Improvements in the Manufacture of Caustic Soda and Caustic Potash.
Year: 1891

page_text: Date of Application, 9th May, 1891
Complete Specification Left, 2nd Feb., 1892-Accepted, 12th Mar., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Caustic Soda and Caustic
Potash.
I, EMILE LOUIS CONSTANT MARTIN, of 7, Rue Coutant, Ivry-Port (Seine)
France Chemist, do hereby declare the nature of this invention to be as follows:-
My invention has for its object the production, on a commercial scale, of caustic
soda or caustic potash by means of sodium chloride or potassium chloride by the
following method.
1st. I decompose sea salt, rock salt, or potassium chloride by double decom-
position between the sodium or potassium chloride and magnesium sulphate;
2nd. I then decompose the magnesium chloride formed by heat, whereby
magnesia is deposited and hydrochloric acid is disengaged;
3rd. I treat the sodium sulphate or potassium sulphate in solution, with neutral
or acid sulphite of barium or strontium, whether separately or together, in the cold
or hot, in suitable proportions, the mixture being effected in vessels provided with
stirrers. In this manner barium sulphate is formed, which precipitates and is
extracted, and neutral and acid sulphite of sodium or potassium, which remains in
solution;
4th. By boiling in a suitable apparatus the neutral and acid sulphite of sodium
solution is caused to disengage one half of its sulphurous acid which is collected
and then, by means of lime containing a suitable proportion of hydrated caustic
baryta, I decompose the neutral sulphite remaining whereby calcium sulphite and
barium sulphite are precipitated and which are separated by decantation from the
caustic soda solution which remains as the final result of the cycle of chemical
reactions above described;
5th. I treat the calcium sulphite and barium sulphite obtained in the preceding
operation, with sulphurous acid, either in the gaseous form or in solution, at a
suitable temperature in order to form acid sulphite of calcium and bariuin which I
employ for decomposing fresh quantities of sodium or potassium sulphate, as
herein before described.
COMPLETE SPECIFICATION.
. Improvements in the Manufacture of Caustic Soda and Caustic
Potash.
I, EMILE LOUIS CONSTANT MARTIN, of 7, Rue Coutant, Ivry-Port (Seine)
France, 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 :-
My invention has for its object the production, on a commercial scale, of caustic
soda or caustic potash by means of sodium chloride or potassium chloride by the
following method.
1st. I decompose sea-salt, rock-salt, or potassium chloride, by double decom-
position between the sodium or potassium chloride and magnesium sulphate;
2nd. I then decompose the magnesium chloride formed by heat whereby
magnesia is deposited and hydrochloric acid is disengaged;

page_text: 3rd. I treat the sodium sulphate or potassium sulphate in solution with neutral
or acid sulphite of barium or strontium whether separately or together, in the cold
or hot, in suitable proportions the mixture being effected in vessels provided with
stirrers. In this manner barium or strontium sulphate is formed which precipitates
and is extracted and neutral and acid sulphite of sodium or potassium which
remains in solution;
4th. By boiling in a suitable apparatus the neutral and acid sulphite of sodium
solution is caused to disengage one-half of its sulphurous acid which is collected
and then by means of lime containing any suitable proportion of hydrated caustic
baryta, I decompose the neutral sulphite remaining, whereby calcium sulphite and
barium sulphite are precipitated and which are separated by decantation from the
caustic soda solution which remains as the final result of the cycle of chemical
reactions above described;
5th. I treat the calcium sulphite and barium sulphite, obtained in the preceding
operation, with sulphurous acid either in the gaseous form, or in solution, at a
suitable temperature in order to form acid sulphite of calcium and barium, which I
employ for decomposing fresh quantities of sodium or potassium sulphate, as
herein before described.
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 :-
1st. The series or cycle of operations hereinbefore described constituting the
herein described process of treating sodium sulphate or potassium sulphate for
obtaining caustic soda or potash therefrom, substantially as specified.
2nd. In the herein described process, the step which consists in decomposing
sodium or potassium sulphate by means of neutral or acid sulphite of barium,
either separately or mixed together, for obtaining commercially, by a double
re-action, insoluble barium sulphate (BaO, SO³) and neutral sodium sulphite
(SO³Na³) or acid sodium sulphite (SO'NaH) or neutral potassium sulphite (SO³K²)
or acid potassium sulphite (SO³KH).
3rd. In the herein described process, the step which consists in decomposing
sodium or potassium sulphate by means of neutral or acid sulphite of strontium,
either separately or mixed together, for obtaining commercially, by a double
reaction, strontium sulphate (SO'STO) and neutral sodium sulphite (SO³Na³) or
acid sodium sulphite (SO'NaH) or neutral potassium sulphite (SO³K²) or acid
potassium sulphite (SO'KH).
4th. In the herein described process, the step which consists in converting the
barium and calcium sulphite obtained into acid barium and calcium sulphite and
adding the same to fresh quantities of sodium or potassium sulphate, for the purpose
of decomposing the same, as specified.
נית
دم
1000
E. L. C. MARTIN,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.