Year: 1885

page_text: declare the nature of this invention to be as follows:-
All the processes at present in use of treating auriferous and auroargentiferous
minerals produce residues or tailings containing more or less of the precious
metals.
Up to the present time an economical method of separating from these residues
the greater part of the gold and silver which they contain has been sought for
without success.
The present invention has for its object a new method of treatment by which
these residues can be considerably impoverished-it consists in a pounding carried
on till a very fine powder is obtained combining with an amalgamation effected in
still water so conducted as only to allow the mineral and the water to escape, after
a complete arrangement according to density has been effected and an intimate
contact of the mercury with the particles even the smallest of gold or of auro-
argentiferous matter has been brought about in a very complete manner which
has not been done up to the present time.
The pounding may be carried on in the dry state or in the presence of water
by crushing or stamping, or by passage through apparatus such Carr's and
Vappart's and other of a similar sort or by crushing under or between mill-stones
or cylinders, in short, by any process which gives a sufficient fineness, which in
certain cases should be carried as far as a mesh of a hundred to 120 of the silk
Bieve.
The products of this pounding are classed according to size so as to furnish a
uniform product all of a certain size, and all matter of larger size is taken back
continually to the pounding operation-This classing can be carried on either in the
dry state by sifting or by the use of depositing chambers suitably arranged and it
may from water, but it is necessary during the pounding and sorting measures to
take precautions to avoid loss from the escape of the fine particles of gold-In
consequence of the extreme difficulty of avoiding these losses I consider pounding
and sifting in a dry state to be very much to be preferred.

page_text: The classing by density and the amalgamation are brought about by prolonged
and regular agitation of the mineral from 3 to 6 hours in a vessel partly full of
water and containing a quantity of mercury, from a thousand to two thousand
times the quantity by weight of the gold contained in the charge of the apparatus.
My apparatus is composed of a bed of cast iron or wood or masonry in which is
mounted a semi-cylindrical vessel the axis of this vessel is perfectly horizontal-
Upon the opposite sides of this vessel and of the frame, bearings are set up, in
which the necks of an horizontal axis are received-This axis is arranged so as to
occupy exactly the axial line of the vessel-upon one of the necks of the axle is
mounted on the outside a crank handle or the axis may be rotated in any other
appropriate manner. The axis carries within the vessel an agitator. It is an
open frame so that in passing through the liquid it produces the least possible
disturbance and agitation.
The movement of the agitator is alternate and circular and it should be perfectly
regular.
At one end of the vessel and its frame an orifice is provided, it is provided with
a sliding door-This door is moved vertically by a screw nut working on the
threaded end of the stem to which the door is fixed.
The operation is conducted as follows:-
The apparatus having received the proper quantities of water and of mercury
the agitator is set to work and the powdered mineral which may or may not have
been previously roasted is introduced by degrees.
In consequence of the alternating circular movement of the agitator which
repeatedly lightly scrapes the bottom of the vessel, the mineral thus introduced is
constantly kept in suspension in a quantity of water which is as little distributed
as possible and by the action of gravity it tends continually to fall.
In this free fall constantly repeated in the midst of a mass of water which is
nearly still, the density of the constituent elements of the mineral intervenes to
bring about a separation which is completed and perfected as the operation is
prolonged. Gold, silver, and the auriferous compounds being the most dense go to
the bottom of the vessel and there meet with the bed and minute drops of mercury
and they become amalgamated. When the operation has lasted a sufficient time,
which is ascertained by experience, with each sort of mineral, so that the amal-
gamation may be considered practically complete, the orifice is opened by
progressively lowering the door. The movement of the agitator is continued and
a current of water is led in and the stony matters are washed away.
The movement of the sliding door should not be sufficient to permit the vessel
to empty completely, besides the bottom of the vessel is so arranged as to prevent
it being emptied completely.
Finally there only remains at the bottom of the vessel mercury the amalgam
and a small quantity of the heaviest of the mineral matters.
Generally one charge of mercury may be employed for many successive
operations, the sliding door is consequently raised and the operation recommenced
with another charge of mineral.
When the proportion of amalgam which has been formed is considered sufficient
after the washing similar to that described above, the lower stopper will be
removed and the mercury mixed with the amalgam, and the remains of the mineral
will be collected-The final washing will be effected by hand according to known
methods and the precious metals will be separated from the mercury by distillation
in a close vessel and the mercury will be again used.
Dated this 27th day of October 1885.

