Improvements in Means and Apparatus for Separating Gold, Silver, and other Metals from their Öres.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improvements in Means and Apparatus for Separating Gold, Silver,
and other Metals from their Öres.
1, GEORGE JONES ATKINS, of Hutchin's Wharf, Millwall, in the County of
Middlesex, Electro-metallurgist, do hereby declare the nature of the said invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement, reference being had to the accom-
panying four sheets of drawings, and to the letters and figures marked thereon, that
is to say:
This invention relates to that kind of apparatus for separating gold, silver and
other metals from their ores for which a Patent was granted to me bearing date
the 28th September 1886 No. 12,295 in which apparatus crushed or pulverized ore
is subjected to electrolytic action in the anode compartment of an electrolytic
apparatus, such anode compartment being provided with devices by which the said
ore is retarded in its descent through the said anode compartment, so as to
keep the particles of ore in motion and in contact with the anode pole, in the
electrolytic solution, for a sufficient period of time to allow the chemical action,
such as oxidation, chlorinization, or treatment with cyanogen, etcetera, to take
place; such crushed or pulverized ore being then subjected to the action of mercury
in an amalgamating apparatus either connected directly with the aforesaid electro-
lytic apparatus or separate therefrom.
In the drawings hereto annexed
Figure 1 is an elevation, Figure 2 a sectional elevation taken on line 1-1 of
Figure 1, and Figure 3 a sectional elevation taken on line 2-2 of Figure 2, of an
electrolytic and amalgamating apparatus of the kind above referred to with certain
of my present improvements applied thereto.
A is a cylindrical vessel of copper or other suitable material forming the containing
vessel or chamber, and cathode pole of the electrolytic apparatus; it is conveniently
made in two halves bolted together by flanges as shown, in order to enable ready
access to be had to the anode pole contained therein. The said anode pole consists
of a broad bladed screw D composed of carbon, lead, peroxide of lead or any other
suitable material which is a conductor of electricity; but not soluble in the
electrolytic solution employed. It is preferably constructed in the manner described
in the Specification of a Patent granted to me bearing date the 19th June 1889
No. 10,061 and is mounted on a shaft C2 the upper end of which is carried in a
bearing C supported by the framework or bracket Cx. Rotatory motion is
imparted to the shaft C' and consequently to the screw D, by means of the bevil
wheel C which receives its motion from the bevil wheel C7 fixed on the shaft C8
driven by a belt or otherwise. The shaft C2 is insulated electrically, by any of
the well known arrangements for that purpose, from the framework or bracket C*
and together with the screw D is connected with one pole of a dynamo or other
source of electricity by means of the brush + while the cathode pole A is connected
with the other pole of such dynamo or other source of electricity. A porous
partition or filter is usually interposed between the anode pole D and the cathode
pole A. The lower end of the electrolytic chamber and cathode pole A is connected
with the inlet passage M' of the amalgamating apparatus, which latter consists of
a horizontal cylinder N of cast iron for example with closed ends containing a
revolving drum O carried by the gudgeons or shafts P P revolving respectively
in a bearing. Q and in a stuffing box Q' in the covers of the cylinder N. The
periphery and ends of the drum O fit more or less closely the interior of the said
cylinder N. Grooves or channels S are formed on the surface of this drum and
the spaces thus formed, as well as the clearance spaces between the drum and the

page_text: cylinder, are filled with mercury, a well or sumph T for a reserve of mercury being
also preferably provided at the bottom of the cylinder N.
The electrolytic chamber A having been filled with any one of the usual well
known suitable solutions, according to the nature of the ore to be acted on, and
the result to be obtained, and the amalgamating apparatus being filled with mercury
the ore to be treated, after having been crushed or pulverized in the usual way, is
introduced gradually and continuously through the hopper A' or other feeding
device into the top of the chamber A. The ore falls on to the retarding screw D
and gravity causes it to roll down the inclined surface of the screw thread, but as
the latter is rotated, preferably in the direction of the arrow, it tends to raise the
said ore towards the top of the chamber. The passage of the ore from the top to
the bottom of the chamber through the solution is thus retarded and the whole of
the ore is kept for a considerable time in contact with the anode pole D so as to
form a soluble portion thereof whilst every particle is exposed to the action of the
products of electrolysis liberated at the said pole D such as oxygen, chlorine,
cyanogen and so forth according to the solution used and the ore under treatment.
