improvemaining Gold from Refractory Ores or other Auriferous Substances.
Year: 1886

page_text: Date of Application, 2nd Nov., 1886.
Complete Left, 22nd July, 1887.
Complete Accepted, 23rd Aug., 1887.
improvemaining Gold from Refractory Ores or other
Auriferous Substances.
I, JAMES BALLANTYNE HANNAY, of Cove Castle, Loch Long, in the County of
Dumbarton, North Britain, Chemist, do hereby declare the nature of this Invention
to be as follows, that is to say :-
My said Invention has for its object to improve and render more effective,
economical and satisfactory processes of the kinds in which chlorine is employed for
obtaining gold from refractory ores or other auriferous substances.
In carrying out my Invention I employ liquefied chlorine, that is gaseous chlorine
reduced to the liquid state by well known means; or I employ nascent chlorine
evolved by electrolysis as in what is known as the Cassel process. The gold ore or
auriferous substance is reduced to a fine powder and mixed with water or a suitable
solution; and the chlorine is injected into the mixture by means of its own expansive
force. In the cases of some ores or substances the gold is at once obtained in solution
as chlorine in a more or less pure condition and can be recovered therefrom by well
known processes. In many cases however, the gold ores or auriferous substances
contain iron or other metals which are dissolved by the action of the chlorine and
become reduced to protochlorides, or other proto salts, and which in that form cause
the premature precipitation of any gold that has been dissolved as chloride. An
important part of my Invention consists in the means which I employ to avoid this
premature precipitation of the gold.
When using liquefied chlorine as herein before described or when in any other
effective way applying chlorine not electrolytically evolved, I cause an electric
current, which may be comparatively weak, to pass through the solution in which
the powdered gold ore or auriferous substance is mixed and I place one or more
anodes or positive electrodes in such solution, whilst I place one or more cathodes or
negative electrodes in a compartment of the vessel separated by a porous partition or
diaphragm from that containing the gold ore or auriferous substance. And in order
to prevent the premature precipitation of the gold by proto salts of iron or other metal
I dissolve in the water or solution in the compartment containing the cathodes a

page_text: suitable quantity of cyanide of potassium or other suitable soluble cyanide or sulpho-
cyanide, such cyanide having the effect of keeping the gold in solution until it is by
the action of the electric current carried to and deposited upon the cathode or
cathodes.
If the chlorine used is obtained by the action of an electric current as in the Cassel
process, then the electric current being already present, the object in view is obtained
by simply placing a suitable cyanide in solution in the cathode compartment of the
apparatus.
Ordinary commercial cyanide of potassium can be used in carrying out my
Invention. This salt is usually alkaline but in any case it is desirable in using it
to keep the solution alkaline.

page_text: COMPLETE SPECIFICATION.
Improvements in Obtaining Gold from Refractory Ores or other
Auriferous Substances.
I, JAMES BALLANTYNE HANNAY, of Cove Castle, Loch Long, in the County of
Dumbarton, North Britain, 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, that is to say :-
My said Invention has for its object to improve and render more effective
economical and satisfactory processes of the kinds in which chlorine is employed for
obtaining gold from refractory ores or other auriferous substances.
In carrying out my Invention 1 employ liquefied chlorine, that is gaseous chlorine
reduced to the liquid state by well known means; or I employ nascent chlorine
evolved by electrolysis as in what is known as the Cassel process. The gold ore or
auriferous substance is reduced to a fine powder and mixed with water or a suitable
solution; and the chlorine is injected into the mixture by means of its own expansive
force. In the cases of some ores or substances the gold is at once obtained in solution
as chloride in a more or less pure condition and can be recovered therefrom by well
known processes.
In many cases, however, the gold ores or auriferous substances
contain iron or other metals which are dissolved by the action of the chlorine and
become reduced to protochlorides, or other proto salts, and which in that form cause
the premature precipitation of any gold that has been dissolved as chloride. An
important part of my Invention consists in the means which I employ to avoid this
premature precipitation of the gold.
When using liquefied chlorine as heretofore described or when in any other
effective way applying chlorine not electrolytically evolved, I cause an electric current,
which may be comparatively weak, to pass through the solution in which the powdered
gold ore or auriferous substance is mixed, and I place one or more anodes or positive
electrodes in such solution, whilst I place one or more cathodes or negative electrodes
in a compartment of the vessel separated by a porous partition or diaphragm from that
containing the gold ore or auriferous substance. And in order to prevent the pre-
mature precipitation of the gold by protosalts of iron or other metal I dissolve in the
water or solution in the compartment containing the cathodes a suitable quantity of
cyanide of potassium or other suitable soluble cyanide or sulphocyanide, such cyanide
having the effect of keeping the gold in solution until it is by the action of the electric
current carried to and deposited upon the cathode or cathodes.
If the chlorine used is obtained by the action of an electric current as in the Cassel
process, then the electric current being already present, the object in view is obtained
by simply placing a suitable cyanide in solution in the cathode compartment of the
apparatus.
Ordinary commercial cyanide of potassium can be used in carrying out my
Invention. This salt is usually alkaline but in any case it is desirable in using it to
baon the solution alkaline

page_text: 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 :-
1. Using liquefied chlorine substantially in the manner hereinbefore described for
obtaining gold from refractory ores or other auriferous substances.
2. Using cyanide of potassium or other suitable soluble cyanide or sulphocyanide
in combination with an electric current substantially as and for the purposes herein-
before described.