page_text: I SYDNEY PITT of Sutton in the County of Surrey Gentleman (a communication
to me from abroad by Jules Weirich of Béziers Hérault 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 :-
All the processes at present in use of treating auriferous and auroargentiferous
minerals produce, residues or tailings containing more or less of the precious
metals.
4
Up to the present time an economical method of separating from these residues
the greater part of the gold and silver which they contain has been sought for
without success.
The present invention has for its object a new method of treatment by which
these residues can be considerably impoverished. It consists in a pounding carried
on till a very fine powder is obtained combined with an amalgamation effected in
still water so conducted as only to allow the mineral and the water to escape
after a complete arrangement, according to density, has been effected and an
intimate contact of the mercury with the particles, even the smallest, of gold or of
auroargentiferous matter has been brought. about in a very complete manner;
which has not been done up to the present time.
The pounding may be carried on in the dry state or in the presence of water
by crushing or stamping, or by passage through apparatus such as Carr's and
Vappart's Disintegrators and other of a similar sort or by crushing under or
between mill-stones or cylinders, in short, by any process which gives a sufficient
fineness, which in certain cases should be carried as far as a mesh of a hundred to
120 of the silk sieve.
The products of this pounding are classed according to size so as to furnish a
uniform product all of a certain size, and all matter of larger size is taken back'
continually to the pounding operation-This classing can be carried on either in
the dry state by sifting or by the use of depositing chambers suitably arranged
and it may be from water, but it is necessary during the pounding and sorting to
take precautions to avoid loss from the escape of the fine particles of gold: in con-
sequence of the extreme difficulty of avoiding these losses I consider pounding and
sifting in a dry state to be very much preferred.
The classing by density and the amalgamation are brought about by prolonged
and regular agitation of the mineral for from 3 to 6 hours in a vessel partly full of
water and containing a quantity of mercury, from a thousand to two thousand times
the quantity by weight of the gold contained in the charge of the apparatus. The
apparatus which I prefer is represented by the annexed drawing.
DAN
DRAWINA

