Improvements in or relating to the Treatment of Ores and the Precipitation of Precious Metals from their Cyanide Solutions.
Year: 1899

page_text: "
PROVISIONAL DIVIFICATION.
Improvements in or relating to the Treatment of Ores and the
Precipitation of Precious Metals from their Cyanide Solutions.
We, FREDERICK WILLIAM MARTINO, Manufacturer, of 107, Montgomery Road,
Sharrow, Sheffield, in the County of York, and FREDERIC STUBBS, Engineer, of
Edgegate," Osborne Road, Shetfield, in the County of York, do hereby declare
the nature of this invention to be as follows:-
This invention relates to the treatment of ores of the precious metals, and
tailings formed from their treatment, and the precipitation of precious metals
from their cyanide solutions, its object being to set "free," the precious metal
prior to its extraction when it is in the occluded" state, and also to obviate
the necessity for the use of zinc in precipitating precious metals from their
cyanide solutions.
The present invention is a development of that forming the subject of our
previous Application for Letters Patent No. 25979 of 1898. In the specification
accompanying that application we described the use of calcium carbide and
acetylene, but we have now found that similar re-actions take place, when,
instead of calcium carbide, any metallic carbide which produces a hydrocarbon gas
when brought into contact with water, is used. We have also found that all
the hydrocarbon gases which can be so produced, re-act in a substantially similar
way to acetylene, and moreover that this re-action occurs however such hydro-
carbon gases are manufactured. As an example, aluminium carbide, which on
being treated with water produces methane, may be mentioned.
It is to be clearly understood that in this specification wherever the terms
"metallic carbide" or "hydrocarbon gas" are mentioned they are to be read
as indicating respectively, any metallic carbide, or hydrocarbon gas of the kinds
above referred to with the exception of calcium carbide and acetylene.
The hydrocarbon gas, or a mixture of such gas and oxygen, is passed through a
cyanide solution containing gold, or a metallic carbide may be added to the
liquid, thus producing a nascent hydrocarbon gas; in either case the gold is
precipitated. The process is found to be quicker and cleaner if oxygen be passed
through the solution, such oxygen being either in the form of a separate gas, or
mixed with nitrogen in the form of ordinary atmospheric air.
When the precious metals are in the "occluded" state, that is to say, when
they are combined with or intimately enclosed in the metalloids-selenium,
tellurium, fluorine, etc., for example-or the baser metals such as arsenic and
antimony, the ore is finely divided and thoroughly mixed in a dry state with a
metallic carbide. The mixture is then moistened and the result of the re-actions
which then take place is to free the precious metals partially or wholly from
their occluded" state.
The free precious metal may be treated in any convenient way, preferably
the coarser metal is separated by washing and the finer particles dissolved in a

page_text: cyanide solution, which is then subjected to the action of a hydrocarbon gas as
hereinbefore described.
Heat from any outside source, may, if desired, be applied during any of the
stages constituting this improved process.
BOULT & WADE,
Agents for the Applicants.
Improvements in or relating to the Treatment of Ores and the
Precipitation of Precious Metals from their Cyanide Solutions.
We, FREDERICK WILLIAM MARTINO, Manufacturer, of 107, Montgomery Road,
Sharrow, Sheffield, in the County of York, and FREDERIC STUBBS, Engineer, of
Edgegate," Osborne Road, Sheffield, in the County of York, 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 treatment of ores of the precious metals, and
tailings formed from their treatment, and to the precipitation of precious metals
from their cyanide solutions, its object being to set "free," the precious metal
prior to its extraction when it is in the occluded state, and also to obviate
the necessity for the use of zinc in precipitating precious metals from their
cyanide solutions.
14
"
The present invention is a development of that forming the subject of our
previous Application for Letters Patent No. 25979 of 1898. In the specification
accompanying that application we described the use of calcium carbide and
acetylene, but we have now found that similar re-actions take place, when,
instead of calcium carbide, any metallic carbide which produces a hydrocarbon gas
when brought into contact with water, is used. We have also found that all
the hydrocarbon gases which can be so produced, re-act in a substantially similar
way to acetylene, and moreover that this re-action occurs however such hydro-
carbon gases are manufactured. As an example, aluminium carbide, which on
being treated with water produces methane, may be mentioned.
It is to be clearly understood that in this specification wherever the terms
"metallic carbide" or "hydrocarbon gas' are mentioned they are to be read
as indicating respectively, any metallic carbide, or hydrocarbon gas of the kinds
above referred to with the exception of calcium carbide and acetylene.
66
The hydrocarbon gas, is passed through a cyanide solution containing a
precious metal, say gold, or a metallic carbide may be added to the liquid, thus
producing a nascent hydrocarbon gas; in either case the gold is precipitated.
When a hydrocarbon gas is passed through the cyanide solution its action is
found to be promoted by also passing atmospheric air through the liquid.
When the precious metals are in the occluded" state, that is to say, when
they are combined with or intimately enclosed in the metalloids-selenium,
tellurium, fluorine, etc., for example-or the baser metals such as arsenic and
antimony, the ore is finely divided and thoroughly mixed in a dry state with a
metallic carbide. The mixture is then moistened and the result of the re-actions
which then take place is to free the precious metals partially or wholly from
their
"
occluded state.
"
The free precious metal may be treated in any convenient way, preferably
the coarser metal is separated by washing and the finer particles dissolved in a

page_text: cyanide solution, which is then subjected to the action of a hydrocarbon gas as
hereinbefore described.
Heat from any outside source, may, if desired, be applied during any of the
stages constituting this improved process; for instance the cyanide solution may
be heated before, or during treatment, by passing steam through pipes immersed
in it, or the vessels containing the solution may be steam jacketed. Again the
intimate mixture of ore and the metallic carbide, either before or after moistening
may be heated in any convenient form of furnace, such heating being found to
accelerate the process.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that
what we claim is:-
1
1. In the treatment of ores or tailings containing the precious metals the
employment of a metallic carbide of the kind described.
2. In the treatment of ores or tailings containing the precious metals the
employment of a hydrocarbon gas of the kind described.
3. In the precipitation of the precious metals from their cyanide solutions
the employment of a hydrocarbon gas of the kind described with or without
atmospheric air.
4. The precipitation of the precious metals by the addition of a metallic
carbide of the kind described to their cyanide solutions.
5. The treatment of ores or tailings containing the precious metals by finely
dividing the ore mixing it with a metallic carbide of the kind described and
moistening the mixture substantially as described.
Dated this 25th day of August 1899.
FREDERICK WILLIAM MARTINO.
FREDERIC STUBBS.
Boult & Wade,
Agents for the Applicants.