NEW PROCESS OF PREPARING CAUSTIC ALKALIES AND PREPARATIONS OF ALUMINA
Year: 1877

page_text: LETTERS PATENT to William Lloyd Wise, of Chandos Chambers, Adelphi, in
the County of Middlesex, for the Invention of "NEW PROCESS OF PREPARING
CAUSTIC ALKALIES AND PREPARATIONS OF ALUMINA." A communication from
abroad by Doctor F. Loewig, of Goldschmieden, near Deutschlissa, Silesia, and
Gustav Loewio of Dresden Saxon v.
PROVISIONAL SPECIFICATION left by the said William Lloyd Wise at the
Office of the Commissioners of Patents on the 20th April 1877.
WILLIAM LLOYD WISE, of Chandos Chambers, Adelphi, in the County of Mid-
dlesex. "NEW PROCESS OF PREPARING CAUSTIC ALKALIES AND PREPARATIONS OF
ALUMINA," A communication from abroad by Doctor F. Loewig, of Goldschmieden,
near Deutschlissa, Silesia, and Gustav Loewig, of Dresden, Saxony.
This Invention, communicated to me from abroad by Doctor F. Loewig, of Goldsch-
mieden, near Deutschlissa, Silesia, and Gustav Loewig, of Dresden, Saxony, has
reference to,
1. The preparing of caustic alkalies from natron of alumina (alumina soda
[Thonerde-natron]) in the main, as herein-after described.
2. The preparing of aluminates of lime barytum (baryta), strontium (strontia),
and magnesia from natron of alumina (alumina soda Thonerde-natron) in the main,
as herein-after described.
3. The preparing of hydrate of alumina from the aluminates last above
named.
My foreign correspondents describe the nature of their said Invention as
follows:-
To a concentrated waterish solution of potassa of alumina (alumina-potash), or
natron of alumina (alumina-soda), a thin pulp or paste either of lime, or of the
hydrates of strontium, barytium (barium), or magnesia (magnesium) is added,
assisted by the co-operation of heat until the fluid has become perfectly caustic,
and the entire alumina is precipitated.

page_text: The solution of the caustic alkali is obtained whilst a combination of 3 lime
(Ca O to 1 alumina (Al, O,) is separated off perfectly insoluble.
The separation of the solution from the precipitate is then brought about
mechanically.
The solution of the caustic potassa or natron (soda) is either brought to market
as such or as solid hydrate after evaporation.
After perfect ablution of the alumina lime (or respectively the combination of
alumina) with barytium (baryta), strontium (strontia), or magnesia, the same is
divided into two equal parts, whereupon one of the said parts is perfectly dissolved
in muriatic acid, to which solution the other part, after having been stirred to a
thin paste in water, is gradually added until a test by filtering shews that but
small traces of alumina remain in the solution. In this manner a modification of
hydrate of alumina is separated, chloride of calcium respectively chloride of barytium
(barium), chloride of strontium, or chloride of magnesia (magnesium) being formed
simultaneously, which hydrate of alumina constitutes a superior means for dis-
colouring, and in particular for discolouring sugar juice, this hydrate of alumina
being easily soluble in acetic acid. On, however, adding to this muriatic solution
considerable quantities of alumina lime, the combination of alumina, and the
alkaline earths or magnesia will be obtained in any wished-for proportions. All
these combinations may be employed for a variety of technical uses, and they are
saleable in a moist as also in a moderately dried state, which is also the case with
the hydrate of alumina, as described herein-before.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Lloyd Wise in the Great Seal Patent Office on the 20th
October 1877.
WILLIAM LLOYD WISE, of Chandos Chambers, Adelphi, in the County of Mid-
dlesex. "NEW PROCESS OF PREPARING CAUSTIC ALKALIES AND PREPARATIONS OF
ALUMINA." A communication from abroad by Doctor F. Loewig, of Goldschmieden,
near Deutschlissa, Silesia, and Gustav Loewig, of Dresden, Saxony.
