Improvements in or relating to the Precipitation of Precious Metals from their Solutions.
Year: 1895

page_text: Date of Application, 7th Feb., 1895
Complete Specification Left, 7th Nov., 1895-Accepted, 7th Dec., 1895
PROVISIONAL SPECIFICATION.
Improvements in or relating to the Precipitation of Precious Metals
from their Solutions.
I, HENRY LIVINGSTONE SULMAN of 60 Gracechurch Street in the County of
London, Analytical Chemist, do hereby declare the nature of this invention to be
as follows:-
This invention relates in the first place to the precipitation of precious metals
generally, from their solutions, but particularly to gold and silver dissolved in
cyanide solutions.
The precipitant I prefer to employ for cyanide solutions is the condensed metallic
vapours of zinc technically known as zinc dust or zinc fume as stated in my former
Specification No. 18003 dated 21st September 1894.
I find that even this method is improved in rapidity and efficacy by a preliminary
purification of the zinc fume from the oxide of zinc which may be present.
The object of this invention is to remove some or all of the oxide of zinc present,
so that the solution containing the precious metal may be acted upon by the purified
zinc, and this may be effected by digesting the zinc dust with any reagent that will
dissolve the oxide of zinc and leave the metallic zinc unacted upon.
Ammonia, ammonium chloride and ammonium carbonate all answer this require-
ment, and if a solution of one of these reagents be mixed with zinc dust, the oxide
of zinc will be found to be dissolved, and the purified zinc is then ready to be applied
to the solutions of precious metals.
These three reagents ammonia, ammonium chloride and ammonium carbonate may
also be used in solution to purify zinc in any form such as shavings or granules from
any adhering oxide of zinc and so render the zinc more efficacious as a means of
removing precious metals from their solutions; thus avoiding the necessity of
employing freshly turned shavings of zinc for use in removing precious metals from
their cyanide solutions.
Although I have found the three reagents mentioned above fully answer my
requirements it will be understood that other agents may be employed that will
purify the zinc fume from any oxide of zinc present.
Dated this 7th day of February 1895.
BOULT & WADE,
Agents for the Applicant.
Improvements in or relating to the Precipitation of Precious Metals
from their Solutions.
I, HENRY LIVINGSTONE SULMAN of 60 Gracechurch Street, in the County of
London, Analytical 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:-
This invention relates to the precipitation of precious metals generally, from
their solutions, but particularly to gold and silver dissolved in cyanide solutions.
017

page_text: The precipitant I prefer to employ for cyanide solutions is the condensed metallic
vapours of zinc technically known as zinc dust or zinc fume as described in my
Patent No. 18003 of 1894.
I find that even this method is improved in rapidity and efficacy by a preliminary
purification of the zinc fume from the oxide of zinc which may be present.
The object of this invention is to remove some or all of the oxide of zinc present,
so that the solution containing the precious metal may be acted upon by the purified
zinc, and this may be effected by digesting the zinc dust with any reagent that will
dissolve the oxide of zinc and leave the metallic zinc unacted upon.
Ammonia, ammonium chloride and ammonium carbonate all answer this require-
ment, and if a solution of one of these reagents be mixed with zinc dust, the oxide
of zinc will be found to be dissolved, and the purified zinc is then ready to be
applied to the solutions of precious metals.
These three reagents ammonia, ammonium chloride, and ammonium carbonate
may also be used in solution to purify zine in any form such as shavings or granules
from any adhering oxide of zinc and so render the zinc more efficacious as a means
of removing precious metals from their solutions; thus avoiding the necessity of
employing freshly turned shavings of zinc for use in removing precious metals from
their cyanide solutions.
Although I have found the three reagents mentioned above fully answer my
requirements it will be understood that other agents may be employed that will
purify the zinc fume from any oxide of zinc present.
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. The purification of zinc dust or fume from oxide of zinc to render it a better
precipitant of precious metals from their cyanide or other solutions.
2. The employment of zinc dust or fume purified of its oxide for the precipitation
of precious metals from their cyanide or other solutions.
3. The purification of zinc from oxide of zinc substantially as and for the purpose
described.
4. The employment of ammonia, ammonium chloride or ammonium carbonate for
the purification of zinc from oxide of zinc for the purpose described.
5. The method or process of purifying zinc dust or fume from its oxide
substantially as described.
Dated this First day of November 1895.
HENRY LIVINGSTONE SULMAN.
Boult & Wade,
Agents for the Applicant.