IMPROVEMENTS IN PREPARING OR PRO- DUCING CAUSTIC ALKALIS AND PREPARATIONS OF ALUMINA, AND IN PURIFYING PREPARATIONS OF ALUMINA AFTER THEIR EMPLOYMENT IN CLARIFYING JUICES OR FLUIDS
Year: 1879

page_text: LETTERS PATENT to William Lloyd Wise, of 7, Whitehall Place, in the City
of Westminster, for the Invention of "IMPROVEMENTS IN PREPARING OR PRO-
DUCING CAUSTIC ALKALIS AND PREPARATIONS OF ALUMINA, AND IN PURIFYING
PREPARATIONS OF ALUMINA AFTER THEIR EMPLOYMENT IN CLARIFYING JUICES
OR FLUIDS." A communication from abroad by Doctor Friedrich Löewig, of
Goldschmieden, near Deutschlissa, Silesia.
PROVISIONAL SPECIFICATION left by the said William Lloyd Wise at the
Office of the Commissioners of Patents on the 8th August 1879.
WILLIAM LLOYD WISE, of 7, Whitehall Place, in the City of Westminster.
"IMPROVEMENTS IN PREPARING OR PRODUCING CAUSTIC ALKALIS AND PREPARA-
TIONS OF ALUMINA, AND IN PURIFYING PREPARATIONS OF ALUMINA AFTER THEIR
EMPLOYMENT IN CLARIFYING JUICES OR FLUIDS." (A communication from abroad
by Doctor Friedrich Löewig, of Goldschmieden, near Deutschlissa, Silesia.)
This Invention, as communicated to me as aforesaid, has reference to improve-
ments in preparing or producing caustic alkalis and preparations of alumina, and in
purifying preparations of alumina after their employment in clarifying juices or
fluids, and comprises the following features:-
1. It relates to the production of a standard solution of chloride of aluminium or
hydrochloric alumina. Gelatinous alumina, as described in the Specification of
Letters Patent, No. 1556, of A.D. 1877, and as employed for purifying the vegetable
fluids used in dyeing, contains about ninety per cent. of water and ten per cent. of
alumina (in the anhydrous state). This alumina is exposed to a temperature of from
120° to 150° Fahr., which causes it to loose the greater part of its water, leaving a
loose (ie., not dense) tender hydrate (similar to white magnesia), which hydrate
possesses but few discoloring properties. This dried alumina is dissolved in an
equivalent proportion of highly concentrated hydrochloric acid (in a vessel by pre-
ference of wood or stone), and thus a highly concentrated solution of chloride of
aluminium is obtained.
2. The Invention relates to the production of basic chloride of aluminium, or
basic hydrochloric alumina in a solid or liquid form, for which purpose a standard
solution of hydrochloric alumina is evaporated to a perfectly dry state, when one
third of the hydrochloric acid will have escaped, the residue being an easily pounded
and not hygroscopic mass (similar to gum arabic) of basic bydrochloric alumina,
D

page_text: which is perfectly soluble in water, and which solution can be evaporated without
decomposition. This basic solution may be evaporated without any loss of hydro-
chloric acid, and it has the capacity, more particularly in a concentrated state, to
dissolve a still further quantity of gelatinous alumina.
Such super-basic combinations are best obtained by dissolving the gelatinous
alumina in hydrochloric acid up to perfect saturation, and to do this it is best to
employ a surplus of gelatinous alumina, to be afterwards separated from the solution
by decantation or filtration. These super-basic solutions may be again evaporated
without decomposition.
The same super-basic combinations are obtained mixed with other chlorides by
the following plan:-A precipitant, such as pure and carbonate of ammonia, car-
bonic alkali, pure alkali, or carbonic earthy alkali (to which may be added pure
magnesia, or the aluminate or carbonate of same), is gradually added to the standard
solution of chloride of aluminium, the whole being continuously agitated until an
actual precipitate is produced.
