Year: 1898

page_text: I, JOSEPH HEIBLING, of Grenoble (Isère), in the Republic of France, Chemical
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention has for its object a novel process for the electrolytic manufacture
of alkaline bichromates, the said process consisting essentially in subjecting to the
action of an electric current a solution of alkaline chlorides contained in an
electrolytic vat. The same result can be obtained although less economically by
employing a solution of nitrates.
In carrying out the invention the positive pole is formed of bars or plates com-
posed of an alloy of iron and chromium containing a minimum of 55% of
chromium. The negative pole may be formed either of bars of carbon or of plates
of iron.
At the upper part of the cell above the liquid the projecting parts of each pole
are covered by two separate longitudinal collectors forming cups or bells and
designed to collect separately the hydrogen from the negative pole and the
chlorine from the positive pole. The device can also be utilized for the production
of pure hydrochloric acid.
The elements are arranged in batteries upon an inclined plane and in each
battery the lower part of each cell is placed in free communication with the upper
part of the next cell.
All the cells of a battery are connected for quantity or in parallel and the
batteries are connected for tension or in series for the purpose of utilizing the
power of the dynamo in the best possible manner.
With this arrangement, if a stream of saline solution be caused to flow con-
tinuously into the first cell of each battery, the solution will successively flow
through all the cells of each battery and will issue from the last cell completely
transformed into alkaline bichromate whatever the temperature and the degree
of concentration. The chromium is dissolved and the iron has been eliminated in
the form of sesquioxide. It is necessary to employ an alloy having more than
55% of chromium, as otherwise the two metals iron and chromium are oxidized
simultaneously without the production of chromates.
When the alloy encloses crystals in its mass the latter can be recovered with the
graphite at the end of the operation; they can be re-fused and employed.com-
mercially a chromium practically free from iron is obtained.
:
On issuing from the last cell of each battery, the solution is conveyed to a
drier or hydroextractor which separates it from the sesquioxide of iron in suspension
and it is thence conveyed to the evaporators.
The electromotive force necessary for each element is a volt and a half. The
energy used per kilogramme of crystallised bichromate of soda is two kilowatt-
hours,

page_text: I, JOSEPH HEIBLING of Grenoble (Isère), in the Republic of France, Chemical
Engineer, 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
This invention has for its object a novel process for the electrolytic manufacture
of alkaline bichromates, the said process consisting essentially in subjecting to
the action of an electric current by means of anodes of chromium or alloys of
chromium a solution of alkaline chlorides contained in an electrolytic vat.
same result can be obtained, although less economically, by employing a solution
of alkaline nitrates and the process can also be carried out by using as the elec-
trolyte a solution of caustic alkali.
In the accompanying drawing I have shewn an electrolytic cell in vertical section
and also the method of grouping the cells.
The positive pole is formed of bars or plates a composed of an alloy of iron and
chromium containing a minimum of 55% of chromium. The negative pole b may
be formed either of bars of carbon or of plates of iron.
At the upper part of the cell c above the liquid d the projecting parts of each
pole are covered by two separate longitudinal collectors e, f forming cups or bells
and designed to collect separately the hydrogen from the negative pole and the
chlorine from the positive pole. The device can also be utilized for the production
of pure hydrochloric acid.
It is advantageous, for facilitating the liberation and the collection of the
chlorine to provide a number of positive carbon electrodes; to this end, each cell
(or some of the cells only of each battery) is partly provided with anodes formed
of bars of carbon.
The elements are arranged in batteries upon an inclined plane and in each
battery the lower part of each cell is placed in free communication with the upper
part of the next cell.
All the cells of a battery are connected for quantity or in parallel and the
batteries are connected for tension or in series for the purpose of utilizing the
power of the dynamo in the best possible manner.
With this arrangement, if a stream of saline solution be caused to flow con-
tinuously into the first cell of each battery, the solution will successively flow
through all the cells of each battery and will issue from the last cell completely
transformed into alkaline bichromate whatever the temperature and the degree
of concentration. The chromium is dissolved and the iron has been eliminated in
the form of sesquioxide. It is necessary to employ an alloy having more than
55% of chromium, as otherwise the two metals iron and chromium are oxidized
simultaneously without the production of chromates.
When the alloy encloses crystals in its mass the latter can be recovered with the
graphite at the end of the operation; they can be re-fused and employed com-
mercially a chromium practically free from iron is obtained.
On issuing from the last cell of each battery, the solution is conveyed to a drier
or hydroextractor which separates it from the sesquioxide of iron in suspension
and it is thence conveyed to the evaporators.
The electromotive force necessary for each element is a volt and a half. The
energy used per kilogramme of crystallised bichromate of soda is two kilowatt-
hours.

page_text: 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. Apparatus for the electrolytic manufacture of alkaline bichromates consisting
of electrolytic cells containing an alkaline solution which nray be a chloride, an
alkaline nitrate or caustic alkali with anodes of chromium, or of an alloy of iron
and chromium containing at least 55% of chromium, and cathodes of any suitable
composition, the said cells being grouped in batteries and arranged in cascade
in each battery in such a manner that the electrolyte successively flows through
the cells as it is transformed into bichromate, passing freely from one to the other
by reason of the difference of level, substantially as described and illustrated.
2. Apparatus for the electrolytic manufacture of alkaline bichromates com-
prising electrolytic cells containing an alkaline solution, alkaline chloride or
nitrate, with anodes of chromium or of an alloy of iron and chromium containing
at least 55% of chromium, and cathodes of any suitable composition, the different
electrodes being surmounted by separate-collectors forming bells for collecting the
hydrogen and the chlorine which are disengaged respectively at the negative and
positive poles and which can be utilized for the manufacture of
pure hydrochloric
acid, substantially as described and illustrated.
3. In apparatus for the electrolytic manufacture of alkaline bichromates of the
kind described and illustrated, the arrangement wherein a number of carbon
anodes are employed, either in each cell or in several cells of each battery, for the
purpose of facilitating the liberation of the chlorine from the electrolyte.
ր T
1.
1000
the Tay
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.