IMPROVEMENTS IN OBTAINING CERTAIN METALS FROM CERTAIN COMPOUNDS CONTAINING THESE METALS AND IN OBTAINING OTHER PRODUCTS BY THE USE OF CERTAIN COMPOUNDS CONTAINING METALS
Year: 1848

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HUNT, of Dodderhill, in the County of Worcester, Chemist, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date
at Westminster, the Twenty-fourth day of June, in the eleventh year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said William Hunt, Her especial licence, full power, sole privilege and
authority, that I, the said William Hunt, my executors, administrators,
and assigns, and such others as I, the said William Hunt, my executors,
administrators, or assigns, should at any time agree with, and no others, from
time to time and at all times during the term of years therein mentioned,
should and lawfully might make, use, exercise, and vend, within England,
Wales, the Town of Berwick-upon-Tweed, and in all Her Majesty's Colonies
and Plantations abroad, and in the Islands of Jersey, Guernsey, Alderney,
Sark and Man, my Invention of "IMPROVEMENTS IN OBTAINING CERTAIN
METALS FROM CERTAIN COMPOUNDS CONTAINING THESE METALS AND IN OBTAINING
OTHER PRODUCTS BY THE USE OF CERTAIN COMPOUNDS CONTAINING METALS;" in
which said Letters Patent is contained a proviso obliging me, the said William
Hunt, by an instrument in writing under my hand and seal, particularly
to describe and ascertain the nature of my said Invention, and in what
manner the same is to be performed, and to cause the same to be inrolled
in Her Majesty's High Court of Chancery within six calendar months
next and immediately after the date of the said in part recited Letters

page_text: Patent, as in and by the same, reference being thereunto had, will more fully
and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
William Hunt, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, is particularly described
and ascertained in and by the following description thereof, reference being
had to the Drawings hereunto annexed, and to the letters and figures
marked thereon (that is to say):-
My Invention of "Improvements in Obtaining certain Metals from certain
Compounds containing those Metals, and in Obtaining other Products by the
Use of certain Compounds containing Metals;" consists in obtaining iron
from certain compounds known as iron slags, also copper and tin from certain
compounds known as copper slags, by the means herein-after particularly
described; also consists in obtaining sulphate of soda and carbonate of soda
from common salt by the use of certain compounds containing metals (herein-
after particularly described), these compounds containing metals being used in
the manner herein subsequently ascertained.
I will firstly describe the manner in which I carry into effect that part of
my Invention which relates to obtaining iron from certain compounds known
as iron slags. The compounds which I use for this purpose are the iron slags
obtained in the well-known processes of refining, puddling, and reheating iron.
I obtain these slags in a granulated or divided state by causing the slags, when
in a melted state, to be run into a pit provided with a plentiful supply of water;
and I provide a perforated vessel in this pit so placed as to receive the
granulated slag, and by means of suitable hoisting tackle I raise this per-
forated vessel from the pit and take therefrom the granulated slag. I mix
this granulated slag with about one fourth of its weight of small coal, and I
introduce this mixture into a reverberatory furnace, and cover its surface with
small coal. I then expose it to a full red heat-for cementation during a period
of about twenty-four hours, by which cementation oxide of iron contained in
the slag is deprived of its oxygen, and iron is produced in a metallic state.
I withdraw the product which contains metallic iron from the furnace, and cool
it quickly by means of water. When I wish to obtain this iron in the state of
pig iron, I introduce the cemented mixture (as it is procured from the cement-
ing furnace) into an ordinary blast furnace used for smelting iron ore. together
with the materials constituting the usual burden of such furnace, and I
thereby obtain pig iron from such mixture by the ordinary mode of smelting;
or when I wish to obtain malleable iron from such cemented mixture, I prefer,
firstly, to subject it to the well-known operation of buddling or washing with

page_text: water, to separate the heavy metallic iron from the lighter particles with which
it is mixed; and I introduce the iron so separated into an ordinary puddling
furnace, together with pig or plate iron; and by the means usually employed
in working with puddling furnaces I obtain malleable iron therefrom.
I will now describe the manner in which I effect that part of my Invention
which relates to obtaining copper and tin from copper slags. It is well known
to metallurgists that the slags obtained by the usual method of smelting copper
ores consist chiefly of silicate of iron, but thèse contain also, a valuable
quantity of copper and tin, these last metals being sometimes combined with
oxygen and silica, and sometimes with sulphur in such slags. In following the
methods, usually employed for smelting copper ores the melted slags produced
are skimmed from the furnaces into sand beds; and allowed to solidify in
masses; and it is not found practicable (consistently with economy) to obtain
these slags completely deprived of copper, the proportion of this valuable metal.
contained in the slags which are rejected as worthless being usually not less
than one half per cent. of the whole weight. The proportion of tin contained
in these slags necessarily varies with the contents of the copper ore from which
such slags are obtained. It is also well known that in pursuing the.. usual
methods of smelting copper ores it is considered advisable. not to drive off
sulphur from the ore (by previous calcination) to such an extent as that the
regulus obtained by meeting the calcined ore shall contain more than thirty-
five per cent. of copper, otherwise the slags produced contain a still larger
portion of copper than one half per cent., and a. greater loss is consequently
incurred by these slags being rejected. In effecting this part of my Invention
I prefer to prolong the usual calcination of the copper ore to such an extent
that when the calcined ore is melted the regulus obtained therefrom shall
contain about sixty per cent. of copper; and in place of receiving melted slag
from the furnace into sand beds I cause this slag? to flow into a pit provided
with a plentiful supply of water, and by this means the: slag becomes granu-
lated and is obtained in a state of division, provided the copper ore has been
calcined to the extent lastly above mentioned. The slag thus obtained' will
contain about one per cent. of copper; and I operate upon this slag or upon
slag obtained by the ordinary melting of copper ore, and granulated as above
described, by mixing it with sulphurizing or deoxidizing compounds, and
melting the mixture in a suitable furnace. For this purpose I prefer to use
(as the sulphurizing or deoxidizing compounds) raw sulphureous ore of copper
or of iron in powder, mixed with slaked lime and coal dust, and to use for eacli
ton of granulated: slag (containing one per cent. or less of copper) such a
quantity of ore as contains thirty pounds of sulphur, and I add forty pounds of

page_text: slaked lime and twenty pounds of coal dust. I mix these together and add
sufficient water to reduce the mixture to the consistence of a thin paste; I
then add this to the granulated slag, and mix the whole together by turning it
repeatedly. I prefer to melt this mixture in a reverberatory furnace (such as
is used for melting copper ore), but this melting may be effected in a blast
furnace. The products obtained by such melting consist of slag (which is
nearly free from metals except iron) and a regulus containing sulphuret of
copper, sulphuret of tin, and sulphuret of iron. The copper and tin can be
obtained from such regulus by means of the well-known processes usually
employed for obtaining such metals from regulus containing the same. It will
be obvious that copper slag can also be obtained in a state of minute-division
by crushing the slag to powder by means of rollers or stampers, and when so
obtained can be deprived of its valuable metals by the means above described;
but this method of effecting such object is more costly than the granulation of
the melted slag by means of water. In place of using raw sulphureous orc of
copper or of iron as a sulphurizing agent for obtaining copper and tin from
copper slags, I can also use sulphate of soda, sulphate of lime, or the impure
sulphuret of calcium, which is produced in the ordinary method of manufac-
turing soda, and is known as "soda waste." When I use any of these
materials for such purpose, also when I use sulphurcous orc of copper or of
iron, I add to each ton of granulated or crushed slag, containing one per cent.
or less than one per cent. of copper, such a quantity of the sulphurizing agent
employed as will contain about thirty pounds of sulphur; and I increase this
proportion in the direct ratio of any increased proportion of copper which may
be present in the slag. I also add-the proportions of slaked lime and of coal
dust when using sulphate of soda or sulphate of lime, as I have herein-before
indicated as suitable when using sulphureous ore of copper or of iron. I can
also obtain copper and tin from granulated or crushed copper slag by mixing
this with coal dust alone, or, by-preference, with coal dust and slaked linie, or
some other suitable, flux in place of lime, and by exposing this mixture to
a cementing heat for three or four hours, and subsequently melting it. In
this mode of working I prefer to use a reverberatory furnace having two
working beds; and I introduce a charge of slag mixed with other matters, as
before mentioned, on to the bed furthest from the fire whereon the operation
of cementing is effected, whilst another charge of slag is being melted on the
bed nearest to the fire; and when this last-mentioned charge is withdrawn I
transfer the cemented charge on to the bed nearest to the fire to become
melted. In this mode of working I add half a hundredweight of coal dust
alone, or mixed with one hundredweight of slaked lime to one ton of granulated

page_text: or crushed copper slags, and by melting I obtain some copper and tin in a
metallic state, and another portion combined with sulphur as a regulus, from
which I obtain the metallic part by some of the means usually employed for
such purpose.
I will now describe the manner in which I effect that part of my Invention
which relates to obtaining sulphate of soda and carbonate of soda by the use
of certain compounds containing metals. The compounds containing metals
which use to effect this part of my Invention are oxide of iron and artificial
sulphuret of iron, or a mixture of these two compounds, also oxide of man-
ganese and artificial sulphuret of manganese, or a mixture of these two
compounds; and the material containing soda which I employ is common salt
(chloride of sodium). I will first describe the mode of working which I
adopt to effect this part of my Invention when using artificial sulphuret of
iron together with oxide of iron to decompose common salt. Having obtained
a supply of artificial sulphuret of iron by any of the well-known means (but
in preference by the means herein-after described), I ascertain the propor-
tionate quantities of iron and sulphur which this sulphuret contains, and if the
proportion of iron contained therein is not equal to three times that of the
sulphur (which proportion of iron, partly in the state of oxide, will be present
therein when this sulphuret is obtained by the means herein-after described),
I add thereto such a quantity of oxide of iron in powder as will make up the
defeciency of iron, and I then add common salt in powder in the proportion of
two parts of common salt for one part of sulphur contained in the mixture of
sulphuret and oxide employed; I mix the whole together very carefully, and
introduce a charge of this mixture into a furnace heated by transmitted heat
(which I call a sulphating furnace), and I cause atmospheric air to have access
to this furnace. The application of a moderate heat to the charge, with the
resence of atmospheric air, occasions the combustion of sulphur in the sul-
phuret, which is indicated by a blue flame spreading over the surface of the
mixture; and continue to apply a moderate heat so long as this blue flamo
is visible (during which period the mixture will have cohered into lumps),
but when this flame is no longer perceptible I remove the charge into a
part of the same furnace which is more strongly heated, and I break down the
lumps which had been formed in the previous heating, and by the appli-
cation of a stronger heat, with a supply of atmospheric air, I drive off nearly
all the remaining portions of chlorine previously contained in the mixture
employed. Some part of this chlorine will pass off in the state of chlorine
gas, and another part in the state of chloride of iron, and another part in
that of hydrochloric acid; and when it is not an object with me to obtain

page_text: chlorine gas for subsequent use, I introduce a moderate supply of steam into
the furnace, whereby the decomposition of the common salt is much facilitated,
but nearly all the chlorine passes off in the state of hydrochloric acid. The
product remaining in the furnace from this operation consists of a mixture of
sulphate of soda and oxide of iron, and I either lixiviate this mixture with
water, and thereby obtain sulphate of soda and oxide of iron separately, or I
use this mixture for obtaining carbonate of soda and artificial sulphuret of iron
by the means hercin-after described. When I employ artificial sulphuret of
iron alone as the metallic compound used for effecting the production of sul-
phate of soda by the decomposition of common salt, I add common salt thereto
in the proportion of two parts of salt to one part of sulphur contained therein,
and I effect such decomposition in the manner I have herein-before described
for effecting the decomposition of common salt by means of a mixture of
artificial sulphuret of iron and oxide of iron; but I find that the results I
obtain by the use of artificial sulphuret of iron alone are not so beneficial as
those obtained by the use of this compound in mixture with oxide of iron.
When I adopt the use of oxide of iron alone as the metallic compound for
effecting this part of my Invention, as applied to the production of sulphate of
soda from common salt, I mix such a proportion of oxide of iron with
common salt, both substances being in powder, that the weight of the common
salt shall be one half greater than that of the metallic iron contained in the
oxide of iron. I introduce a charge of this mixture into the chamber of a
furnace heated by transmitted heat, and I cause a supply of sulphurous acid
gas (obtained by the combustion of sulphur or of iron pyrites, or by any
other well-known means), together with a supply of atmospheric air, to enter
the chamber of this furnace, and I assist the action of the oxide of iron on
the common salt and sulphurous acid gas by the admission of steam, in which
case all or nearly all the chlorine evolved will be in the state of hydrochloric
acid. I stir the mixture assiduously so as to expose fresh surfaces to the action
of sulphurous acid gas and atmospheric air, and I continue the operation
.(applying a stronger heat towards the end thereof) until the mixture ceases to
evolve any considerable quantity of chlorine or hydrochloric acid.
product remaining in the furnace consists of sulphate of soda and oxide of
iron, which product I lixiviate with water, and thereby obtain sulphate of
soda and oxide of iron separately, and I use the oxide of iron to mix with
a fresh portion of common salt, and expose the mixture to the action of
sulphurous acid gas and atmospheric air in the manner above described,
and thereby obtain a further quantity of sulphate of soda; or I use this
product containing sulphate of soda and oxide of iron for obtaining carbonate
The