By this process three parts of the acid may be withdrawn from the ordinary
hydrochloric alumina without producing any precipitation of alumina. A compara-
tively small quantity of the precipitant will then suffice to precipitate the entire
quantity of the alumina all at once in the gelatinous state from such basic solutions.
In obtaining these solutions it is preferred to use wooden vessels.
3. The Invention relates to the employment of the basic hydrochloric alumina for
industrial purposes. A number of materials are capable of abstracting the surplus
alumina from the solutions of these basic combinations, leaving an acidulous hydro-
chloric alumina (bi-muriate of alumina) solution behind.
This acidulous solution is again converted into a basic one by dissolving in it
gelatinous alumina.
If unsized paper (water leaf) be dipped into a solution of basic hydrochloric
alumina, and afterwards into pure water, it will take ink like sized paper, conse-
quently this solution will not pass through filter paper, and will be particularly
adapted as a mordant in dye works. It may be used in many cases as an equi-
valent for acetic alumina, also for tawing purposes.
In the manufacture of sugar this solution may be advantageously employed for
clarifying muddy juices, even such as would resist tannic acid.
In manufacturing purposes where alumina is separated by a precipitant, much
less of the precipitant will be required if basic hydrochloric alumina be used, by
reason of its considerable intrinsic contents of alumina in proportion to the alumina
to be separated. For the same reason the basic hydrochloric alumina may be sub-
stituted advantageously for sulpbate of alumina and alum.
4. The Invention relates to methods of purifying preparations of alumina, such as
herein before referred to or others, after they have been used for clarifying. These
methods are as follows, premising that in the following description the materials
considered best adapted for the purpose are mentioned, but others may be substi-
tuted; thus, in lieu of the alkaline earths, chlorides, and carbonates, other similar
alkaline earths, chlorides, and carbonates respectively may be substituted; in place
of the hydrochloric acid, or of some of it, other suitable acid may be employed
=
First Method (Treatment of the Alumina with Lime or Carbonate of Lime).-
According to this method pounded lime or milk of lime is mixed with the alumina,
by preference in the proportion of one equivalent of alumina to one of lime, whereby
aluminate of lime is formed. After drying, this mass is heated to destroy the
organic matters and separate therefrom the carbon, which may be subsequently
removed by subjecting the mass to a red heat and admitting air; this however is
not necessary, because after the ensuing solution of the alumina line, either the
carbon may be removed before precipitation of the alumina by filtration or any
other known means, or the alumina may be produced and employed mixed with
carbon, which is rather beneficial than otherwise in clarifying.
If the alumina slime to be operated upon contains nitrogen, the gaining of
ammonia may appropriately be combined with this process. The solution of the

page_text: aluminate, as well as the precipitation of the alumina from the same, is made by the
modes already known.
In place of the alkaline earths their carbonates may be used, as by heating
alumina therewith aluminates are formed, as is well-known, the organic substances
being thereby also destroyed. In the same manner the organic substances may be
destroyed by heating to a red heat the alumina with alkalies and alkaline salts
simultaneously, forming alkaline aluminates, from which alumina is produced by
the usual modes.
Second Method (Treatment of Alumina with Chlorides).-The alumina (pre-
ferably undried) to be purified is mixed with chloride of magnesium, and the mix-
ture is heated when the hydrochloric acid is driven off, and destroys the organic
substances, leaving behind aluminate of magnesium.
The escaping hydrochloric acid is collected in condensing vessels, and may serve
later on for dissolving the aluminate of magnesium.
The heating of the above mixture may be continued until all the carbon is
oxidised, when the aluminate will be freed from organic substances, but, as already
stated with reference to the first method, this is not necessary. The separation of the
alumina from the aluminate is accomplished in the usual manner.
Third Method (Treatment of the Alumina with Acids).—The alumina to be
purified is dissolved in bydrochloric acid. To avoid unnecessary consumption of
acid the alumina should be as basic as possible. When the alumina is entirely dis-
solved, all the foreign substances (i.e., the albuminous substances from the sacchari-
ferous juice) not in solution may be separated by filtration or otherwise. Many
substances which cannot be separated in this manner may be separated by the
addition of a surplus of alumina to the same, or by precipitation of a part of the
alumina in solution and subsequent filtration, or similar mechanical modes of sepa-
ration. These substances are thus kept separate from the undissolved alumina. If
the solution so obtained is not pure enough for further use when precipitating the
alumina, or if the above separations be omitted, hydrochloric acid must be distilled
from the solution until all organic substances have been sufficiently destroyed.
