Improvements in Extracting Silver and certain Base Metals from Ores or Compounds containing the same.
Year: 1892

page_text: Date of Application; 6th July, 1892
Complete Specification Left, 14th Mar., 1893—Accepted, 29th Apr., 1893
PROVISIONAL SPECIFICATION.
Improvements in Extracting Silver and certain Base Metals from
Ores or Compounds containing the same.
I, JOHN DAVID, of Llwyndu, in the Swansea Valley, Wales, Analytical Chemist,
do hereby declare the nature of this invention to be as follows:-
This invention relates to treating ores containing silver, copper, zinc and lead in
combination with sulphur; the objects of the invention being to progressively effect
the extraction of the several metals and to lessen the cost of treatment.
In carrying out my invention, the ore is first reduced to a moderately fine powder,
and is then heated for twelve or more hours in a closed vessel, or in a calcining
furnace so arranged that the ore can be heated in bulk without being subjected to
any draught, whereupon it can be afterwards calcined without scintillating, loss in
calcination being thus avoided. The ore is then washed with hot water acidulated
with sulphuric acid for the purpose of removing the zinc. It is thereupon
washed with hot water, and the washing added to the first washing. The ore
is again washed with a solution of acetate of lime, and the washing mixed with
the previous washings. The sulphate of lead present in the calcined ore is thus
converted into an acetate. The third washing, when mixed with the first and
second washings, precipitates any silver that may have passed into solution; the
precipitate being collected and the silver and lead recovered in the usual way.
The copper in solution is then precipitated in the metallic state by means of
zinc. The solution containing the added zinc, together with the zinc washed
out of the ore, is thereupon drawn off and neutralised with ammoniacal liquor
from gas works. The zine is precipitated as a sulphide by passing a current of
sulphuretted hydrogen gas through the solution. The sulphide of zinc thus
obtained can be collected ready for use in making spelter. The solution which
contains sulphate of ammonia is then evaporated to crystallisation; the sulphuric
acid employed and that formed by the calcination of the ore being thus recovered.
The residue from the washing of the ore can be smelted in the ordinary way.
Dated the 25th day of June 1892
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent.
COMPLETE SPECIFICATION.
Improvements in Extracting Silver and certain Base Metals from
Ores or Compounds containing the same.
I, JOHN DAVID, of Llwyndu, in the Swansea Valley, Wales, 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 treating ores containing silver, copper, zinc and lead
in combination with sulphur; the objects of the invention being to progressively
effect the extraction of the several metals and to lessen the cost of treatment.
In carrying out my invention, the ore is first reduced to a moderately fine
powder, and is then heated for twelve or more hours in a closed vessel, or in
a calcining furnace so arranged that the ore can be heated in bulk without
being subjected to any draught, whereupon it can be afterwards calcined without
scintillating; loss in calcination being thus avoided. The ore is then washed
D
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page_text: with hot water aciduated with sulphuric acid for the purpose of removing the
zinc. It is thereupon washed with hot water, and the wash-water added to
that previously obtained. The ore is again washed with a solution of acetate
of lime, and the wash-water mixed with the previous washings. The sulphate
of lead present in the calcined ore is thus converted into an acetate. Upon the
wash-water being mixed with the first and second washings, any silver that may
have passed into solution is precipitated; the precipitate is collected and the
silver and lead recovered in the usual way. The copper in solution is then
precipitated in a metallic state by means of zinc. The solution containing the
is
added zinc, together with that containing the zinc washed out of the ore,
thereupon drawn off and neutralised with ammonical liquor such as obtained
from gas works. The zinc is precipitated as a sulphide by passing a current of
sulphuretted hydrogen gas through the solution. The sulphide of zinc thus
obtained can be collected and may be applied in the manufacture of spelter or
for other uses; whilst the solution, which contains sulphate of ammonia, may
be evaporated to crystalisation, and the sulphuric acid employed as also that
formed during the calcination of the ore recovered. The residual ore is then
smelted in the ordinary way for the recovery of the silver remaining therein.
Having thus particularly described and ascertained the nature of. my inven-
tion and in what manner the same is to be performed, I claim :-
1. The process of treating ores or compounds containing silver, copper, zinc
and lead in combination with sulphur by successive operations for the separation
of the several metals, substantially as herein described."
2. In the treatinent of ores containing silver and certain base metals, heating
the ground ore, in a closed furnace, substantially as herein described, and
whereby scintillation during the subsequent process of calcination is avoided.
3. In the treatment of ores containing silver and certain base metals, the
employment of ammoniacal liquor for the precipitation of the zinc and the
recovery of the sulphuric acid, substantially as herein described.
Dated the 27th day of February 1893.
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent.