Improvements in Effecting the Separation of Gold from Antimony.
Year: 1889

page_text: Date of Application, 24th Apr., 1889
Complete Specification Left, 24th Jan., 1890-Accepted, 24th May, 1890
PROVISIONAL SPECIFICATION.
Improvements in Effecting the Separation of Gold from Antimony.
I, THOMAS CRISP SANDERSON. of Minas do Corgo near Lixa, Oporto, Portugal
Chemist and Metallurgist, do hereby declare the nature of this invention to be as
follows:-'
This invention has reference to the separation by electrolysis, of gold from antimony
obtained by smelting auriferous antimony ores.
For this purpose the antimony containing the gold is cast into a plate enclosed (or
not) in a porous envelope or container and arranged within a bath of a suitable salt of
antimony and connected with one pole of a suitable source of electricity, such as a
dynamo, to serve as a positive electrode. To the other pole is connected a plate of
suitable metal such as copper, placed in the bath to serve as a negative electrode.
When a current of electricity is passed through the bath the antimony plate will be
dissolved in the hath and then deposited upon the negative electrode, whilst the gold
contained in the antimony plate will be retained in the porous envelope or container.
In carrying out the invention the antimony ore is smelted in the ordinary way, the
gold being collected in the reduced antimony which is cast into plates to serve as
electrodes. The antimony plates thus prepared may in some cases be advantageously
pickled in hydrochloric acid in order to remove any iron sulphide, that may be present
on the plates.
The electrolysing bath, which is a solution of antimony chloride in hydrochloric
acid, can be prepared by treating roughly powdered antimony ore with warm com-
mercial hydrochloric acid until it will dissolve no more, the solution being then
decanted and warmed to free it from sulphuretted hydrogen. In this solution is
placed one or more of the gold bearing antimony plates, enclosed in
porous envelopes
such as calico bags to retain the fine residue contained in the gold. The plate or
plates is or are connected up electrically to form a positive electrode or electrodes.
One or more sheets of copper are also placed in the bath and connected up to serve
as a negative electrode or electrodes and upon it or them the antimony will be
deposited by electrolysis on the passage of an electric current.
The porous envelopes serve to prevent the impurities and contained gold present in
the plate of impure antimony from passing into the bath.
The bath will last until it becomes saturated with the iron or other metal present in
small quantities in the antimony treated.
Fresh quantities of chloride of antimony may be made from time to time as
desired either by dissolving some of the ore in hydrochloric acid or by roasting
the cre with common salt in a furnace. The antimony thus deposited may afterwards
be removed from the negative electrode and cast into ingots if desired. The impurities
contained in the gold are treated in any suitable manner for the recovery of the gold
therefrom.
Dated this 24th day of Anril 1889
W. LLOYD WISE,
Per F. J. Brougham.
COMPLETE SPECIFICATION.
Improvements in Effecting the Separation of Gold from Antimony.
I THOMAS CRISP SANDERSON, of Minas do Corgo, near Lixa, Oporto, Portugal,
Chemist and Metallurgist, do hereby declare the nature of this invention and in
[Price Gidl

