succeeding paragraph. I have only to add here that although there
are not given in the Drawing any appliances for injecting steam into
the still there represented such appliances will usually be desirable
even when working with heated mud, if only for the sake of raising
the temperature of the contents of the still at the end of each operation
for the purpose of driving off the last portions of the chlorine which
has been generated.
XXXVII. Figures 2, 3, and 4 in the accompanying Sheet of Drawings
represent varieties of what I propose to call "continuous stills" into
which hydrochloric acid and manganite mud may be continually being
run, and from which chlorine shall be continually going off by one exit

page_text: or set of exits and residual liquor from another. Figure 2. represents a
continuous still composed of six ordinary stills or other suitable. vessels
A, B, C, D, E, and F, A being connected with B by means of a tube d.
passing from the right side of A through the left side and down nearly-
to the bottom of B, B being similarly connected with C,. C with D, D,
with E, and E with F. The first vessel A is provided with two inlet
pipes passing down nearly to. its. bottom, and the fourth vessel D. is:
provided with one similar inlet pipe. Each of the first four vessels
is also provided with an exit pipe for chlorine. If the six vessels being
so arranged and provided hydrochloric acid be made to run into the
vessel A by one of the two inlet pipes a, a, and manganite. mud be.
made to run into. the same vessel by: the other inlet pipe, the acid and
mud will mix at the bottom of the vessel A, the resulting mixture
will rise up in that vessel to the upper extremity of the pipe d and
then flow by that pipe to the bottom of the vessel B, from which it
will at length similarly overflow into C and so on, until at last it runs.
from the vessel F by the pipe e, while if the proportions of acid and
mud be properly regulated and the contents of the vessels A, B, C,
and D be maintained at a temperature, say, between 170° F. and 220° F.
but preferably between 180° F. and 200° F., either by external heating
or by injection of steam or by the acid and mud, the one or the other
or both being sufficiently heated before entering the vessel A, liberation
of chlorine will go on all the time in the first four vessels or some
of them, the chlorine so liberated passing off by the tubes c, c, c, c..
If the proportions of the acid and mud which enter the vessel A be
such that the acid is somewhat in excess, what will reach the vessel D.
will be simply an acid solution of MnCl, mud to more or less completely
neutralize which can be added by the inlet tube b. If it be completely
neutralized by manganite mud, what will run off from the vessel F by
the pipe e will be a residual solution containing some undissolved MnO*
in suspension, which undissolved MnO' will have to be allowed to
settle in a subsequent vessel. There are not shown in the Drawing
any pipes for the injection of steam, because the vessels composing such
a still may conveniently be small enough to admit, without difficulty,
of heat being applied to them externally. Moreover when working
with such a still it will be especially desirable to use heated mud and
the hottest possible acid, when doing which it will probably not be
necessary to apply further heat to the contents of the still. When it
is necessary, however, to additionally heat the contents of any part of
n

page_text: such a still, this may of course be done by injection of steam if preferred.
I may add that Figure 2 is intended only to illustrate the general plan
of a "continuous still." It represents exactly one which is now nearly
ready for use and which will be the first large continuous still, (for I
have as yet had no experience of such a still on more than a laboratory
scale,) but in some of its details it probably does not represent the best
and certainly does not represent the only arrangements, which are
conceivable.
XXXVIII. A "continuous still " need not necessarily be composed
of just six vessels as in Figure 2, but may be composed of any
number
of suitable vessels not less than two, and these vessels may be of almost
any shape or size, and instead of being connected together as in Figure 2
may be connected together as in Figure 3 or in any one of a great
variety of other obvious ways. Moreover, instead of being composed of
two or more distinct vessels suitably connected together, a "continuous
still" may be composed of a single vessel divided interiorly into two
ōr more compartments, and the fundamental idea of such a still may
also be more or less completely carried out by placing small open vessels
inside larger closed ones, and so arranging that whatever enters the
closed vessel shall go first to the bottom of the inner open vessel and
shall be obliged before it can issue from the closed vessel to rise to
the top of the inner open vessel and overflow into the space between
the sides of that inner vessel and the sides of the containing closed
vessel. Figure 4 presents an example in which both the two expedients
last mentioned are embodied. A, A, is a rectangular vessel divided
into two compartments by the partition o; and a, a, is a small vessel
placed within one of the compartments of the large vessel A, A. The
tubes b, b, are to admit acid and mud, which then meet at the bottom
of the small vessel a, a, the resulting mixture then rising up and flowing
over the top of this small vessel, then passing to the bottom of that
compartment of the large vessel in which the small vessel is placed,
then passing into the next compartment by an aperture near the bottom
-f the partition o, and finally flowing off by the tube f. The tube c
is to admit steam into the first compartment; and the tube d to admit
manganite mud into the second compartment when it is desired to
neutralize the acid perfectly, or nearly so..
XXXIX. I have much desired to turn to account the chloride of
calcium which is the residual product of the process described in this

