Improvements relating to the Manufacture of Alkaline Carbonates and Silicates.
Year: 1893

page_text: Date of Application, 27th Sept., 1893
Complete Specification Left, 27.h June, 1894-Accepted, 8th Sept., 1894
PROVISIONAL SPECIFICATION.
Improvements relating to the Manufacture of Alkaline Carbonates
and Silicates.
I, JULIUS REICH, of 3 Czerningasse, Vienna Il, in the Empire of Austria,
Chemist, do hereby declare the nature of this invention to be as follows:-
My invention relates to a process for manufacturing alkaline carbonates, in which
an alkaline fluoride (as such or in the form of a double salt) producible from a
soluble alkaline salt is transformed into an alkaline compound that can be converted
by carbonic acid into an alkaline carbonate, part of the alkaline compound being
separated. Such alkaline compounds are alkaline silicates and alkaline aluminates.
For manufacturing an alkaline silicate according to my said invention use is made
of the alkaline fluoride in the form of its double salts, especially in the form of an
alkaline silicon fluoride, or an alkaline boron fluoride, or also as such, that is to
say as an alkaline fluoride, the same main product, an alkaline silicate, being always
obtained. As in the manufacture on a large scale it is desirable to use a natural
product as a raw material it will mostly be preferred in practice not to purchase
the said alkaline fluoride compounds but to produce them during the operation.
For this purpose are adapted the soluble alkaline salts occurring in nature (more
particularly sodium chloride and potassium chloride), from which I will start in the
following description of the invention.
A saturated solution of an alkaline salt, such as sodium chloride or potassium
chloride, is mixed with fluosilicic acid until a dense precipitate of an alkaline
silicon fluoride is produced. Water will in many cases be the solvent used for the
alkaline salt, but other solvents, such as alcohol, may of course also be employed.
The alkaline silicon fluoride precipitate is separated from the liquid in a suitable
manner, say by filtering or decanting, and is preferably dried at between about
40 and 50 degrees centigrade, when it dissociates to form a white powder which
may be used in the subsequent process. Dried alkaline silicon fluoride powder is
intimately mixed with silicic acid, preferably with quartzose sand which has been
heated, and is then powerfully heated in a retort of refractory clay.
The quantities of the two materials required in practice may be easily deter-
mined from the following equations which explain the reactions taking place in
two phases, and in which the alkaline metal is designated by A.
In the first place two molecules of silicic acid act, while two molecules of silicon
fluoride escape, with formation of an alkaline silicon oxyfluoride (first phase),
which at an increased temperature comes into mutual action with the third molecule
of silicic acid, the last portion of fluorine escaping in the form of silicon fluoride,
and yields an alkaline silicate as a final product (second phase).
The escaping silicon fluoride gas may be collected over water and the fluosilicic
acid formed may be used again in the before-described manner.
According to the nature of the alkali employed, potassium silicate or sodium
silicate remains behind in the retort. This silicate is removed from the retort and
is dissolved in boiling water, if it is not designed to be used as such, for instance
in the manufacture of glass, but for the production of an alkaline carbonate.
Price

page_text: Into this solution I introduce carbonic acid, thereby separating silicic acid in the
form of powder, while dissolving the alkaline carbonate produced.
The solution of the alkaline carbonate is drawn from the silicic acid which has
settled at the bottom of the vessel, and is slowly evaporated while stirring con-
tinually, so that the alkaline carbonate precipitates as a crystalline powder. The
silicic acid obtained in this process may be used in any desired manner, for instance
as a substitute for the quartz powder to be employed in the present process. As
before stated, the alkaline fluoride may also be used in another form, for example
as an alkaline boron fluoride and an alkaline fluoride, in a similar manner.
The process of double decomposition may in this case be explained similarly to
the mutual action of an alkaline silicon fluoride and silicic acid as taking place in
two phases, an alkaline silicon oxyfluoride being formed in the first phase, while in
the second phase, precisely as described in respect of the alkaline silicon fluoride,
this compound with the remaining silicic acid is decomposed to produce an alkaline
.silicate with escape of the silicon fluoride gas formed from the remainder of the
fluorine. In the use of an alkaline boron fluoride, which may be produced from a
soluble alkaline salt and boron hydrofluoric acid, boron fluoride is accordingly
formed in the first phase in lieu of silicon fluoride, whilst when employing a common
alkaline fluoride in the first phase no boron or silicon fluoride will be formed beside
the alkaline silicon oxyfluoride. The second phase passes off in both instances
exactly as in the case of the alkaline silicon fluoride.
I will proceed to explain how the process is carried out with regard to the
production of an alkaline fluoride and an alkaline boron fluoride from soluble
alkaline salts, selecting an alkaline chloride by way of example.
