A Process of Manufacture of Sulphide of Aluminium, which may or may not be Combined with other Sulphides (or Sulphurets).
Year: 1896

page_text: Date of Application, 27th May, 1896
Complete Specification Left, 1st Feb., 1897-Accepted, 3rd Apr., 1897
A Process of Manufacture of Sulphide of Aluminium, which may or
may not be Combined with other Sulphides (or Sulphurets).
I, DMITRY ALEXANDROWITCH PENIAKOFF of Rue Bauduin Pierre Huy in the
Kingdom of Belgium Chemist, do hereby declare the nature of this invention to be
as follows:-
The process forming the subject of this invention is based upon the principle of
the double decomposition taking place between anhydrous aluminium salts and the
sulphides or sulphurets of alkalies or alkaline earths in consequence of the fusion of
these bodies in a suitable flux.
If there be taken for example, a single or double halogen aluminium salt (such as
a fluoride, chloride or the like) in the anhydrous state, mixed with the sulphide of
an alkali or of an alkaline earth, and if such salt he melted, using an alkaline
mixture, (of, say, chloride and fluoride) as a flux, then a double decomposition
will take place in accordance with the following formulæ :-
In order to carry out my improved process in practice, a crucible may be heated to
the temperature requisite for the fusion of the materials employed, and these materials
may either be introduced into such crucible after having previously been mixed in the
proportions stated; or the aluminium may be admitted first, with the flux, and then,-
after these have been brought to a state of fusion,-the alkaline or alkaline-earthy
sulphide may be added.
The sulphide of aluminium thus obtained, may, without being removed from the
bath, be reduced to aluminium in the condition of metal, either by the action of an
electric current or by means of reducing gases (such as hydro carbons, for example).
In this case it is important that the bath should be fed with the elements or agents
necessary for reconstituting sulphide of aluminium, in proportion as it is reduced to
metallic aluminium.

page_text: This operation of feeding the bath may be readily carried out in those cases where
fluoride of aluminium is used in the production of sulphide of aluminium; and such
is hereinafter assumed to be the case."
By referring to the reactions 1 and 2 it will be noticed that as the sulphide of
aluminium is formed and reduced the alkaline fluoride only will be left in the bath.
In order to reform the fluoride of aluminium in the bath, such bath may be fed with
sulphate of alumina, which, in the presence of the alkaline fluoride in the state of
fusion, will give rise to this well known reaction :-
The alkaline sulphate resulting from this reaction, may, in its turn, serve to
re-produce the alkaline sulphide in the bath, if care be taken to add, along with
sulphate of alumina, the carbon necessary for the conversion of the alkaline sulphate
which has formed, into the sulphide which is required for the double decomposition
with the re-generated fluoride of aluminium.
It will thus be seen that in order to bring about the reactions hereinabove
indicated, it is only necessary to supply the bath with sulphate of alumina and
carbon, the fluorine invariably remaining in the bath.
To compensate for any slight loss of fluorine which may be sustained in the long
run, it is sufficient to add to the bath, from time to time, minute quantities of an
alkaline fluoride or of a double salt (such as cryolite, fluo-sulphate of aluminium
or the like).
Even where the sulphide of aluminium produced in the bath is subjected to
electrolysis, the sulphide alone may undergo the electrolytic action, and not the
fluoride, as the latter requires for its electrolytic decomposition, a far greater
electromotive force than that which suffices to bring about the decomposition of
the sulphide of aluminium. Besides, where electrolysis is resorted to, the sulphur
separated from the aluminium serves, for the most part, to reduce the alkaline
sulphate to the condition of alkaline sulphide, thus adding its effect to the action
of the carbon.
Dated this 27th day of May 1806
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.
A Process of Manufacture of Sulphide of Aluminium, which may
or may not be Combined with other Sulphides (or Sulphurets).
I, DMITRY ALEXANDROWITCH PÉNIAKOFF of Rue Bauduin Pièrre, 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 :-
The process forming the subject of this invention is based upon the principle of the
double decomposition taking place between anhydrous aluminium salts and the
sulphides or sulphurets of alkalies or alkaline earths in consequence of the fusion of
these bodies in a suitable flux.
If there be taken, for example, a single or double halogen aluminium salt (such as
a fluoride, chloride or the like) in the anhydrous state, mixed with the sulphide of
an alkali or of an alkaline earth, and if such salt be melted, using an alkaline

