Year: 1886

page_text: Date of Application, 20th July, 1886.
Complete Left, 20th Apr., 1887.
Complete Accepted, 20th May, 1887.
I, HENRY LIEPMANN, Managing Director of the Liepmann Carbon Company,
Limited, of Nelson Wharf, Millwall, London, in the County of Middlesex, Chemist,
Ph.D., F.C.S., etc., do hereby declare the nature of this invention to be as follows:-
In the process for treating auriferous substances where chlorine is generated by
electrolyzing a solution of common salt or other suitable substance, and caused to
dissolve the gold at the anode, and then carry the chloride of gold over to the cathode
to be deposited, the anode and cathode being separated by a partition of asbestos or other
suitable material (such a process being described in the specification of a patent
granted to Henry Renner Cassel, No. 3873, dated 9th August, 1883), it has been
found necessary in practice during the first stage of the process, to prevent the alkaline
liquors produced at the cathode during the electrolysis of such alkaline chlorides, from
diffusing or passing back through or around the asbestos partition into the anode ▸
compartment.
This diffusion or return of alkaline liquors is injurious during this first stage of
the operation, because the chlorine is readily absorbed by these alkaline liquors, and
sufficient decomposition of the compounds constituting the refractory elements of the
ores cannot, therefore, take place under the circumstances, and the gold remains in a
more or less unattached state.
It being expedient and even essential to the success of the operation described in the
patent granted to Henry Renner Cassel above referred to, to act upon the base metals
or refractory elements by the nascent chlorine, precautions must be taken in the first
instance to prevent this diffusion of the alkaline liquors and ensure the action of the
chlorine taking place by having either an acid or a neutral anode solution. In order
to ensure that the liquors in the anode compartment shall not become alkaline during
the first stage of the process, but shall be permanently maintained during such stage

page_text: In such a state as to permit of the above described free and unimpeded action of the
chlorine, I proceed as follows:-
I first place the ores in the anode compartment of an apparatus in which nascent
chlorine is generated by electrolysis at the anode, and the anode and cathode are
separated by means of a removable porous partition, such as carthenware, terra cotta
or other similar well known substance. This porous partition may be constructed
of various substances. I may for instance compress or otherwise combine layers of
asbestos cloth so tightly together that they form a porous plate, i.e. one which shall
prevent the diffusion or passage of the cathode liquors into the anode compartment,
without however preventing electrolysis. The porous partition is preferably placed at
the back of the simple asbestos filter described in the patent above referred to.
When the decomposition has proceeded for a certain time with this porous plate inter-
posed, and the refractory elements in the ores in the anode department have been
sufficiently acted upon, I may remove the porous partition and add lime or other
suitable substance as described in Henry Renner Cassel's Patent No. 4879, dated
13th October 1883, and continue the action, by which means solutions of base metals
and other substances which have been formed, will be precipitated.
The interposition of the porous plate above described has a further advantage, inas-
much as it prevents these base metals brought into solution by the action of the
chlorine from being carried over during the first stage and being deposited at the
cathode, so that after the addition of lime and removal of the porous partition the gold
will be enabled to pass over to be deposited at the cathode, while practically no electro-
lysis of the base metallic substances will have occurred. The gold will thus be deposited
in a practically pure state.
In some cases instead of or in conjunction with the addition of lime, I may remove
the porous partition and allow the alkaline liquors to diffuse back through the asbestos
filter into the anode compartment, and by this means neutralize the acids formed and
precipitate the iron and other metallic solutions.
The apparatus employed to carry out my improved process may be of any suitable
form, but it is preferably constructed in such a manner that the removable porous
partition may either be inserted and withdrawn, or shifted, so as to separate the anode
and cathode, or not, at the different stages of the operation as above described, and
further it is preferably used in conjunction with a fixed partition of asbestos separating
the anode and cathode and acting as a filter, so as to prevent any of the crushed ore
reaching the cathode.
1
Dated this 20th dow of Tul. 1000
ALLISON BROS.,
Agents for the Applicant.

page_text: Improvements in the Process for Treating Auriferous Substances
by Electrolysis.
I, HENRY LIEPMANN, Managing Director of the Liepmann Carbon Company,
Limited, of Nelson Wharf, Millwall, London, in the County of Middlesex, Chemist,
Ph.D., F.C.S., etc., 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:-
In the process for treating auriferous substances where chlorine is generated by
electrolyzing a solution of common salt or other suitable substance, and caused to
dissolve the gold at the anode, and then carry the chloride of gold over to the cathode
to be deposited, the anode and cathode being separated by a partition of asbestos or
other suitable material (such a process being described in the specification of a patent
granted to Henry Renner Cassel, No. 3873, dated 9th August, 1883), it has been found
of advantage in practice during the first stage of the process, to prevent the alkaline
liquors produced at the cathode during the electrolysis of such alkaline chlorides, from
diffusing or passing back through or around the asbestos partition into the anode
compartment.
This diffusion or return of alkaline liquors is injurious during the first stage of the
operation, because the chlorine is readily absorbed by these alkaline liquors and
complete decomposition of the compounds constituting refractory elements of the ores
cannot, therefore, take place under the circumstances, and the gold remains in a more
or less unattached state.
The object of this invention is to maintain, during the first stage of the operation
cither an acid or a neutral solution in the anode compartment so that the nascent
chlorine may act with full power upon the base metals or refractory elements.
The apparatus constituting a part of this improvement is illustrated in the accom-
panying drawings in which Fig. 1 is a side elevation thereof. Fig. II is a vertical
section of one end thereof, and Fig. III is a transverse section on line i ii of Fig. II.
Similar numerals indicate corresponding parts in the different figures.
The apparatus comprises two similar hollow standards 1 mounted on suitable
supports 2, a rotary drum 3 and tubular trunnions 4 attached to the ends of said drum
and having their bearings in the hollow standards. A driving shaft 5 is supported in
bearings attached to one of the standards, said shaft being provided with a driving
wheel 6 at one end and a pinion 7 at the opposite end. The drum is provided with a
cogwheel & with which the pinion 7 meshes for causing the rotation of the drum. The
tanks may be connected with each other by a pipe 9.
The drum constitutes the anode compartment of the apparatus and the hollow
trunnions and hollow standards constitute the cathode compartments thereof. The

