IMPROVEMENTS IN THE MANUFACTURE OF ALUMINA
Year: 1859

page_text: LETTERS PATENT to William Edward Newton, of the Office for Patents,
66, Chancery Lane, in the County of Middlesex, Civil Engineer, for the
Invention of "IMPROVEMENTS IN THE MANUFACTURE OF ALUMINA."-A com-
munication from abroad by Mr. Le Chatelier, of Paris.
Sealed the 29th September 1859, and dated the 16th April 1859.
PROVISIONAL SPECIFICATION left by the said William Edward Newton
at the Office of the Commissioners of Patents, with his Petition, on the
16th April 1859.
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 MANUFACTURE OF ALUMINA," to be
as follows:-
This Invention has for its object various manufacturing or industrial pro-
cesses to be employed for precipitating alumina (either pure or in combination
with other substances) from its solutions in alkalies in the state of aluminate
of soda or potash. This combination of the alumina precipitated with foreign
substances may take place either with matters introduced in the process of
manufacture of the alumina, and of no known utility, without inconvenience
for the ulterior applications of the alumina, or with matters useful for the

page_text: ulterior applications of the alumina, or the incorporation of which with the
precipitated alumina already constitutes a useful application.
The precipitation of the alumina may be effected, 1st, by the action of
carbonic acid gas upon a solution of alkaline aluminate, either in a horizontal
cylinder provided with an agitator, and which brings the liquid into a fine
state of division, the gas and the solution moving either in the same or in a
contrary direction, or in a tower arranged in such a manner as to divide the
solution as it falls from step to step, and multiply the points of contact. 2nd,
by treating the alkaline aluminate with bicarbonate of soda, the carbonic acid
of which in excess saturates the soda, and sets the alumina free. 3rd, by
treating the alkaline aluminate with carbonate or bicarbonate of ammonia.
4th, by the formation of an aluminate supersaturated with alumina, and the
spontaneous separation of a portion of the alumina by settling. 5th, by the
treatment of the alkaline aluminate with an acid employed in quantity
equivalent to the soda of the aluminate, and more especially muriatic (hydro-
chloric acid, as this aluminate may be employed for the condensation of the
last vapors of muriatic acid in the manufacture of that acid. 6th, by the
treatment of the alkaline carbonate in solution by a solution of hydro-chlorate
of ammonia, or of chloride of calcium, &c. 7th, by the treatment of the
alkaline aluminate in solution with chloride of aluminium, the result being
the double precipitation of the alumina of the aluminate, and also that of the
chloride. 8th, by the treatment of the alkaline aluminate by a metallic
salt, and particularly chlorides, and the precipitation of the metallic oxide
intimately combined with the alumina, and forming metallic lakes in variable
proportions, according to whether the metallic salt contains a greater or less
proportion of free acid, or whether the aluminate be more or less alkaline, or
mixed with a greater or less excess of caustic or carbonated alkali. 9th, by
the employment of any other substances having the property of precipitating
alumina from its solutions in alkalies. Before precipitating the alumina from
the alkaline aluminates by one of the above-mentioned processes, there may
be mixed with the solution of alkaline aluminate organic or inorganic matters
soluble or rendered soluble, not having by themselves the property of pre-
cipitating the alumina, but capable of being precipitated with it. Lakes will
also be produced by this means more advantageously than by the processes
now in use. These reactions having for their object to precipitate the alumina
combined with coloring or other matters, may be varied in many different
ways, according to whether it be desired to prepare matters reserved for
ulterior use, or to precipitate the alumina upon the articles or substances in
the preparation of which it is to be employed.