The cathions resulting from the solution of the metals are deposited upon the
surface of the cathode as a pulverulent metallic deposit which ultimately falls to
the bottom of the chamber A. The ore, with the gold or silver or both, together
with the aforesaid pulverulent deposit from the surface of the cathode pole A,
having reached the bottom of the chamber A, passes through the passage M' into
the amalgamating cylinder N, is there brought into contact with the mercury
therein by being carried round through the same in the grooves or channels S in
the drum O by the revolution of the latter until it reaches an outlet passage U
through which it rises, on account of its inferior density, through the mercury, and
passes away by the spout V. In passing through the amalgamator the particles
of ore are kept in a constant state of agitation, and are brought into intimate or
rubbing contact with the mercury; and consequently any gold or silver contained
in, or mixed with, the ore is retained by the said mercury in the form of an
amalgam, which is periodically drawn off through the tap W and the gold and
silver is then separated from the mercury in the usual way.
Having thus described the general arrangement and action of one example of
the means and apparatus to which my present improvements relate I will now
proceed to describe the nature of my said improvements and the manner of
carrying the same into effect.
Heretofore the ore and metal delivered at the lower end of the electrolytic
chamber has been passed direct to the amalgamating apparatus through the
passage M¹, its first contact with the mercury taking place at the lower end of
the said passage, or in some cases in the cylinder N itself. I have found however
that I obtain better results by providing a mercury cup at the bottom of the
electrolytic chamber A, into which the ore and metal is delivered from the lower
end of the anode pole D. This cup may be formed and arranged in various
ways; but I have found the arrangement shown in Figure 3 to be both effective
and convenient. M2 is a disc of copper or other suitable metal but preferably
one the surface of which will amalgamate with mercury. M³ is a pipe of similar
metal formed with or rivetted to the disc M. The upper end of this pipe projects
somewhat above the upper surface of the disc M³, the space between the upper
part of the said pipe and the side of the chamber A forming an annular cup
which is in electrical connection with the cathode pole A and is kept supplied with
mercury through the supply pipe e to be hereafter more fully described in
connection with another of my improvements. M' is a stirrer or paddle connected
to the lower end of the screw D and either made of non-conducting material, or,
if of conducting material, insulated from the screw D. The ore and metal
delivered at the lower end of the chamber A falls on to the mercury in the cup,
is scraped round over the surface of the said mercury by the stirrer or paddle M*
and then falls over the upper edge of the pipe M³ along with, and in contact with,
the mercury which ov rflows from the cup and trickles down the inner surface of

page_text: the pipe M. The ore, metal and mercury thus find their way, in contact with one
another, into the amalgamating apparatus, where they are received by the drum ①
and operated on as above explained. The above described arrangement effects a
kind of preliminary or preparatory amalgamation of the metal before it reaches
the amalgamator proper, whereby the action of the latter is facilitated.
As above stated a porous partition, or filter, is usually interposed between the
anode pole D and the cathode pole A; according to my present improvement I
make this partition or filter E, see Figure 3, of an internal diameter corresponding
to the outer diameter of the anode screw D so that it fits closely round the latter,
and is secured thereto by any suitable means so as to turn therewith; it serves to
prevent the ore and metal, fed into the apparatus and rolling down on the surface of
the screw thread, from falling over the outer edge of the said screw and thus
finding its way direct to the bottom of the chamber A, without having been kept
sufficiently long in contact with the anode pole D. The said partition or filter may
be made of woven coir or asbestos matting or of other suitable well known material,
or combination of materials, which will allow a free circulation of the electrolyte
between the anode and cathode poles but will not allow the ore or gangue to pass
through it.
I sometimes dispense with the porous partition or filter altogether and employ
instead thereof a kind of shoe fixed along the outer edge of the screw D as shown
at E in Figure 4, such shoe having a kind of flap E3 which extends across the
space between the anode pole D and the cathode pole A to prevent the ore or metal
from falling direct to the bottom of the chamber without passing down over the
surface of the screw. The shoe E may be made of any suitable material and the
flap E3 which is preferably made of flexible non-conductive material, such as india-
rubber for example, may be secured to it; but I prefer to make the shoe and the
flap of indiarubber in one piece as shown in the drawing. The flap E³, being
flexible, yields to any slight irregularities there may be on the surface of the cathode
pole; and as it is carried round by the rotating pole D it sweeps over the surface
of the cathode pole, removing therefrom any pulverulent metallic deposit which
may have accumulated thereon. The flap E³ may be turned upwards as shown at
Figure 5 so as to form a lip to prevent the ore or metal from falling over the edge
of the screw D. When either of the arrangements shown in Figures 4 and 5 is
employed the shoe, when made of non-conductive material, serves as an insulator
to prevent the passage of the current direct from the edge of the screw D to the
cathode A and in any case it is desirable to interpose a non-conductor of some kind
between the edge of the screw D and the cathode for that purpose.