That there may not be undissolved alumina formed by excessive heating, a surplus
of hydrochloric acid is added when requisite, so as to produce an acid solution of
alumina; such acid may be added before the heating is commenced. The alumina
is afterwards precipitated, as in the first method, after or without the previous sepa-
ration of the carbon, in the usual manner.
.
Fourth Method (Treatment of Alumina with Chlorides and Acids).-The alumina
is first dissolved in muriatic acid to remove certain organic substances; afterwards
it is mixed with chloride of magnesium, and by evaporating and heating the mag-
nesium, aluminate is produced, and hydrochloric acid is obtained both from the
chloride of aluminium and from the chloride of magnesium. The alumina is sepa-
rated from the aluminates as usual.
Fifth Method (Treatment of alumina with caustic alkali).-Alumina to be
purified is dissolved in caustic alkali whereby portions of the foreign substances
absorbed by the alumina, and not soluble in caustic alkali, will be rendered capable
of separation by filtration or otherwise.
The alumina may be precipitated from the solution of the alkaline aluminate as
aluminate of alkaline earth, portions of the organic substances remaining dissolved
in the caustic alkali, or the solution of the alkaline aluminate may be evaporated,
and the organic substances contained in it destroyed by exposure to a red heat, the
product being again dissolved and the alumina precipitated as aluminates of the
earths.
Caustic alkalis may be used to free the aluminate of any oxide of iron that it may
have absorbed, either by separating the oxide of iron during the solution of the
alumina in the caustic alkali, or during the solution of the alkaline aluminate.
These alkalis may also be used to obtain substances from the alumina which might
suffer by the action of acids.
This process may be combined with the preceding methods in various ways.

page_text: Foreign substances obtained according to these methods of purifying preparations
of alumina which have been employed in clarifying juices or fluids may be used in
the manufacture of other products, as for example, of ammonia, and also for
manuring purposes.
5. The Invention relates to :-
(a.) Purification of lies of alkali of alumina by lime or other alkaline earths or
magnesia.
"
(b.) Preparation of a compound of alumina, alkali, and carbonic acid, by pre-
cipitating aluminate of alkali through precipitation of alkali aluminate by means
of bicarbonate of the corresponding alkalis.
If to a solution of natron of alumina a saturated solution of bicarbonate of soda
is added a voluminous precipitate is formed, which after being kept for a while in
moderate heat swells and has the external appearance of hydrate of alumina which
it has hitherto been considered to be. According to the investigations made by my
foreign correspondent, however, it is a product or compound of natron of alumina
and carbonic answering the empiric formula:-
3 Al, O, 3 Na, O, 5 CO₂.
Therefore 5 molcules of bicarbonate will give or deliver 5 molecules of carbonic
acid to 3 molecules of natron of alumina, while 5 molecules of carbonate of soda
remain in the solution, by differences in the temperature the compound will however
show small deviations. If, instead of natron of alumina, potash of alumina is used,
and instead of bicarbonate of soda the bicarbonate of potash the corresponding
compound of potash will be formed.
If the solution of natron of alumina is pure, viz. :-if it answers the formula:
Na,, O, Al,, O, the above named precipitation created by the use of bicarbonate
will be complete and a perfectly pure one.
If however the solution of natron of alumina, besides the alumina contains
portions of silicic acid, titanic acid, oxyde of iron, etcetera, these substances will be
precipitated along with the above sediment, and if the latter is to be obtained pure,
these substances must be removed before the above mentioned precipitation.
These substances will however always be present in those solutions of natron of
alumina, which result from the lixiviation of molten masses, gained from fluxed
cryolith or bauxite, the latter particularly containing, besides alumina, always
variable quantities of those substances above mentioned; and this is the reason
why the alumina gained from the above described natron-of-alumina-lye always
contains particles of the above substances.