A saturated solution of a soluble alkaline salt is mixed with boron hydrofluoric
acid or hydrofluoric acid for effecting the double decomposition into an alkaline
boron fluoride or an alkaline fluoride. When use is made of an alkaline chloride
the cessation of the effervescence of escaping bydro-chloric acid shows that the
quantity corresponding to the alkali has been added. As a solvent for the alkaline
salt, water is employed as a rule, but other solvents such as alcohol may be used
instead.
The solution produced of the alkaline boron fluoride or alkaline fluoride is
evaporated until the dissolved alkali has been separated in the form of crystals at
the bottom of the vessel. In case an alcoholic solution of an alkaline chloride was
used this evaporation is preferably effected in a distilling vessel having a cooled
receiver, wherein the alcohol vapours generated are volatilized and collected. The
alkaline boron fluoride or alkaline fluoride obtained is preferably dried at between
40 and 50 degrees centigrade, being thus dissociated to form a white powder.
This dry crystalline powder is intimately mixed with silicic acid, preferably quartzose
sand which has been heated, and is then strongly heated in a retort of refractory
material. The chemical reactions then taking place in two phases may be
represented by the following equations, from which also the quantitative proportions
may be determined for the ingredients of the mixture to be heated, and in which
the alkaline metal is designated by A.
Was the alkaline baron fluoride.

page_text: Accordingly the reaction takes place in the before-described two phases, in which
the second phase, commencing after the completion of the first phase at an increased
temperature, is exactly similar to the second phase of the reaction described in the
case of the alkaline silicon fluoride. The silicon fluoride gas generated in this
second phase is preferably collected over water in a receiver, and the silicon
hydrofluoric acid formed is used as may be desired, say for the reproduction of
hydrofluoric acid.
The boron fluoride which escapes in the first phase when employing an alkaline
boron fluoride is likewise preferably collected over water in a receiver but in the
form of boron hydrofluoric acid, whereupon after the completion of the first phase
the receiver is changed, in order to collect over water the silicon fluoride generated
at an increased temperature.
After the termination of the process potassium silicate or sodium silicate,
according to the nature of the alkali employed, will remain behind in the retort
exactly as in the case of the alkaline silicon fluoride, which silicate may be further
treated as described in respect of the alkaline silicon fluoride.
In the above described employment of an alkaline fluoride the production of an
alkaline carbonate may also be achieved by an alkaline aluminate if the silicic acid
is replaced by alumina. There will then however be no intermediate formation of
an alkaline silicate, but of an alkaline aluminate with secondary production of an
alkaline aluminum fluoride (cryolite), which latter may be used for any desired
purposes. Similarly as the alkaline silicate, this alkaline aluminate may be decom-
posed by carbonic acid into an insoluble portion which is separated (in this case
alumina in lieu of silicic acid) and into a soluble portion combining with carbonic
acid to form a soluble alkaline carbonate. For this purpose an alkaline fluoride is
heated together with alumina. The reaction and the quantitative proportions to
be employed will be seen from the following equation, in which the alkaline metal
is designated by A:
12. AF +2 A₁₂O₁ = A₁₂F¸ 6 AF + Al, (OA).
Accordingly the aluminum fluoride formed in the place of silicon fluoride has
combined with further quantities of an alkaline fluoride to produce an alkaline
fluoride aluminium fluoride (cryolite). The heated product is removed from the
retort into water which dissolves the alkaline aluminate whilst it leaves the cryolite
Accordingly the aluminum fluoride formed in the place of silicon fluoride has
combined with further quantities of an alkaline fluoride to produce an alkaline
fluoride aluminium fluoride (cryolite). The heated product is removed from the
retort into water which dissolves the alkaline aluminate whilst it leaves the cryolite
behind. The solution of the alkaline alumina is treated with carbonic acid
similarly as described in the case of the alkaline silicate, thereby forming aluminium
bydroxide which precipitates and an alkaline carbonate which dissolves.
Dated this 27th day of September 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
Improvements relating to the Manufacture of Alkaline Carbonates
and Silicates.
I, JULIUS REICH, of 3 Czerningasse, Vienna II, in the Empire of Austria,
Chemist, do hereby declare the nature of this invention, and in what manner the
same is to be performed, to be particularly described and ascertained, in and by
the following statement :-
My invention relates to a process for manufacturing alkaline carbonates, in which
an alkaline fluoride (as such or in the form of a double salt) producible from a
soluble alkaline salt is transformed into an alkaline compound that can be converted
by carbonic acid into an alkaline carbonate, part of the alkaline compound being
separated. Such alkaline compounds are alkaline silicates and alkaline aluminates.