This Invention, communicated to me by Doctor F. Loewig and Mr. Gustav
Loewig has for its object new process of preparing caustic alkalies and preparations
of alumina, and is described as follows:-
The processes for the production of caustic soda (Na O. H. O) most generally in
use are limited to the gaining of same from soda lye, or by the decomposition of
carbonate of soda. (Na O. C. O₂) by means of hydrate of lime (Ca O. H. O), as
most of the other proposed methods are too expensive to appropriate them to
industrial purposes.
It is clear that the production of caustic soda from other combinations of sodium (Na)
must at all times be accompanied by the gaining of more or less valuable by-products,
and that the application of such a method will mainly be influenced by the value of
these by-products, as also upon the simplicity and readiness of its execution.
Besides this the degree of pre-eminence of a mode of producing caustic soda will also
mainly depend upon the degree of purity of the product gained, and whether it
will be specially free of the salt of sodium made use of, or will only contain slight
traces of the same.
It follows from the fact that caustic soda of a high procental standard attains a
disproportionately higher price in the market than an inferior quality will do, that
the attainment of its greatest purity is of infinite importance. This difference in
price results from the fact that the manufacture of pure caustic soda causes difficulties
which are not combated with in making the impure article.
Of the combination of oxyd of sodium (Na O), which easily admits of the
separation of the caustic soda from the substances bound to it, the combination

page_text: with alumina (Al, O,) may be named in the first instance. This material is at present
produced on a large scale, and serves principally for gaining hydrate of alumina
with simultaneous formation of carbonate of soda by introducing carbonic acid (CO₂)
into the solution, which combination we make use of for producing caustic soda.
The production of this combination takes place for this object in the same way
as heretofore; but it must be observed that by the decomposition of the cryolite
by means of lime or carbonate of lime by an exalted temperature the simultaneous
formation of carbonate of soda must be prevented, as the latter (as has been already
stated) will mix with the caustic soda to be produced, thereby reducing its intrinsic
worth. This evil can be remedied, if, by adding such substances which will raiso
the quantity of alumina in the mixture to be worked, pains are taken to gain the
entire quantity of soda as aluminate of soda, or as a mixture of the latter with
caustic soda. This is best attained by the employment of the ores of Les Baux or
of Wochein (bauxite), or similar ores, which besides oxyde of iron contain more or
less alumina. By heating equal equivalents of alumina and soda a combination
consisting of 1 equivalent of alumina and 1 equivalent of soda may be attained.
If for this purpose such an amount of the specified ore is added to the cryolite
mixture that the entire quantity of alumina arising from the cryolite and con-
tained in the bauxite, will be in equal equivalent proportion to the soda in
formation or in excess, then soda of alumina (aluminate of soda) composed as
above will be produced without any addition of carbonate of soda.
A second method to produce soda of alumina (aluminate of soda) consists
therein that carbonate of soda is heated with bauxite, care being taken for the
objects in question that only such proportions of the two materials are made
use of that soda of alumina (aluminate of soda) free of carbonate of soda will be
the result.
If it is desired to attain a perfectly pure product, care must be taken to employ
only pure materials, avoiding sulphates. Hence only such cryolite containing no
sulphuret and only perfectly pure soda can be employed.
The decomposition of soda of alumina (aluminate of soda) will be best effected
by the use of caustic lime, and in vessels of any suitable form, by preference in
iron cylinders hermetically closed, and supplied with agitators and sieve bottoms.
The soda of alumina (aluminate of soda) is let into such cylinder, and a thick pulp
of lime is suffered to flow in, agitating all the while, or vice versa; gradually the
entire alumina will be precipitated.
In order to use no more line than is necessary for the object in view, and not to
arrive at a mixture of alumina lime with lime, it will be needful towards the close of
the operation to examine repeatedly whether the solution is free from alumina.
To arrive at this a small quantity of the solution of the residue is filtered, adding
to the attained clear liquid bicarbonate of soda until the entire soda will be bound
to the carbonic acid. As soon as no more of the residue is in such manner formed
the decomposition of the alumina soda will be completed. This having been
achieved the solution of the caustic soda is drawn off from the alumina lime, which
latter must be retained under the sieve bottom, and this concentrated solution is
then evaporated and calcined. The alumina lime still containing and being mixed
with caustic soda must now be washed, which can be effected in the same vessels,
making in the first instance use of diluted caustic soda lye, which has been gained
by washing other lots of alumina lime, thus attaining stronger solutions of caustic
soda, and then employing water.
