Process of and Apparatus for the Treatment of Auriferous and other Minerals by Amalgamation.
Year: 1899

page_text: .Date of Application, 7th June, 1899
Complete Specification Left, 7th Mar., 1900-Accepted, 7th Apr., 1900.
PROVISIONAL SPECIFICATION.
A Process of and Apparatus for the Treatment of Auriferous and other
Minerals by Amalgamation.
I, LUIS LAGARRIGUE, of 12, Boulevard Malesherbes, Paris, in the Republic of
France, Engineer, do hereby declare the nature of this invention to be as
follows:
The process which I have devised is based upon a novel principle which I
have discovered, which I term the principle of capillary immersion. This
principle I will first of all describe.
The principle consists in introducing into a mass of mercury, and at any
desired depth, sand, dust and any other pulverulent materials, utilising their
adherence to the surface of a solid body to which is imparted a continuous move-
ment and which is caused to enter the mass of mercury and to then leave the
same.
This adherence of sand and dust upon a surface in movement is doubtless the
consequence of capillary phenomena which modify the horizontality of the
surfaces of the liquids producing either a concave or convex meniscus according
as it adheres or does not adhere to the immersed solid body.
These capillary phenomena exert a direct influence upon the adherence of
solids one with the other. Thus it is found that the adherence of two solids
in contact is not modified when they are immersed in a liquid which is not
capable of moistening them, that is to say which does not adhere to their surfaces;
on the contrary, this adherence diminishes and even disappears when the
liquid wets the surfaces. This fact is experienced by taking two plates of
copper one only of which is amalgamated. By covering both of them with sand
and causing mercury to flow over their surfaces it will be found that upon the
amalgamated plate the mercury carries away all the sand. On the other hand,
the plate which has no adherence with the mercury retains upon its surface
the whole of the sand however considerable the quantity of mercury which is
caused to flow over it.
The logical conclusion is that it is the form of the meniscus which causes
this phenomenon, since the fluid is able or unable to enter between the surfaces
of contact of the sand with the solid according as its meniscus is concave or
convex.
It is also found in this manner that the relative densities of the sand and
mercury have no influence whatever upon the result, since sand invariably con-
tinues to adhere to the plate whatever may be the thickness of the sheet of
mercury which flows over it.
Upon the same principle a plate covered with sand may be immersed in a
trough containing mercury without this latter becoming detached from the plate,
and it is obvious that the plate may be so immersed to any desired depth
since the conditions of equilibrium, that is to say the relative densities of sand
and mercury, are not altered by the pressure.

page_text: In accordance with this principle a large number of appliances may be con-
structed which comprise a continuous surface entering the mercury and which,
as there is imparted to it a certain movement, carries with it the sand with
which it is in contact and causes this sand to enter the mass of mercury to any
desired depth the said sand always remaining attached to the surface in move-
ment and becoming detached therefrom only when this latter returns to the
level of the mercury.
The practical importance of the application of this principle to the process.
of amalgamation is very great, as by its means there is obtained a uniform and
intimate contact between the ores and the mercury, the following results being
attained: The mercury acts physically upon the metals capable of amalgamation,
(gold, silver, tin and so forth), that is to say by means of its adherence, whilst
this latter is nil upon the sand and earth. The mercury also acts chemically
upon these metals owing to its solvent action.
The pressure of several atmospheres to which the mercury is submitted in
proximity to the bottom of the reservoir is doubtless highly conductive to its
physical adherence and to its chemical action upon the metals capable of
amalgamation.
Several types of apparatus realising this principle of capillary immersion may
be readily established, as it is only necessary that a cylindrical surface of some
kind should be displaced within a reservoir containing mercury in order to
constitute an apparatus for dry amalgamation.
In carrying out my said invention the apparatus may consist merely of a
plane cylinder having a circular base immersed in a trough containing mercury,
said cylinder being caused to rotate. The sand is introduced into the hopper;
those portions of the sand which are in contact with the surface of the cylinder
at the point of immersion, are carried away by this cylinder and descend to the
lower portion, then rise to the surface of the mercury leaving the same at a
point where they become separated from the cylinder and fall, owing to their
own weight, outside the reservoir upon the discharge board.
This arrangement is only theoretical and does not fulfil the conditions which
are necessary in practice. The cylinder should be hollow in order to avoid
dead weight; but its axis would then be submitted to a very considerable effort,
equal to the difference between the weight of the cylinder and that of the volume
of mercury displaced. In addition to this, the path traversed by the sand
through the mercury would be relatively very small having regard to the large
volume of the apparatus.
A far more suitable arrangement comprises a sheet of any non-amalgamable
material, which turns between two cylinders. The diameter of one the cylinders,
the immersed cylinder may be as small as is consistent with obtaining stiffness
of the sheet. It is advantageous to employ for the sheet a non-porous material,
as under the pressure the mercury penetrates materials such as leather, india-
rubber, fabrics, paper and so forth, and the mercury which has filled the pores
in the material is forcibly driven out when the sheet passes over the upper
cylinder and is tightly pressed against the same. Polished steel which has
been reduced to the condition of an exceedingly thin sheet, appears to me to
fulfil all the necessary conditions of flexibility and durability; it is only
requisite that there should be perfect continuity in the band, which necessitates
careful and special manufacture.
The employment of endless bands enables two, three or a greater number of
such bands to be arranged in a single mercury reservoir thus causing the sand
and the metalliferous earths to traverse a considerable surface of mercury
Increasing velocities may advantageously be imparted to the bands in order to
obtain perfectly regular operation, and in this case the sand and earth which
becomes detached from one band upon its issuing from the mercury are again
carried by the following band into the interior of the reservoir.
By means of these endless bands the path of the earths at the lower portion