page_text: mixture of, say, chloride and fluoride as a flux, then a double decomposition will take
place in accordance with the following formulae :-
In order to carry out my improved process in practice, a crucible may be heated to
the temperature requisite for the fusion of the materials employed, and these materials
may either be introduced into such crucible after having previously been mixed in the
proportions stated; or the aluminium may be admitted first, with the flux, and then,―
after these have been brought to a state of fusion,-the alkaline or alkalino-earthy
sulphide may be added.
The sulphide of aluminium thus obtained may, without being removed from the
bath, be reduced to aluminium in the condition of metal, either by the action of an
electric current or by means of reducing gases (such as hydro-carbons, for example).
In this case it is important that the bath should be fed with the elements or agents
necessary for reconstituting sulphide of aluminium, in proportion as it is reduced to
metallic aluminium.
This operation of feeding the bath may be readily carried out in those cases where
fluoride of aluminium is used in the production of sulphide of aluminium; and such
is hereinafter assumed to be the case.
By referring to the reactions 1 and 2 it will be noticed that as the sulphide of
aluminium is formed and reduced the alkaline fluoride only will be left in the bath.
In order to re-form the fluoride of aluminium in the bath, such bath may be fed
with sulphate of alumina, which, in the presence of the alkaline fluoride in the state
of fusion, will give rise to this well-known reaction:-
The alkaline sulphate resulting from this reaction may, in its turn, serve to
re-produce the alkaline sulphide in the bath, if care be taken to add,-along with
sulphate of alumina,-the carbon necessary for the conversion of the alkaline sulphate,
which has formed, into the sulphide which is required for the double decomposition
with the re-generated fluoride of aluminium.
It will thus be seen that in order to bring about the reactions already indicated, it is
only necessary to supply the bath with sulphate of alumina and carbon, the fluorine
invariably remaining in the bath.
To compensate for any slight loss of fluorine which may be sustained in the long
run, it is sufficient to add to the bath, from time to time, minute quantities of an
alkaline fluoride or of a double salt (such as cryolite, fluo-sulphate of aluminium or
the like).

page_text: Even where the sulphide of aluminium produced in the bath is subjected to
electrolysis, the sulphide alone may undergo the electrolytic action, and not the
fluoride, as the latter requires for its electrolytic decomposition, a far greater
electromotive force than that which suffices to bring about the decomposition of the
sulphide of aluminium. Besides, where electrolysis is resorted to, the sulphur
separated from the aluminium serves, for the most part, to reduce the alkaline sulphate
to the condition of alkaline sulphide, thus adding its effect to the action of the
carbon.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is :-
1. A process of manufacture of sulphide of aluminium, either by itself or combined
with other sulphides, by a double decomposition of the anhydrous salts of aluminium
and of the sulphides of the alkalies or alkaline earths in a flux, substantially as
.described.
2. As a special example of the process described in the first claim, obtaining
sulphide of aluminium by the treatment of an anhydrous halogen salt of aluminium,
such as a single or double fluoride, with the sulphide of an alkali or of an alkaline
earth, in a flux consisting of an alkaline mixture in suitable proportions of fluoride
and chloride, substantially as described.
3. Feeding the bath referred to in the second claim in proportion as the sulphide of
aluminium is formed and reduced (either by electricity or gas) with sulphate or
fluo-sulphate of alumina and carbon, so as to re-constitute the fluoride of aluminium
and the alkaline sulphide, substantially as described.
Dated this 1st day of February 1897.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.