In order to prevent the absorption of carbonic acid by admitting atmospheric
air it may be recommended to operate with several apparatuses simultaneously, 80
that while the one is being filled the other is made use of to wash out (agitating all
the while) in such manner that the diluted lyes of the alumina lime, which has
undergone the most perfect washing-out, will be forced by pumps into such alumina
lime as contains more soda. This will concentrate the more diluted lye and reduce
the cost of evaporation considerably.
In order to be enabled to let the washing-out take place in such manner the

page_text: apparatuses must be connected by pipes, which will permit the lye to be pressed
through several of them at the same time, the washing-out being so well advanced
in one apparatus that the alumina lime is nearly free from caustic soda; it may
then be recommended to interrupt the supply of water occasionally, and to entirely
press the fluid from out of the vessels by means of compressed air or steam, in
order to prevent the continuous production of lyes more and more diluted.
For precipitating the alumina from the alumina soda, as aluminate, not only lime
but strontium and magnesia may be made use of without the necessity of altering
the procedure. As, however, the alumina heated with the other alkaline carbonates
will form soluble aluminates, this quality may be profited by for the manufacture
of caustic potash in suffering, for instance, bauxite to act on the alkaline carbonate
operating with the alkaline aluminate, as herein-before described. In place of the
ores named herein, more or less pure artificial hydrate of alumina may be employed
and meet with industrial realization.
It may be important to prepare for renewed use a hydrate already procured, not
for the formation of other substances but merely as an auxiliary, for instance, for
discolouring; for this object we recommend to employ the same in place of bauxite,
as herein-before described, and to regain the alumina from the obtained alumina
soda according to the new mode, herein-after described, or according to older
procedures.
The employment of this hydrate for heating with caustic alkalies is however also
possible when only the manufacture of caustic alkalies is in view, in which case the
alumina is repeatedly precipitated and made use of. This would, however, involve
the loss of a considerable advantage of our process. In this case it will be preferable
to entirely avoid the formation of alumina soda and to substitute pure oxyd of
iron for the alumina, as the former equally possesses the quality to expel the car-
bonic acid from alkaline carbonates heated to redness. The necessary decomposition
of the formed combination of caustic soda with oxyd of iron is of a simple nature,
as on treatment with water the caustic soda will be separated from the oxyd of
iron and will be dissolved, whereas the oxyd of iron will remain undissolved. The
separated oxyd of iron, possessing a bright red colour, may be employed as
colouring substance or for further operations in caustisizing soda.
a
The aluminates obtained by the lierein-before described new method of producing
the caustic alkalies may be decomposed in many and various manners. If an acid
is added to them, which will be capable of forming soluble combinations with the
alkaline earths and the alumina, for instance, muriatic acid in an equivalent pro-
portion of both ingredients, then the aluminate will be entirely dissolved. But if
only one half of the muriatic acid is applied to aluminates which are regularly
composed, id est, to such which consist of 3 equivalents of alkaline earth and 1
equivalent of alumina, then only the alkaline earth will be dissolved and the alu-
mina will be separated; hence these aluminates are well adapted for the production
of bydrate of alumina. If the alumina is to be separated from the same, it must be
understood that such alumina will vary in its qualities according to the mode of
its production, it must therefore be kept in mind when determining the mode of
separation for which purposes the hydrate of alumina is eventually to be employed.