page_text: The alumina may be found to contain a small quantity of iron, arising in
certain cases from superoxidation, and in others from the sulphuration of the
ferruginous parts of the ore submitted to the action of the alkalies. In order
to remedy this evil, carbon or charcoal may be introduced into the compounds
in suitable quantity to prevent the super-oxidation, or the deposit of sulphuret
of iron, which is held in solution by sulphuret of sodium, may be facilitated by
decomposing this latter by means of carbonic acid, or by chlorine, &c. The
alumina having been precipitated together with some traces of iron, may, after
having been stoved or calcined, be again taken up by an alkali, and again
precipitated from the aluminate after filtration. In any case the employment
of water charged with ferruginous salts and organic matters should be avoided
as much as possible.
'
The alumina precipitated by carbonic acid contains a certain quantity of
carbonate of soda, and which is too intimately combined with it to admit of
its being separated by repeated washings. In general the presence of this
soda will not be attended with inconvenience; it may, however, be separated
by the addition of a small excess of muriatic or nitric acid, assisted by the
application of heat, or recourse may be had to digestion with chloride of
aluminium in excess.
"
The washing of the alumina obtained by any of the processes above men-
tioned must be effected by decantation at first, when the liquor is sufficiently
dilute, and the precipitate can be easily agglomerated; then, by filtration, by
means of centrifugal force, or by a vacuum; the liquid may then be finally
pressed out by means of an bydraulic press.
The alumina obtained by the above processes may be applied to various
useful purposes in the arts, among others, to the manufacture of aluminium ;
the acetate, sulphate, and salts of alumina generally; the manufacture of
artificial emery; the preparation of paper pulp; the manufacture of refractory.
or colored porcelains; the production of paintings upon porcelain and glass;
painting in general; the printing and dyeing of fabrics; the manufacture of
refractory crucibles or melting pots for the melting of steel; and for other
purposes generally, where great resistance to the action of fire is required.

page_text: 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 15th October 1859.
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 Sixteenth day of April, in the year of our Lord
One thousand eight hundred and fifty-nine, in the twenty-second 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
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
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF ALUMINA," being a com-
munication from Mr. Le Chatelier, of Paris, 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 manufacture of alumina has for its
object various manufacturing or industrial processes, to be employed for
precipitating alumina, either pure or in combination with other substances,
from its solutions in alkalies, in the state of aluminate of soda or potash.
This combination of the alumina, precipitated with foreign substances, may,
without inconvenience for the ulterior applications of the alumina, take place
either with matters introduced in the process of manufacture of the alumina,
and of no known utility, or with matters useful for the ulterior applications of
the alumina, or the incorporation of which with the precipitated alumina

page_text: already constitutes a useful application. The most direct process for
precipitating alumina from its solutions in alkalies, such as aluminate of
potassa or of soda, is by means of carbonic acid. The contact of this gas with
the alkaline aluminates in solution will effect their decomposition, carbonate
of soda being formed, and the alumina precipitated abundantly in the form of
a jelly, which is separated by decantation and by filtration, either on the
centrifugal principle in a "turbine," or in vacuo. In the latter case, the
gelatinous matter is laid on a filter, the bottom of which is made to
communicate either with an air-pump, such as those used on atmospheric
railways, or with a vessel, into which is introduced a jet of steam, which is to
be afterwards condensed. This vessel may be made either in the same
manner as a steam engine condenser, or it may be similar to the apparatus
employed for boiling syrup in vacuo, or according to other known processes.
It will be found advantageous to introduce the jet of steam under the
filter itself, and not in a separate vessel, the steam being introduced at a high
pressure, so as to be forced through the gelatinous, alumina, which requires
filtering, or has been already filtered. The alumina (together with the fluids
which it contains) being thus exposed to the action of steam and heat, it
becomes contracted and the filtration, which begins when the vacuum is
produced, is thereby facilitated. This mode of filtration is applicable to the
precipitate of alumina obtained by means of carbonic acid gas, as well as to
other precipitates obtained during the processes hereafter described. When
the alumina has been precipitated by the carbonic acid, a certain quantity of
soda is combined with it, which cannot be removed by repeated washings.
This inconvenience, however, may be avoided by indirect, although practical
means, and the alumina thus obtained free from soda (or potassa). For this
purpose the carbonic acid gas, which is to saturate the soda contained in the
aluminate, is made to combine with some substance, which will prevent
its affinity for alumina, and at the same time allow of its action on the alkali.
The bicarbonate of soda (or potassa) will have this double effect; and, there
fore, it is sufficient to use the carbonic acid gas which has been previously
employed for producing bicarbonate of soda (or potassa), according to the
processes already known, and to cause this bicarbonate to digest with the
alkaline aluminate dissolved in the requisite quantity of water, in order
to avoid the formation of the liquid into a mass by the production of gelatinous
alumina. The alumina is thus mixed with a double quantity of carbonate of
soda, so that when the operation has been started, the first liquors obtained
by filtration may be employed for the production of crystallized carbonate of
soda; and the other liquors added to the water used for washing may form a

