Improvements in the Separation of Gold from its Chloride Solution.
Year: 1892

page_text: Date of Application, 31st Dec., 1892-Accepted, 4th Feb., 1893
COMPLETE SPECIFICATION.
Improvements in the Separation of Gold from its Chloride Solution.
I, JOSEPH WILLIAM SUTTON, of Eagle Street, Brisbane, in the Colony of
Queensland, Engineer, do hereby declare the nature of my invention for
"IMPROVEMENTS IN THE SEPARATION OF GOLD FROM ITS CHLORIDE
SOLUTION," and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
My invention relates to the separation of gold from the solution obtained by the
action of chlorine on gold or ores containing it.
The object of these improvements is to effect a thorough and rapid separation of
the gold from the chlorine solution and to obtain the gold in a concentrated form
and in such a state that it can be easily filtered out.
Heretofore, in practice, the usual precipitants for gold from its chloride solution
have been either sulphate of iron or charcoal, but both of these have been found
unsatisfactory, the former chiefly on account of a portion of the gold passing
through the filters in a fine state of division, necessitating in some cases a second
filtration, and the latter on account of the large quantity of charcoal which has to
be used in proportion to the gold saved, and the difficulties arising from the
separating of the gold from the charcoal.
One part of my invention consists essentially in utilising a hydro-carbon fluid
preferably a cheap mineral oil such as kerosene as a collector of the gold when
sulphate of iron or other reagent is used for decomposing the solution of gold,
while the other part of my invention consists essentially in using a volatile hydro-
carbon fluid or a resin preferably of turpentine as a collector of gold from its
chloride solution.
Although a hydro-carbon fluid alone will act as a collector of precipitated gold
if accompanied by continued agitation, in carrying my invention into practice I
prefer to add an alkali such as caustic soda or borax to the solution so as to
facilitate the distribution of the hydro-carbon, the alkali, after the gold has been
precipitated (preferably by sulphate of iron), being neutralised by dilute sulphuric
acid.
The hydro-carbon being thus set free, the fine particles of gold are carried with
it either to the top or bottom of the vat according to the specific gravity of the
hydro-carbon used which is then separated from the other liquid and filtered to
recover the gold.
In using a volatile oil or a resin to deposit gold from its chloride solution
the operation is similar to that herein before described with the exception that I
prefer to warm the solution in order to hasten the operation and that I do not add
sulphate of iron or other reagent as the oil or resin (preferably rendered alkaline)
deposits the gold.
But in order that my invention may be thoroughly understood I will now
describe how to carry the same into practice.
In one form of my process I proceed as follows:-Having approximately
ascertained the number of grains of gold which the chloride solution carries to the
gallon for example say 10 grains to the gallon-I add fifteen times the weight
say 150 grains of a saturated, solution of borax or a similar quantity of a 50 per
cent. solution of an alkali, and then add thirty times the weight of hydro-carbon,
say kerosene oil that is 300 grains or one per cent. to the gallon of chloride
solution.
The whole is then well agitated and while in a state of agitation I add 150 grains
of a saturated solution of sulphate of iron or about fifteen times the weight of the
gold contained in the solution.

page_text: After this agitation has been continued for about three or four minutes the
whole is then run into a vat or receiver and allowed to stand for-say fifteen
minutes, when it will be found that the whole of the gold (and the surplus iron
which has been precipitated by the alkali) rises to the top leaving the lower portion
of the vat free from gold. I then run off the surplus waste solution as near as
practicable to the floating mass to which I then add dilute sulphuric acid which
serves a threefold purpose by dissolving the iron precipitated by the alkali;
by freeing the oil particles and by increasing the density of the solution. The
oil having been set free by the acid carries the particles of gold with it to the
surface.
The whole is then filtered and the acid and oil afterwards separated by gravity.
The oil is then ready for fresh operations while the acid may be further
strengthened with iron and used again as sulphate of iron.
The gold which is all left in the filter is now in a state to be melted into
ingots.
In using a volatile oil or a resin to separate the gold I proceed as follows:-
To a chloride of gold solution carrying say 10 grains of gold to the gallon I add
150 grains of a saturated solution of borax or a similar quantity of a 50 per cent.
alkaline solution. I then add 300 grains of turpentine or thirty times the weight
of the gold contained in the solution.
The whole is then agitated for about thirty minutes during which time I heat
the solution to about 180 degrees Fahrenheit to facilitate the operation.
I then add dilute sulphuric acid to free the oil which rises to the surface
carrying the gold with it. The contents of the vat are then filtered and the
operation continued as hereinbefore described.
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. In the precipitation of gold from its chloride solution by sulphate of iron or
other reagent the use of a hydro-carbon fluid as a collector of the gold substantially
as hereinbefore described and explained.
2. In the precipitation of gold from its chloride solution by sulphate of iron or
other reagent the use of a hydro-carbon fluid mixed with an alkali as a collector
of the gold substantially as hereinbefore described and explained.
3. Separating gold from its chloride solution by means of a volatile oil or resin,
or a mixture thereof, substantially as hereinbefore described and explained.
4. Separating gold from its chloride solution by means of a volatile oil or resin,
or a mixture thereof, rendered alkaline by the addition of borax or other alkali or
alkaline salt, substantially as herein before described and explained.
Dated this S1st day of December 1892.
Dated GHIS DIST Ɑday of December 1892.
J. W. SUTTON.
Abel & Imray,
Agents for the Applicant.