page_text: For manufacturing an alkaline silicate according to my said invention use is made
of the alkaline fluoride in the form of its double salts, especially in the form of an
alkaline silicon fluoride or an alkaline boron fluoride, or also as such, that is to say
as an alkaline fluoride, the same main product, an alkaline silicate, being always
obtained. As in the manufacture on a large scale it is desirable to use a natural
product as a raw material it will mostly be preferred in practice not to purchase the
said alkaline fluoride compounds but to produce them during the operation. For
this purpose are adapted the soluble alkaline salts occurring in nature (more
particularly sodium chloride and potassium chloride), from which I will start in the
following description of the invention.
A saturated solution of an alkaline salt, such as sodium chloride or potassium
chloride, is mixed with fluosilicic acid until a dense precipitate of an alkaline silicon
fluoride is produced. Water will in many cases be the solvent used for the alkaline
salt, but other solvents, such as alcohol, may of course also be employed. The
alkaline silicon fluoride precipitate is separated from the liquid in a suitable manner,
say by filtering or decanting, and is preferably dried at between about 40 and
50 degrees centigrade, when it dissociates to form a white powder which may be
used in the subsequent process. Dried alkaline silicon fluoride powder is intimately
mixed with silicic acid, preferably with quartzose sand which has been heated, and
is then powerfully heated in a retort of refractory clay.
The quantities of the two materials required in practice may be easily determined
from the following equations which explain the reactions taking place in two phases
and in which the alkaline metal is designated by A.
2. 2 A,F,SiO2 + SiO2 = 2 A2SiO3 + SiF→
In the first place two molecules of silicic acid act, while two molecules of silicon
fluoride escape, with formation of an alkaline silicon oxyfluoride (first phase),
which at an increased temperature comes into mutual action with the third molecule
of silicic acid, the last portion of fluorine escaping in the form of silicon. fluoride,
and yields an alkaline silicate as a final product (second phase).
The escaping silicon fluoride gas may be collected over water and the fluosilicic
acid formed may be used again in the before-described manner.
According to the nature of the alkali employed, potassium silicate or sodium
silicate remains behind in the retort. This silicate is removed from the retort and
is dissolved in boiling water, if it is not designed to be used as such, for instance in
the manufacture of glass, but for the production of an alkaline carbonate.
Into this solution I introduce carbonic acid, thereby separating silicic acid in the
form of powder, while dissolving the alkaline carbonate produced.
The solution of the alkaline carbonate is drawn from the silicic acid which has
settled at the bottom of the vessel, and is slowly evaporated while stirring con-
tinually, so that the alkaline carbonate precipitates as a crystalline powder. The
silicic acid obtained in this process may be used in any desired manner, for instance
as a substitute for the quartz powder to be employed in the present process.
before stated, the alkaline fluoride may also be used in another form, for example
as an alkaline boron fluoride and an alkaline fluoride, in a similar manner.
As
The process of double decomposition may in this case be explained similarly to
the mutual action of an alkaline silicon fluoride and silicic acid as taking place in
two phases, an alkaline silicon oxyfluoride being formed in the first phase, while in
the second phase, precisely as described in respect of the alkaline silicon fluoride,
this compound with the remaining silicic acid is decomposed to produce an alkaline
silicate with escape of the silicon fluoride gas formed from the remainder of the
fluorine. In the use of an alkaline boron fluoride, which may be produced from a
soluble alkaline salt and boron hydrofluoric acid, boron fluoride is accordingly
formed in the first phase in lieu of silicon fluoride, whilst when employing a common

page_text: alkaline fluoride in the first phase no boron or silicon fluoride will be formed beside
the alkaline silicon oxyfluoride. The second phase passes off in both instances
exactly as in the case of the alkaline silicon fluoride.
I will proceed to explain how the process is carried out with regard to the
production of an alkaline fluoride and an alkaline boron fluoride from soluble
alkaline salts, selecting an alkaline chloride by way of example.
A saturated solution of a soluble alkaline salt is mixed with boron hydrofluoric
acid or hydrofluoric acid for effecting the double decomposition into an alkaline
boron fluoride or an alkaline fluoride. When use is made of an alkaline chloride
the cessation of the effervescence of escaping hydrochloric acid shows that the
quantity corresponding to the alkali has been added. As a solvent for the alkaline
salt, water is employed as a rule, but other solvents such as alcohol may be used
instead.
The solution produced of the alkaline boron fluoride or alkaline fluoride is.
evaporated until the dissolved alkali has been separated in the form of crystals at
the bottom of the vessel. In case an alcoholic solution of an alkaline chloride was.
used this evaporation is preferably effected in a distilling vessel having a cooled
receiver, wherein the alcohol vapours generated are volatilized and collected..
