Improvements in the Treatment of Solutions of Zinc Chloride for the Purification thereof for Electrolytic Purposes.
Year: 1894

page_text: Date of Application, 24th Nov., 1894
Complete Specification Left, 24th Aug., 1895-Accepted, 28th Sept., 1895
PROVISIONAL SPECIFICATION.
Improvements in the Treatment of Solutions of Zinc Chloride for
the Purification thereof for Electrolytic Purposes.
We JOHN BROCK Director of The United Alkali Company Limited ARTHUR
EDWARD WAREING Chemist and FERDINAND HURTER Ph.D. Chemist all of
G11 Exchange Buildings Liverpool in the County of Lancaster do thereby
declare the nature of this invention to be as follows :-
When zinc chloride solutions are prepared from impure oxides of zinc, such as
are obtained by roasting zinc blende, the solutions are contaminated with sulphate
of zinc. The sulphuric acid is derived partly from the impure zinc oxide and
partly from the commercial hydrochloric acid used for dissolving the oxide
of zinc.
•
When such solutions containing sulphate are electrolysed for the purpose of
obtaining metallic zinc and free chlorine, the presence of the sulphate causes the
evolution at the anode of a mixture of chlorine and oxygen gas instead of pure
chlorine, and a rapid corrosion of the carbon anodes is the result.
This invention has for its object to effect the removal from the solutions of zinc
chloride of the sulphuric acid contained therein. For this purpose we add to the
solution of zinc chloride a solution of chloride of calcium, or chloride of barium, or
chloride of strontium, in such quantity as will precipitate the sulphuric acid as far
as possible. The sulphate of calcium, barium or strontium, as the case may be, is
then separated as completely as possible either by settling or by filtration.
The solution thus purified is then ready for electrolysing.
Dated this 24th day of November 1894.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements! in the Treatment of Solutions of Zinc Chloride for
the Purification thereof for Electrolytic Purposes.
We JOHN BROCK, Director of The United Alkali Company, Limited, ARTHUR
EDWARD WAREING, Chemist, and FERDINAND HURTER, Ph.D. Chemist, all of
G11 Exchange Buildings, Liverpool, in the County of Lancaster, do hereby
declare the nature of our said invention, and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement :-
When zinc chloride solutions are prepared from impure oxides of zinc, such as
are obtained by roasting zinc blende, the solutions are contaminated with sulphate
of zinc. The sulphuric acid is derived partly from the impure zinc oxide and
partly from the commercial hydrochloric acid used for dissolving the oxide
of zinc.
When such solutions containing sulphates are electrolysed for the purpose of
obtaining metallic zinc and free chlorine the presence of the sulphate causes the

page_text: evolution at the anode of a mixture of chlorine and oxygen gas instead of pure
chlorine, and a rapid corrosion of the carbon anodes is the result.
This invention has for its object to effect the removal from the solutions of zinc
chloride of the sulphuric acid contained therein. For this purpose we add to the
solution of zinc chloride a solution of chloride of calcium or chloride of barium, or
chloride of strontium, in such quantity as will precipitate the sulphuric acid as far
as possible. The sulphate of calcium, barium or strontium as the case may be, is
then separated as completely as possible either by settling or by filtration.
The solution thus purified is then ready for electrolysing.
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 :-
Purifying zinc chloride solutions before subjecting them to electrolysis, by
adding thereto either calcium chloride, or strontium chloride or barium chloride,
substantially as and for the purpose herein before described.
Dated this 23rd day of August 1895.
JOHNSONS & WILLCOX,
Agents.