Improvements in Plates for Collecting or Separating Gold.
Year: 1898

page_text: Date of Application, 13th Jan., 1898-Accepted, 12th Mar., 1898
COMPLETE SPECIFICATION.
Improvements in Plates for Collecting or Separating Gold.
I, CHARLES EDWARD GREENE, residing at No. 423, Pine Street, in the City and
County of Providence, and State of Rhode Island, U.S.A., Electro Plater, do
hereby declare the nature of this invention and in what manner the same is to
be performed to be particularly described and ascertained by the following
statement and accompanying drawings:-
My invention relates to a new composition of matter for gold-collecting plates;
it also relates to the form of the plates. My improved plates have the property
or characteristic of attracting, collecting and holding particles or atoms of gold
on their upper or working surfaces.
"
In gold-mining operations, especially in gold placer mining, the auriferous sand
is as a rule of the kind termed low grade," the separation of the gold therefrom
being effected in various ways. The usual method, however, is to employ "sluices,"
in or on which are located "riffles" or pockets adapted to arrest more or less of the
larger particles or pieces of gold, etc., carried by the sand or gravel and water
passing along the sluiceway. The pockets are sometimes charged with quicksilver;
this metal, as is well known, possesses an affinity or attraction for gold, therefore
its function when thus used is to arrest and retain the smaller particles of gold,
thus forming an amalgam. One of the disadvantages to the successful employ-
ment of quicksilver is that its exposed surface soon becomes oxydized, as it were,
or covered with a skin or thin coating having more or less tenacity. As this
skin has no especial affinity for gold the finer particles, in a float, dust or powder
form, in passing over said skin are not arrested and absorbed by the quicksilver,
consequently such fine or float material flows into the refuse dump or tailings
and becomes lost. The larger pieces or particles of the gold are, however, collected
in the mass of quicksilver by reason of the superior weight of the gold, since they
break through the thin skin which covers the quicksilver, and sink into it.
"
"
I am aware that amalgamed plates as well as mechanical and chemical processes
are employed for separating or extracting gold from the ore or other material with
which the superior metal may be associated. When such amalgamated plates are
used the action of the sand, etc., flowing over the surfaces thereof, soon wear
through the thin coating or film covering the plates thereby seriously affecting if
not wholly destroying their efficiency. In other cases the working surface of the
plates is covered with successive layers of quicksilver with which the gold is
amalgamated. Amalgam plates have to be renewed frequently, owing to the
abrading action of the sand, etc.; this wearing action operates not only to materially
increase the cost of maintenance but the percentage of gold collected or extracted
is much less than it would be were the plate's surface kept in the normal condition.
The object I have in view is to produce an improved gold-collecting plate
possessing much greater efficiency in separating and collecting free gold from
auriferous sand or disintegrated ores than amalgamated plates or other gold-
extracting processes heretofore employed.
To that end my invention consists essentially in combining certain metallic

page_text: substances or elements to produce a new composition of matter. It also consists
in the method or process of combining the elements referred to, and it consists,
finally, in combining said composition of matter with a suitable base, thereby
increasing the strength of the plate, all as more fully hereinafter set forth.
That is to say, in my improved composition of matter, forming the gold-collect-
ing plate referred to, I employ zinc, quicksilver and metallic sodium, in such
proportions as preferred. These elements may be prepared and combined
substantially as follows. The desired amount of the metallic sodium (usually kept
in oil to exclude air and moisture) is first taken and rolled or pressed on absorbent
paper for the purpose of extracting all or nearly all traces of the oil, after which
the thus treated sodium is introduced into the mass of quicksilver, the latter being
contained in a suitable vessel, and the whole heated to a temperature say of
100 degrees F., the mixture meanwhile being stirred or agitated, until the resulting
gases formed at the top are ignited, thereby as it were fusing or uniting the
molecules of the quicksilver into a more liquid state; the result of the union being
to neutralize the tendency of the quicksilver to separate into and assume globular
forms. This binary compound in cooling thickens to the consistency of paste.
I next provide a suitable vessel or ladle containing the desired quantity of zinc
in a molten state and gradually add to the latter, after it has cooled somewhat,
the proper quantity of the previously prepared quicksilver, meanwhile stirring
the composition so as to thoroughly incorporate the elements composing it. While
the mixture is in this state it is in condition to be poured into the mould.
In preparing to cast the thus fused composition to produce the gold-collecting
plates I first properly place a suitable base-plate, preferably of iron, in the mould,
which latter too I prefer to make of iron, and then heat the whole, after which
the previously described composition or ternary compound is poured from the
ladle into the mold. After being cooled the thus cast composition is removed
from the flask and is then ready to be mounted for use.
I prefer to make the stiffening or base-plate above referred to of iron or steel
galvanized with zinc, the same being provided with a series of holes or pins or
other equivalent means by which the plate is adapted to be rigidly secured or
united to the composition during the process of casting the gold-collecting plate.
The latter may be made as thick as desired or necessary and as large in area as
practicable. In order to produce a very large collecting plate several of the
smaller ones, or units, may be secured by bolts; screws or clamps, to a suitable
bed or table; this latter may have a flat or curved surface as may be preferred.
When thus made the entire surface presents an area or face possessing a strong
affinity or attraction for gold, platinum, etc., the baser metals, however are un-
influenced by the properties of the composition.
By means of my invention the said stiffening member or base-plate also serves
to prevent the quicksilver in the gold-collecting plate from becoming intimately
or actively combined therewith, or in other words, the base-plate operates to some
extent as a reactionary element to the quicksilver.
By means of the employment of the composition forming the subject of this
invention I am enabled to produce a gold-collecting plate having a continuously
lubricated working surface. By the term lubricate, used in this connection, it
is meant that the exposed surface is covered with a moist or apparently greasy
film; this is due to the presence of the quicksilver. In this case, however, the
film possesses active properties, and is in no sense analogous to the non-active or
oxydized film or "skin" before referred to which forms upon the surface of a mass
of uncombined quicksilver when exposed to the air and being incapable of having
an affinity for gold in a float or powdered state.
may further add that since the quicksilver is thoroughly incorporated through-
out the mass of composition forming the collecting plate, the maximum efficiency
of the latter is maintained during its entire life, or until it is practically worn
down to the iron base. It may be added that such wearing away or abrading
action to which the gold-collecting plates are subjected is occasioned by the

