Improvements in and connected with the Nanufacture of Caustic Alkalies by Means of Alkaline Aluminates..
Year: 1898

page_text: Date of Application, 18th Apr., 1898
Complete Specification Left, 2nd Jan., 1899 -Accepted, 18th Apr., 18))
Improvements in and connected with the Nanufacture of Caustic
Alkalies by Means of Alkaline Aluminates..
I, DMITRY ALEXANDROWITCH PENIAKOFF, of Selzaete, in the Kingdom of Belgium,
Gentleman, do hereby declare the nature of this invention to be as follows:-
:-
The object of the process described in the Specification of my Patent of May 13,
1896, No. 10252, is to reduce to the minimum the quantities of alkaline earths
and acid employed for the decomposition of alkaline aluminates, which object is
in fact achieved in as much as, on proceeding according to the process of the
main patent above referred to, only from 20 to 30 per cent. of the amounts of
alkaline earths and acid, previously required, are consumed.
The object of the present improvement is to entirely avoid the use of acids
which are after all lost as inconvenient waste products, and in their place to treat
the aluminates of alkaline earths, obtained according to the process described in
the main patent, or by other means, with concentrated solutions of suitable
alkaline salts.
I have especially examined the relation between alkali carbonates and bi-car-
bonates on the one hand and the above mentioned aluminates of alkaline earths
on the other hand and I have found that between these bodies a practical quan-
titative double decomposition takes place the alkaline earths are precipitated
in the form of insoluble carbonates and the alkaline aluminates formed remair.
in the solution. It is evident that one molecule of an alkaline bi-carbonate
decomposes as much aluminate of alkaline earths as two molecules of a simple
alkaline carbonate, but that the alkaline aluminates obtained in this latter case
will be twice as rich in alkali as in the former; thus a means is afforded by which,
according to requirement, a larger or smaller amount of basic alkaline aluminate
solutions can be produced. If the latter contain a large percentage of surplus
alkali they may be advantageously employed for ensuring a more easy and com-
plete dissolution of fresh quantities of raw aluminates supplied from the calcina-
tion furnaces. Otherwise these solutions rich in alumina are treated in con-
formity with the process described in my said patent, i.e. the larger portion of
the alumina, is precipitated by agitation and the solution filtered from the very
basic aluminate is again treated with alkaline earths, whereby the aluminates
of the alkaline earths formed are precipitated and the alkalis set free are then
subjected to concentration.
This process of producing caustic alkalies by treating the respective carbonates
or bi-carbonates with aluminates of alkaline earths, permits of employing far
more concentrated solutions of carbonates than is the case if carrying out the
process by treating with the alkaline earths; (for example lime) heretofore em-
ployed, so that the caustifying apparatus of equal capacity are rendered far more
efficient whilst the enormous expenses of concentrating the solutions are reduced
to a minimum.
Analogous, reactions are obtained, between the aluminates of alkaline earths

page_text: and the alkaline sulphates and bisulphates with the formation on the one hand
of soluble alkaline aluminates and on the other of insoluble sulphates of the
alkaline earths. For the aluminate of barium this reaction has already been
previously described but as regards aluminate of calcium which is but slightly
soluble and which is here of special interest I have for the first time determined
the phenomenon which occurs. Although the double decomposition in this case
it not so active or so speedy as in the case of the alkaline carbonates and bi-car-
bonates, still the yields obtained are very satisfactory especially if the operation
be carried on under pressure and with suitably concentrated solutions. More-
over it must be remembered in this case that the sulphate and bisulphate have a
value considerably less than the alkaline carbonates and bicarbonates.
The change takes place in the inverse sense, that is to say the alumina remains
as, residue, and the alkaline earths pass into solution, if aluminates of alkaline
earths be treated with sal-ammoniac (ammonia muriate) while slightly heated;
the ammonia set free by this reaction is recovered, and utilized in the ordinary
way, and the insoluble alumina is separated from the soluble alkaline earth
chlorides by washing and filtration."
Dated thi 1011 1
L 1000
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., 'Agents.
Improvements in and connected with the Manufacture of Caustic
Alkalies by Means of Alkaline Aluminates.
I, DMITRY ALEXANDROWITCH PENIAKOFF, of Selzaete, in the Kingdom of Belgium,
Gentleman, 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:-
The object of the process described in the Specification of my Patent, dated
May 13, 1896, No. 10252, is to reduce to the minimum the quantities of alkaline
earths and acid employed for the decomposition of alkaline aluminates, which
object is achieved in as much as, by proceeding according to the process described
in the said patent, only from 20 to 30 per cent. of the amounts of alkaline earths
and acid, previously required, are consumed.
The object of the present improvement is to entirely avoid the use of acids
which are after all lost as inconvenient waste products, and in their place to treat
the aluminates of alkaline earths, obtained according to the process described in
the aforesaid patent, or by other means, with concentrated solutions of suitable
alkaline salts.
I have especially examined the relation between alkaline carbonates and bi-car-
bonates on the one hand, and the above mentioned aluminates of alkaline earths
on the other hand, and I have found that between these bodies a practical quan-
titative double decomposition takes place; the alkaline earths are precipitated
in the form of insoluble carbonates, and the alkaline aluminates forined remain
in the solution. It is evident that one molecule of an alkaline bi-carbonate
decomposes as much aluminate of alkaline earths as two molecules of a simple
alkaline carbonate, but that the alkaline aluminates obtained in this latter case
will be twice as rich in alkali as in the former; thus a means is afforded by which,
according to requirement, a larger or smaller amount of basic alkaline aluminate
solutions can be produced. If the latter contain a large percentage of surplus