page_text: what manner the same is to be performed to be particularly described and ascertained
in and by the following statement :-
This invention has reference to the separation, by electrolysis, of gold from the
antimony obtained by the smelting of auriferous antimony ores.
For this purpose the antimony containing the gold is according to this invention,
placed in a bath of a suitable salt of antimony and connected up with one pole
of an electric generator, such as a dynamo, to serve as a positive electrode or anode.
To the other pole is connected a plate of suitable conducting material such as carbon,
or antimony free from gold or copper, that is placed in the bath to serve as a
negative electrode or cathode and a current of electricity is passed through the
bath between the electrodes whereby the antimony plate will be dissolved in the
bath by electrolytic action leaving a mud containing most of the impurities originally
present in the plate and practically the whole of the gold present. Metallic antimony
will at the same time be deposited upon the negative electrode from the bath or
electrolyte.
In carrying out the invention the auriferous antimony ore is smelted in the
ordinary way, the gold therein being collected in the reduced antimony which is used
in any suitable form such as a block or plate (hereinafter referred to as a plate) to
serve as an electrode. The antimony plate thus obtained may, when sulphide of iron
is present thereon, advantageously be pickled in hydrochloric or sulphuric acid in
order to remove the sulphide of iron.
For the electrolysing bath it is preferred to use a solution of chloride of antimony
commonly called "Butter of Antimony." This compound can be prepared by treating
roughly powdered antimony ore with warm cominercial hydrochloric acid until the
acid will dissolve no more. The solution is then decanted from the insoluble matter
and warmed to free it from sulphuretted hydrogen.
"
Chloride of antimony as is well known cannot be mixed with water without
undergoing decomposition, but it can be diluted to a very large extent with a strong
solution of commion salt, or with equivalent solutions of chlorides of potash or
ammonium, without becoming decomposed. A solution of "Butter of Antimony
in strong brine, that has been found to give satisfactory results is made by adding
one measure of butter of antimony containing 35% of antimony chloride (Sb Cl₂) to
three measures of saturated brine. The solution should be made slightly acid with
hydrochloric acid. In the solution or electrolyte thus prepared is or are placed one,
or more, of the gold bearing antimony plates. The plate, or each of them if there be
more than one, is connected up with an electric generator to form a positive electrode,
and one or more plates of conducting material such as hereinbefore mentioned are
also placed in the bath and connected up with the electric generator to serve as a
negative electrode, or electrodes, upon which the antimony will be electrolytically
deposited on the passage of an electric current through the bath. Satisfactory results
have been obtained with a current having an electro motive force of 0.5 volt.
For the purpose of collecting the auriferous mud resulting from the solution of the
auriferous antimony plates in the electrolyte, the plates may each be suspended or
enclosed within a porous envelope or container of suitable material as for example
calico, flannel, or asbestos cloth or fibre. It is however preferred in practice to use
the following arrangement. A rectangular frame of wood is employed over both
sides of which is stretched porous material of the kind mentioned. The upper part
of the frame is cut away so as to leave an opening through which the plate to
serve as the negative electrode is introduced so as to rest upon the bottom of the
frame, when the same is placed in the vat or other vessel in which the process is to be
effected. The frame is suspended in this vessel so as not to reach to the bottom
thereof. The antimony plates constituting the positive electrodes are suspended in
the vessel between frames containing negative plates as just described. To circulate the
solution for the purpose of keeping it in a uniform condition, it is drawn from the
bottom of the vessel passed through a filter to remove the auriferous mud, and
again introduced into the vessel through the top of the frames containing the

page_text: negative electrodes. By this means the passage of the strong muddy solution from
the surface of the positive electrodes through the porous envelope or container and
the closing of the pores therein by the mud, such as would be the case if the positive
electrodes were enclosed in porous material, are avoided, and a constant passage of
clean solution from each negative electrode through the porous material towards the
positive electrode is obtained.
The mud resulting from the solution of the auriferous antimony plate or plates is
treated by any of the well known methods suitable for the recovery of the gold
therein, and the antimony deposited upon the negative electrode or electrodes is
removed from time to time and may be melted down into ingots if desired.
Instead of making the bath by adding "Butter of Antimony" to brine it may be
made by simply using brine acidified with hydrochloric acid. On the passage of a
current through the bath the positive electrode of antimony will dissolve and a bath of
chloride of antimony in brine will be formed and after a time the antimony will
commence to be deposited upon the negative electrode as before.
The antimony bath employed for the herein described electrolytic process, may be
used until it becomes too strongly charged with the iron or other metal present in
small quantities in the antimony treated. It must then be replaced by a fresh solution
of chloride of antimony, which may be made from time to time, as required in either
of the ways hereinbefore mentioned.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. Effecting the separation of gold from auriferous antimony by making such
antimony the positive electrode in a suitable bath or electrolyte, dissolving the antimony
by electrolytic action, and extracting the gold from the impurities or mud remaining
after the solution of the antimony substantially as herein before described.
2. In the separation of gold from antimony by electrolysis as referred to in the
preceding claim, the use of a bath or electrolyte consisting of a solution of chloride of
antimony in brine substantially as hereinbefore described.
ديم
1
- 1900
Dated Muay
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.