page_text: of the reservoir may be prolonged in order to take advantage of the higher
pressures. It is only necessary to provide two independent reservoirs each of
which is furnished with a suitable number of bands, and to connect them by
means of a passage at their lower portions, such passage being traversed by
another conveying band.
With these appliances, the yield depends upon the degree of crushing, since
the layer of earth which becomes attached to the conveying band in so much
the thinner according as the crushing is carried further. The yield also depends ¨*
upon the velocity with which the conveying takes place.
Whatever may be the arrangement of the machine employed in order to
carry the process into practice, all the idle or useless spaces of the reservoirs
should preferably be filled with a substance of some kind, such as wood or cast
iron for example, in order to prevent the necessity for employing too great a
quantity of mercury, it being only necessary that the mercury should, be
present in the portion of the apparatus which is in contact with the earths
adhering to the band and for a small depth.
Dated this 7th day of Luna 1900
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.
A Process of and Apparatus for the Treatment of Auriferous and other
Minerals by Amalgamation.
I, LUIS LAGARRIGUE, of 12, Boulevard Malesherbes, Paris, 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:-
-
The process which I have devised is based upon a novel principle which I
have discovered, which I term the principle of capillary immersion. This
principle I will first of all describe.
The principle consists in introducing into a mass of mercury and at a sufficient
depth, sand dust and other pulverulent materials, utilising their adherence to
the surface of a solid body to which is imparted a continuous movement and
which is caused to enter the mass of mercury and then to leave the same.
This adherence of sand and dust upon a surface in movement is doubtless the
consequence of capillary phenomena which modify the horizontality of the-sur-
faces of the liquids, producing either a concave or convex meniscus according
as it adheres or does not adhere to the immersed solid body.
These capillary phenomena exert a direct influence upon the adherence of
solids one with the other. Thus it is found that the adherence of two solids
in contact is not modified when they are immersed in a liquid which is not
capable of moistening them, that is to say which does not adhere to their surfaces;
on the contrary this adherence diminishes and even disappears when the
liquid wets the surfaces. This fact is demonstrated by taking two plates of
copper one only of which is amalgamated. By covering both of them with sand
and causing mercury to flow over their surfaces it will be found that the mercury
carries away all the sand from the amalgamated plate. On the other hand,
the plate which has no adherence with the mercury retains upon its surface the
whole of the sand however considerable the quantity of mercury which is
caused to flow over it.