It is now found that by adding a small quantity of caustic lime in the form of
lime water to the raw lye these substances are entirely removed, and the clarifying
of the lye is rapidly effected. To 1,000 litres of raw lye of 30° to 32° Beaumé, a
quantity of 500 to 750 gr. of lime will be sufficient; the sediment precipitated
through this process is a sandy powder, and is a mixed silicate composed variably
according to the nature of the raw materials used for the manufacture of the raw lye.
It is a matter of course that those preparations of alumina gained from the lye
after the above described purification has been effected must be also pure and free
from iron, etcetera.
Instead of caustic lime other alkaline earths or magnesia may also be used, which
will of course change the compositions of the silicates resulting therefrom.
The above described product created by the mixture of bicarbonate of soda with
natron of alumina (3 Al₂, O,, 3 Na₂, O, 5 CO₂), I shall now call "carbolic alkali of
alumina," and in order to prepare this product on a large scale the raw lye, after
being purified as above described (which raw lye still contains caustic soda and
carbonate of soda), must be constantly stirred while being mixed with the bicar-
bonate till the aluminate is completely precipitated, which is the case as soon as a
sample drawn from the fluid and filtered, is not rendered turbid by the admixture
of a solution of sal-ammoniac; it is however advisable to take a surplus of
bicarbonate in the mixture.
The sediment or precipitate has to be separated from the lye after some time, and

page_text: has to be washed and dried in a temperature of 122° to 133° F., and results at
last in a transparent, waxlike, hard, and amorphous product which is insoluble in
water, which shews no change when exposed to the air, and which contains on an
average about 50° water.
As mentioned above the "Carbonic Alkali of Alumina" answers the empirical
formula:-
3 Al,, O₂, 3 Na, O, 5 CO₂,
and may therefore be regarded as composed of
3 (Na,, O, CO₂) × 3 Al,, О, 2 CO,
this however does not agree with the whole chemical nature of this product. If it
contained completely formed carbonate of soda it would while in a wet state
decompose, and the carbonate of soda would appear on its surface, especially
during drying, which decomposition will always take place in presence of actually
free carbonate of soda.
If this product however after being pressed, but before being washed, is put for a
short time only in a warm place the surplus of carbonate of soda will soon appear
on its surface, and may then be easily washed out, while the remainder. will be the
final product, as above described.
Besides this the "Carbonic Alkali of Alumina" dissolves entirely in acids like a
simple carbonate, and if the solution in acid is completely saturated a surplus of
the product added to the solution will not decompose, but will remain undissolved
without separating the alumina.
This however would not be the case if the product consisted of carbonate of soda
and carbonate of alumina, because hydrate of alumina would then be eliminated
and the solution would only contain an alkali salt solution.
In a saturated solution in muriatic acid the alumina appears with the chloride of
sodium as a basic salt, Al,, Cl, the same is the case in a solution in acetic acid, in
which solution the proportion will not be 3, but only 2 molecules of acetic acid to
one molecule alumina.
The "Carbonic Alkali of Alumina" is not only of scientific interest but also of
great importance for industrial purposes.
While up to the present time the manufacture of a solution of alumina in acetic
acid, entirely free from iron, for. the use of dye works, has always presented great
difficulties such a solution can be very easily and directly made with the aid of
this "Carbonic Alkali of Alumina," which is easily dissolved even in highly diluted
acetic acid.
Alum of soda and potash can also be very easily prepared from the "Carbonic
Alkali of Alumina," and will be entirely free from iron.

page_text: 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 7th
February 1880.
WILLIAM LLOYD WISE, of 7, Whitehall Place, in the City of Westminster.
"IMPROVEMENTS IN PREPARING OR PRODUCING CAUSTIC ALKALIS AND PREPARA-
TIONS OF ALUMINA, AND IN PURIFYING PREPARATIONS OF ALUMINA AFTER THEIR
EMPLOYMENT IN CLARIFYING JUICES OR FLUIDS." (A communication from abroad
by Doctor Friedrich Löewig, of Goldschmieden, near Deutschlissa, Silesia.)
