A Process for Obtaining or Extracting Caustic Alkalies from Alkaline Aluminates and Hydrate of Barium and Alumina from Barium Aluminate.
Year: 1896

page_text: Date of Application, 13th May, 1896
Complete Specification Left, 26th Jan., 1897-Accepted, 10th Apr., 1897
A Process for Obtaining or Extracting Caustic Alkalies from Alkaline
Aluminates and Hydrate of Barium and Alumina from Barium
Aluminate.
I, DMITRY ALEXANDROWITCH PÉNIAKOFF of Rue Bauduin Pierre, Huy, in
the Kingdom of Belgium, Chemist, do hereby declare the nature of my invention
to be as follows:-
It is well known that in order to obtain pure caustic alkalies, aluminate lyes or
solutions are treated with oxides or hydrates of alkaline earths.
The latter are added in equivalent proportions to the alumina contained in the
lyes and separate from the solution in the form of a voluminous precipitate, as
aluminates of alkaline earths, soluble with difficulty or not at all. The
consumption of alkaline earths in this stage of operation is, however, very
considerable and filtration is attended with serious difficulty.
When it is desired to set free the alumina from the aluminates of alkaline earths,
acids have to be used in quantities equivalent to the amounts of alkaline earths
employed, so that altogether the process becomes a somewhat expensive one.
The object of my present invention is to avoid the drawbacks in the method of
operation I have described, or at all events to reduce them to a minimum.
To this end the clear aluminate lyes or solutions are treated in the well known
manner in vats or tanks fitted with stirring devices, until by far the greater part
(attaining as much as 80 per cent.) of the alumina is precipitated. The clear lyes
resulting from this operation still contain the whole of the alkali, but only one fifth
of the alumina originally contained in the solution. These lyes are decanted or
drawn off and mixed with a quantity of alkaline earths, equivalent to the amount of
alumina remaining behind in the solution.
By such means, the whole of the caustic alkali is enabled to be recovered with
the employment of one-fifth only of the quantity of alkaline earth that had to be
used hitherto. This advantage, taken in conjunction with the fact that, in
separating the caustic alkalies from the residue, precipitates have to be dealt with,
which are less in quantity and volume than those which had to be treated before,
constitutes the main improvement embodied in this process.
The pure solution of caustic alkalies is decanted off from the small amount of
precipitated matter, evaporated and melted down to the condition of caustic
alkalies.
The precipitate, consisting of aluminates of alkaline earths, is treated with any
suitable acid, so as to dissolve the alkaline earths or the alumina, and thereby to
separate them from each other.
The quantity of acid consumed in the course of this operation also amounts to
one-fifth only of that which was required in carrying out the process previously
known.
As barium aluminate, owing to its peculiar properties, is very like the aluminates
of the alkalies, this process is applicable also to the preparation or extraction of
hydrate of barium and alumina from barium aluminate.
Dated this 13th day of May 1896.

page_text: A Process for Obtaining or Extracting Caustic Alkalies from Alkaline
Aluminates and Hydrate of Barium and Alumina from Barium
Aluminate.
I, DMITRY ALEXANDROWITCH PÉNIAKOFF, of Rue Bauduin Pierre, Huy, in
the Kingdom of Belgium, 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:-
It is well known that in order to obtain pure caustic alkalies, aluminate lyes or
solutions are treated with oxides or hydrates of alkaline earths.
The latter are added in equivalent proportions to the alumina contained in the
lyes, and they separate from the solution in the form of a voluminous precipitate, as
aluminates of alkaline earths, soluble with difficulty or not at all. The consumption
of alkaline earths in this stage of operation is, however, very considerable and
filtration is attended with serious difficulty.
When it is desired to set free the alumina from the aluminates of alkaline earths,
acids have to be used in quantities equivalent to the amounts of alkaline earths
employed, so that altogether the process becomes a somewhat expensive one.
The object of my present invention is to avoid the objections in the method of
operation I have described, or at least to reduce them to a minimum.
To this end the clear aluminate lyes or solutions are kept in vigorous motion for
a considerable time in any suitable vessels or tanks by means of stirring whereby as
is well known a partial decomposition of the aluminate solution is effected and up
to 80 per cent. of the alumina present in solution can be precipitated. The clear
lyes resulting from this operation still contain the whole of the alkali, but only
one fifth of the alumina originally contained in the solution. These lyes are
decanted or drawn off and mixed with a quantity of alkaline earths, equivalent to
the amount of alumina remaining behind in the solution.
By such means the whole of the caustic alkali can be recovered with the
employment of only one fifth of the quantity of alkaline earth which it has been
necessary to use hitherto. This advantage, taken in conjunction with the fact that
in separating the caustic alkalies from the residue, precipitates have to be dealt
with, which are less in quantity and volume than those required to be treated
hitherto, constitutes the main improvement embodied in this process.
The pure solution of caustic alkalies is decanted off from the small amount of
precipitated matter, evaporated and melted down in the ordinary manner to the
condition of caustic alkalies.
The precipitate, consisting of aluminates of alkaline earths, is treated with any
suitable acid, so as to dissolve the alkaline earths or the alumina and thereby
to separate them from each other.
The quantity of acid consumed in the course of this operation also amounts to
one-fifth only of that which was required in carrying out the process previously
known.
As barium aluminate, owing to its peculiar properties, is very like the aluminates
of the alkalies, this process is applicable also to the preparation or extraction of
hydrate of barium and alumina from barium aluminate.
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 I
claim is :-
1. A process for extracting caustic alkalies from alkaline aluminates, characterized

page_text: by the special or preparatory separation of the greater part of alumina, as such so
that only the alumina remaining behind in the lyes (or solutions) is precipitated by
means of alkaline earths, substantially as described.
2. The application of the process described in the preceeding claiming clause for
the preparation or extraction of hydrate of barium and alumina from barium
aluminate.
Dated this 26th day of January 1897
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.