IMPROVEMENTS IN THE PRODUCTION OF ALUMINA AND SALTS OF ALUMINA
Year: 1860

page_text: PROVISIONAL SPECIFICATION left by the said William Edward Newton
at the Office of the Commissioners of Patents, with his Petition, on
the 30th October 1860.
I, WILLIAM EDWARD NEWTON,
of the Office for Patents, 66, Chancery Lane,
in the County of Middlesex, Civil Engineer, do hereby declare the nature of
the said Invention for IMPROVEMENTS IN THE PRODUCTION OF ALUMINA AND SALTS
OF ALUMINA," to be as follows:-
The principle upon which the author of the present Invention bases his new
processes consists in employing a mode of precipitation, which at the same
time that it produces alumina by means of substances which are abundant in
nature, or in the arts, gives another substance, which possesses a value sufficient
to pay at least a part of the expense of manufacture. It also employs the
sulphate of alumina in a state of solution or pasty state, without the necessity of
bringing it into a solid state, which latter requirement contributes considerably
to enhance the cost of alumina as at present produced.
In carrying out the present Invention three principal reagents are employed,
[Pric

page_text: namely, 1st, magnesia, which when operating by direct precipitation gives
sulphate of magnesia; 2nd, sea salt or chloride of sodium, which mixed in
solution with sulphate of alumina and subjected to a low temperature gives
crystallized sulphate of soda and a solution of chloride of aluminium; 3rd,
sulphate of barytes, which converted into sulphuret of barium, then into
chloride of barium, gives by double decomposition sulphate of barytes and
chloride of aluminium. In the two latter cases the chloride of aluminium
having been prepared, the alumina may be separated by calcination, by pre-
cipitation, by means of caustic or carbonated lime, magnesia, or barytes, or
by an alkaline or earthy sulphuret. In the latter of these two cases the
chloride of aluminium is mixed with a solution of sulphuret of barium, and
it will take up a sufficiency of chloride of barium for the precipitation of the
sulphuric acid, the alumina is precipitated and the sulphuretted hydrogen is
disengaged. The 3rd process will serve to complete the separation of the
sulphuric acid, when the 2nd process shall not have done so effectually. The
iron may be separated either in the solution of sulphate of alumina, or in the
solution of chloride of aluminium by any of the known means, especially by
the use of prussiate of potass either after the precipitation of the alumina, if
this latter is intended to be calcined by the action of hydrochloric acid gas;
for these different purifications the author of the present Invention reserves 10
himself the right of using any of the processes specified in his former Patents.
When the alumina is to be employed in the state of a salt recourse should
be had to the second or third process, and the operation should be arrested at
the proper point.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Edward Newton in the Great Seal Patent Office on
the 30th April 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane, in the County
of Middlesex, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirtieth day of October, in the year of our
Lord One thousand eight hundred and sixty, in the twenty-fourth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said William Edward Newton, Her special license that I, the said
William Edward Newton, my executors, administrators, and assigns, or such

page_text: others as I, the said William Edward Newton, 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 Inven-
tion for "IMPROVEMENTS IN THE PRODUCTION OF ALUMINA AND SALTS OF ALUMINA,'
being a communication from Mr. Louis de Chatelier, Engineer, of Paris, in the
Empire of France, upon the condition, amongst others, that I, the said William
Edward Newton, by an instrument in writing under my hand and seal, 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 William Edward Newton, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and by
the following statement (that is to say):-
This Invention of "Improvements in the Production of Alumina and Salts
of Alumina," as communicated to me by my foreign correspondent, relates to
the production of alumina either alone or in combination with other substances
in the form of salts, which are nothing more than the various forms under
which this useful substance may be employed in the arts. The Invention has
for its object the application (for this production of alumina or its salts) of the
sulphates of alumina either direct or by applying them to the production of
a kind of artificial ore of alumina or by the help of the natural ores, which are
perfectly analogous to the artificial ores, both as regards their composition and
mode of treatment. The sulphates of alumina employed may be the result of
the action of sulphuric acid upon argils, kaolins, or other aluminous sub-
stances, and may be in this case more or less mixed with sulphate of iron,
esepcially if they be prepared with the ores or argils from Les Baux, of which
the Inventor has already claimed their application for the extraction of alumina.
The sulphates of alumina may be produced by the spontaneous or artificial
combustion of certain pyritous earths containing iron pyrites in combination
with lignite or other combustible matter by the combustion of certain pyritous
schists or other substances, which furnish by lixiviation a mixture of sulphate
of alumina and sulphate of iron. The sulphates of alumina may be all found
in nature or may come from any other source, or especially they may be found
in combination with sulphate of potash in alum or alunite.
Three principal agents may be employed for the direct extraction of alumina.

