Improvements relating to the Electrolysis of Metals.
Year: 1891

page_text: Date of Application (in United Kingdom), 31st Dec.. 1891
Complete Specification Left, 23rd Sept., 1892-Accepted, 10th Dec., 1892
PROVISIONAL SPECIFICATION.
Improvements relating to the Electrolysis of Metals.
We EMILE PLACET and JOSEPH BONNET, both of 95 Boulevard Beaumarchais,
Paris, in the Republic of France, Chemists, do hereby declare the nature of this
invention to be as follows:-
In a Patent dated Nov. 27th 1890, No. 19344, granted to us, we have stated
that to extract metals from solutions, or to refine electrolytically these metals, it is
expedient to prevent the injurious disengagement of bubbles of gas at the negative
pole. To this effect, we submitted our baths to a pressure more or less strong, or
rather (that which amounts to the same thing, in certain cases), we augmented the
density of our baths by dissolving therein a series of substances, so to speak, inert
in themselves, and which we have indicated.
We have said that generally to prevent the deposit of oxides at the negative
pole, we added to our baths a certain quantity of acid.
Since then, we have found that instead of adding the acid directly to our baths
(which requires always many long trials to arrive exactly at the quantity desired),
there are very great advantages in employing, for the formation of our baths, salts
very acid in themselves, such as the bi-sulphates, bi-phosphates, bi-acetates.
The acid which is found combined in these salts in definite proportions, acts (for
the end which we have in view) under much better conditions than when the acid
is added directly to the baths.
Thus, for example, in the bath that we have indicated, for obtaining deposits of
chromium, that is to say, 10 to 15 grammes chrome alum, 10 to 15 grammes
sulphate of soda, potash, or ammonia, or a mixture of these sulphates ;-100 gr. of
water, plus a certain quantity of acid (sulphuric, phosphoric, or other acid), it is
very difficult to arrive exactly at the requisite quantity of acid to be added. A
bath which gives magnificent deposits of chromium, is obtained immediately, and
without experimenting, by substituting, for the ordinary sulphate, a bi-sulphate
and composing the bath thus:-
10 to 15 grammes chrome alum ;
10
17
matach
ammonia
or a mixture

page_text: The composition of the baths, and their maintenance, is thus rendered very
simple, by the employment of bi-sulphates. The advantages that we find in the
employment-of-bi-sulphates are also to be found, in an analogous manner, in the
employment of bi-phosphates, bi-chlorides, bi-acetates, and other acid salts, in
the state of bi salts or polyatomic salts, produced from organic, as well as
mineral acids.
That which we have just said about the baths of chrome, applies equally to
baths of other metals, such as aluminium, copper, nickel, cobalt, tin, antimony,
silver &c.
We produce and maintain these baths in the same manner as we have indicated
in the Patent above referred to. They can be treated, like the others, to obtain
metallic deposits of different shades of colors.
They can also be mixed together to obtain alloys of different metals.
We have found that there are very great advantages, in the composition and the
keeping up of electrolytic baths, by replacing totally or partially the ordinary
neutral salts by acid salts in the state of bi-salts, or polyatomic salts, not only
because they avoid the uncertainty, and the experiments to find the convenient
quantity of acid that it is necessary to add to the baths, but still more because the
acid which is combined in definite proportions in these salts is presented under
more favorable conditions for the deposition of metals by electricity, than when
the acid is added directly to the baths, as is ordinarily the case.
Dated this 31st day of December 1891.
NEWTON & SON,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements relating to the Electrolysis of Metals.
We, EMILE PLACET and JOSEPH BONNET both of 95 Boulevard Beaumarchais
Paris, in the Republic of France, Chemists, 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 :-
In a Patent dated November 27th 1890 No. 19344 granted to us we have stated
that to extract metals from solutions or to refine electrolytically these metals it is
necessary to prevent the injurious disengagement of bubbles of gas at the negative
pole. To this end we submitted our baths to a pressure more or less great or rather
(that which amounts to the same thing in certain cases) we augmented the density
of our baths by dissolving therein a series of substances, so to speak, inert in
themselves, and which we have indicated.
We have stated that generally to prevent the deposit of oxides at the negative
pole we added to our baths a certain quantity of acid.
Since then we have found that instead of adding the acid directly to our baths,
(which requires always many long experiments to arrive exactly at the quantity
desired) there were very great advantages in employing for the formation of
our baths salts acid in themselves, such as the bisulphates, bi-phosphates, and
bi-acetates.
The acid which is found combined in these salts in definite proportions acts (for
the end which we have in view) under much better conditions than when the acid
is added directly to the baths.
For example in the bath that we have indicated for obtaining deposits of
chromium :

page_text: plus a certain quantity of acid (sulphuric, phosphoric or other acid) it is very
difficult to arrive exactly at the requisite quantity of acid to be added.
In order that a bath be immediately obtained which gives magnificent deposits of
chromium the ordinary sulphate is simply replaced by the bisulphate and the bath
is composed thus :-
10 to 15 grammes chrome alum
The composition of the baths and their maintenance is thus rendered very simple
by the employment of bisulphates. The advantages that we find in the employment
of bisulphates are also to be found in an analogous manner in the employment of
bi phosphates, bi-chlorides bi acetates and other acid salts in the state of bisalts or
polyatomic salts produced from organic as well as mineral acids.
What we have just stated with regard to the baths of chromium applies equally
to baths of other metals, such as aluminium, copper, nickel, cobalt, tin, antimony,
silver, etc.
We produce and maintain these baths in the same manner as we have indicated
in the Specifications of our two Applications of even date, Nos. 22855 & 22856
of 1891. They can be treated like the others to obtain metallic deposits of
different shades of color.
They can also be mixed together to obtain alloys of different metals.
We have found that there are very great advantages in the composition, and the
keeping up of electrolytic baths, by replacing totally or partially the ordinary
neutral salts by acid salts in the state of bi-salts or polyatomic salts, not only
because they avoid the uncertainty and numerous experiments to find the convenient
quantity of acid that it is necessary to add to the baths, but still more because the
acid which is combined in definite proportions in these salts is presented under much
more favourable conditions for the deposition of metals by electricity than when the
acid is added directly to the baths as is ordinarily the case.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
The employment of polyatomic acid salts alone or mixed with neutral salts to
obtain deposits of chromium, aluminium, copper, iron, nickel, cobalt tungsten,
molybdenum, antimony, tin, silver etc. and the alloys of these metals electrolytically
as described above.
Dated this 22nd day of Sentember 1800
NEWTON & SON,
Agents for the Applicants.