In the single chamber apparatus, illustrated in Figures 1, 2 and 3, the inlet of
the amalgamating apparatus receives not only the material which has passed down
in contact with the anode pole but also that which has been deposited on the
cathode pole. In another arrangement of the apparatus in which the anode pole is
contained in one compartment of the electrolytic apparatus and the cathode pole in
another compartment separated from the first by a porous partition or filter, the
amalgamating apparatus is connected with the lower end of the anode compartment.
so as to receive only the material which has passed through such compartment, the
material collected in the cathode compartment being removed therefrom from time
to time, or continuously, for subsequent treatment or disposal according to its
nature and other circumstances. Now according to another of my present improve-
ments I, in some cases, as for example when treating ore containing a considerable
quantity of silver, cause the ore which has been acted on in the anode compartment
to be withdrawn from the bottom thereof and to be introduced into the top of the
cathode compartment which may also be provided with a screw or other retarding
device, similar to that in the anode compartment. The ore thus treated may then
be withdrawn from the lower end of the cathode compartment and be removed for
subsequent treatment by amalgamation or otherwise in separate apparatus, or it
may pass direct to amalgamating apparatus similar to that shown in Figures 1, 2
and 3, but placed at the bottom of the cathode compartment, instead of at the

page_text: bottom of the anode compartment; suitable means being provided for conveying
the ore acted on in the anode compartment from the lower end thereof to and
delivering it into the upper end of the cathode compartment. This arrangement is
applicable, for example, when treating ore containing sulphide of silver, with a
solution of chloride of sodium in the anode compartment.
When the electrolytic apparatus is used alone without being connected directly
to an amalgamating apparatus, it may be arranged as shown diagrammatically in
Figure 6 in which A is the electrolytic chamber and cathode pole and D the
revolving anode pole as in Figures 1, 2 and 3. The lower end of the chamber A
opens into a compartment A2 from which there extends upwards, in an oblique
direction, a pipe A³ in which works a bucket elevator A. The electrolytic
solution stands at the same level in the chamber A and in the pipe A³. The ore
acted on in the chamber A falls from the screw D on to the buckets of the
elevator A', is carried up thereby out of the solution and is delivered into the
shoot A', whence it may be conveyed away for further treatment as may be desired.
The buckets of the elevator A should be perforated to allow as much as possible
of the solution to drain away from the material before the latter is thrown out of
them.
The electrolytic part of the apparatus is usually connected electrically with the
amalgamating apparatus in such manner that the latter and the mercury contained
therein shall form part of the negative or cathode pole of such electrolytic apparatus
(or shall otherwise be made electrically negative to the anode pole) whereby the
corroding action of the electrolytic solution on the said amalgamating apparatus
and on the mercury contained therein is prevented when the said amalgamating
apparatus is formed of metal such as cast iron for example, and when the solution is
of a nature that would otherwise cause it to act upon such amalgamating apparatus
or on the mercury contained therein. This arrangement also preserves the mercury
in a clean condition. Now another of my improvements consists in placing a
positive pole a (see Figure 2) formed of a block of carbon or other suitable
conducting substance in the mouth of the outlet U and insulated from the
amalgamating apparatus, such block a being placed in electrical connection with the
anode pole of the electrolytic apparatus, or with the positive pole of a dynamo,
the anode pole D forming the positive pole at the inlet of the amalgamating apparatus
while the said block a forms a positive pole at the outlet thereof This electric
connection of the amalgamnating apparatus and of the mercury with the electrolytic
apparatus causes the direct deposition in and amalgamation by the mercurial
cathode thus formed of part of the gold and silver contained in the solution, the
remainder of the gold and silver being deposited upon the cathode A of the
electrolytic apparatus from whence it falls into the mercury direct and is then
amalgamated therewith. When a sodium solution is employed, a valuable sodium
amalgam is formed in the amalgamator by the direct deposit of the sodium into the
mercury, which sodium amalgam facilitates the amalgamation of the metals.