The alkaline boron fluoride or alkaline fluoride obtained is preferably dried at.
between 40 and 50 degrees centigrade, being thus dissociated to form a white powder.
This dry crystalline powder is intimately mixed with silicic acid, preferably
quartzose sand which has been heated, and is then strongly heated in a retort of
refractory material. The chemical reactions then taking place in two phases may
be represented by the following equations, from which also the quantitative
proportions may be determined for the ingredients of the mixture to be heated, and.
in which the alkaline metal is designated by A.
3. For the alkaline boron fluoride:
Accordingly the reaction takes place in the before described two phases, in which
the second phase, commencing after the completion of the first phase at an increased
temperature, is exactly similar to the second phase of the reaction described in the
Case of the alkaline silicon fluoride. The silicon fluoride gas generated in
this second phase is preferably collected over water in a receiver, and the silicon
hydrofluoric acid formed is used as may be desired, say for the reproduction of
bydrofluoric acid.
The boron fluoride which escapes in the first phase when employing an alkaline
boron fluoride is likewise preferably collected over water in a receiver but in the
form of boron hydrofluoric acid, whereupon after the completion of the first phase
the receiver is changed, in order to collect over water the silicon fluoride generated
at an increased temperature.
After the termination of the process potassium silicate or sodium silicate
according to the nature of the alkali employed, will remain behind in the retort,
exactly as in the case of the alkaline silicon fluoride, which silicate may be further
treated as described in respect of the alkaline silicon fluoride.
In the above described employment of an alkaline fluoride the production of an
alkaline carbonate may also be achieved by an alkaline aluminate if the silicic acid

page_text: is replaced by alumina. There will then however be no intermediate formation of
an alkaline silicate, but of an alkaline aluminate with secondary production of an
alkaline aluminium fluoride (cryolite), which latter may be used for any desired
purposes. Similarly as the alkaline silicate, this alkaline aluminate may be decomposed
by carbonic acid into an insoluble portion which is separated (in this case alumina in
lieu of silicic acid) and into a soluble portion combining with carbonic acid to form
a soluble alkaline carbonate. For this purpose an alkaline fluoride is heated
together with alumina. The reaction and the quantitative proportions to he
employed will be seen from the following equation, in which the alkaline metal is
designated by A:
12 AF + 2 AO, = AF¸ 6 AF + Al, (OA).
Accordingly the aluminium fluoride formed in the place of silicon fluoride has
combined with further quantities of an alkaline fluoride to produce an alkaline
fluoride aluminium fluoride (cryolite). The heated product is removed from the
retort into water which dissolves the alkaline aluminate whilst it leaves the cryolite
behind. The solution of the alkaline aluminate is treated with carbonic acid
similarly as described in the case of the alkaline silicate, thereby forming aluminium
hydroxide which precipitates and an alkaline carbonate which dissolves.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what 1
claim is
First. A process for manufacturing an alkaline compound (alkaline silicate and
alkaline aluminate) suitable for the production of alkaline carbonate, which com-
pound can be converted for this purpose by means of carbonic acid into soluble
alkaline carbonate and into a portion which precipitates, characterized by the
feature that alkaline fluoride is glowed with the substance (silicic acid, alumniña)
analogous to the portion which precipitates.
Second. The process, characterized by the first claim, for manufacturing alkaline
silicate suitable for the production of alkaline carbonate, which silicate can for this
purpose be converted by means of carbonic acid into soluble alkaline carbonate and
silicic acid which precipitates, carried out by glowing alkaline fluoride (free or in a
combined state, such as alkaline fluoride, alkaline silicon fluoride, alkaline boron
fluoride) with silicic acid, with escape of silicon fluoride which can be transformed
by water into silicon hydrofluoric and silicic acid.
Third. For the process characterized by the first and second claims the employ-
ment of a soluble alkaline salt. by subjecting the same first to the action of
hydrofluoric acid (free or combined, such as hydrofluoric acid, silicon hydrofluoric
acid, boron hydrofluoric acid) and then submitting the alkaline fluoride obtained
(free or combined) to the process characterized in the first and second claims,
the silicon fluoride produced at the same time being adapted to be converted by
water into fluosilicic acid and silicic acid which can be used again for the
process.
Fourth. The process characterized by the first, second and third claims, used for
the production of alkaline carbonate by first producing according to the said
process the characterized alkaline compound (alkaline silicate or alkaline aluminate)
decomposable by carbonic acid, dissolving the same, introducing carbonic acid into
the solution and thereby producing on the one hand alkaline carbonate which is
dissolved, and on the other hand a precipitate which consists of the portion (silicic
acid, alumina) combined with the alkali in the alkaline compound produced
according to the first, second and third claims.
Deted this 27th dox of Lune 1801
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.