Improvements in the Treatment of Gold and Silver Ores by the Hydro-metallurgical or Wet Method.
Year: 1889

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Treatment of Gold and Silver Ores by the
Hydro-metallurgical or Wet Method.
I, JOHN HARPER, of 24 Lower Phillimore Place High Street Kensington do hereby
declare the nature of the said invention to be as follows:-
This invention is applicable to the treatment of any ores of gold and silver, and
other suitable metals; but more particularly to those in which the gold is associated
with sulphur etc. called refractory ores.
In carrying out my invention, I first roast my ore (if necessary) with a certain
proportion of salt and poor copper ore, and introduce it into a barrel, which I call a
chlorinator, together with sufficient water, or solution of copper chloride and salt
(the former chemical prepared by roasting salt with poor copper ore and then boiling
in water) I then add chloride of lime and sulphuric acid in small quantities, for the
formation of chlorine. I then close my chlorinator, and revolve it for the space of
one and a half hours, more or less, and then turn the contents into a filter with a
false bottom, all being enclosed with the exception of a manhole at the top for the
introduction of the ore, and a hole at the bottom for the escape of the liquid and
having a pipe inserted in its top for the introduction of air under pressure, for the
purpose of foreing all the solution through the ore together with any additional
solution, hot or cold-from a reserve tank hereafter mentioned that may be found
necessary for the purpose of washing out all the metals in solution. I may employ
suction instead of pressure. The obtained solution I conduct into a suitable mixer,
placed on one side of the barrel, into which I introduce a sufficient quantity of poly-
sulphide of calcium to precipitate the gold only. The obtained precipitate and solution
then flow out of suitable orifices into filters in which, either by suction, pressure or
gravitation the redundant solution is passed into another mixer, where a sufficient
quantity of polysulphide of calcium is added to precipitate the silver only; after which
it is again filtered and the metal or metals in solution precipitated either in another
mixer or in tubs, with an excess of polysulphide of calcium, for the purpose of
obtaining all the copper and other metals which may be precipitated. The redundant
solution is now pumped up into a reserve tank, which I call my reserve tank No. 1
ready (if desirable) for precipitating the next charge. I may heat my solution in
such reserve tank, and use it in such manner as to cause it to circulate from the tank
and through the above described filters. Instead of the first mixer for gold, I may
employ a single filter of subsulphide of copper, either pure, or held in sawdust, sponge
etc. through which I pass the solution for the purpose of obtaining the gold, and
then treat the filtrate or redundant solution for silver and copper as above
described.
The ore remaining in the first filter being deprived of only a certain quantity of
its silver, if it be rich in that metal, I pass through a manhole in the lower part of
the filter vessel, and just above the filter bed-which I construct of layers of basket
work, pebbles, coarse sand etc., the basketwork being uppermost, or if I employ
suction, I dump the ore out of the open top of such filter into a reserve tank, capable
of holding as many charges as the barrel or barrels will pass through in twelve hours
nore or less. Such quantity of ore is tipped into a filter of similary capacity, fitted
with a false bottom in a similar manner to the filter into which the ore falls from the
barrel, placed on the side opposite to the gold mixer etc., so that solution from a
reserve tank No. 2 (or I may use only one tank for both) may be sucked by a common
suction pump, or be pressed or may gravitate through into a series of mixers and
ilters, being precipitated with polysulphide of calcium, firstly for silver and then

page_text: for copper as in the case of the above described gold solution, after the gold has
been extracted.
A circulation of the liquid from the heated reserve tank No. 2 is maintained through
the ore, precipitation of the metais taking place. The liquid passes through the
mixers and filters until all the soluble silver and copper and any trace of gold,
remaining from the first treatment may have been recovered; which will be in the
space of about twelve hours.
Such arrangement of roasting, chlorinators, filters, and mixers, and the use of the
particular chemicals mentioned, combine to make a very rapid process for the teatment
of gold and silver and other suitable ores.