In the amalgamating apparatus shown and described in the Specification of my
aforesaid Patent No. 12,295 of 1886 the cylinder and drum are very short, and the
inlet is placed at one side and the outlet at the other, so that the ore and metal
have only a short distance to travel through the mercury in their passage from the
inlet to the outlet of the amalgamating apparatus. Another of my present
improvements has for object to keep the ore and metal for a much longer time in
contact with the mercury. For this purpose I make the cylinder N and drum O of
much greater length than that shown in my aforesaid former Specification, and I
make the grooves or channels S on the periphery of the drum O oblique or helical
as shown in Figure 3 in such direction that as the drum revolves, the said grooves
or channels tend by their obliquity to propel the material from the inlet end of the
cylinder N slowly towards the outlet end at the same time that they carry the said
material round and round many times through the mercury so as to keep it a long
time in contact therewith to enable the latter to combine or amalgamate with all
the metal in or mixed with the ore, and I prefer to place the inlet passage M¹, to

page_text: which the electrolytic apparatus is attached, immediately over the axial line of the
drum O and at one end of the cylinder N and the outlet U at the side of the other
end of the said cylinder.
When the grooves or channels S in the drum O of the amalgamating apparatus
are formed helically or obliquely thereon as above described, and shown in
Figure 3, they have a tendency to force the mercury up out of the cylinder N into
the outlet passage U and to correspondingly depress the level of the mercury at the
inlet of the amalgamator. In order to neutralise this action I provide a circulating
pipe N which conveys such mercury back from the outlet U to the lower part of
the inlet end of the cylinder N as shown in Figures 1, 2 and 3.
In order to prevent the gangue, with any metal it may still contain after passing
through the amalgamator cylinder, from creeping up the side of the outlet Ů
without being thoroughly surrounded by mercury I provide in the said outlet a
guide or deflector U¹ which leads the said gangue or ore into or near to the centre
of the outlet passage so that, as it rises through the mercury in the upper part of
the said outlet passage, each particle of gangue or ore is surrounded on all sides by
the mercury and the latter is free to combine with every particle of metal present
in the ore or gangue.
The length of the amalgamator cylinder N and drum O does not require to be
so great for some ores as for others, it is therefore desirable to have a ready means
whereby the cylinder and drum can be made of the proper length without having to
make special castings for each particular case. This is specially desirable in many
cases in order to economise as much as possible the quantity of mercury required
for the amalgamators. To effect this object I construct the cylinder N and drum O
in sections or parts, any required number of which can be bolted together to make
up the required length. It will be seen by reference to Figures 1, 2 and 3 that
the sections or parts of the cylinder N are bored and their flanges faced and
recessed into each other so that when bolted together by their said flanges they
make a practically true cylinder; and that the sections or parts of the drum O are
turned, faced and recessed into each other so that when bolted together by the long
bolts N2, running through all the sections or parts, they form a continuous and
sufficiently true drum. The end sections or parts of the drum O have fitted and
secured to them the gudgeons P P¹ by one of which rotatory motion is imparted to
the drum by a belt or otherwise.
In order to assure the whole of the mercury in the amalgamating apparatus being
brought into action, I employ the circulating arrangement shown in Figures 1, 2
and 3 in which b is a pump of any suitable construction operated by a crank from
the stirrer shaft U' as shown or otherwise. This pump draws the mercury by the
pipe from the bottom of the sumph T and forces it through a straining box c
furnished with a wash leather or other strainer c' suitable for straining the amalgam
from the mercury, which latter then flows through the pipe e to the chamber A
where it is delivered into the cup M2 from whence it overflows over the upper edge
of the pipe M³ and returns to the amalgamator where it takes up more metal and
finds its way back to the sumph T whence it is again withdrawn by the pump band
forced thereby through the straining box c to the chamber A, and so on
continuously, fresh mercury being added from time to time as required. Taps g
and hand a bye-pass i, in which is a third tap j, may be provided to allow of the
removal of the amalgam from the straining box c without interfering with the
circulation of the mercury. That is to say when the circulation takes place
through the straining box c the taps g and h are open, and the tap j closed; but
when it is required to remove the amalgam from the straining box c the taps g and h
are closed, and the tap j opened, when the mercury passes through the bye-pass i
without going through the straining box c.
When it is required to recover gold from ore containing silver, or one or more of
the baser metals in considerable quantity, I sometimes employ the modified form of
amalgamator illustrated in vertical section in Figure 7, which is somewhat similar
to that shown in Figure 2, but is furnished with a supplementary collecting shoot

page_text: or outlet V in communication with an outlet V**. When the metals of lower
specific gravity than the gold and mercury, but of higher specific gravity than the
gangue, are carried round by the periphery of the drum O to the opening or
outlet V, they are thrown out through the said opening or outlet by centrifugal
action, and, being lighter than the mercury in the shoot V*, they ascend to the
surface of such mercury and may be withdrawn therefrom through the tap V³ in
the form of "scum or light amalgam. Any metals which are heavier than the
mercury (whether they amalgamate therewith, as in the case of gold, or not, as in
the case of platinum) sink by gravity to, and collect in, the sumph T at the bottom
of the amalgamator.