page_text: of soda and artificial sulphuret of iron, by the micans herein-after described.
I have stated that when a supply of steam is admitted into the chamber
of a furnace, in which sulphato of soda is being produced by the action of
artificial sulphuret of iron and oxide of iron, together with atmospheric air on
common salt, or by the action of oxide of iron, together with sulphurous acid
and atmospheric air on common salt, the chlorine evolved passes off entirely
or nearly so in the state of hydrochloric acid. I have also stated that this
admission of steam greatly facilitates the decomposition of common salt under
the circumstances mentioned. The hydrochloric acid so evolved can be
obtained in the liquid state by some of the well-known means of condensation
ordinarily employed for such purpose. When I desire to obtain chlorine
gas by the decomposition of common salt, under the circumstances above
mentioned, I take care to exclude water or steam, so far as may be practi-
cable, from the chamber of the furnace in which such common salt is under-
going decomposition by the actions above described, and I then obtain a large
quantity of chlorine gas, mixed with azote, remaining from the atmospheric
air; but as this chlorine gas is usually mixed with some hydrochloric acid, I
cause the gaseous product to be passed through such an apparatus as is
commonly employed for condensing hydrochloric acid by means of water, and
I thus obtain chlorine gas mixed with azote, but free from hydrochloric acid,
in a state suitable to be passed into apparatus for the manufacture of chloride
of lime, or other compounds of chlorine; and when I am thus working, so
as to obtain chlorine gas, I prefer to effect the passage of atmospheric air,
or of atmospheric air with sulphurous acid gas, through the chamber of the
furnace herein before referred to; and the passage of the gases proceeding
from this furnace to the condensing apparatus for absorbing hydrochloric acid
also the passage of the gases from this condensing apparatus to the apparatus
for manufacturing chloride of lime or other chlorides, by means of some of
the well-known pumping or blowing machines, arranged as regards the
materials of which there may be constructed, so as to be suitable for such
purposes.
I have described certain processes by means of which I obtain sulphate
of soda, in mixture with oxide of iron, by the action of artificial sulphuret of
iron and oxide of iron together with atmospheric air, on common salt, or by
the action of oxide of iron, together with sulphurous acid gas and atmospheric
air, on common salt; and I will now describe the means by which I cause
sulphate of soda so obtained to become decomposed by the action of oxide of
iron so obtained, so as to produce, by such decomposition, carbonate of soda and
artificial sulphuret of iron, the latter compound being suitable to be used for

page_text: the decomposition of common salt and production of a further quantity of
sulphate of soda and oxide of iron. I have herein-before mentioned.a furnace
heated by transmitted heat (which I have called a sulphating furnace), in
which furnace I have described the production of sulphate of soda in mixture
with oxide of iron to have taken place; and for the purpose of decomposing
this product I prefer to employ a furnace of a similar construction, as respects
the method of heating (I call this furnace a cementing furnace), and to placo
this cementing furnace so contiguous to the sulphating furnace that the
mixture of sulphate of soda and oxide of iron can be transferred in a heated
state to the cementing furnace (the construction and arrangement of these
furnaces, and other apparatus connected therewith, are exhibited in the
Drawings hereunto annexed, and are herein-after described). In the opera-
tions of decomposing common salt by means of metallic compounds under the
circumstances herein-before mentioned, I take the precaution. (as before
stated) to use certain proportions of common salt relatively. to sulphur or iron
contained in such compounds, and I so arrange the charges introduced into
the sulphating furnace that when one of these charges is transferred therefrom
to the cementing furnace I know the quantity of common salt which has been
used in the production of this charge, and can infer very nearly the quantity of
sulphate of soda this charge will contain. I add small coal or coke to the
mixture of sulphate of soda and oxide of iron when this has been transferred
into the cementing furnace, in the proportion of about sixty-six pounds of small
coal or coke for cach one hundred pounds- of common salt, which has been
used for the production of the charge so transferred, and by means of rakes I
mix this small coal or coke as intimately as may be practicable with the
mixture of sulphate of soda and oxide of iron constituting such charge. I
regulate the fire of this furnace so that the charge-contained therein may be
kept at a full red heat, at which heat its decomposition, by cementation
without fluxing, takes place, and the result of this action is the production of
carbonate of soda, artificial sulphuret of iron, and metallic iron. I continue
this cementing operation during a period of about four hours, during which I
occasionally throw a little coal into the chamber of the furnace near the door
to prevent any unconsumed oxygen getting: access to the charge. I then draw
out the cemented charge (as quickly as possible, so as to avoid the action of
the air upon it,) into iron vessels, and transfer these vessels; with their contents,
into a tank of cold water. When the product thus obtained (which is in the
state of a slightly coherent mass) is sufficiently cooled to prevent the rapid
action of the air upon it, I spread it in a thin layer upon a brick or stone floor,
and allow it to be exposed to the atmosphere for about twelve hours, by which