page_text: The logical conclusion is that it is the form of the meniscus which produces
this phenomenon, since the fluid is able or unable to enter between the surfaces
of contact of the sand with the solid according as its meniscus is concave or
convex.
It is also found that the relative densities of the sand and mercury have no
influence whatever upon the result, since sand invariably continues to. adhere
to the plate whatever may be the thickness of the sheet of mercury which flows
over it.
,'
Upon the same principle a plate covered with sand may be immersed in a
trough containing mercury without the sand becoming detached from the plate,
and it is obvious that the plate may be so immersed to any desired depth
since the conditions of equilibrium, that is to say the relative densities of sand
and mercury, are not affected by the pressure.
In accordance with this principle a large number of appliances may be con-
structed which comprise a continuous surface entering the mercury and which,
as there is imparted to it a certain movement, carries with it the sand with
which it is in contact and causes this sand to enter the mass of mercury to any
desired depth, the said sand always remaining attached to the surface in move-
ment and becoming detached therefrom only when this latter returns to the upper
surface of the mercury.
The practical importance of the application of this principle to the process
of amalgamation is very great, as by its means there is obtained an intimate
and uniform contact between the ores and the mercury, the following results
being obtained, the mercury acts physically upon the metals capable of amal-
gamation (gold, silver, tin and so forth) that is to say by means of its adherence,
whilst this latter is nil upon the sand and earth. The mercury also acts
chemically upon these metals owing to its solvent action. By reason of the depth
of 50 centimetres to one metre, or even more, to which the sand and earth are
caused to descend in the mercury, whereby a pressure of one or more atmospheres
is produced, the certain amalgamation of all the pulverulent ores of gold, even
pyritous ores, is effected without its being necessary to roast them.
The form of apparatus which I prefer to employ is represented in the accom-
panying drawing in Figure 1. It comprises an endless sheet a of any suitable
non-amalgamable material which turns between two cylinders b and c. The
diameter of the immersion cylinder b may be as small as the stiffness of the
sheet will admit of. It is advantageous to employ for the sheet a non-porcas
material, as under pressure, the mercury would penetrate materials such as
leather, india rubber, fabrics and the like, and the mercury which has filled
the pores in the material is forcibly driven out when the sheet passes over the
upper cylinder c in a compressed condition. Paper of a high degree of smooth-
ness and in a somewhat thin sheet, but at the same time of considerable strength,
appears to me to fulfill all the necessary conditions of flexibility and durability.
The employment of endless bands enables two, three or a greater number of
such bands to be arranged in a single mercury reservoir (see Figure 2) thus
causing the sand and auriferous earths to traverse a considerable surface of
mercury. Increasing velocities may advantageously be imparted to the bands
in order to obtain perfectly regular operation, and in this case the sand and
earth which becomes detached from one band upon its issuing from the mercury
are again conducted by the succeeding band into the interior of the reservoir.
By means of these endless bands, the path of the earth at the lower portion
of the reservoir may be prolonged in order to take advantage of the higher
pressures. This may be effected by means of the arrangement shewn in
Figure 3, two independent reservoirs being provided, each of which has a suit-
able number of hands, and having a passage e connecting said reservoir at their
lower portion, such passage being traversed by another conveying band f.
With these appliances, the yield depends upon the degree of fineness of the
crushing, since the layer of earth which becomes attached to the conveying band

page_text: is so much the thinner according as the crushing is carried further. The yield
also depends upon the velocity with which the conveying takes place.
Whatever may be the arrangement of the machine employed in order to
carry the process into practice, all the idle or useless spaces of the reservoirs
should be filled with a substance of some kind, such as wood or cast iron for
example, in order to prevent the necessity for employing too great a quantity
of mercury, it being only necessary that the mercury should be present in that
portion of the apparatus which is in contact with the earths adhering to the
band and for a small thickness.
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 for the treatment of pulverulent sands and ores of gold, silver
and other metals by amalgamation, consisting in causing these sands or dusts
to be conveyed into and immersed in a deep trough containing mercury, either
in a wet or dry condition, in a very thin layer which adheres naturally to the
movable endless conveyor band, the sand or dust so conveyed remaining adherent
to the endless band during the immersion and being submitted to a pressure
which increases in proportion to the depth of immersion in the mercury, the
said sand or dust becoming detached from the conveyor surface only upon
arriving at the upper surface of the mercury.
2. The apparatus for carrying the process, into practice and comprising an
endless band in movement and plunging vertically into a deep trough con-
taining mercury and receiving upon one side at its upper portion the pulverulent
ore which is conveyed by adherence to the endless band into the mercury and
is thus caused to penetrate further and further into this metallic liquid whereby
it undergoes a progressively increasing pressure which ensures the amalgama-
tion of ores offering the greatest resistance to this treatment, the amalgamated
ores leaving the apparatus at its other side at the upper level of the mercury.
3. The arrangement of several successive conveyor surfaces which produce a
corresponding number of immersions of the sand and metallic dusts in the
mercury in order to ensure that complete exhaustion shall take place, these
different sheets or bands being arranged in continuation one of the other.
Tad this 4h dow of Wu 1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.