On decomposing a solution of aluminate of soda by carbonic acid gas a very indif-
ferent preparation is obtained, which possesses but very inferior discolouring qualities,
it is easily dissolvable in sulphuric acid but not or only partially and with difficulty
soluble in concentrated muriatic acid. Its employment is therefore limited, and it
will principally only serve for producing sulphate of alumina and alum. Con-
siderably different to this is the hydrate in form of gelatinous alumina, containing
much water, which makes it in a high degree bulky; but even this may appear in
different modifications. For instance, if the alumina is precipitated from a solution
in acids by alkalies or ammonia, it still possesses, even after perfect washing and
when in a moist state, an enormous discolouring power, it dissolves very easily in
diluted muriatic acid, also when newly procured in diluted acetic acid; in mixing
the alumina with water it will swell similar to starch paste; but it loses these

page_text: attributes in part after having stood under water for some time; they will even be
partly lost if slowly dried in a warm temperature; if dried in 100° C. the alumina
will pass over into the same state as the precipitated solution from the alkaline
solution by carbonic acid (C O,,). If, on the other hand, the alumina is precipi-
tated from an alkaline solution by means of diluted sulphuric acid, muriatic acid,
or acetic acid, the hydrate will indeed be obtained in a gelatinous state, but its
discolouring power is very inferior as well as its solubility in muriatic acid and
acetic acid.
We pass over the modifications of the alumina soluble in water as discovered by
W. Crum and Graham, and will now remark that we considered as our task to
gain gelatinous alumina from aluminates of a nature possessing discolouring
qualities in as high a degree as possible, as doubtless such an article may be
appropriated to the most extensive and inost manifold industrial purposes.
Our mode of proceeding to produce this hydrate now consists therein, that we
solute the said aluminates of the alkaline earth with muriatic acid, hence we pass
the alumina into a solution of chloride of alumina, and then, by the addition of
alkaline earths, principally lime or its carbonates, we precipitate the alumina from
this solution.
The entire operation of precipitating and washing the precipitated alumina may
be effected in an apparatus lined with lead, similar to the one described herein-
before for the production of caustic alkalies, and by combining several apparatusses
the concentration of the obtained solutions of the salts of the earths may be brought
about.
In order to obtain discolouring gelatinous alumina the same may also be precipi-
tated in place of the said precipitating means by another lot of the same aluminate,
which has been employed for the production of the muriate of alumina by
separating the alumina simultaneously from the chloride of alumina and from the
aluminates which have been used for precipitation. The alumina thus obtained may
be employed directly on account of its discolouring and other attributes, in cases
where heretofore the hydrate to act more powerfully was forced to be separated
from combinations with acids.
Doubtless many new applications will be found for this alumina, which were
rendered impossible hitherto for want of a cheap product. For all such purposes
for which alumina is not made use of for the production of other substances, and
where it is perhaps only employed as an auxiliary, for example, for discolouring
organic substances, it will be found of considerable importance that after such
perusal this hydrate will either be adopted for the manufacture of aluminate of
soda, as herein-before described, or will meet with renewed use by heating with the
alkaline earths or their carbonates, as well as with chloride of calcium, for the
production of aluminates of these earths; it will also be made use of for regaining
of the gelatinous alumina and its combinations. On heating the alumina with
chloride of calcium by introducing steam, the process may be very well executed in
such manner that the chloride of calcium gained by separating the alumina from
the aluminates of lime is employed, from which chloride of calcium the lime is
again regained as aluminate of lime and likewise the muriatic acid necessary for
separating the alumina from the aluminates of lime. This our method will also
prove highly important for the adaptability of alumina salts, of which many may
be produced at a far cheaper rate and in a more concentrated state with the help
of our alumina. With the assistance of this alumina the production of chloride of
alumina is also rendered possible, which will contain 3 equivalents of muriatic acid
in 2 and 3 equivalents of alumina, the use of which may be obtained in a pasty
state and promises peculiar advantages both to dyers and paper manufacturers.
Having described the nature of the said Invention, and explained the manner of
performing it as communicated to me as aforesaid, I hereby declare that what I
claim as scoured to me under the Letters Patent herein-before in part recited is,-
1. The new modes of manufacture of caustic alkalies, herein-before described.
2. The new methods of producing aluminates, as herein-before described.

page_text: 3. The production of gelatinous alumina, as described, by separating the same
from the aluminates of lime, strontium, and magnesia, by means of hydrochloric
acid, and respectively by precipitating the same from chloride of alumina.
In witness whereof. I, the said William Lloyd Wise, have hereunto set
my hand and seal, this Twentieth day of October, in the year of our
Lord One thousand eight hundred and seventy-seven.