This Invention, as communicated to me as aforesaid, has reference to improve-
ments in preparing or producing preparations of alumina, and in purifying pre-
parations of alumina after their employment in clarifying juices or fluids, and
comprises the following features:-
1. It relates to the production of a standard or normal solution of chloride of
aluminium or hydro-chlorate of alumina, gelatinous alumina, as described in the
Specification of Letters Patent, No. 1556, of A.D. 1877, and as employed for
purifying the vegetable fluids used in dyeing contains about ninety per cent. of
water, and ten per cent. of alumina (in the anhydrous state). This alumina is
exposed to a temperature of from 120° to 150° Fahr. which causes it to loose the
greater part of its water, leaving a loose (i.e., not dense) soft hydrate (similar to
white magnesia), which hydrate possesses but few discoloring properties. This dried
allumina is dissolved in an equivalent proportion of highly concentrated hydro-
chloric acid (in a vessel by preference of wood or stone), and thus a highly con-
centrated solution of chloride of aluminium is obtained.
2. The Invention relates to the production of basic chloride of aluminium or
basic hydrochlorate of alumina in a solid or liquid form, for which purpose a
standard solution of hydrochlorate of alumina is evaporated to a perfectly dry
state, when one third of the hydrochloric acid will escape, the residue being an
easily pounded and not hygroscopic mass (similar to gum arabic) of basic hydro-
chlorate of alumina which is perfectly soluble in water, and which solution can be
evaporated without decomposition. This basic solution may be evaporated without
any loss of hydrochloric acid, and it has the property more particularly in a con-
centrated state of dissolving a still further quantity of gelatinous alumina.
Such super-basic combinations are best obtained by dissolving the gelatinous
alumina in hydrochloric acid up to perfect saturation, and to do this it is best to
employ a surplus of gelatinous alumina to be afterwards separated from the solution
by decantation or filtration. These super-basic solutions may be again evaporated
without decomposition.
The same super-basic combinations are obtained mixed with other chlorides by
the following plan. A precipitant such as ammonia and carbonate of ammonia,
alkaline carbonates, caustic alkali, or carbonates of the alkaline earths (to which
may be added pure magnesia, or the aluminate or carbonate of same) is gradually
added to the standard solution of chloride of aluminium, the whole being continuously
agitated until a permanent precipitate is produced.
By this process three parts of the acid may be withdrawn from the ordinary
hydrochlorate of alumina without producing any precipitation of alumina. A com-
paratively small quantity of the precipitant will then suffice to precipitate the
entire quantity of the alumina all at once in the gelatinous state from such basic
solutions. In obtaining these solutions it is preferred to use wooden vessels.
3. The Invention relates to the employment of the basic bydrochlorate of
alumina for industrial purposes. A number of materials are capable of abstracting
the surplus alumina from the solutions of these basic combinations, leaving an acid
hydrochlorate alumina (bi-chloride of alumina) solution behind.
This acid solution is again converted into a basic one by dissolving in it gelatinous
alumina.

page_text: If unsized paper (water leaf) be dipped into a solution of basic hydrochlorate of
alumina and afterwards into pure water it will take ink like sized paper, con-
sequently this solution will not pass through filter paper, and is particularly
adapted as a mordant in dye works. It may be used in many cases as an equivalent
for acetate of alumina; also for tawing purposes.
In the manufacture of sugar, this solution may be advantageously employed for
clarifying muddy juices, even such as would resist tannic acid.
In manufacturing purposes, where alumina is separated by a precipitant, much
less of the precipitant will be required if basic hydrochlorate of alumina be used,
in consequence of the considerable proportion of alumina it contains in proportion
to the alumina to be separated. For the same reason the basic hydrochlorate of
alumina may be substituted advantageously for sulphate of alumina and alum.
4. The Invention relates to methods of purifying preparations of alumina, such as
herein before referred to, or others after they have been used for clarifying.