page_text: I
means it becomes powdery; I then transfer it to suitable vessels, in which I
lixiviate it with water, and thereby obtain carbonate of soda, together with
some caustic soda and sulphuret of sodium in solution, which solution I treat
by some of the well-known means, so as to obtain dry carbonate of sodo or
crystals of soda therefrom. By the said lixiviation I also obtain a residuum con-
sisting of artificial sulphuret of iron, together with excess of iron, partly in the
metallic state and partly in that of oxide, and it is this residuum which I prefer
to use for effecting the decomposition of common salt, and the production of
sulphate of soda and oxide of iron. In using this residuum for such purpose
prefer not to reduce it to a state of dryness, but to employ it in the state of
soft paste. I ascertain the proportion of sulphur which it contains, and
add such a quantity of common salt thereto, proportionately to this sulphur,
as I have herein-before indicated. I mix this salt with the residuum, and intro-
duce the mixture into the sulphating furnace herein-before mentioned, and
proceed with the operation of decomposing the salt, as herein-before described.
It will be understood from the particulars herein-before stated, that in decom-
posing common salt by the use of artificial sulphuret of iron, sulphur (previously
contained in such sulphuret) becomes transferred to soda (obtained from com-
mon salt), so as to produce sulphate of soda; also that in decomposing
sulphate of soda (so obtained) by the use of oxide of iron, sulphur (previously
contained in such sulphate. becomes transferred to iron, so as to reproduce
artificial sulphuret of iron, which product is suitable to be used for the produc-
tion of a further quantity of sulphate of soda; and these operations of trans-
ferring sulphur from artificial sulphuret of iron, and thereby decomposing
common salt so as to produce sulphate of soda, and of transferring sulphur
from such sulphate of soda by the use of oxide of iron, and thereby obtaining
artificial sulphuret of iron, can be repeated alternately for many times. In fact
if the repeated transfers of sulphur by the use of the metallic compounds men-
tioned could be effected without any loss of this material, these repetitions
could be made almost indefinitely, and an almost unlimited quantity of sulphate
of soda could be produced by the use of a definite quantity of iron repeatedly
employed in the state of artificial sulphuret for decomposing common salt; and
a corresponding quantity of soda (as carbonate or otherwise) could be produced
by the use of the same iron in the state of oxide for decomposing sulphate of
soda obtained by such decomposition of common salt; but I find, in practical
workings, that some loss of sulphur takes place, and I replace the sulphur so
lost by some of the means I am about to describe for this purpose. During
the operation of cementing a charge consisting of sulphate of soda and oxido
of iron with coal in the cementing furnace, as herein-before mentioned, and