"
Figure 7 also shows an improved means of regulating the level of the mercury in
the amalgamator; it consists of a solid or hollow displacement body X which can
be lowered or raised in the mercury contained in the collecting shoot or outlet V*
by means of the screw X' or other suitable device so as to raise or lower the
working level or head of the said mercury as may be required.
Similar letters of reference relate to like parts in all the figures of the drawings.
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 :-
First In an electrolytic apparatus of the kind herein referred to, for separating
gold, silver and other metals from their ores, the employment of a mercury cup at
the lower end of the electrolytic chamber, so placed as to receive on the surface of
the mercury contained therein the ore and metals which have passed through the
said electrolytic apparatus, the said mercury being connected electrically with the
cathode pole, substantially as herein before described, and illustrated in Figure 3 of
the drawings.
Second In an electrolytic apparatus of the kind herein referred to, the
combination, with the revolving retarding screw, of the porous partition or filter
secured thereto and revolving therewith and adapted to prevent the ore from falling
over the edge of the said retarding screw, as hereinbefore described, and illustrated
in Figure 3 of the drawings.
Third-In an electrolytic apparatus of the kind herein referred to, the use, on
the edge of the revolving retarding screw, of a flap or lip to prevent the ore from
falling over the edge of the said retarding screw, as hereinbefore described, and
illustrated in Figures 4 and 5 of the drawings.
Fourth In an electrolytic apparatus of the kind herein referred to, the process
which consists in passing the ore, after it has passed through the anode
compartment, through the cathode compartment, as hereinbefore described, and for
the purpose specified.
Fifth--The electrolytic apparatus consisting of the vertical electrolytic cathode
chamber, and a revolving retarding anode screw, in combination with an inclined
delivery pipe and bucket elevator as herein before described, and illustrated in
Figure 6 of the drawings.
Sixth-In an amalgamating apparatus of the kind herein referred to, the use of
a positive pole in the outlet passage as hereinbefore described, and illustrated in
Figure 2 of the drawings.
Seventh-In an amalgamating apparatus of the kind herein referred to, the
improvement which consists in constructing the same with a cylinder having the
inlet at one end and the outlet at the opposite end and in forming the grooves or
channels on the periphery of the internal drum in an oblique or helical direction,
as hereinbefore described, and illustrated in Figures 1, 2 and 3 of the drawings and
for the purpose specified.
Eighth In an amalgamating apparatus of the kind herein referred to, the use of
a circulating pipe or passage N¹ for the purpose of returning the mercury from the
outlet passage to the inlet end of the amalgamator cylinder, as hereinbefore
described, and illustrated in Figures 1, 2 and 3 of the drawings.

page_text: Ninth In an amalgamating apparatus of the kind herein referred to, the use of
a guide or deflector U¹ in the outlet passage U as hereinbefore described, and
illustrated in Figure 2 of the drawings and for the purpose specified.
Tenth The construction of the amalgamating cylinder and drum in parts, fitted
and connected together so that the length of the apparatus can be adapted to
requirements, substantially as hereinbefore described, and illustrated in Figures 1, 2
and 3 of the drawings.
Eleventh In an amalgamating apparatus of the kind herein referred to, the
arrangement for circulating the mercury which consists of the pump, straining box,
taps, bye-pass and connecting pipes, arranged, combined and operating substantially
as hereinbefore described, and illustrated in Figures 1, 2 and 3 of the drawings.
Twelfth-The improvement in the amalgamating apparatus which consists in the
addition thereto of the second outlet passage V** and corresponding shoot V× as
hereinbefore described, and illustrated in Figure 7 of the drawings, and for the
purpose specified.
Thirteenth In an amalgamating apparatus of the kind herein referred to, the
vertically adjustable displacement body X adapted to be immersed more or less in
the mercury for the purpose of regulating the level thereof as hereinbefore
described, and illustrated in Figure 7 of the drawings.
Dated thie 19th dove of Amil 1900
Dated this
ᎠᎭᏂ
9th day of Ap="
Ail
1800
G. J. ATKINS,
Per W. H. Beck,
115, Cannon Street, London, E.C., Agent.