page_text: For sulphates of alumina.
These agents are magnesia, baryta, and sea salt or
common salt, which is in England dug out of the bowels of the earth in the
form of rock salt. The employment of these agents is combined in such
manner as to obtain an an accessory product, matters useful or susceptible of
being utilized if it be thought desirable to collect them, and which may
eventually economize the cost of manufacture.
First, magnesia may be employed either in a caustic state, in which state it
may be obtained at a cheap rate by the decomposition of chloride of mag-
nesium, which is produced by the treatment of the mother waters of salt
swamps existing in the southern part of the Continent, or in any other manner.
or in the state of carbonate when it is possible to collect this substance from
beds in nature. The sulphate of alumina, either pure or ferruginous, neutral,
or acid in the state of solution, and as obtained directly from the treatment of
argils by sulphuric acid or the lixiviation of burnt aluminous earths or schists
is brought into the presence of a quantity of magnesia equivalent to the sul-
phuric acid, either free or combined with oxide of iron; it is stirred to effect
more intimate combination, and if required, it may be heated in order to
facilitate the operation. A deposite of alumina, more or less mixed with oxide
of iron, is obtained, which is separated by decantation, and filtered either upon
ordinary filters or upon a vacuum filter, or in a turbine, of which apparatus
the Inventor has already specified the application to similar operations. The
sulphate of magnesia in solution may be concentrated by evaporation, and
collected more or less completely by successive crystallisations. In most cases
the alumina precipitated will be mixed with oxide of iron, and will constitute
an ore pure and easy of treatment by the application of the processes already
patented by the Inventor. The principal of which consists in forming an
aluminate of soda, and afterwards extracting therefrom the alumina, if necessary,
or any other known substance having alumina for its base.
Second, bartya may be employed in some cases in the same way as
magnesia, by the use of a certain mode of manufacture. Carbonate of baryta
is found in abundance in the native state in the United Kingdom. After
having been pulverized it is digested with the solutions of sulphate of alumina
to be treated in quantity equivalent to the sulphuric acid to be saturated. By
this means will be produced at the same time a precipitate of baryta, which
will form with a facility angmenting with the dilution and temperature of the
liquor a precipitate of alumina or of alumina, and peroxide of iron will be ob-
tained in the form of a gelatinous precipitate floating on the top of the sulphate
of baryta, and capable of being perfectly separated therefrom by successive
decantations. This will be also a method of preparing an artificial ore of

page_text: alumina applicable to the preparation of aluminate of soda or any other
aluminous products. The natural carbonate and sulphate of baryta previously
converted into sulphate of barium by known processes, may be employed to
prepare solutions of chloride of barium or any other soluble salt of baryta.
This solution mixed in equivalent proportions with lixivium of sulphate of
alumina, either pure or ferruginous, furnishes by double decomposition a pre-
cipitate of sulphate of baryta and chloride of aluminium more or less mixed
with chloride of iron. The solution, when the deposit of sulphate of baryta is
complete may be saturated, if it be necessary, to neutralize it with alumina
already prepared and remaining in the state of hydrate, either by carbonate of
baryta or lime. If there be only a moderate quantity of oxide of iron in solution,
it may be separated by yellow prussiate of potash, or any other other equivalent
reagent. In this case a solution of chloride of aluminium will be obtained free
from iron, which will constitute one of the forms under which alumina may be
employed in the arts for dyeing, paper staining, and other processes. This
solution when evaporated to dryness will give by the calcination of the
residuum dry and porous alumina, which may be employed for various pur-
poses, especially for the manufacture of aluminium. Alumina may also be
precipitated from the solution (if it be desired to obtain hydrated alumina)
by magnesia, lime, carbonate of line, carbonate of magnesia, double carbonate
of lime and magnesia, alkalies, alkaline or earthy sulphurets, and especially
the sulphuret of barium obtained by the decomposition of sulphate of baryta.
In this latter case there will be the advantage of regenerating the chloride of
barium necessary for a subsequent operation. In the case where very ferru-
ginous sulphate of alumina has been operated upon, the solution of chloride
may be concentrated, and most of the iron got rid of by the process which the
Inventor specified under his Patent of Sixteenth April, One thousand eight
hundred and fifty-nine; the case just specified is then resorted to; but the
alumina may be precipitated, together with the oxide of iron, either by means
of lime or the carbonate of lime, or by any other reagent. The chlorides
may be evaporated and decomposed by calcination at a red heat. In either
case an artificial ore of alumina will have been formed, as before, for the pre-
paration of aluminate of soda or other salt.
Third, common or sea salt is the most important agent from its abundance
and cheapness. It application to the production of alumina and salts of
alumina is based upon the difference of the relative solubility of the salts at
different temperatures.
A solution of sulphate of alumina, either pure or
ferruginous, neutralized, if necessary, by lime, baryta, soda, or alumina itself
arising from a previous operation, is mixed with a solution of marine salt

