Year: 1887

page_text: Date of Application, 26th May, 1887
Complete Left, 16th Jan., 1888
Complete Accepted, 17th Feb., 1888
I, JULES WEIRICH, of Béziers, Hérault, in the Republic of France, Engineer, do
hereby declare the nature of this invention to be as follows:-
Processes of direct amalgamation when applied either to simple or complex pyrites
minerals containing more or less gold have up to the present time only effected the
extraction of a small part of the gold and very often the treatment involves a
heavy loss of mercury. The most improved mechanical processes have not been able
to overcome the difficulty.
The chlorine processes, the process by roasting and fusion in presence of lead, and
the electric processes have equally failed in the extraction of a sufficient proportion of
the gold which the minerals contain.
The present invention has for its object a new process for the treatment of
concentrated ore and auriferous pyrites which consists in heating the pulverized mineral
in the presence
of a feeble current of air at a temperature carefully adjusted between
330 and 450 degrees Centigrade according to the chemical composition of the mineral
whether simple sulphuret or more complex as arsenio and antimonio sulphuret. In
no case is the temperature applied to be sufficient for the ignition of the pyrites.
This treatment, which as far as I am aware has never been practised up to the
present time, effects a partial decomposition of the auriferous pyrites, setting the gold
free and eliminating by volatilization a part of the sulphur capable of attacking
mercury at ordinary temperatures and causing a loss in the treatment.
This operation will require four or five hours according to the nature of the
mineral.
Any arrangement of stove or apparatus provided with an agitator which will
allow a thin layer of the pulverized material to be maintained for several hours at a

page_text: carefully adjusted, definite and constant temperature in the presence of a feeble
current of air may be adopted.
I recommend for this purpose the employment of a bain-marie of lead the
temperature of fusion of which assures under ordinary circumstances a degree of
heat sufficient to produce the chemical re-actions above mentioned.
The minerals having been thus prepared are afterwards submitted to a process of
amalgamation and preferably by the process described in a former patent No. 12909
in the year 1885.
CARPMAEL & Co.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
f
Improvements in the Treatment of Auriferous Minerals.
I, JULES WEIRICH, of Béziers, Herault, in the Republic of France, Engineer,
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:
Processes of direct amalgamation when applied either to simple or complex pyrites
minerals containing more or less gold have up to the present time only effected the
extraction of a small part of the gold and very often the treatment involves a heavy
loss of mercury. The most improved mechanical processes have not been able to
overcome the difficulty.
The chlorine processes, the process by roasting and fusion in presence of lead,
and the electric processes have equally failed in the extraction of a sufficient
proportion of the gold which the minerals contain.
The present Invention has for its object a new process for the treatment of
concentrated ore and auriferous pyrites which consists in heating the pulverized
mineral in the presence of a feeble current of air at a temperature carefully adjusted
between 330 and 450 degrees Centigrade according to the chemical composition of
the mineral whether simple sulphuret or more complex as arsenio and antimonio
sulphuret. In no case is the temperature applied to be sufficient for the ignition of
the pyrites.
This treatment, which as far as I am aware has never been practiced up to the
present time, effects a partial decomposition of the auriferous pyrites setting the gold
free and eliminating by volatilization a part of the sulphur capable of attacking
mercury at ordinary temperatures and causing a loss in the treatment.

page_text: mineral.
Any arrangement of stove or apparatus provided with an agitator which will allow
a thin layer of the pulverized material to be maintained for several hours at a
carefully adjusted, definite and constant temperature in the presence of a feeble
current of air may be adopted.
1 recommend for this purpose the employment of a bain-marie of lead the
temperature of fusion of which assures under ordinary circumstances a degree of heat
sufficient to produce the chemical re-actions above mentioned.
The lead can be alloyed with other metals modifying the point of fusion according
to the nature of the minerals under treatment and the best temperature for the
elimination of the sulphur or it may be replaced by other substances capable of giving
the necessary degree of stable heat.
The minerals having been thus prepared are afterwards submitted to a process of
amalgamation and preferably by the process described in a former British Patent
No. 12,909 in the year 1885.
To facilitate the carrying out of my Invention I give the arrangement represented
by the annexed drawings.
The arrangement shown will be found suitable and convenient to the application
of my process for the treatment of auriferous pyrites preparatory to their reduction by
the mercurial method.
Figure 1 is a vertical transverse section of the furnace on the line Y, Y,
Figure 2.
Figure 2 is a vertical longitudinal section taken on the line X, X, Figure 1.
Figure 3 is a sectional plan on the line Z, Z, in Figure 2.
The arrangement consists essentially of a furnace of ordinary construction the
interior of which is divided horizontally into two distinct chambers H and J by two
pans of strong sheet iron B, C, adapted the one to the other as the drawing indicates,
and rivetted together all round their edges. Near the front end of the upper
chamber H the upper pan B is pierced with an opening D fitted with a tight cover
as is seen in Figures 2 and 3. The outer edge of the coupled pan rests on a shoulder
within the furnace as the drawings show, and for greater security also the lower pan
rests upon iron bars c, c, placed transversely and inserted at their ends into the
masonry of the furnace. The barse support the weight of the pans and their
contents and prevent them bulging under the influence of the weight and the
heat.
The upper pan B receives the pyrites mineral to be treated, spread out by
preference in a layer of 5 to 6 centimetres in thickness, it is introduced by the
door E at the back.
For this purpose the pans at the hinder end are made with no projection above the
bottom of the upper pan B, as is clearly seen in Figures 2 and 3, so as to facilitate
the charging and discharging of the furnace.
The lower pan C which can, if desired, be furnished with a suitable inner lining,
receives lead to form the bath for heating the mineral placed in the pan B. The
lead is introduced in a melted state or in pieces by the opening provided with the
cover at D. Under the influence of the heat from a fire at F' the lead melts; more
lead is added until the interval between the two pans is filled with melted metal
and the metal rises to the mouth D. The cover is then put into its place and firmly
secured.
Under these conditions the mineral spread upon the bottom of the pan B is
submitted to a uniform heat of from 350 to 400 degrees Centigrade which is very
suitable in the majority of cases to secure the success of the operation.
The fire at F is fed with fuel by the door G. Air is allowed to enter by the
perforation g which serves also to stir the fire. Air also enters the ash-pit underneath
the fire-bars. The draught of the chimney causes the products of combustion to
pass over the bridge into the flue K, which leads to the chimney.
The current of air intended for the desulphurization of the mineral spread out in

page_text: the pan B is admitted by the perforation e formed in the door E. The air thus
entering and drawn in by the draught of the furnace passes over the whole of the
surface of the mineral and then escapes with the sulphurous vapours which are
disengaged into the flue I, leading into the lower, flue K communicating with the
chimney.
The intensity of the current of air is regulated at pleasure by covering the hole e
more or less.
The layer of mineral is raked about and turned over almost continuously by means
of paddles or rakes which are inserted through the hole e¹.
When the treatment of the mineral is finished, as is easily ascertained by observing
the nature of the vapours disengaged, the mineral is withdrawn by the door E¹ and
the furnace is then re-charged.
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 1
claim is :-
1. The treatment above described of concentrated ores or auriferous pyrites by
heat regulated according to the directions above set forth by which I sensibly reduce
the consumption of mercury in the course of the amalgamation.
2. Heating the ore with a bath of molten lead or other metal or substance capable
of affording a steady temperature in conformity with the requirements substantially
as described.