June 26th 1889
JOHN HARPER,
24, Lower Phillimore Place, High Street, Kensington.
COMPLETE SPECIFICATION.
Improvements in the Treatment of Gold and Silver Ores by the
Hydro-metallurgical or Wet Method.
I, JOHN HARPER, of 24, Lower Phillimore Place, High Street, Kensington, in the
County of London, 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:—
This invention relates to the treatment of ores containing gold, silver and other
suitable metals, more particularly those in which the gold is associated with sulphur &c.,
and usually called refractory ores.
In carrying out my invention I first crush the ore sufficiently fine to pass a 30 sieve
and then roast it if necessary with a suitable proportion say from 5 to 20%
of salt and about one per cent. of poor copper ore or copper pyrites, and then if the
ore contain more than 1 oz. of gold per ton, introduce it into a barrel which serves
as a chlorinator (or I may use several of such barrels) together with sufficient water,
(or a solution of salt and copper chloride prepared by roasting such salt with a poor
copper ore and then boiling in water) and chloride of lime and sulphuric or hydro-
chloric acid in small quantities for the formation of chlorine.
I then close my chlorinator and revolve it for the space of one and a half hours,
more or less, and then turn the contents into an air tight filter provided with a false
bottom and an aperture (and means for closing the same) at the top for the intro-
duction of the ore, a hole having a cover being provided at the bottom for the escape
of the liquid. The filter has a pipe inserted in its top for the introduction of air
under pressure, for the purpose of forcing all the solution through and away from the
mass of ore together with any additional hot or cold solution from a reserve tank
hereinafter mentioned that may be found necessary for the purpose of washing out
all the soluble gold and silver, or I may for this purpose apply suction to the false
bottom, in which case the filter is not air tight.
Should the ore not be so rich as is hereinbefore stated, that is to say, if it contain
less than 1 oz. of gold per ton, I introduce it into the filter with the hereinbefore
described solution without first treating it in a chlorinator.
The obtained solution I conduct into a suitable mixing vat, into which is also
introduced at the same time a sufficient quantity of polysulphide of calcium to
precipitate the gold and silver, the obtained precipitate and solution flowing out through
suitable orifices into filters in which either by suction, pressure or gravitation the
redundant solution is pumped up into reserve tanks which I call my reserve
tanks Nos. 1 and 2 ready for leaching the next charge. I may if found desirable
heat my solution in one of such reserve tanks and use it in such manner as to cause
it to circulate to and from the tank through the above described filters, precipitating
each time until all the gold and silver, and as much of the copper as is desired inay
be extracted

page_text: I construct my filter beds of layers of basket work, moss, pebbles, and coarse
sand, the basket work being uppermost and the sand filling the interstices.
In order to enable my invention to be fully understood I will describe how it
can be carried into practical effect by reference to the accompanying drawing, in
which,
Figure 1 is an elevation of an arrangement of apparatus which I have found suitable
for treating gold and silver ores according to my invention.
Figure 2 is a detached vertical section of the filter in which the crushed and roasted
ore is introduced, it being represented as partly filled and arranged to work with air
under pressure.
Figure 3 is a similar view of the filter arranged to work with suction.
Similar letters in all the figures indicate similar parts.
a is the vessel which I term my chlorinator constructed of wood or other suitable
material into which as herein before stated the ores when they contain more than one
and a half ounces of gold to the ton are placed and treated with chloride of calcium
and sulphuric or hydrochloric acid.