page_text: when this operation has been carried on to such an extent that the charge con-
tains a considerable quantity of metallic iron, or about an hour previously to
drawing the charge), I add to the charge a quantity of iron pyrites in powder,
and by means of rakes I mix this as thoroughly as may be practicable with the
charge. The heat of the charge causes the iron pyrites mixed therewith to part
with a portion of its sulphur, and thus to become proto-sulphuret of iron, and
sulphur so given up combines with metallic iron contained in the charge, and
the whole sulphuret thus becomes artificial sulphuret of iron, suitable (when
separated from the salts of soda) to be used for the production of sul-
phate of soda by its action in decomposing common salt.
I add such a pro-
portion of iron pyrites to the charges of sulphate of soda and oxide of iron
when these are undergoing the operation of cementing, as herein-before
described, as I find to be sufficient to replace sulphur which has been lost in
the preceding operations. It will be understood that in adding iron pyrites, as
above mentioned, such addition will occasion an accumulation in the quantity
of oxide of iron contained in the mixture of sulphate of soda and oxide of iron
subsequently obtained by the action of the resulting artificial sulphuret of iron
on common salt, and when this accumulation has taken place to such an
extent that I find the quantity of oxide of iron present in this mixture exceeds
that of the sulphate of soda, I lixiviate a portion of this mixture with water,
and thereby obtain sulphate of soda in solution, which I add to the mixture of
artificial sulphuret of iron and common salt, previously to this being introduced
into the sulphating furnace, and thereby increase the proportionate quantity of
sulphate of soda contained in the mixture of sulphate of soda and oxide of iron
obtained by such operation. I have herein-before described certain means by
which I obtain sulphate of soda by using oxide of iron together with sulphurous
acid gas and atmospheric air to decompose common salt, and have stated that
I sometimes lixiviate the mixture produced, and thereby obtain sulphate of
soda in solution. In this case I prefer to use the solution in the manner I
have just described for using a similar solution of sulphate of soda, and I
thereby make up the loss of sulphur herein-before referred to.
I will now describe another method of using metallic compounds, by which
I obtain sulphate of soda by the decomposition of common salt, and make up
the loss of sulphur herein-before referred to. In the Drawings hereunto
annexed Fig. 1 is a plan view in section, and Fig. 2 is a vertical section of
such an apparatus as I prefer to use under certain circumstances for effecting
the absorption of sulphurous acid gas in the presence of atmospheric air by a
mixture of common salt and oxide of iron. A is a kiln for burning iron
pyrites, of the same construction as the kilns ordinarily employed for this pur-

page_text: pose in the manufacture of sulphuric acid, to be used for decomposing common
salt. The sulphurous acid gas proceeds from this kiln by a channel or passage
B. C is a vertical chamber formed of brickwork, and nearly filled with small
masses, consisting of a mixture of artificial sulphuret. of iron, together with
oxide of iron, (obtained by, the decomposition of sulphate of soda with oxide of
iron, as herein before described,) and common salt, this mixture having; been
made by adding salt to pasty sulphuret of iron, as herein-before mentioned, and
the pasty mixture thereby obtained having been transferred to a furnace, where,
by the application of transmitted heat, it had. become coagulated, and was sub-
sequently broken into small masses. D is a chamber of the apparatus formed
of brick arches, so arranged that heat can be applied to the contents of this
cliamber through such arches. E is a fire grate, and F, F; are flues conducting
the products of combustion from the fire in contact with the arches forming the
chamber of this apparatus. These flues are also extended so as to conduct flame
round the vertical chamber C, and thereby give heat to its contents. G is an
exit flue communicating with a chimney. His a passage through which
chlorine in the state of chlorine gas, or that of hydrochloric acid, is conducted
from this apparatus. I work with this apparatus by filling the chamber C nearly
full with the mixture before mentioned, the kiln A at the same time containing
iron pyrites in the state of combustion. Sulphurous acid gas proceeding from
the combustion of the pyrites, together with atmospheric air, escapes from the
kiln, and these gases percolate through the contents of the chamber C, and by
the influence of the oxide of iron and air this acid gas decomposes common
salt, and produces sulphate of soda. A portion of the contents of the chamber
C is from time to time removed from its lower part and spread in the chamber D
(a fresh portion of mixture being then introduced into the chamber C), where
increased heat is applied to it until nearly all, the chlorine is expelled from the
mixture, and the residuum is then withdrawn for use. This chlorine: percolates
through the chamber C and passes off through the passage H together with
other gases.
It will be understood that by this method of working the quan-
tity of sulphate of soda in the mixture of sulphate of soda and oxide of iron
thereby obtained is increased without increasing the quantity of iron contained
therein. In the Drawings hereunto annexed, Figures 3, 4, and 5 exhibit such
a set of apparatus as I prefer to use for effecting the decomposition of common
salt by the use of artificial sulphuret of iron alone, or with oxide of iron, or
by the use of artificial sulphuret of manganese alone, or with oxide of man-
ganese as herein-before described; also for effecting the decomposition of
sulphate of soda by the use of oxide of iron or oxide of manganese, as hercin-
before described. Fig. 3 is a plan view in section, and Fig. 4 is a vertical