page_text: Specification and more especially to recover therefrom the chlorine
which it contains. I have now to mention two methods of doing this.
One consists in adding mangnesia to. the chloride of calcium in solution
and then treating the resulting mixture with carbonic acid gas pre-
ferably under pressure so as to obtain carbonate of lime and solution
of chloride of magnesium, which last can be readily resolved by
evaporation and gentle heating into hydrochloric acid and magnesia
for use over again. The carbonic acid used in this operation may be
that contained in products of combustion, which products may be
applied just as they are obtained, the other gases associated with the
carbonic acid gas in such products escaping from the vessel in which
the operation is performed when it is performed under pressure by
lifting a suitably loaded valve. The other method consists in decom-
posing the chloride of calcium under the influence of heat by the joint
action of silica and steam. These methods are of course applicable
to the decomposition of chloride of calcium produced otherwise than
as a bye product of my methed of manufacturing chlorine.
XL. It may sometimes be an advantage when treating MnO whether
or not having CaO associated with it with atmospheric or. other gaseous
oxygen in the wet, way, to promote the peroxidation of such MnO by
adding to the mixture containing it, either before the commencement
of the treatment. of such mixture with the gaseous oxidizing agent
employed or at some stage during the progress of that treatment, any
salt capable of imparting oxygen to the oxide or oxides of manganese
contained in such mixture and then absorbing oxygen to replace that
with which it has thus parted from the gaseous oxidizing agent which
is being applied to the mixture containing the said salt and the said
MnO, in such wise that a comparatively small quantity of such salt
may carry
oxygen to a comparatively large quantity of oxide of
"
manganese.
"
XLI. I have obtained some indications, not however yet confirmed,
of there possibly being an exception to the law above announced, that
MnO formed by peroxidation of MnO in the wet way absolutely
requires to combine at the moment of its formation with a base. This
is so at ordinary temperatures, and at higher than ordinary temperatures.
I am not sure that it is so at very much lower than ordinary temper-
atures. MnO2 formed by peroxidizing MnO in the wet way at high
temperatures has at the moment of its formation such intense chemical

page_text: energy that it siezes and combines with two atoms of MnO. MnO
formed in the same way at ordinary temperatures is so much less
energetic that it can combine only with one equivalent of MnO; might
not MnO³ similarly formed at very low temperatures have so much
less energy still as not to be able to combine with even one equivalent
of base? I have found some reason to think that this possibly may
be so, in which case it would be advisable whenever the utmost possible
economy of acid was desired to use little or no CaO with the MnO,
but both before and during the peroxidizing treatment to cool as low
as practically possible the mixture containing it.
XLII. The reservoir of milk of lime, marked E in Figure 1 in the
accompanying Sheet of Drawings, need not necessarily be in the relative
position there represented, although I greatly prefer that position for it.
If placed in any lower position there should, of course, be duly adapted
to it either a force or lift pump or other suitable appliance for lifting or
forcing known quantities of milk of lime into the oxidizer. The vessel,
marked G in Figure 1, into which the deposit which forms in the tanks
C and C is run off from time to time, may also be in any other con-
venient position, and should preferably have a filter bottom, so that all
manganese liquor accompanying the said deposit may drain therefrom
into the well B. In some cases it might be well to wash this deposit
with water, in order that as little manganese as possible may be thrown
away with it. Or adherent liquor might be separated from it by means
of centrifugal hydro-extractors.
XLIII. As already indicated all those parts of the present Invention
which do not consist of special methods of forming compounds con-
taining MnO2, apply to all compounds formed by treating either with
air or with any other gaseous oxidizing agent in the wet way either
oxide of manganese only or oxide of manganese admixed with other
substances, by whatever method, means, or appliances, or by whatever
mode of procedure such treatment thereof may be performed. Moreover,
with respect to compounds which may be produced by adding solution
of chloride of manganese gradually to milk of lime, and either injecting
air or other oxidizing gas into the resulting mixture, or agitating this
mixture in contact with air by means of revolving paddle wheels, or
otherwise, I further specially claim, firstly, the preliminary purification
of the chloride of manganese liquors treated as stated, by first neu-
tralizing these liquors, and then leaving them to deposit their Al'O',

page_text: SFO, FeO', and CaSO'; secondly, the use, in the production by the
method in question of compounds containing MnO%, of excess of Ca
in accordance with the proportion of the MnO treated which it is
required to peroxidize, and for the use, in the production by such method
of such compounds, of lime enough to secure the obtainment of
products the oxide of manganese in which, reckoned by itself, shall
contain more than sixty per cent. of MnO"; thirdly, the method
of running or transferring such compounds from vessel to vessel in
the state of mud, and more especially of sending them in that state
into the stills in which they are to be dissolved; and, fourthly, all
the details applicable to such compounds which are described in the
previous parts of the present Specification. I make the same claims
also with respect to such compounds as are producible by treating with
air or other gaseous oxidizing agent a mixture of previously prepared
hydrated oxide or oxides of manganese with water instead of with
solution of chloride of calcium.
XLIV. Seeing that manganite of calcium, or CaMnO', is only of the
same valuc, precisely, in respect of the quantity of chlorine which it can
liberate from a given quantity of acid, as manganite of manganese, or
MnMnO (otherwise sesquioxide of manganese), it may be well to
explain why it is preferable to produce and re-produce the former com-
pound rather than the latter. The reasons for this are two: there is,
firstly, the obvious reason that when all the manganese is converted
into MnO3, twice as much work is done, per given bulk of material
operated upon, as when only half the manganese is converted into
MnO2; and this, of course, would be a very important consideration,.
even if the conversion of chloride of manganese into manganite of
calcium occupied the same time as its conversion into manganite of
manganese. Really, however, (and this is the second and main reason,)
the former operation, in which all the manganese is converted into
MnO2, does not occupy more than a very small proportion of the time
required for the latter operation, in which only half the manganese is
converted into MnO; and, hence, while the manufacture of chlorine
by means of perpetually regenerated manganite of calcium effects
enormous economies, it is questionable whether chlorine could be manu-
factured by means of manganite of manganese, regenerated by the same
method, more cheaply than by means of manganese ores.
XLV. Finally, to avoid all chance of any misunderstanding of the

page_text: chemical symbols which have been used above, I may state that by
Al I have intended to signify aluminium; by Fe, iron; by SiO³, silica;
by AO, alumina; by FeO', sesquioxide of iron; by CaSO', sulphate
of calcium; by CaO, lime; by MnO, protoxide of manganese; by MnO³,
binoxide or peroxide of manganese; by MnCl, chloride of manganese;
by CaCl, chloride of calcium; by AICI, sesquichloride of aluminium;
by Fe C, sesquichloride of iron; by HCl, hydrochloric acid, and by
CO, carbonic acid.
XLVI. Having now fully and particularly described and ascertained
the nature of my said Invention, and the manner in which the same
is to be performed, I wish it to be understood that what I consider
novel therein, and therefore claim as my Invention and desire to
havo secured to me by the herein-before in part recited Letters Patent
is as follows:-
a. The regulation, on the principles and in the manner fully set forth
in paragraphs V. to XI. of the foregoing Specification, of the quantity
of lime employed to promote the peroxidation of protoxide of manganese
by treatment thereof with atmospheric or other gascous oxygen in the
wet way, by whatever method such treatment may be performed, and
the employment of such lime in quantity proportionate to the quantity
of peroxide of manganese which it is proposed to gain thereby, in
accordance with the instructions given in the paragraphs aforesaid.
b. The method of addition of the lime so employed to promote the
peroxidation of protoxide of manganese by treatment with atmospheric
air or other gaseous oxidizing agent in the wet way, which consists
in adding such lime gradually, by more portions than one, and all the
details relating to this method which are described in the present
Specification.
c. The addition of chloride of manganese, after that of the lime
employed to promote the peroxidation of the protoxide of manganese,
when treating with atmospheric air or other gaseous oxidizing agent in
the wet way, protoxide of manganese obtained by decomposing the
chloride of manganese in the residual liquors of the manufacture of
chlorine, using lime to promote the peroxidation of such protoxide, and
adding such lime gradually as aforesaid; and all the details relating to
such addition of chloride of manganese which are described in the
present Specification.

page_text: d. The plan of passing in the state of fluid mud into the stills in
which they are to react upon hydrochloric acid, and of admitting there-
into by means of pipes and cocks, S or U tubes, or hydraulic lutes any
compounds formed by first transforming into protoxide the chloride of
manganese in the residual liquors of the chlorine manufacture, and
then treating such protoxide, admixed or not with other substance or
substances, with atmospheric air or other gaseous oxidizing agent in
the wet way, the said fluid mud consisting (at least perferably) of a
mixture of such compounds with a portion of the liquid in which they
were produced; and all the details relating to such plan or method
which are described in the present Specification.
e. The method of putting hydrochloric acid into the stills first and
then adding thereto gradually the aforesaid fluid mud, and regulating
the rate of addition of such mud by the rate at which it is desired
that chlorine shall be generated; and all the details relating to this
method of procedure which are described in the present Specification.
f. The method of putting the aforesaid fluid mud into the stills first,
and then adding gradually thereto hydrochloric acid, regulating the
rate of addition of such acid according to the rate at which it is
desired that chlorine shall be generated; and all the details relating to
this method of procedure which are described in the present Specifi-
cation.
g. The method of making the acid and the fluid mud enter the stills
simultaneously, and all the details relating to this method which are
described in the present Specification.
h. The plan of using in the stills an excess of the aforesaid mud,
and all the details relating to this plan which are described in the present
Specification.
i. The use for the generation of chlorine by means of the compounds
produced as aforesaid, of stone stills of greater depth than breadth or
width, and preferably of much greater capacity than the largest stills
which have hitherto been used by manufacturers of chlorine.
j. The construction and working, upon the plan and system described
in paragraphs XXXVII. and XXXVIII. of the present Specification, of
"continuous stills," formed either by suitably connecting together two
or more distinct vessels, or by suitably dividing one vessel into two or
moré compartments, or by placing open vessels inside closed ones, or by

page_text: combining all these plans, or any two of them, and the employment of
such stills for the generation of chlorine.
k. The heating, before they are admitted into the stills, of the
aforesaid fluid mud, or of the hydrochloric acid from which it is
required to liberate chlorine, or, if not of both, of either of them; and
all the details relating thereto which are described in the present
Specification.
1. The employment for the neutralization of residual liquors of the
chlorine manufacture, preliminarily to treating these liqours for the
regeneration from then, in the wet way, of compounds containing
peroxide of manganese of carbonate of lime in a somewhat fine state of
division.
m. The methods of utilizing any free hydrochloric acid which may
be contained in the residual liquors produced when manufacturing
chlorine by means of artificial compounds containing peroxide of man-
ganese formed in the wet way which are described in paragraph XXV.
of the present Specification.
n. The methods of utilizing the chloride of calcium which is produced
as a bye product of the manufacture of chlorine as aforesaid, which
are described in paragraph XXXIX. of the present Specification.
o. The construction of the vessels which I have called "oxidizers"
of the material and in the shapes indicated in paragraph XXXV. of the
present Specification, and all the details relating thereto, and the details
concerning the arrangements for conducting the oxidizing blast into
these vessels and distributing it throughout their contents, which are
described in that and succeeding paragraphs.
p. The construction, in or of the materials indicated for them res-
pectively, of other parts of the apparatus described in the present
Specification.
q. The general arrangements and dispositions of apparatus to be used
for the regeneration in the wet way from residual products of the
manufacture of chlorine, and the modes of procedure and methods of
operating to be employed for that object which are described in the
present Specification.
r. The manufacture of chlorine by means of artificial compounds
containing peroxide of manganese, in the production of which compounds

page_text: any of the improvements described in the present Specification have
been employed.
8. Finally, all details relating to the regeneration in the wet way
from residual products of the manufacture of chlorine, of compounds
containing peroxide of manganese; and all details relating to the
manufacture of chlorine by means of such compounds; and all details.
relating to apparatus, arrangements, and modes of procedure in order to
the accomplishment of these objects, which are described in the present
Specification, but are not more particularly enumerated in this its forty-
sixth and final paragraph.
In witness whereof I, the said Walter Weldon, have hereunto set
my hand and seal, this Ninth day of September, in the year of
our Lord One thousand eight hundred and sixty-nine.
WALTER WELDON. (L.S.)