page_text: The mixture on being allowed to cool at the natural temperature in shallow
vessels or submitted to artificial cooling at a temperature less than or little
above the freezing point of water, will deposit a large quantity of crystallized
sulphate of soda. In order to render the operation more complete and
diminish the volume of the solutions to be evaporated subsequently, the sea
salt intended to act as a reagent may be dissolved directly in the hot lixivium
of sulphate of alumina, and a primary deposit of sulphate of soda obtained by
cooling down to about fifteen degrees centigrade. The operation may then be
completed by cooling down to the temperature of the formation of ice or below
it. The reaction will be facilitated by adding an excess of marine salt so
long as this excess shall not prove injurious to the operation or to ulterior
applications.
Sulphate of soda will be obtained of very pure quality, and of very advan-
tageous application for many purposes, if it has been obtained from a not very
ferruginous sulphate of alumina, and a solution will result containing a large
quantity of chloride of aluminium, and also containing chloride of iron. sulphate
of alumina, or sulphate of soda and sea salt. The sulphuric acid may be got rid
of by precipitating it by means of chloride of barium, oxide of iron (if it be in
small quantity) or by prussiate of potash, and the final product will be chloride
of aluminium free from iron and sulphate of alumina mixed only with sea salt.
The solution may be employed direct for certain purposes, after having been, if
requisite, concentrated; it will by evaporation and calcination of the residuum
furnish anhydrous alumina mixed with sea salt, which latter substance may be
easily removed by simple washings. Advantage may also be taken of the property
of crystallization possessed by hydrated chloride of aluminium, especially if
iron be present in pretty large quantity, the chloride of iron and sulphate of
alumina remaining in the mother water.
Lastly, the solution may be evaporated to dryness, and the residuum calcined
without taking the trouble to separate the iron and sulphate of alumina; this
latter will be decomposed by the heat, either alone or in the presence of an
excess of sea salt, and there will finally remain, as in the preceding cases, a very
pure ore of alumina, fit for the manufacture of aluminate of soda, and its
compounds, or of any other aluminous product.
The Inventor under his first Patent specified a process which consists in
calcining a mixture of marine salt and sulphate of alumina more or less mixed
with sulphate of iron, and in submitting the residuum of the calcination to the
process invented by the French chemist Leblanc, to obtain aluminate of soda
directly. This process may be modified and subdivided into two distinci
operations. An intimate mixture of the sea salt and sulphate of alumina is

