A NEW OR IMPROVED PROCESS FOR TREATING GOLD ORES OR OTHER AURIFEROUS SUBSTANCES, AND MORE ESPECIALLY REBELLIOUS OR REFRACTORY GOLD ORES AND CONCENTRATES, BY ELECTROLYSIS WITHOUT PREVIOUSLY FURNACING THE SAME "
Year: 1883

page_text: LETTERS PATENT to Henry Renner Cassel, of the City and State of New
York, United States of America, temporarily of 41 Southampton Buildings,
Holborn, in the County of Middlesex, for an Invention of "A NEW OR
IMPROVED PROCESS FOR TREATING GOLD ORES OR OTHER AURIFEROUS
SUBSTANCES, AND MORE ESPECIALLY REBELLIOUS OR REFRACTORY GOLD ORES
AND CONCENTRATES, BY ELECTROLYSIS WITHOUT PREVIOUSLY FURNACING THE
SAME
"
PROVISIONAL SPECIFICATION left by the said Henry Renner Cassel at the
Office of the Commissioners of Patents on the 13th October 1883.
HENRY RENNER CASSEL, of the City and State of New York, United States of
America, temporarily of 41 Southampton Buildings, Holborn, in the County of
Middlesex, "A NEW OR IMPROVED PROCESS FOR TREATING GOLD ORES OR OTHER
AURIFEROUS SUBSTANCES, AND MORE ESPECIALLY REBELLIOUS OR REFRACTORY GOLD
ORES AND CONCENTRATES, BY ELECTROLYSIS WITHOUT PREVIOUSLY FURNACING
THE SAME
"
In treating free gold ores or other auriferous substances by electrolysis a solution
of chloride of sodium is advantageously used. The solution is decomposed by
electrolytic action, and the nascent chlorine thus generated rapidly combines with
the gold, and the chloride of gold formed is easily dissolved in the water of the
solution. Of course any other salt in solution, capable of generating chlorine under
electrolytical decomposition may also be employed.
When, however, rebellious or refractory gold ores and concentrates (such as
pyrites for example) are treated with such a solution, a secondary action takes
The reason of
place and prevents the extraction of the gold contained in the ore.
this is that the chlorine and hydrogen liberated combined and form hydrochloric
•

page_text: acid, which attacks any compound of iron in the ore, and changes it into a proto
salt, and this proto salt immediately precipitates the gold in solution as fast as it
is formed. The presence of free hydrochloric acid is further objectionable as it also
attacks any antimony, arsenic or other rebellious or refractory elements contained
in the ore.
The object of my invention is to prevent this, and for this purpose I propose to
add to the ore or to the solution a substance which will neutralize the hydrochloric
acid as soon as it is formed, but which will not precipitate the gold. Since no free
bydrochloric acid can exist in the presence of such a substance, any compound of
iron contained in the ore will not be attacked, and its proto salt cannot, therefore,
be formed, so that the gold consequently will not be precipitated and can easily be
extracted from the ore. Further, the other refractory elements present in the ore
will also remain unaffected, so that it will be unnecessary to first furnace or roast
the ore for the purpose of eliminating the rebellious or refractory elements.
The substance I propose to employ is lime, but any suitable alkaline earth or
other chemical compound or element for which the hydrochloric acid has a stronger
affinity than for the compounds of iron in the ores, but which will not precipitate
gold, may be employed. Or I may use a solution which will itself by electrolytical
decomposition, yield a base capable when free of neutralizing the hydrochloric acid
formed, but which will not precipitate the gold.
The apparatus employed for carrying on my improved process above described
may be of any suitable construction.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Henry Renner Cassel in the Patent Office on the 12th April
1884.
HENRY RENNER CASSEL, of the City and State of New York, United States of
America, temporarily of 41 Southampton Buildings, Holborn, in the county of
Middlesex, "A NEW OR IMPROVED PROCESS FOR TREATING GOLD ORES OR OTHER
AURIFEROUS SUBSTANCES, AND MORE ESPECIALLY REBELLIOUS OR REFRACTORY GOLD
ORES AND CONCENTRATES, BY ELECTROLYSIS WITHOUT PREVIOUSLY FURNACING
THE SAME."
In treating free gold ores or other auriferous substances by electrolysis a solution
of chloride of sodium is advantageously used. The solution is decomposed by
electrolytic action, and the nascent chlorine thus generated rapidly combines with
the gold, and the chloride of gold formed is easily dissolved in the water of the
solution. Of course any other salt in solution, capable of generating chlorine under
electrolytical decomposition may also be employed.
When, however, rebellious or refractory gold ores and concentrates (such as
pyrites for example) are treated with such a solution, a secondary action takes
place and prevents the extraction of the gold contained in the ore. The reason of
this is that by this secondary action hydrochloric and hypochlorous acids are
formed and attack any compound of iron in the ore, changing it into a proto salt,
and this proto salt immediately precipitates the gold in solution as fast as it is
formed. The presence of free acid is further objectionable as it also attacks any
antimony, arsenic or other rebellious or refractory elements contained in the ore.
The object of my invention is to prevent this, and for this purpose I propose to
add to the ore or to the solution a substance which will neutralize the acids as
soon as they are formed, but which will not precipitate the gold. Since no free
acid can exist in the presence of such a substance, any compound of iron contained
in the ore will not be attacked, and its proto salt cannot, therefore, be formed, so
that the gold consequently will not be precipitated and can easily be extracted from
the ore.
Further, the other refractory elements present in the ore will also remain
unaffected, so that it will be unnecessary to first furnace or roast the ore for the
purpose of eliminating the rebellious or refractory elements.
The substance I propose to use is lime, but any suitable alkaline earth or other
chemical compound or element for which the acids have a stronger affinity than
for the compounds of iron in the ores, but which will not precipitate gold, may be
employed. Or I may use a solution which will itself by electrolytical decomposition,
yield a base capable when free of neutralizing the acids formed, but which will not
precipitate the gold.
The apparatus employed for carrying on my improved process may be of any
suitable construction.
Having now described the nature of the said invention and in what manner the
same is to be carried into effect, I wish it to be understood that what I claim is :-
The employment in the process above described for the treatment of gold ores or
other auriferous substances, and more especially rebellious or refractory gold ores
and concentrates, of lime or any suitable alkaline earth or other chemical compound
or element, for which any acids generated during the electrolytic action have a

page_text: stronger affinity than for the compounds of iron in the ore, but which will not
precipitate gold, or of a solution which itself under electrolytical decomposition will
yield such a base, substantially for the purpose specified.
In witness whereof, J, the said Henry Renner Cassel, have hereunto set my
hand and seal, this twelfth day of April in the year of our Lord one thousand
eight hundred and eighty-four.
212ADE
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