These methods are as follows, premising that in the following description the
materials considered best adapted for the purpose are mentioned, but others may be
substituted. Thus, in lieu of the alkaline earths, chlorides, and carbonates, other
similar alkaline earths, chlorides, and carbonates respectively may be substituted.
In place of the hydrochloric acid, or of some of it, other suitable acid may be
employed:-
First Method (Treatment of the Alumina with Lime or Carbonate of Lime).-
According to this method, pounded lime or milk of lime is mixed with the alumina,
by preference in the proportion of one equivalent of alumina to one of lime, whereby
aluminate of lime is formed. After drying, this mass is heated to destroy the
organic matters and separate therefrom the carbon, which may be subsequently
removed by subjecting the mass to a red heat and admitting air; this however is
not necessary because after the ensuing.solution of the aluminate of lime either the
carbon may be removed before precipitation of the alumina by filtration or any other
known means, or the alumina may be produced and employed mixed with carbon,
which is rather beneficial than otherwise in clarifying. If the aluminate of lime to
be operated upon contains nitrogen, the gaining of ammonia may appropriately be
combined with this process. The solution of the aluminate as well as the precipi-
tation of the alumina from the same is made by the methods already known.
In place of the alkaline earths their carbonates may be used, as by heating
alumina therewith aluminates are formed, as is well known, the organic substances
being thereby also destroyed. In the same manner, the organic substances may be
destroyed by heating to a red heat the alumina with alkalies and alkaline salts,
simultaneously forming alkaline aluminates, from which alumina is produced by
the usual modes.
Second Method (Treatment of. Alumina with Chlorides).-The alumina (prefer-
ably undried) to be purified is mixed with chloride of magnesium and the mixture
is heated, when the hydrochloric acid is driven off and destroys the organic
substances, leaving behind aluminate of magnesium.
The escaping hydrochloric acid is collected in condensing vessels and may serve
later on for dissolving the aluminate of magnesium.
The heating of the above mixture may be continued until all the carbon is
oxidised, when the aluminate will be freed from organic substances, but, as already
stated with reference to the first method, this is not necessary. The separation of
the alumina from the aluminate is accomplished in the usual manner.
Third Method (Treatment of the Alumina with Acids)-The alumina, to be
purified is dissolved in hydrochloric acid. To avoid unnecessary consumption of
acid the alumina should be as basic as possible. When the alumina is entirely
dissolved all the foreign substances (i.e., the albuminous substances from the sac-
chariferous juice) not in solution may be separated by filtration or otherwise.
Many substances which cannot be separated in this manner may be separated by
the addition of a surplus of alumina to the same, or by precipitation of a part of
the alumina in solution and subsequent filtration, or similar mechanical modes of

page_text: separation. These substances are thus separated from the dissolved alumina. If
the solution so obtained is not pure enough for further use when precipitating the
alumina, or if the above separations be omitted, hydrochloric acid must be distilled
from the solution until all organic substances have been sufficiently destroyed.
That there may not be insoluble alumina formed by excessive heating, a surplus of
hydrochloric acid is added, when requisite, so as to produce an acid solution of
alumina. Such acid may be added before the heating is commenced. The alumina
is afterwards precipitated, as in the first method, after or without the previous
separation of the carbon in the usual manner.
Fourth Method (Treatment of Alumina with Chlorides and Acids).—The alumina
is first dissolved in hydrochloric acid to remove certain organic substances, after-
wards it is mixed with chloride of magnesium, and by evaporating and heating the
magnesium aluminate is produced, and hydrochloric acid is obtained both from the
chloride of aluminium and from the chloride of magnesium. The alumina is
separated from the aluminates as usual.
Fifth Method (Treatment of Alumina with Caustic Alkali).-Alumina to be
purified is dissolved in caustic alkali, whereby portions of the foreign substances
absorbed by the alumina and not soluble in caustic alkali will be rendered capable
of separation by filtration or otherwise.
