A Method of Extracting Chromium by the Aid of Electrolytic Baths with Chromic Acid Base.
Year: 1891

page_text: Date of Application (in United Kingdom), 31st Dec., 1891
Complete Specification Left, 23rd Sept., 1892-Accepted, 31st Dec., 1892
PROVISIONAL SPECIFICATION.
A Method of Extracting Chromium by the Aid of Electrolytic
Baths with Chromic Acid Base.
We EMILE PLACET and JOSEPH BONNET, both of 95 Boulevard Beau-
marchais, Paris, in the Republic of France, Chemists, do hereby declare the nature
of this invention to be as follows:-
The object of this invention is to obtain deposits of chrome by the aid of
electrolytic baths with a chromic acid base.
Our baths are formed by means of a solution of chromic acid.
This solution may be but little concentrated (1 to 2 grammes of chromic acid in
100 grammes of water are sufficient); however, the more concentrated is the
solution, the more abundant is the deposit.
We vary the shade of the metal deposited, by adding to the solution a small
quantity (for example, 5 to 10 grammes per litre) of one of the following acids :-
Phosphoric, sulphuric, oxalic, benzoic, formic, gallic, pyro-gallic, picric, phenic,
salicylic acids, which give white deposits of chromium.
Acetic and bydro-fluosilicic acids give brilliant deposits, but darker.
Boric acid gives dull deposits, but very abundant.
Finally, sulphuric, nitric, hydrochloric, arsenious, tartaric, citric, lactic, tannic
acids, give deposits of a shade more or less dark according to the quantity
employed.
To prepare our solution of chromic acid, we employ chromic acid obtained by
the ordinary processes.
Or we produce the chromic acid in the bath itself at the same time as the
chromium deposits are made.
In this case we employ, as a bath, a solution of an alkaline bi-chromate, and we
pour into this solution, by successive small quantities, an acid (sulphuric, nitric,
hydro-fluosilicic, or any other acid), which, combining with the alkaline base, liberates
the chromic acid.
Or we prepare the chromic acid by putting in suspension the oxide of chromium,
hydrated in a solution of oxalic acid, or any other organic acid, and causing an
electric current to pass through the liquid.
At the end of a short time, under the influence of electricity, the oxide of
chromium is transformed into chromic acid.
We obtain alloys of chromium, and divers metals, by dissolving, in our baths,
the oxides or carbonates which do not decompose the chromic acid, such as the oxides
or the carbonates of copper, iron, tungsten, molybdenum, nickel, silver, &c.
Dated this 31st day of December 1891.
NEWTON & SON,
Agents for the Applicants.

page_text: COMPLETE SPECIFICATION.
A Method of Extracting Chromium by the Aid of Electrolytic
Baths with Chromic Acid Base.
We EMILE PLACET and JOSEPH BONNET both of 95 Boulevard Beau-
marchais, 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 :-
The object of this invention is to obtain deposits of chrome by the aid of
electrolytic baths with a chromic acid base.
Our baths are formed by means of a solution of chromic acid.
This solution may be but little concentrated (1 to 2 grammes of chromic acid in
100 grammes of water are sufficient) however the more concentrated is the solution
the more abundant is the deposit.
:-
We vary the shade of the metal deposited by adding to the solution a small
quantity (for example 5 to 10 grammes per litre) of one of the following acids :-
Phosphoric, sulphuric, oxalic, benzoic, formic, gallic, pyrogallic, picric, phenic,
salicylic, acids which give white deposits of chromium.
Acetic and hydrofluosilicic acids give brilliant deposits but darker.
Boric acid gives dull deposits but very abundant.
Finally sulphuric, nitric, hydrochloric, arsenious, tartaric, citric, lactic, tannic
acids give deposits of a shade more or less dark according to the quantity
employed.
To prepare our solution of chromic acid we employ chromic acid obtained by the
ordinary processes.
Or we produce the chromic acid in the bath itself at the same time as the
chromium deposits are made.
In this case we employ as a bath a solution of an alkaline bichromate and we
pour into this solution by successive small quantities, an acid (sulphuric, nitric,
hydrofluosilicic, or any other acid), which, combining with the alkaline base,
liberates the chromic acid.
Or we prepare the chromic acid by putting in suspension the oxide of chromium,
hydrated in a solution of oxalic acid, or any other organic acid, and causing an
electric current to pass through the liquid.
At the end of a short time, under the influence of electricity, the oxide of
chromium is transformed into chromic acid.
We obtain alloys of chromium, and divers metals, by dissolving, in our baths,
the oxides or carbonates which do not decompose the chromic acid, such as the
oxides or the carbonates of copper, iron, tungsten, molybdenum, nickel, silver, &c.
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 electrolytic baths having a chromic acid base, in the manner
and for the purposes herein before indicated.
Dated this 30th day of September 1892.
NEWTON & SON,
Agents for the Applicants.