page_text: The
first calcined until the disengagement of hydrochloric acid has ceased; the
residuum is then submitted to a methodical lixiviation, and solutions of sulphate
of soda are obtained, which are first crystallized by cooling to the ordinary
temperature, and then by the application of natural or artificial cold.
residue of the lixiviation will constitute an ore of alumina, more or less ferru-
ginous, which may be applied to the preparation of aluminate of soda or other
compounds of alumina.
The mixtures of oxides of iron and alumina or artificial ores above-mentioned
may be especially employed by their treatment with muriatic acid (when too
strong a calcination has not rendered the alumina unattackable) for the pro-
duction of chloride of aluminium by crystallization.
The Inventor of the present improvements has insisted on the formation of
alumina and oxide of iron, which he has called artificial ores of alumina,
because the aluminate of soda (a substance which he has in his previous
Patents given the means of manufacturing) with matters which had not
hitherto been employed for this purpose, appears to be the form under which,
above all others, the new alumina will receive its principal industrial applica-*
tions, or will be sent into the market.
The artificial ore may also be obtained by calcination, and at an elevated
temperature from ferruginous sulphates of alumina, either direct or after
admixture with a small quantity of charcoal, which facilitates the decomposition
of the sulphuric acid. The Inventor has completed his geological researches
on the ores of Les Baux, and he has discovered that the principal varieties
were composed of alumina, peroxide of iron, and titanic acid with water, and
traces only of silica. This composition compared with the form assumed by
the ores when they appear in the midst of calcareous soils, leads to the sup-
position that they owe their origin to emanations of volatile chlorides, which
after having been dissolved in mineral springs, have been decomposed by the
carbonate of lime of the soil through which these springs rose. This formation
is perfectly similar to the production of the artificial ore obtained by the
precipitation of chlorides by carbonate of lime. The only difference is the
presence of titanic acid and silica, which enter into its composition in the
proportion of some hundredth parts only, and sometimes less than one hundredth
in the natural ore, and remain inert in the manufacture.
Whether the mixture of oxide of iron and alumina be natural or artificial,
the mode of treatment is the same as regards the production of aluminate of
soda, alumina, and its compounds. The Inventor has indicated several pro-
cesses for effecting this object, and although it may be observed that recourse
may be had, with advantage in many cases, for the treatment of the various

page_text: primary matters to the action of caustic soda lye (brought to the consistence
of syrup by evaporation) which attacks aluminous substances with remarkable
energy, the Inventor proposes here to specify in a more complete manner the
process which appears to him the most practical, and which best effects the
formation of a normal aluminate of soda capable of taking a form perfectly
suitable for purposes of commerce, and also to lay down the principle of various
other processes tending to the same end.
already in the state of
These matters are very
The artificial or natural ore is pulverized, (if not
powder), sifted, and mixed with soda ash of commerce.
intimately mixed in a dry state, then wetted, and again mixed into a paste. If
the mixture of oxide be gelatinous and damp, it is made into a pasic incor-
porating therewith the soda ash (a mixture of carbonate of soda, caustic soda,
with a small quantity of sulphate of soda and sea salt, as obtained in
manufactories by the evaporation of raw soda lye.) This mixture is introduced
into a very hot soda oven or furnace. This is continued to be heated, and occa-
sionally stirred with a rake, in order to turn the matter over and cause all parts
of the mass to pass successively near the fire-place. The state of the operation
may be ascertained from time to time by taking specimens from different parts
of the furnace, mixing them together, and after having diluted them with
water, ascertaining whether they do not give off carbonic acid, by this it is
known that the reaction is complete. The rough aluminate is taken from the
furnace and submitted to lixiviation, either by the processes ordinarily used for
the purpose, especially for raw soda, or in the vacuum filter which the Inventor
has described, and of which he has already specified several applications, several
vacuum filters set together would allow of a methodical lixiviation being
obtained by this process, which would furnish solutions of aluminate of soda of
very great strength. If the aluminate of soda be intended to be kept in a
liquid state, a lye must not be made of a higher degree of strength than from
seventeen degrees to eighteen degrees of Beaume's arcometer, more highly
concentrated liquors would allow alumina to be deposited on cooling, and the
aluminate would have a tendency to become caustic.
In order to produce dry aluminate diluted solutions may be employed after
some time, but it is advisable to use the concentrated liquors immediately.
The liquid aluminate is evaporated in a boiler or a pan of cast iron or other
metal, or in a reverberatory furnace with a bed of metal, or formed of iron,
siliceous matters, of raw ore, for example, stirring continually when the liquor
becomes viscous, in order to prevent it from rising and running over. It is
to be stirred briskly when the mass solidifies, which takes place when it still
contains about twenty per cent. of water, in order to prevent it from adhering

page_text: TO &C SIQES DI LIC
Vessel
THe
action of the rable to a granulated state is then thrown upon the bed
of an ordinary reverberatory furnace, where it is calcined at a bright red heat.
In this state it is anhydrous and nevertheless may be entirely redissolved in
pure water (that is to say), water free from carbonic acid and earthy salts.
It contains from forty-eight to fifty per cent. of alumina. In order to preserve
it, it must be kept from contact with the air; it is sent into the market in
In order to
barrels, either in a granulated state, or ground into powder.
obtain a perfectly neutral aluminate, and which may be easily preserved, the
ore must be put in excess into the mixture of ore and soda ash; the pro-
portions of each may vary considerably: a natural ore coming from the
environs of Toulon, in France, gives very satisfactory results. by heating
together eight hundred pounds of pulverized ore, and four hundred pounds
of soda ash, at ninety degrees centigrade. About nine hundred and thirty
pounds of raw aluminate, and five hundred and twenty pounds of pure and
'dry aluminate are obtained. This is however but an example given for
the completion of the details, relative to the production of the aluminate
of soda under the commercial form. The aluminate of soda obtained by
the action of caustic soda brought to a syrupy consistence may also after
lixiviation be brought to a day state, or, if necessary, in order to be more sure
of its attaining the normal composition, the caustic soda may be evaporated
to dryness upon the ore, and heat the vessel to redness. By this means,
a double guarantee of saturation is obtained. It will be understood that
all that has been stated with respect to aluminate of soda is equally applicable
to aluminate of potash, if it were required to manufacture this latter article.
The residuum of the lixiviation of raw aluminate, when artificial ore is
used, (in which case it will only be necessary to put in excess what will be
necessary to ensure the saturation of the soda), will be oxide of iron mixed
with a small quantity of alumina, which may be applied to various purposes,
especially after having calcined it, if requisite, as for polishing. In the case
of natural ore employed in considerable excess, washing may be proceeded
with for the purpose of separating the hydrated oxide of iron mixed with
a small quantity of alkaline silico aluminate, or titante of soda, and with
the finest portions of unattacked ore. This product of the washing may be
employed for various purposes, and particularly for the purification of illumi-
The residue of
nating gas, the decoloration of syrups, and other purposes.
the washing operation. formed of unattacked ore and its less fine particles.
may be again treated in the same manner as fresh ore, after having been
pulverized, if necessary, or it may after calcination at a high temperature

page_text: and for a length of time,
product), be used as artificial emery.
(ICSIT CAT Wimpyre are y
The Inventor includes in the present Invention various other processes
based upon the same principle as the calcination of the ore with the carbonate
of soda, and intended to furnish as the same principal product. aluminate
of soda (or potash).
First, the artificial or natural ore reduced to powder of greater or less
fineness. is to be intimately mixed with nitrate of soda, or nitrate of potash
of commerce, and calcined, either in reverberatory furnaces, or in closed vessels.
In this latter case the operation is precisely similar to that which was formerly
employed for the preparation of nitric acid by the calcination of a mixture
of argil and saltpetre, but the produce instead of being an alkaline silico
aluminate, which it was necessary to treat with sulphuric acid, in order to
utilize it will be an alkaline aluminate to be separated by lixiviation. The
nitrous vapours arising from the decomposition of the alkaline nitrate will
be condensed or may be conveyed into the leaden chambers used in the
manufacture of sulphuric acid.
Second, the artificial or natural ore is to be intimately mixed with sulphate
of soda, and the mixture calcined at a high temperature in a closed vessel.
or in a reverberatory furnace, either alone or with the addition of a certain
quantity of powdered wood charcoal, coal, or coke, the purest substance being
the best. In this latter case the charcoal will facilitate the reaction by
decomposing the sulphuric acid, in order to bring it into the state of
sulphurous acid, and the product will be greater; besides, if carbon be not
incorporated in a solid state with the mixture, it may be submitted to the
action of a reducing flame. If there be in the product of lixiviation double
sulphuret of sodium and of iron, this may be got rid of by leaving the lyc
exposed to the air during one or two days, or by passing through it a weak
current of carbonic acid, or chlorine, or by any other process, none of the
alumina or only a small portion thereof being precipitated.
In this process
as in all others, the natural or artificial ore calcined may be employed after
having been freed from the greater quantity of oxide of iron, which it may
contain for this purpose muriatic acid of commerce is employed in quantity
about equivalent to that of the oxide of iron, by digesting the mixture at
a temperature more or less elevated, or with muriatic acid diluted with water,
the action of which will be prolonged by raising the temperature.
A con-
venient mode of effecting this reaction consists in forming with the pulverized
ore with the addition of a suitable quantity of concentrated acid, a thick
paste which is dried in a reverberatory furnace gradually, and at the boiling