The alumina may be precipitated from the solution of the alkaline aluminate as
aluminate of an alkaline earth, portions of the organic substances remaining
dissolved in the caustic alkali, or the solution of the alkaline aluminate may be
evaporated with the organic substances contained in it, destroyed by exposure to a
red heat, the product being again dissolved and the alumina precipitated as
aluminates of the earths.
Caustic alkalies may be used to free the aluminate from any oxide of iron that
it may contain, either by separating the oxide of iron during the solution of the
alumina in the caustic alkali or during the solution of the alkaline aluminate. These
alkalies may also be used to obtain such substances from the alumina as would be
injured by the action of acids.
This process may be combined with the preceding methods in various ways.
Foreign substances obtained according to these methods of purifying preparations
of alumina which have been employed in clarifying juices or fluids, may be used in
the manufacture of other products, as for example, of ammonia, and also for manuring
purposes.
5. The Invention relates to,―
(a). Purification of lyes of alkali of alumina by lime or other alkaline earths, or
magnesia.
(b). Preparation of a compound of an aluminate of an alkali and carbonic acid by
precipitating the aluminate of an alkali by means of the bicarbonate of the
corresponding alkali.
If to a solution of aluminate of soda a saturated solution of bicarbonate of soda
is added, a voluminous precipitate is formed, which after being kept for a while at a
moderate heat, swells, and has the external appearance of hydrate of alumina, which
it has hitherto been considered to be. According to the investigations made by
my foreign correspondent, however, it is a product or compound of aluminate of
soda and carbonic acid answering the empirical formula,―
3 Al, O, 3 Na,, 0, 5 CO,.
Therefore 5 molecules of bicarbonate will yield 5 molecules of carbonic acid to 3
molecules of aluminate of soda, while 5 molecules of carbonate of soda remain in
the solution at different temperatures, the compound will, however, shew small
deviations. If instead of aluminate of soda aluminate of potash is used, and instead
of bicarbonate of soda bicarbonate of potash, the corresponding compound of potash
will be formed. If the solution of aluminate of soda is pure, viz., if it answers the
formula Na, O, A₁₂, O₂, and the above-named precipitation produced by the use
of a bicarbonate will be complete and the product perfectly pure.
If, however, the solution of aluminate of soda besides the alumina contains silicic

page_text: acid, titanic acid, oxide of iron, etcetera, these substances will be thrown down
along with the above precipitate, and if the latter is to be obtained pure these
substances must be removed before the above mentioned precipitation.
These substances will, however, always be present in those solutions of aluminate
of soda which result from the lixiviation of fused masses obtained from fluxed
cryolite or bauxite, the latter particularly containing besides alumina always
variable quantities of those substances above mentioned, and this is the reason
why the alumina obtained from the above described aluminate of soda lye always
contains traces of the above substances.
It is now found that by adding a small quantity of caustic lime in the form of
lime water to the lye these substances are entirely removed and the clarifying of
the lye is rapidly effected. To 1,000 litres of lye of 30° to 32° Beaumé, a quantiy
of 500 to 750 grms. of lime will be sufficient; the sediment thus precipitated is a
sandy powder, and is a mixed silicate of variable compositions, according to the
nature of the raw material used for the manufacture of the raw lye.
It is a matter of course that those preparations of alumina obtained from the lye
after the above described purification has been effected must be also pure and free
from "iron," etcetera.
Instead of caustic lime other alkaline earths or magnesia may also be used, which
will of course change the compositions of the silicates resulting therefrom.
The above-described product formed by the mixture of bicarbonate of soda with
aluminate of soda (3 Al,, O,, 3 Na,, O, 5 Co.) I shall now call "carbonic alkali of
alumina," ("aluminate of an alkaline carbonate,") and in order to prepare this
product on a large scale, the fresh lye, after being purified, as above described
(which lye still contains caustic soda and carbonate of soda), must be constantly
stirred while being mixed with the bicarbonate till the aluminate is completely
precipitated, which is the case as soon as a sample drawn from the fluid and filtered
is not rendered turbid by the admixture of a solution of sal ammoniac; it is, how-
ever, advisable to use an excess of bicarbonate.