page_text: section of the said apparatus, and Fig. 5 is a vertical section taken through
the dotted line Y, Z, in Fig. 3. In these several Figures the same letters of
reference are used to indicate similar parts. A, A, are chambers (formed of
brick arches); of what I have called sulphating furnaces, into which the mixture
of artificial sulphuret of iron or of manganese and salt is introduced. B, B,
are similar chambers into which this mixture is transferred from the chambers
A, A; and wherein it is exposed to a higher temperature to drive off chlorine:
C, C, are flues to conduct chlorine and other gases from these furnaces to other
apparatus. D, D, are fire grates. E, E, are flues through which the products
of combustion are conducted in contact with the brick arches of the chambers;
and F, I, are flues communicating with a chimney: G, G, are similar
chambers, constituting what I have called a cementing furnace. H is the
fire grate of this furnace. I, I, are the flues through which the products of
combustion are conducted in contact with the brick arches. J is a fluc con-
ducting to a chimney. K is a passage to admit of gases escaping from: the
chambers G, G. L, L, are passages from the chambers B, B, to the chambers
G, G; these passages may be closed by double dampers M, M. N, N, arc
hoppers for introducing charges into the chambers A, A. In working with
this apparatus I introduce a charge consisting of a mixture of artificial
metallic sulphuret, with or without oxide and common salt, as herein-before
mentioned, into each of the chambers A, A, of the sulphating furnaces, and I
spread these charges over the floors of such chambers, and heat. being applied
through the brick arches forming such chambers, at the same time that atino-
spheric air has access to the chambers,, the charges speedily become dried, and
form masses which ignite with a blue flame. At the end of about five hours
from charging this blue flame ceases to be visible, and I then transfer the
charges from the chambers A, A, to the chambers B, B, of the sulphating
furnaces, and I break down the lumps of mixture. In the chambers B, B, I
apply a stronger heat also with access of atmospheric air and occasionally
steam, as herein-before mentioned, and at the end of about five hours from the
period of transferring the charges I find that these have given up nearly all
the chlorine previously contained therein. I then remove the dampers M, M,
and transfer the mixture-of-sulphate-of-soda-and-oxide of iron or oxide of
manganese obtained through the passages L, L, into the chambers G, G, of
what I have called a cementing furnace. I then replace the dampers M, M,
and add small coal or coke-to-the-mixture of sulphate. of soda and oxide of
iron or oxide of manganese, as herein-before mentioned, and having mixed
these well together I allow the process of cementation to continue about four
hours, when I draw the. cemented charges as quickly as possible into iron

page_text: vessels. In the meantime new charges of metallic sulphuret and salt will have
been introduced into the chambers of the sulphating furnaces, and these
charges will in due time be transferred to the chambers of the cementing
furnaces. It will thus be understood that a period of about ten hours is
sufficient for effecting the decomposition of a charge of common salt by the
use of artificial metallic sulphurets, and a further period of about four hours
for effecting the decomposition of sulphate of soda by the use of metallic
oxides, as herein-before described. I have stated that I effect the decom-
position of sulphate of soda by means of oxide of iron in mixture therewith
by the addition of small coal or coke, and cementing the mixture at a red
heat without causing it to become fluxed. I greatly prefer this method of
effecting such decomposition to that of fluxing the mixture; in fact, I have
found by experience that although a mixture of sulphate of soda and oxide of
iron obtained by decomposing common salt with native iron pyrites may be
readily fluxed, yet the mixture of sulphate of soda and oxide of iron produced
by the decomposition of common salt by the use of artificial sulphuret of iron
(obtained as herein-before described), requires such an intense heat to become
fluxed as to occasion much inconvenience and loss in the operation, whilst the
process of decomposition by cementation is effected at a very moderate heat
and with great economy.
I have also found, as herein-before mentioned, that
the decomposition. of common salt by the use of certain artificial metallic
sulphurets and oxides mixed therewith may be effected in a period of about
ten hours, and requires the consumption of a comparatively small quantity of
coal, and the employment of very little labor, whilst it is well understood
that the decomposition of common salt by the use of iron pyrites, or
other native sulphurous ores, requires a tenfold period of time, and con-
sequently a much larger consumption of coal and employment of labour.
When I use oxide of manganese, or artificial sulphuret, of manganese, or a
mixture of these two compounds, for effecting that part of my Invention which
relates to obtaining sulphate of soda and carbonate of soda, I obtain artificial
sulphuret of manganese by any well-known means, such as decomposing
sulphate of manganese by heating it in mixture with small coal, but I prefer
to obtain this artificial sulphuret by the means herein-after described.
ascertain the proportionate quantities of manganese and sulphur which this
sulphuret contains, and if the proportion of manganese contained therein is not
equal to three times that of the sulphur, I add thereto such a quantity of oxide
of manganese in powder as will make up the deficiency of manganese; I then
add conimon salt in powder, in the proportion of two parts of common salt for
one part of sulphour contained in the mixture of sulphuret and oxide employed;
I