page_text: My apparatus is composed of a bed of cast iron or wood or masonry A in which
is mounted a semi-cylindrical vessel B. The axis of this vessel is horizontal and it
is made according to local circumstances, of stone, cement, wood, metal or other
solid and watertight material. Upon the opposite sides of this vessel and of the
frame, bearings are set up, in which the necks of an horizontal axis C. are
received This axis is arranged so as to occupy exactly the axial line of the
vessel B. upon one of the necks of the axle is mounted on the outside a crank
handle D. or the axis may be rotated in any other appropriate manner. The
axis C carries within the vessel an agitator E. of which the drawing sufficiently
indicates the construction.
This agitator E is of wood but with metallic connections provided the solution
be not acid. It is fixed to the axis-C by two bolts e. e. which pass through it and
on each of the projecting ends are screw nuts F. F. by means of which the length
of the agitator is adjusted so that it may always lightly scrape the inner surface of
the vessel B.-The agitator is an open frame so that in passing through the liquid
it produces the least possible disturbance and agitation.
The movement of the agitator is alternate and circular and it should be perfectly
regular; it is limited as the drawing shews in its to and fro movement by the
height of the vessel. The speed will vary according to the nature of the gangue,
the size of the pulverized matter and the stage of the operation, but it should
always be such that the mass remains in suspension in the liquid.
The dimensions of the apparatus will vary according to the quantities of mineral
which it is intended to treat and the nature of the gangues. The apparatus
represented in the drawing will be suitable for the treatment at each operation of a
thousand kilos of mineral.
The depth of water will vary from 60 Cm to one metre-Supposing the mineral
to contain a hundred grammes of gold or auroargentiferous matter per ton it will
be suitable to employ 150 to 200 kilos of mercury, and the period of each operation
should be 4 hours which, with the time occupied in changing and washing, will
represent 6 hours. Four operations can be made in the 24 hours and the same
mercury may be employed during an entire week-There will thus be passed
through the apparatus in 6 days 24,000 kilogrammes of mineral, representing
2400 grammes of gold or of auroargentiferous matter, of which 2000 about will be
dissolved in the mercury and will be recovered in the distillation.
It is unnecessary to say that the duration of the operation will vary according
to the nature of the mineral-It will generally be from 3 to 6 hours and will be
prolonged in case of need.
At one end of the vessel and its frame an orifice G. is provided, it is provided
with a sliding door H-This door is moved vertically by a screw nut I working
on the threaded end of the vertical sliding stem J to which the door H. is fixed
by means of the straps j.j. By turning the hand wheel upon the nut I in the
direction to lower the door the orifice is uncovered in such a manner as to let out
the contents of the vessel-By turning it in the opposite direction the door is
raised and the orifice is closed.
The operation is conducted as follows:-
The apparatus having received the proper quantities of water and of mercury
the agitator is set to work and the powdered mineral which may or may not have
been previously roasted is introduced by degrees.
In consequence of the alternating circular movement of the agitator which
repeatedly lightly scrapes the bottom of the vessel, the mineral thus introduced is
constantly kept in suspension in a quantity of water which is as little disturbed as
possible and by the action of gravity it tends continually to fall...
In this free fall constantly repeated in the midst of a mass of water which is
nearly still, the density of the constituent elements of the mineral intervenes to
bring about a separation which is completed and perfected as the operation is
prolonged Gold, silver, and the auriferous compounds being the most dense go to
the bottom of the vessel and there meet with the layer and also minute drops of

page_text: mercury and they become amalgamated. When the operation has lasted a sufficient
time, which is ascertained by experience, with each sort of mineral, so that the
amalgamation may be considered practically complete, the orifice G is opened by
progressively lowering the door H by means of the screw nut I-(this lowering
movement may be automatic). The movement of the agitator is continued and a
current of water is led in and the stony matters are washed away-If the nature
of the minerals renders it desirable to separate the different gangues, the water will
be led off by several different channels into as many different depositing basins-
The movement of the sliding door should not be sufficient to permit the vessel to
empty completely, but besides the bottom of the vessel is so arranged as to prevent
the vessel being completely emptied.
Finally there only remains at the bottom of the vessel mercury, the amalgam,
and a small quantity of the heaviest of the mineral matters.
Generally one charge of mercury may be employed for many successive
operations. The sliding door is now raised and the operation recommenced with
another charge of mineral.
When the proportion of amalgam which has been formed is considered sufficient,
after the washing similar to that described above, the lower stopper K will be
removed and the mercury mixed with the amalgam, and the remains of the mineral
will be collected in a movable apparatus. The final washing will be effected by
hand according to known methods and the precious metals will be separated from
the mercury by distillation in a close vessel and the mercury will be again used. In
place of the arrangement above described for emptying the vessel, other arrange-
ments effecting the same object may be provided, such as superposed orifices or
siphons and the like.
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. The process substantially as above described having for its object the almost
complete extraction of gold and auroargentiferous compounds contained in minerals
and consisting in the combination of operations following:-
:-
Pounding the mineral to the state of very fine powder and returning to the
pounding apparatus all the matter which has not been brought to the
requisite degree of fineness.
Amalgamation of the gold and auroargentiferous products progressively brought
into contact with mercury in the sorting which takes place by the free
fall of the minerals in the midst of a limited quantity of water renewed
only at the end of the operations.
Systematic washing of the residues; and
Distillation of the amalgam.
2. The special arrangement of the amalgamating vessel with its agitator as
above described and represented in the drawing.
1.1.°
1000