page_text: continuod flowing over their surface of the water, sand, ore, etc., containing the
gold to be extracted.
When the collecting plates have become loaded or charged with gold to a
certain extent, as may be determined by the attendant or person in charge, they
are washed or flushed with water, after which the gold adhereing to and collected
upon the plates is removed in any suitable manner, as by means of a brush. The
gold thus collected is practically pure and uncombined with other materials,
therefore it can be treated or reduced at a comparatively small cost.
While I do not desire to limit or restrict the proportions of the elements entering
into the composition of my gold-collecting plates, as they may be varied to suit
different conditions, I find that as a rule the following proportions give the best
general results; that is to say, I employ four parts, by weight, of zinc to one part
of quicksilver, a small amount of metallic sodium being added to the quicksilver
for the purpose of neutralizing that property of the latter which causes it to assume
globular forms, the whole being combined and cast in a mold substantially as before
described.
In the accompanying sheet of drawings are represented certain forms of my
gold-collecting plates. That is to say, Figure 1 is a perspective view of the plate
provided with a flat working surface. Fig. 2 is a longitudinal sectional view,
showing the working or gold-collecting surface provided with a series of ribs or
riffles. Fig. 3 is a plan view of the iron base-plate. Fig. 4 is a sectional view,
showing the base-plate completely surrounded or enveloped by the composition
forming the gold-collecting plate proper. Fig. 5 is a side elevation of a curved
collecting plate. Fig. 6 is an end view of a circular shaped plate, and Fig. 7 is a
side view of the same, in partial section.
In the drawings a designates the gold-collecting plate as a whole; 6 the moulded
composition portion hereinbefore described, and the galvanized strengthening
or base-plate rigidly united or connected to the part b. The said member c may
have holes formed therethrough, as shown in Fig. 3, or it may be provided with
headed pins cl, as shown in Fig. 2. By this means the molten composition when
poured into the mould containing the plate c is cast onto and around the latter,
thereby as it were practically uniting them together. In Fig. 4 the plate is
located centrally of the composition ; as thus constructed it is evident that after
the upper portion of the plate a has been worn away it may be inverted and the
other or under side brought into use. If desired the plate e may extend beyond
the part b, as shown in Figs. 5 and 7, thereby adapting the gold-collecting mem-
ber a to be readily secured to any suitable holder or table.
Having now particularly described and ascertained the nature of this my said
invention and in what manner the same is to be performed, I declare that what I
claim is:
1. The herein described new composition of matter for gold-collecting plates,
the same being composed essentially of zinc, quicksilver and a suitable fluxing
agent, all combined in a molten state but which hardens when cold, as dis-
tinguished from amalgam plates in which successive layers or washes of mercury
composition in a soft or plastic state is applied to the surface of the plates.
2. As a new composition of matter, a compound consisting of quicksilver and
a small quantity of sodium added thereto, to prevent the quicksilver from separat-
ing into balls or globules, thus forming an amalgam, combined with an amount of
zinc equal to about four times the weight of said amalgam, the whole being fused
together and forming when cast a hard and solid composition capable of attracting
or having an affinity for gold, substantially as described.
3. The combination with the composition of matter herein before described,
composed essentially of zinc, quicksilver and sodium, of a strengthening or base-
plate united to said composition while the latter is in a molten state, the resulting
product forming a hard and solid homogeneous gold-collecting plate in which the

page_text: exposed or working surface thereof possesses an equal affinity for gold throughout
its mass, substantially as described.
4. The combination with the new composition of matter herein before described,
composed essentially of zinc and suitably treated quicksilver, of a metallic
strengthening or base-plate united or fused to said composition while the latter
is in a molten state, substantially as described.
5. The process of producing the gold-collecting plate hereinbefore described,
the same consisting in thoroughly incorporating into a mass of molten zinc a
suitable quantity of prepared quicksilver, then pouring the mixture into a heated
mould containing a piece of metal as c, adapted to form a strengthening plate,
thereby welding or uniting the composition to the plate, and finally cooling and
removing the casting from the mould.
6. As a new article of manufacture, a cast metallic gold-collecting plate having
quicksilver fused into the composition and incorporated throughout its mass,
substantially as hereinbefore described, whereby the working surface of the plate
is kept continuously in a moist or "lubricated" state, as distinguished from the
usual amalgam plates or even porous plates charged with quicksilver.
7. The gold-collecting plate herein before described, the same consisting of a
composition of zinc, quicksilver and sodium, combined when in a molten state
but which becomes hard and solid when cold, and a suitable strengthening or
base-plate united or otherwise secured to said composition, the said base-plate
possessing little or no affinity for the quicksilver.
Dated this 18th day of January 1898.
CHARLES EDWARD GREENE,
By Day, Davies & Hunt,
Chartered Patent Agents, 321, High Holborn, London, W.C.,
Agents for the Applicant..