page_text: drum is provided with a series of carbon anodes 10 the ends of which project through
the ends of the drum, and are connected by metallic bands 11. Brushes 12 properly
insulated and supported in brackets 13, attached to the hollow standards, bear upon the
bands 11 and serve to conduct the current to the anodes within the drum, being con-
nected with the positive pole of the apparatus by means of wires 14. The hollow
standards are connected with the negative pole of the apparatus by means of wires 15.
The drum is provided with hand-holes covered by hand-hole plates 16, the plates being
preferably packed with rubber to effect tight joints.
The opposite ends of the drum are provided with openings 17 over which filtering
diaphragms 18, composed of asbestos or other suitable material, are fixed. These
diaphragms are of such a character as to prevent the escape of the ores within the
drum, and at the same time to permit the passage of the current and of the metals in
solution from the drum or anode compartment into the trunnions constituting cathode
compartments.
As thus described the apparatus is similar to that shown in the application of Henry
Renner Cassel hereinbefore referred to.
In this case supplemental or removable diaphragms 19 are placed over the
diaphragms 18 and are designed to be held over the openings 17 against the
diaphragms 18 during the first stage of the process. This removable diaphragm or
partition may be composed of earthenware or of compressed layers of asbestos cloth, and
must be constructed with such density or thickness as to prevent the diffusion or passage
of the cathode liquors or the metals in solution into the anode compartment while at the
same time permitting the passage of the electric current. This diaphragm is mounted
on a frame 20 which is connected with an adjustable screw-rod 21. This screw-rod is
supported at its outer end in the end of the trunnions, passing through a stuffing-
box 22 therein. At its inner end it is supported by an eye 23 in the cross bar 24
fixed within the trunnion, the eye and rod being screw-threaded so that the turning of
the rod will cause a longitudinal movement thereof and effect the adjustment or removal
of the diaphragm 19. That part of the trunnion within the hollow standard is provided
with openings or perforations 25 to establish communication with the hollow standard.
In carrying out this process, the ores in a powdered condition are placed in the
anode compartment which is separated from the cathode compartment by the removable
partition or diaphragm of sufficient density to prevent the passage of the cathode
liquors in solution while permitting the passage of the electric current; the drum is
then set in motion and the electric current switched on. The ores are thus agitated
and subjected to the electric current and to the nascent chlorine until the refractory
elements are sufficiently decomposed, the dissolved metals being retained within the
anode compartment during this step of the process. The dense porous partition is then
removed and lime or alkaline earth (as described in letters patent No. 4879 dated
13th October 1883) is added to the anode solution, the anode compartment being then
separated from the cathode compartment by the thin porous filter which permits the
passage of the metals in solution as well as the electric current, while preventing the
escape of the ores from the anode compartment.
The electric subjection and mechanical agitation of the charge is then continued in
the presence of the lime, and the base metals and other substances will be precipitated,
while the chloride of gold will pass through the thin diaphragm and the gold will be
deposited at the cathode in a practically pure state.
In some cases the addition of lime in the second stage of the process may be omitted,
as the removal of the dense porous diaphragm permits the alkaline liquors to diffuse
back through the thin asbestos diaphragm into the anode compartiment, and the acids
formed will thus be neutralized, and the iron and other metallic solutions precipitated
without the aid of lime.
Having now particularly described and ascertained the nature of my said Invention,
and in what manner the same is to be performed, I declare that what I claim is :-
1. In an apparatus for separating metals from ores or alloys by electrolysis, the
combination of an anode compartment, a cathode compartment, a filtering diaphragm,

page_text: as described, separating said compartments, a dense porous diaphragm for separating
said compartments during one step of the operation, and mechanism whereby the
dense porous diaphragm may be placed in apposition with or removed from the opening
between the anode and cathode compartments, substantially as described.
2. In an apparatus for separating metals from ores or alloys by electrolysis, the
combination with a journalled drum constituting the anode compartment, of a trunnion
constituting the cathode compartment, said drum having an opening at its end into said
trunnion, a movable porous diaphragm for closing said opening, an adjustable screw-rod
to which said diaphragm is attached, and supports within the trunnion for said screw-
rod, substantially as described.
ALLISON BROS.,
Agents for the Applicant.