page_text: and I operate with this mixture in the same manner as I have herein-before
described for operating with a similar mixture of common salt with artificial
sulphuret of iron and oxide of iron, and I thereby obtain sulphate of soda in
mixture with oxide of manganese; and I decompose this mixture of sulphate
of soda and oxide of manganese by the same means which I have herein-before
described for decomposing a similar mixture of sulphate of soda and oxide of
iron, and I thereby obtain carbonate of soda and artificial sulphuret of man-
ganese, in mixture with oxide of manganese, which latter compounds are
suitable to be used for decomposing another portion of common salt, and
producing a further quantity of sulphate of soda and oxide of manganese. I
make up the loss of sulphur which occurs in this repetition of processes with
compounds of manganese by exposing a mixture of common salt and oxide
of manganese to sulphurous acid gas and atmospheric air, and thereby
obtain sulphate of soda in the same manner as I have herein-before described
for obtaining sulphate of soda, by exposing a mixture of common salt and
oxide of iron to sulphurous acid gas and atmospheric air.
I am aware that Letters Patent have been granted to William Longmaid,
formerly of Plymouth, in the County of Devon, for bis Inventions connected
with the manufacture of sulphate of soda, carbonate of soda, and chlorine, in
the Specifications of which. Inventions the said William Longmaid claims to
manufacture sulphate of soda and chlorine by decomposing common salt in
mixture with iron pyrites, or other native sulphurous ores, and it will be well
understood that the said William Longmaid must require to purchase a fresh
portion of iron pyrites, or other native sulphurous ores, for decomposing each
portion of common salt from which he may obtain sulphate of soda and
chlorine. The said William Longmaid has also claimed to manufacture
carbonate of soda by fluxing the mixture of sulphate of soda and oxide of iron
(which he obtains by the use of iron pyrites, or other native sulphurous ores
and common salt,) in mixture with coal, and thereby saving the expense of
lime, which is commonly employed in manufacturing carbonate of soda
from sulphate of soda. I would, therefore, have it understood that my Inven
tion does not relate to the use of iron pyrites, or other native sulphurous ores,
for decomposing common salt in mixture therewith, nor does it relate to the
use of such oxide of iron as is produced by the decomposition of common salt
by means of iron pyrites or other native sulphurous ores for decomposing
sulphate of soda.
I have herein-before described certain apparatus which I have found to be
suitable for effecting the objects of my Invention, but I do not confine myself
to the use of such apparatus, as these may be modified to a great extent, and

page_text: yet be suitable for such purpose. I have also described certain proportions in
which I use certain materials in effecting the objects of my Invention,
and 1 have herein stated certain details of the manner in which I prefer
to use such materials for such purpose, but I do not restrict myself to use
these materials in the exact proportions, or according to the precise details
berein-before mentioned, as these may be varied to a considerable extent without
deviating from the nature of my Invention, which Invention consists in obtaining
iron from iron slags, granulated, as hercin-before mentioned, by cementing
such granulated slags in mixture with small coal, so as to reduce oxide of iron
contained therein to metallic iron, as herein-before described; also consists in
obtaining copper and tin, or one of these metals, from copper slags, granulated
or crushed as herein-before mentioned, by treating such granulated or crushed
copper slags with sulphurizing or deoxidizing compounds, as herein-before
described; also consists in obtaining sulphate of soda from cominon salt by the
use of artificial sulphuret of iron or artificial sulphuret of manganese, to-
gether with atmospheric air, or by the use of oxide of iron or oxide of
manganese and sulphurous acid gas, together with atmospheric air, as herein-
before described; also consists in obtaining carbonate of soda by decomposing
such sulphate of soda (so obtained) by the use of oxide of iron or oxide of
manganese, in such manner as to produce artificial sulphuret of iron, or artificial
sulphuret of manganese, together with such carbonate of soda, as herein-
before described.
In witness whereof, I, the said William Hunt, have hereunto set my
hand and seal, this Twenty-second day of December, in the year of
our Lord One thousand eight hundred and forty-eight.