This vessel is rotated by means of a pulley b driven by a band c from the driving
shaft d of the apparatus and is made with filling and discharge openings closed by
covers e, e.
f is the filter in which the finely ground and roasted ores are supported on a false
bottom g made of basket or wicker work perforated wood and canvas g² and sand
or spun glass g³ placed between them. The filter when worked with suction is open
(as shown in Figure 3) and the liquid consisting of water or a solution of salt and
copper chloride and chloride of lime and sulphuric or hydrochloric acid entering
through a pipe m leading from a tank al is drawn through and away from the mass of
ore in the filter f by means of a pump t. a² is the cover of an opening through which
the refuse is discharged from the filter f.
q is the mixing vat fitted with an agitator or reciprocating stirrer operated from
the driving shaft d and into which the solution drawn from the filter fis conducted
by the suction pipe 7 and delivery pipes of the pump t driven from the main shaft d,
the gold and silver being herein precipitated together from the solution by the
addition thereto of polysulphide of calcium contained in a vessel 61; c¹ is a cock
for regulating the flow of the precipitant from the vesssel into the mixing
vat 9.
When working the filter f with air pressure I construct it as shown in Figure 2
and dispense with the use of the pump h,hare the apertures, provided with covers,
through which the ores are introduced into the filter f, the said apertures being made
in the cover of the filter; / is the pipe for the introduction of air under pressure
for forcing the solution admitted through the pipe m through and away from the mass
of ore p; n
an aperture with cover, for allowing of the insertion of a rake o for
levelling the surface of the ore p.
u is the filter into which the thick liquid consisting of the precipitate and solution
flows out of the mixing vat q through a cock v, the said filter retaining all the solid
matter while the redundant solution is drawn off through the suction pipe w of a
pump x driven from the main shaft d.
y is my reserve tank No. 1 into which the said solution is discharged by the delivery
pipe z of the pump x for re-use.
dis a pipe for passing the reserve liquid from the No. 1 tank to the tank a¹
which I call my No. 2 reserve tank; e¹ is a cock for regulating the flow of such
liquid.
fis a hot water tank from which a pipe g¹ passes over the bottom of No. 2 tank
for the purpose of heating the solution contained therein; ¹ is a pipe leading from
the tank to the furnace chamber (not shown in the drawing); is a pipe for
supplying the filter f with hot water from the tank f1 for the purpose of washing out
the filter when the leaching is finished; 1 is a cock for controlling the supply of the
hot water to the filter f.
is a cock in the pipe m.

page_text: m² is a pipe leading from No. 2 tank into the mixing vessel 9 for supplying liquid
for the purpose of precipitating copper (separately from the gold and silver) for roasting
purposes; n is a cock in the said pipe.
o is a trolley for removing the refuse from the treated ore from the filter f. pi is
an evaporating tank for obtaining chlorides for roasting with the ores; g' is a pipe
for supplying the tank pl with liquid from No. 2 tank for the evaporation.
By means of the herein before described apparatus it is evident that the solution
contained in the tanks y and a¹ can be repeatedly used for treating the ore in the filter f,
the resulting rich liquid being treated by the polysulphide of calcium until all the
gold and silver and as much of the copper as is desired are precipitated or
extracted.
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.) The herein described method of treating ores containing gold and silver con-
sisting in first roasting the ore with a suitable proportion of salt and poor copper ore
or copper pyrites and then introducing it (if the ore contain more than 1 oz. of
gold per ton) into a chlorinator together with sufficient water or a solution of salt and
copper chloride and chloride of lime and sulphuric or hydrochloric acid, afterwards
turning the contents of the chlorinator into a filter from which the solution is forced
or drawn into a mixing vat in which the gold and silver are precipitated through the
medium of polysulphide of calcium, the obtained precipitate and the solution then
passing into a filter from which the redundant solution is transferred to a tank or tanks
for re-use substantially as set forth.
(2.) The modification of the method referred to in Claim 1 in which the ore, when
it contains less than 1½ oz. of gold per ton is introduced into the first mentioned
filter without first treating it in a chlorinator, substantially as set forth.
(3.) The use in the treatment of gold and silver by the hydro-metallurgical or
wet method, of the filters herein before described and illustrated in Figures 2 and 3 of
the accompanying drawing.
(4) The improved apparatus for treating gold and silver ores by the hydro-
metallurgical or wet method herein before described with reference to the accom-
panying drawing.
Dated th
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.