An Improved Method of and Apparatus for Amalgamating Gold and other Metals.
Year: 1888

page_text: Date of Application, 14th May, 1888
Specification Accepted, 26th Oct., 1888
An Improved Method of and Apparatus for Amalgamating Gold and
other Metals.
I, SIGWART THEODOR DAHL, of Bommeló, in the Kingdom of Norway, Mining
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 object of this invention is to allow of a single apparatus being employed for
uninterruptedly treating a large quantity of material, instead of being obliged, as
hitherto, to employ several amalgamators for this purpose.
In apparatus formerly used, for instance, in Moley's and Humboldt's apparatuses,
the size of the apparatus is limited, in consequence of the difference between the speed
at the centre and that at the periphery of the amalgamating pan being so considerable,
that in pans of large dimensions an equal distribution of the material cannot be
produced and consequently perfect amalgamation cannot be effected.
When working at a slow speed the apparatus becomes choked up at the centre,
and when working at a speed which is sufficient to cause the material, to be
distributed, the quicksilver becomes floured at the periphery and a loss of quicksilver
is caused.
In order to avoid this objection and to obtain an equal distribution of the
material and consequently an uniform amalgamation, I make use of the outer
portion or rim only of the pan for amalgamating instead of using the whole surface
thereof whereby the difference between the speed at the inlet and outlet is
considerably decreased. In this way I obtain an uniform amalgamation and at
the same time the apparatus can be constructed of as large a size as may be
required.

page_text: In the accompanying drawing
Figure 1 is a vertical section partly in elevation, and
Figure 2 is a sectional plan of an amalgamating apparatus constructed according to
my invention.
Similar letters in both the figures indicate similar parts.
A the apparatus, wherein the material is introduced under pressure.
B the apparatus, wherein the material is introduced without pressure.
Unlike the apparatuses of Humboldt, Moley, and others, the base of my apparatus
is preferably of masonry covered with cement. The apparatus is provided with bevel
gearing a directly in connection with the driving shaft b, by which power is trans-
mitted to the vertical shaft e resting on the base of the apparatus. On the shaft c
are placed two or more arms e which carry vertical conducting rods fattached to the
cylindrical ring g made of wood or other insulating material, which to a certain
extent is immersed in the quicksilver contained in a recess in the base of masonry.
This ring, when the material is introduced under pressure has on the under side a
rabbet which causes the material (the finely crushed ore or mud mixed with water)
to be forced through a passage containing quick silver besides the passages at the
inlet and outlet 1. The rabbet in the base is provided in order to reduce the
required quantity of quicksilver.
The necessary electricity is produced for the purpose by a "dynamo" one terminal
of which is placed in connection with the vertical shaft of the apparatus by means of
a brush m on a copper ring n insulated from the shaft by the piece n attached to the
same; the current flows from here to an iron or copper ring p attached to the inner
edge of the ring g The other terminal of the dynamo is connected to a ring 9
placed in the outer side of the recess in the base; by this means the electricity is
forced to thoroughly traverse the quicksilver so as to keep it clean, steady, and fit for
the amalgamation.
This apparatus, which can be used either with or without pressure is in the first
case (see figure 1. A) provided with several tubes or pipes placed in or outside the
base. The material or pulp is introduced into a funnel whence it passes down into
a pipe of suitable length placed in the base which pipe may simultaneously lead to
several amalgamators. This pipe is connected with two or more pipes which are of
such a height that the quicksilver shall not rise in the same; the pipes t discharge
into horizontal pipes t having two or more arms u which discharge below the quick-
silver. On the bends where connection exists between the pipes t, and u are
placed cocks or plugs in order to allow the pipes to be easily cleaned and stoppages
to be removed therefrom and in order to still further facilitate the removal of the
said stoppages glass tubes with india rubber tubes are provided on the respective
cross-pieces. In the other case (see fignre 1 B) where pressure is not used the ring g
must be turned in such a manner that its lower side shall not be rabbeted but flat.
The ring is lowered to such an extent that it will only touch the quicksilver, after
which it is fixed to the arms by the screws v. Instead of being led through pipes into
the base, the material is conducted down into a receiver w placed round the vertical
shaft of the apparatus and resting on the crosspiece e; from this receiver the
material or pulp is discharged through the pipe into the recess y in the base from
which the pulp again runs over down into the recess in the base, where, by means
of the centrifugal action, it is forced below the ring and finally having passed the
latter is discharged at 2.
Amongst the advantages which this apparatus possesses over those heretofore in use
may be mentioned the following.
1. The continuity of the process does not depend on the size of the apparatus.
2. The pulp can be distributed equally as well either without or with pressure.
3. The cost of erection is small as the whole base of the apparatus can be constructed
of masonry and therefore can be conveniently made on the spot where the apparatus
is required for use.
4. Great capacity.

page_text: 6. Accidental stoppages can easily be prevented and remedied so that these
stoppages cannot to any appreciable extent interfere with the course of the process.
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. In amalgamating apparatus having horizontal amalgamating pans, obtaining a
practically equal distribution of the material over the whole amalgamating or frictional
surface by an arrangement of annular quicksilver receiver situated near the outer
periphery of the apparatus and in which a revolving ring g is placed the material
instead of being introduced at the centre of the apparatus being conducted to the
inner side of the receiver that being the part where the amalgamation commences.
2. In amalgamating apparatus of the kind claimed in claim 1 the arrangement for
supplying the material either with or without pressure, substantially as hereinbefore
described and illustrated in the accompanying drawing.
3. In amalgamating apparatus of the kind referred to in claim 1, the arrangement
of one or several rabbets in the lower side of the ring g with or without corresponding
edges in the bottom of the receiver for the purpose of causing the material when
introduced under pressure to pass through one or several passages containing
quicksilver.
4. In amalgamating apparatus such as is referred to in claims, 1, 2, and 3, a base
which can be conveniently made of cemented brick-work, and the centre part of
which forms a support for the vertical shaft, an annular recess y being formed in the
said base, also an annular recess for quicksilver in which works a revolving ring g
which operates on the material during the amalgamation.
5. In amalgamating apparatus such as is referred to in claims, 1, 2, 3 and 4, the
arrangement of parts and the details substantially as hereinbefore described and
illustrated in the accompanying drawings.