page_text: alkali they may be advantageously employed for ensuring a more easy and com-
plete dissolution of fresh quantities of raw aluminates supplied from the calcina-
tion furnaces. Otherwise these solutions rich in alumina, are treated in con-
formity with the process described in my aforesaid patent, i.e. the larger portion of
the alumina, is nrecipitated by agitation, and the solution filtered from the very
basic aluminate is again treated with alkaline earths, whereby the aluminates
of the alkaline earths formed are precipitated and the alkalis set free are then
subjected to concentration.
This process of producing caustic alkalies by treating the respective carbonates
or bi-carbonates with aluminates of alkaline earths, permits of employing far
more concentrated solutions of carbonates than is the case if carrying out the
process by treating with the alkaline earths (for example, lime) heretofore em-
ployed, so that the caustifying apparatus of equal capacity are rendered far more
efficient whilst the enormous expenses of concentrating the solutions are reduced
to a minimum.
Analogous reactions are obtained between the aluminates of alkaline earths
and the alkaline sulphates and bi-sulphates, with the formation on the one hand
of soluble alkaline aluminates and on the other of insoluble sulphates of the
alkaline earths. For the aluminate of barium this reaction has already been
previously described, but as regards aluminate of calcium, which is but slightly
soluble and which is here of special interest, I have for the first time determined
the phenomenon which occurs. Although the double decomposition in this case
it not so active or so speedy as in the case of the alkaline carbonates and bi-car-
bonates, still the yields obtained are very satisfactory, and more especially if the
operation be carried on at or about boiling point under slightly increased pressure
say about 5 atmospheres and with solutions of sulphate of soda containing
under 15% of sulphate of soda. Moreover it must be remembered, in this case,
that the sulphate and bisulphate have a value considerably less than the alkaline
carbonates and bi-carbonates.
The change takes place in the inverse sense, that is to say, the alumina remains
as residue, and the alkaline earths pass into solution. if aluminates of alkaline
earths be treated with el-ammoniac (ammonium chloride, NHC) while slightly
heated, the ammonia set free by this reaction is recovered and utilized in the
ordinary way, and the insoluble alumina is separated from the soluble alkaline
earth chlorides by washing and filtration.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
1. The hereinbefore described process for the manufacture of alkaline aluminates
and their caustic alkalies and alumina, by treating an aluminate of an alkaline
earth with suitable alkaline-salt solutions.
2. For carrying out the process of manufacturing caustic alkalies and alumina,
as described in general form in the preceding claiming clause, the use for the
alkaline salt solutions of the following:-
-
a). Carbonates and bicarbonates of potassium and sodium.
.) Sulphates and bisulphates of potassium and sodium.
c.) Sal-ammoniac (ammonium chloride) with the simultaneous production
of alumina, ammonia and chlorides of the alkaline earths.
Dated this 2nd day of Ta
1000
JOHNSONS & WILLCOX.
47, Lincoln's Inn Fields, London, W.C.. Agents.