page_text: point of muuriatic acid, which is afterwards washed out. If the quantity of
oxide of iron, requires too much acid for the paste to possess sufficient
consistency, and for the operation to be effected at once, it is divided into
several operations. The different ores do not behave in the same manner
with muriatic acid. or with the other acids, which may in some cases be
substituted for it. All varieties are to be met with from certain kinds of
ores, from the locality of Les Beaux, which contain nearly twenty-five per
cent. of water of hydration to the natural emery of Naxos, and other sources.
which enters into the category of natural substances to which the processes
of the Inventor are applied, and which owes its properties to a natural
baking, or metamorphosis. By treating a certain ore experimentally the
proportions, state of concentration, temperature, and duration of the operation
most suitable for freeing that ore from the oxide of iron which it contains
may be ascertained. Generally there will be a certain quantity of alumina
dissolved. and the operator may in most cases vary the proportion of it at
pleasure, so that by evaporation to dryness and calcination of the chloride
of iron, serving to regenerate the muriatic acid employed, oxides of iron may
be obtained, proper amongst other uses, for making an excellent substance
for polishing hard bodies.
Third, lastly, the Inventor claims the application of a process which consists
in calcining in a closed vessel or a reverberatory furnace at a high tempera-
ture, and under the action of a current of steam (superheated, if desired.) an
intimate mixture of common salt with natural or artificial ore of alumina. By
this means, by taking the primary matters in the state in which they are found
in nature, and by the successive treatment of the intermediate products, hydro-
chloric acid, carbonate of soda, or any other salt of soda and alumina may be
obtained. The Inventor claims the substitution of potash and its salts for soda.
and its salts in all parts of the present Specification where this has not been
expressed. As has been already remarked, aluminate of soda constitutes the
most general form that can be taken by alumina, and expresses most simply
and completely the new manufacture of the Inventor. It may he employed
direct in the operation of dyeing, or in the preservation of organic matters.
By means of carbonic acid or other acids, ammoniacal salts and salts having
alumina for their base, pure hydrated alumina may be precipitated, and with
this latter may be prepared all the series of salts having alumina for their
base, or calcined alumina, fit for ceramic purposes, may be produced, or lakes
may be produced with any salts having metallic oxides for their base, and with
various organic substances: resinate of alumina necessary for the manufac-
ture of paper may be produced direct from it, either by mixing two solutions

page_text: the one of aluminate of soda and the other resinate of soda, and Saturating the
mixture with carbonic acid or any other acid. The resin may even be incorpo-
rated with the aluminate of soda by digesting this latter in the state of a hol
solution upon the resin, and precipitating the resinate of alumina, as in the
preceding case, either separately or in the paper pulp. This matter is so much
the more precious that when it is prepared with care it is obtained perfectly
free from iron, which is a considerable advantage for most of the applications of
alumina.
Colors produced upon fabrics by mordanting direct with aluminate of soda,
either alone or mixed with other reagents, have often a peculiar brightness,
and give peculiar tints which open a new field in the art of dyeing. The
aluminate of soda can, by modifying its action, be used as a mordant on various
dyeing stuffs by dipping the threads, worsted, or fabrics into liquors containing
acids, salts, or other reagents. Sulphate of alumina, which may be obtained
pure and neutral and rich in alumina to the extent of from 18 to 20 per cent.
imparts to colors a rare brightness and purity. Lastly, as crystallization is not
necessary for the separation of the iron, a true soda alum may be obtained by
the addition of a certain quantity of sulphate of soda, or an intermediate pro-
duct by merely saturating with sulphuric acid the two elements of aluminate of
soda. The production of the jellies of alumina necessary for printing upon
fabrics becomes by the employment of the aluminate of soda or its derivatives
as easy as it is advantageous.
The production of alkaline aluminates is also a general means for the puri-
fication of impure aluminas obtained from various primary matters, and
especially those produced from the purest sulphates of alumina, or for ren-
dering soluble calcined aluminas, which are insoluble in acids.
The aluminate is a kind of reservoir, from which the manufacturer will
obtain his alumina in the various forms required for his peculiar branch of
industry.
In witness whereof, I, the said William Edward Newton, have here-
unto set my hand and scal, the Twenty-seventh day of April, in the
year of our Lord One thousand eight hundred and sixty-one.
Witness,
J. W. MOFFATT,
66, Chancery Lane.