page_text: solution of alkaline bicarbonate, mixed or unmixed with some precipitated
bicarbonate, according to the degree of saturation. This solution is made to
digest with the alkaline aluminate, already more or less concentrated.
In this process bicarbonate of ammonia may be used in place of the bi-
carbonates of soda or potassa; but the neutral carbonate of ammonia has the
same action, for ammonia does not combine with alumina, and is set at
liberty. The whole of the carbonic acid contained in the bicarbonate of
ammonia will, therefore, be disengaged, and brought into action; whereas the
bicarbonates of soda and potassa only part with half their carbonic acid. For
reactions, which take place at ordinary temperatures between liquid matters,
no special apparatus is required; some wooden or metallic troughs, a
few wooden or iron rakes of the simplest shape, and, if needed, some
mechanical stirrer or agitator, either moveable or steadily fixed, will be
sufficient, with a little attention, for this purpose. The engineer will apply his
skill to combine the troughs, so as to facilitate the operations of dissolution,
decantation, filtration, &c., as in other similar departments of industry. The
small affinity of soda for alumina gives place to some simple reactions, which
may be turned to useful account by the Inventor, according to the locality in
which the manufacture of alumina is carried on, the purpose to which it is to
be applied, and other circumstances. By the perfect saturation with acids of
soda or potassa, combined with alumina, the alumina is precipitated with great
perfection, and the reaction thus produced becomes a new process in industry,
which may be useful in some cases; thus the aluminate of soda, exposed
to the contact of the last vapours of sulphuric, muriatic, nitric, or other acids,
which are incompletely condensed in the usual apparatuses, may be the means
of completing this condensation, and at the same time of obtaining either
alumina or salts of alumina, if the saturation be carried still further. In
order to render this condensing operation as complete as possible, the stirring
apparatus which has been recommended for the carbonic acid may be used.
Acids too dilute and useless for other purposes could likewise be thus made
useful. The hydroclorate of ammonia easily decomposes the alkaline alumi-
nates, ammonia being set free, and alumina precipitated as pure as in
the former case. This reaction, used in laboratories, has no very useful
application in the arts, but it leads to very important processes, which
are, it may be said, the chief object of the present Invention. Alumina
being insoluble and very easily precipitated, it might be imagined that
the alkaline aluminates, in the presence of earthy or metallic salts which
have insoluble bases or give insoluble combinations with alumina, would
behave according to the principle of double decomposition, and part

page_text: with their alumina. This the Inventor has ascertained to be the fact by
a simple and curious experiment. Acting with two solutions, one of
chloride of aluminium, and the other of aluminate of soda, in which the pro-
portions of sodium and chlorine are equivalent, the whole of the alumina is
precipitated, and common salt only remains in the liquor. The alumina thus
obtained is flaky and easily washed. This reaction is not only instructive, but
leads to some very important and practical applications. It may be used for
preparing alumina by means of the chloride of aluminium, or other salts,
obtained by the condensation of acids, and better still, by means of the chloride
of aluminium supplied directly by the ore from "Les Baux," upon which the
Inventor has grounded his previous Patent for the preparation of alkaline
aluminates.
This ore on being made to digest (at a temperature which may not exceed
50 or 60° centigrade) with commercial bydrochloric acid, gives up its oxide of
iron, then a large portion of alumina, which immediately dissolves. By
decanting and evaporating the solution until it is brought to a syrup-like
consistence, and then cooling, an irregular crystalline mass is formed, consist-
ing of hydrated chloride of aluminium impregnated with perchloride of iron.
This mass is drained dry in a funnel-shaped vessel, the neck of which is closed
by some spongy substance, such as asbestos, cotton, sand, &c., the liquid
perchloride of iron is separated, and the perchloride which remains adherent,
imbibes moisture from the open air, and runs through also. After some little
time there is nothing left but hydrated chloride of aluminium almost pure,
which may be removed by washing with a saturated solution of purified
chloride of aluminium, or it may be dissolved and purified by the yellow
prussiate of potash, or by other suitable, means. The hydrated chloride of
aluminium thus obtained may be used for decomposing the aluminates, or like
the chloride prepared at once from artificial alumina and hydrochloric acid, it
might be applied to any industrial purpose for which it might be suitable.
The alumina may be also extracted from the chloride by precipitation, by
means of caustic or carbonated soda or potassa without excess or by ammonia,
lime, or carbonate of lime, &c. It may also serve for the preparation of
metallic aluminates, as will be hereafter explained. The Inventor considers
this preparation of the chloride of aluminium, by the direct action of hydro-
chloric acid upon a natural mineral substance, as a peculiar feature of his
process.
The alkaline aluminates may be decomposed by the soluble salts of lime,
magnesia, or baryta, the base of which will precipitate itself in intimate com-
bination or mixture with alumina, the mixture being homogeneous. This

