Improvements in or relating to the Treatment of Ores for the Extraction of Metals therefrom.
Year: 1894

page_text: Date of Application, 27th Apr., 1894
Complete Specification Left, 16th Jan., 1895-Accepted, 16th Feb.,
1895
PROVISIONAL SPECIFICATION.
Improvements in or relating to the Treatment of Ores for the
Extraction of Metals therefrom.
1, HENRY LIVINGSTONE SULMAN of 60 Gracechurch Street, in the County
of Middlesex, Analytical Chemist, do hereby declare the nature of this invention
to be as follows:
During the preparation of ores-whether gold-bearing or of silver, lead, tin, or
other metals,-varying quantities of very finely divided material are produced by
the action of the stamps rolls or other apparatus used in crushing such ores which
owing to the extreme fineness of the grains or particles composing them are
frequently impermeable, or permeable only with difficulty by liquids and are
therefore unsuitable to treatment by aqueous solutions or "leaching." These
finely divided products are technically known as "slimes."
In the case of gold and silver ore slimes, these being unleachable by solutions
of potassic cyanide, soda hyposulphite, chlorine, and other solvents for precious
metals, or leachable only with extreme difficulty, these products are not only of no
practical value notwithstanding their containing gold or silver, but the means taken
to avoid their formation viz. by avoiding as far as possible fine crushing of the
original ores, tends to create other difficulties-for instance the imprisoning of fine
particles of gold or silver in the imperfectly crushed ore.
In a great many instances therefore the present methods of crushing are merely
a compromise between these two causes of loss both of which would however
disappear completely if the slimes in whatever quantities produced could be readily
leached with suitable solvents.
This I effect by using in connection with the moist or wetted slimes a combination
of agents capable of producing a coagulum in greater or less quantity throughout
the entire mass. I have found by these means that a slime totally impermeable to
water has been rendered readily leachable by the desired solvent.
The agents employ are such as give a good coagulum insoluble in the solvent
with which it is desired to leach the slime subsequently-such as treatment of the
slime first with a solution of gelatine and then with one of tannic acid or a metallic
salt such as precipitates the gelatine with formation of a coagulum.
Some of these coagulume are more suitable for such purposes than others and for
the specific purpose of leaching gold ore slimes I have found that the coagulum
obtained by precipitating ordinary soap by lime or other suitable precipitant gives
excellent results: and a quite impermeable slime becomes readily permeable and
can be percolated by water or aqueous solvents when treated first with a solution
of soap in water followed by a thorough admixture of quicklime made into a milk
or cream with water.
If desired the slimes may first be treated with the cyanide of potassium or other
suitable solution and when the action of this solvent for the gold is judged to be
completed, the soap solution may be mixed with the mass, followed by the
admixture of the milk of lime and the whole inass may then be discharged into
suitable leaching tanks or filters when the gold or silver bearing solution will
readily filter off, and the last traces of this liquid can be removed from the now
depleted slime by percolation with water.
I do not confine myself to any particular coagulum or to the treatment of any
particular slime, the above given example showing merely how I proceed in the

page_text: case of an unleachable gold or silver ore slime: but I may vary the nature,
quantities and proportions of the coagulating agents I employ according to the
requirements of the ore slime under treatment.
The above method of treatment applies also to slimes or finely divided deposits
obtained from hydraulic workings of alluvial or similar ores.
Dated this 27th day of April 1894.
W. P. THOMPSON & BOULT,
Agents for the Applicant.
Improvements in or relating to the Treatment of Ores for the
Extraction of Metals therefrom.
I, HENRY LIVINGSTONE SULMAN, of 60 Gracechurch Street, in the County of
Middlesex, 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:-
During the preparation of ores-whether gold-bearing or of silver, lead, tin, or
other metals, varying quantities of very finely divided material are produced by
the action of the stamps, rolls or other apparatus used in crushing such ores which,
owing to the extreme fineness of the grains or particles composing them, are
frequently impermeable or permeable only with difficulty by liquids and are
therefore unsuitable to treatment by aqueous solutions or leaching." These
finely divided products are technically known as "slimes."
<<
In the case of gold and silver ore slimes, these being unleachable by solutions of
potassic cyanide, soda hyposulphite, chlorine, and other solvents for precious metals,
or leachable only with extreme difficulty, these products are not only of no practical
value notwithstanding their containing gold or silver, but the means taken to avoid
their formation viz.: by avoiding as far as possible fine crushing of the original
ores, tends to create other difficulties-for instance the imprisoning of fine particles
of gold or silver in the imperfectly crushed ore.
In a great many instances therefore the present methods of crushing are merely
a compromise between these two causes of loss both of which would however
disappear completely if the slimes in whatever quantities produced could be readily
leached with suitable solvents.
This I effect by using in connection with the moist or wetted slimes a combination
of agents capable of producing a coagulum in greater or less quantity throughout
the entire mass. I have found by these means that a slime totally impermeable to
water has thus been rendered readily leachable by the desired solvent.
The agents I employ are such as give a good coagulum insoluble in the solvent
with which it is desired to leach the slime subsequently, such as treatment of the
slime first with a solution of gelatine and then with one of tannic acid or a metallic
salt such as precipitates the gelatine with formation of a coagulum.
Some of these coagulums are more suitable for such purposes than others and
for the specific purpose of leaching gold ore slimes I have found that the coagulum
obtained by precipitating ordinary soap by lime or other suitable precipitant gives
excellent results and a quite impermeable slime becomes readily permeable and
can be percolated by water or aqueous solvents when treated first with a solution
of about 5 to 10 lbs. soap in water to 1 ton of slimes (reckoning the latter upon the
dry material) followed by a thorough admixture of 2 to 3 lbs. of quicklime made
into a milk or cream with water.
If desired the slimes may first be treated with the cyanide of potassium or other
suitable solution and when the action of this solvent for the gold is judged to be

page_text: completed, the soap solvent may be mixed with the mass, followed by the admixture
of the milk of lime and the whole mass may then be discharged into suitable
leaching tanks or filters when the gold or silver bearing solution will readily filter
off, and the last traces of this liquid can be removed from the now depleted slime
by percolation with water.
I do not confine myself to any particular coagulum or to the treatment of any
particular slime, the above given example shewing merely how I proceed in the
case of an unleachable gold or silver ore slime; but I may vary the nature
quantities and proportions of the coagulating agents I employ according to the
requirements of the ore slime under treatment.
The above method of treatment applies, also to slimes or finely divided deposits
obtained from bydraulic workings of alluvial or similar ores.
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 above method of treating slimes or analogous deposits so as to render
them permeable by the formation of a coagulum substantially as described.
2. The employment in the treatment of slimes and analogous deposits of soap
with a precipitant substantially as described.
Dated this 15th day of January 1895.
HENRY LIVINGSTONE SULMAN.
Boult & Wade,
Agents for the Applicant.
HENRY LIVINGSTONE SULMAN.
Boult & Wade,
Agents for the Applicant.