The sediment or precipitate is separated from the lye after some time, and
then washed and dried at a temperature of 122° to 133° Fahr., the result being a
transparent, waxlike, hard, and amorphous product which is insoluble in water,
which shews no change when exposed to the air, and which contains on an average
about 50 per cent. of water.
As mentioned above, the "carbonic alkali of alumina" answers the empirical
formula,
3 Al, O, 3 Na, O, 5 CO₂,
and may therefore be regarded as composed of
3 (Na, O, CO₂) ×, Al₂, O₂, 2 CO₂,
this, however, does not agree entirely with the chemical nature of this product.
If it contained completely formed carbonate of soda it would, while in a wet
state, decompose, and the carbonate of soda would appear on its surface, especially
during drying, which decomposition will always take place in presence of actually
free carbonate of soda.
If this product, however, after being pressed, but before being washed, is put for a
short time only in a warm, place, the surplus of carbonate of soda will soon appear
on its surface, and may then be easily washed out, while the remainder will be the
final product, as above described.
Besides this, the "carbonic alkali of alumina" dissolves entirely in acids like a
simple carbonate, and if the solution in acid is completely saturated, a surplus of
the product added to the solution will not decompose, but will remain undissolved
without separating the alumina.
This, however, would not be the case if the product consisted of carbonate of
soda and carbonate of alumina, because hydrate of alumina would then be elimi- .
nated, and the solution would only contain an alkali salt in solution.
In a saturated solution in hydrochloric acid the alumina appears to be combined
with the chloride of sodium as a basic salt Al,, Cl, the same is the case in a

page_text: solution in acetic acid, in which solution the proportion will not be 3, but only 2
molecules of acetic acid to 1 molecule of alumina.
The "carbonic alkali of alumina" is not only of scientific interest, but also of
great importance for industrial purposes.
While up to the present time the manufacture of a solution of alumina in acetic
acid, entirely free from iron, for the use of dye works, has always presented great
difficulties, such a solution can be very easily and directly made with the aid of
this "carbonic alkali of alumina," which is easily dissolved even in highly diluted
acetic acid.
Soda and potash alums can also be very easily prepared from the "carbonic
alkali of alumina," and will be entirely free from iron.
Having described the nature of the said Invention, and explained the manner of
carrying it into practical effect, as communicated to me as aforesaid, I would have
it understood that what I consider to be novel and original, and therefore claim
as the Invention secured to me under the Letter Patents first hereinbefore in part
recited is,―
1. The methods, substantially as hereinbefore'described, of producing normal and
basic chloride of aluminium, or basic hydro-chlorate of alumina, liquid and solid, by
dissolving gelatinous alumina in bydrochloric acid or in a normal solution of chloride
of aluminium.
2. The production of gelatinous alumina by means of caustic and carbonated
alkalies or carbonated alkaline earths, or magnesia or aluminate of magnesium,
substantially as herein before described.
3. The production of gelatinous alumina from basic chloride of aluminium, sub-
stantially as herein before described.
4. The method of removing foreign substances from spent alumina by the appli-
cation of red heat during the conversion of the alumina into aluminates, substantially
as hereinbefore described.
5. The method of removing foreign substances from spent alumina by treating
such alumina with chlorides, hydro-chloric acid, evaporation, and heat, substantially
as described.
6. The method of removing and recovering foreign substances from spent alumina
by dissolving such alumina in hydro-chloric acid or in caustic alkalies, substantially
as described.
7. The method of removing and recovering foreign substances from spent alumina
by a combination of the processes above referred to in claims 4, 5, and 6.
8. The method of purifying lyes of aluminate of an alkali by the use of lime or
other alkaline earth or magnesia, as above described.
9. Preparing a compound of alumina alkali and carbonic acid by precipitating an
aluminate of an alkali by means of the bicarbonate of the corresponding alkali, as
above described.
In witness whereof, I, the said William Lloyd Wise, have hereunto set my
hand and seal, this Sixth day of February, in the year of our Lord One