page_text: reaction may be turned to account for preparing clay for the manufacture of
pottery and earthenware.
The reaction of magnesian salts may be adapted to the extraction of
alkaline bromides from the brine waters of salt lakes or salt springs. Thus
the mother waters of the salt lakes in the South of France, after the 5
the extraction therefrom of certain salts by M. Balard's processes, will be
composed as follows :—
By mixing this solution with a solution of aluminate of soda containing a
quantity of soda, combined or mixed, but equivalent to the acids combined
with the magnesia, the latter base will be entirely precipitated with the
alumina, and the solution of chloride of sodium, of sulphate of soda, and of
bromide of sodium thus obtained, will by successive evaporations furnish a
salt very rich in bromine. The aluminate of magnesia on being again treated
with a weak acid will give up its alumina in a state more or less pure; or if
this matter had no immediate use, it could be converted into alumina orc, and
treated for the preparation of aluminates by the carbonate of soda or by any
other suitable process.
The above details show to what various purposes the aluminates may be
applied; it would hardly be possible to specify all the various purposes, but
they are consequent on the industrial preparation of alkaline aluminates, and
also on their easy decomposition by the weakest acids, and the ammoniacal
earthy and metallic salts. The reaction of metallic salts upon the alkaline
aluminates is exactly the same as the reaction of salts of alumina, with this
difference, that instead of obtaining the alumina pure, or merely containing
traces of iron if the reagents contained any, the alumina is combined or
intmately and homogeneously mixed with various metallic oxides. These
mtallic aluminates or lakes are in fact but one of the forms in which alumina
my be precipitated from alkaline aluminates; they may besides be made to
dier from pure alumina in their composition as much as required, without
ar alteration in the process, and by mere changes in the composition of the
regents used. If, for instance, an aluminate of soda saturated with alumina,
a holding no caustic or carbonated soda, is treated by a chloride of iron, to

page_text: which has been added a large quantity of acid, or which is mixed with a
solution of some salt of alumina, such as the chloride of aluminium, the pro-
portions of the mixture being such that the soda saturates exactly the acid
combined with the iron or the alumina and the free acid, then alumina will
considerably predominate in the mixture, and the lake will be very slightly
colored, even to the extent that the alumina may be but slightly tinged by
the oxide of iron; on the contrary, with neutral chloride of iron and a
strongly alkaline aluminate of soda, an oxide of iron may be obtained more or
less pure, but intimately mixed with alumina; or if alumina be considered as
combined in the precipitate, an intimate mixture of aluminate of iron and of
oxide of the same will be obtained. These lakes, thus obtained according to
a regular and predetermined formula, may be dried or calcined after filtration
and washing, and converted into an important article of commerce.
With some organic matters, precipitates of alumina or organic lakes may
be obtained either by reacting upon alkaline aluminates with organic matters
of any kind, but having the property of disengaging alumina and uniting with
it in its insoluble state, or by mixing unprecipitating organic matters in
solution with alkaline aluminates, and precipitating the alumina by one of the
processes above specified. These matters might be particularly useful as
dyeing matters. If the precipitation is effected by a liquid acid, in some
cases the matter which precipitates with alumina in order to form a lake may
be combined with this acid; or with an earthy salt such as the choloride of
aluminium or the chloride of calcium, and even in some cases with a metallic
salt, the matter or the matters, if there were several of them to be precipitated
at the same time, may be dissolved simultaneously in the alumina and in the
precipitating substance. Lakes may also be prepared by themselves when
they are to be sold as articles of commerce or employed in manufactures, but
they may, as well as the disengaged alumina, be precipitated on the substances
or materials which they are to impregnate, either by immersing these matters
in successive baths, or by immersing them in one single bath and exposing
them afterwards to the action of an atmosphere containing carbonic acid, or
to an artificial current of carbonic acid gas. The alumina may be purified
either previously to or after its preparation; the substances from which it is
chiefly to be freed are, the alkali which has been used for preparing the
alumina, and the oxide of iron. With regard to the alkalies, if there is any
need to remove them from the alumina as completely as possible, the best
process is that which prevents them from forming, and consists in avoiding the
use of free carbonic acid, and adopting the methods above described; the
precipitate of alumina will be washed and separated repeatedly from the

