An Improved Apparatus for Precipitating Gold and Silver from⚫ Cyanide Solutions.
Year: 1894

page_text: Date of Application, 23rd Jan., 1894-Accepted, 23rd June, 1894
CUMI LEIE DI ECIFICATION
An Improved Apparatus for Precipitating Gold and Silver from⚫
Cyanide Solutions.
We, ALFRED HENRY BELL and CHARLES CARTER, both of Ibapah, Poole
County, Utah United States of America, Metallurgists, 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 :-
Our invention relates to the mechanical precipitation of gold and silver from
cyanide solutions.
It is well known that a weak solution of cyanogen will dissolve gold and silver
and leave the base metals practically undissolved; the precious metals contained in
the solution are precipitated by passing through zinc. Generally this is accom-
plished by means of zinc shavings which as soon as covered with the precious
metals have to be smelted into bars and then refined.
In our device the solution passes up slowly through a pipe leading to a settling
chamber and thence to zinc balls travelling in a zinc pathway, so that as fast as the
metals are deposited on the zinc balls or rings they are rubbed off and descend into
the settling chamber by gravitation.
The device illustrated in the accompanying drawing is intended to overcome the
objections and embody the advantages above set forth.
It should be noted that the device is not intended for pulverization but simply to
bring about complete precipitation of the precious metals.
As shown in the accompanying drawing the apparatus consists of a circular
vessel or receptacle A, arranged in a suitable frame-work H and provided with a
base A', having a central seat c for the reception of a driving shaft C. The base
has a footstep as shown to provide an annular recess or chamber M, into which the
solution is forced by gravity and which serves as a receptacle for the precipitate as
will be hereinafter set forth.
At one side of the centre of the base a groove G, is bored out (or an integral
opening is left when cast) to form a channel for the passage of the solution through
openings g g to the chamber M.
The driving shaft C, has secured to it (integral or keyed thereto) a disc B,
having a zinc ring or plate D, secured thereto. Opposite this ring and secured to
the lower part of the vessel A is another ring of zinc E. These rings do not meet
but have a space left between them for the passage of the solution into the body of
the receptacle A.
Resting on these rings are zinc balls F, as many as may be deemed advantageous.
The solution enters the channel G, from the tank T, and passes upward through the
opening g into the chamber M, and thence between the zinc rings E, D, into the
vessel A. Motion is imparted to shaft C, by a suitable pulley K, and this in turn
imparts a motion of rotation and translation to the balls. This motion of the balls
in contact with the rings tends to keep the balls and rings constantly clear of the
precipitate and therefore bright, as well as to throw the fine particles of zinc into
suspension by friction. This suspension of the zinc particles is absolutely necessary
in the complete precipitation of the small traces of gold and silver in solution. As
the vessel A becomes filled the overflow passes off to a filter S, from whence it is
conducted back to the solution tank. It is obvious that the solution in the vessel A
is kept in a state of agitation and as particles of zinc are thrown off by wearing
contact of the balls and rings there is greater opportunity to precipitate small
traces of gold and silver in solution.
The precipitate gradually settles in the chamber M and is taken out at suitable
intervala

page_text: Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. The method of precipitating gold and silver from solution which consists in
causing the solution to rise up against and between movable and stationary zinc
surfaces, in keeping the solution while in such contact in a state of agitation and
the zinc surfaces bright by friction.
2. In a device for the precipitation of gold and silver from solution, by
mechanically cleaning zinc surfaces and throwing particles of zinc into suspension
in the solution, and collecting the said precipitate by gravitation, a vessel for
holding said solution, said vessel having a base provided with openings to a
precipitate chamber in said base and to the vessel, as set forth.
3. In a device of the nature set forth, the combination with a solution vessel
having a base provided with openings for the passage of the solution to the vessel
and a
precipitate chamber, of a zinc ring or path and of a revolving disc also
provided with a zinc ring or path, and zinc balls moving upon such rings or paths,
substantially as herein stated.
4. In a device for the precipitation of gold and silver from solution as set forth,
the combination of a vessel having a base and zinc path as described, of a revolving
disc also provided with a zinc path, said paths not being in contact to allow the
precipitate to fall between, and a series of zinc balls moving on said zinc paths,
whereby the solution is kept in agitation and the paths and balls kept bright and
free from precipitate, and particles of zinc are thrown into suspension, substantially
as hereinbefore stated.
Dated this 93rd day of January 1901
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.