page_text: imbibing water by submitting it to the action either of a turbine or of a filter
in vacuo, and it might be finally submitted to the action of an hydraulic press.
These operations are to take place at the ordinary temperature if the alumina
is to possess again the property of being easily dissolved in weak acids. The
alumina having been precipitated by carbonic acid, and containing soda or
potassa, may be purified by various processes. When calcined at a moderate
temperature, its combination with the carbonic acid and the alkali is destroyed,
and the alkaline aluminate thus formed may be separated by washing; the
resulting alumina is pure, but insoluble in weak acids. By adding to the
alumina a small excess, with regard to the alkali, of muriatic or some other
acid, or by adding chloride of aluminium or some other salt of soda, and
leaving the mixture to digest, the purification will be more or less complete;
however, by calcining it, the alkali will combine with greater certainty without
any aluminate of soda being re-formed. This last method is well adapted to
alumina required for manufacturing aluminium, and if proper care has been
taken with regard to the hydrochloric acid being in excess, the resulting
alumina will be porous and well suited to the preparation of the double
chloride of aluminium and sodium, which it is unnecessary to wash, as common
salt must be afterwards added to it.
When the presence of iron is to be avoided, the means of purification may
be likewise preventive, especially when the ore from "Les Baux" has been
calcined with carbonate of soda, or when any similar treatment has been
followed. By introducing a small quantity of charcoal into the mixture, in
order to prevent the superoxidation of iron, and the formation of an alkaline
ferrate, this evil is avoided. If the solution of alkaline aluminate contains iron,
and if this iron is in the state of a ferrate, it might be attempted by means
of carbonic acid or any other acid to form a partial precipitate of alumina,
which would bring it down. If the iron which it contains is a sulphuret,
it might be superoxidized by means of chlorine. Whenever precipitated
alumina contains oxide of iron, the gelatinous precipitate may be taken up
again by a caustic alkaline solution, but it would be preferable to previously
calcine it, and treat it with caustic alkali brought down to a state of concen-
tration which would ensure success upon attaining a syrup-like consistence.
Lastly, the alumina may be dissolved in an acid, more especially bydro-
chloric acid, and the iron precipitated from the solution by the yellow prussiate
of potassa, by sulphuretted hydrogen, or by an alkaline sulphuret. The solu-
tion, when clear, after decantation or filtration is to be evaporated, and the
residue calcined or precipitated by an alkali or lime.
An indirect process, but which ensures the production of alumina free from

page_text: iron, consists in treating the ore from "Les Baux" with bydrochloric acid, as
the Inventor stated in his Letters Patent of the 1st September 1858, and
instead of considering the residue as alumina more or less pure, in treating it
in the same way as alumina ore with carbonate of soda, or caustic soda free
from iron.
The ore from "Les Baux," specified by the Inventor as one of the chief
sources for the manufacturing of aluminium, contains a certain proportion of
vanadium. If this metal, which forms an alkaline vanadate mixed with the
aluminate, is to be extracted, it will be convenient to use as a reagent for
precipitating alumina, sulphuretted hydrogen produced in any convenient
manner which will act like carbonic acid, or any acid whatever. This method,
which cannot generally be very profitable, becomes in this case an industrial
process for manufacturing alumina, which the Inventor includes in his Speci-
fication. This process might also be made the means of obtaining the
sulphuretted hydrogen combined in mixtures with other gases by decomposing
the sulphuret of sodium with carbonic acid or any other acid.
Having now described the Invention of improvements in the manufacture
of alumina, as communicated to me by my foreign correspondent, and having
explained the manner of carrying the same into effect, I claim as the Invention
secured to me by Letters Patent, the mode or modes herein described of
obtaining alumina, either pure or in combination with other substances from
its solutions in alkalies.
In witness whereof, I, the said William Edward Newton, have hereunto
set my hand and seal, this Fifteenth day of October, in the year
of our Lord One thousand eight hundred and fifty-nine.
Witness,
J. W. MOFFATT,
66, Chancery Lane.
W. E. NEWTON. (L.S.)