IMPROVEMENTS IN EXTRACTING AND SEPARATING GOLD AND SILVER FROM THEIR ORES OR MATRICES
Year: 1865

page_text: LETTERS PATENT to William Crookes, F.R.S., of Wine Office Court,
Fleet Street, in the City of London, for the Invention of "IMPROVEMENTS
IN EXTRACTING AND SEPARATING GOLD AND SILVER FROM THEIR ORES OR
MATRICES."
Sealed the 4th August 1865, and dated the 11th February 1865.
PROVISIONAL SPECIFICATION left by the said William Crookes at the
Office of the Commissioners of Patents, with his Petition, on the 11th
February 1865.
I, WILLIAM CROOKES, F.R.S., of Wine Office Court, Fleet Street, in the
City of London, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN EXTRACTING AND SEPARATING GOLD AND SILVER FROM THEIR
ORES OR MATRICES," to be as follows:-
This Invention relates to certain improvements in the method of treating
the ores or substances containing gold and silver by amalgamation, and,
whereby those metals can be more perfectly and completely extracted and
separated therefrom than by the processes hitherto adopted. A solid amalgam
of sodium is in the first place formed by combining about one part of
sodium with about thirty parts by weight of mercury. The solid amalgam
thus formed is then added to the mercury employed for the purposes of amal-
gamation, the proportions varying according to the quantity of metal contained

page_text: and the state in which it occurs in the ore or matrix.
If, however, the pro-
portion of the alkali metal exceeds that of one part to from one hundred and
twenty to one hundred and fifty parts of mercury, the amalgam becomes viscid-
and its manipulation inconvenient. The effect of thus combining the sodium
with the mercury is to impart to the latter a greater affinity for or power of
adhesion to the metal under treatment than it possesses in its simple and.
uncombined condition. Instead of using the solid amalgam as herein-before
mentioned, the sodium may be combined directly with the mercury employed,
the proportions varying according to the requirements of the case.
This Invention can be used in conjunction with any machine or apparatus
for performing the amalgamating process, and in cases where amalgamating
vessels or receptacles constructed of iron are employed, an additional advantage
arises from the fact that mercury combined as before-mentioned with sodium
forms a thin film over the surface of the iron, thus collecting very minute
quantities of the metal under treatment, and which may be removed by the
ordinary process, and subjected to the subsequent treatment usually employed.
Although sodium'has been herein-before mentioned as being used, potassium
or lithium may be employed in lieu thereof in combination with mercury for
the purposes of this Invention.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Crookes in the Great Seal Patent Office on the
11th August 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
CROOKES, F.R.S., of Wine Office Court, Fleet Street, in the City of London,
send greeting.
⚫ WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eleventh day of February, in the year of our Lord
One thousand eight hundred and sixty-five, in the twenty-eighth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said William Crookes, Her special licence that I, the said William
Crookes, my executors, administrators, and assigns, or such others as I,
the said William Crookes, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times there-
after during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain and
Ireland; the Channel Islands; and Isle of Man, an Invention for "IMPROVE-

page_text: MENTS IN EXTRACTING AND SEPARATING GOLD AND SILVER FROM THEIR ORES OR
MATRICES," upon the condition (amongst others) that I, the said William
Crookes, my executors or administrators, by an instrument in writing under
my, or their, or one of their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the same was
to be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said William Crookes, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement :-
My said Invention relates to certain improvements in the method of treating
ores or substances containing gold and silver by amalgamation, and whereby
those metals can be more perfectly and completely extracted and separated
therefrom than by the processes hitherto adopted.
The mode of treatment employed is as follows:-An amalgam of sodium is in
the first place formed by combining sodium with mercury. The proportions
way be varied within wide limits, that is to say, from less than three to more
The
than thirty parts of sodium to one hundred parts by weight of mercury.
sodium and mercury must be caused to unite, and the amalgam prepared with
the customary precautions well known to and understood by chemists. The
last-mentioned method of forming the sodium amalgam is that which I usually
prefer in actual practice, but, if desired, the amalgam may be prepared electro-
chemically, as described by Becquerel and other chemical authors, or by any
other suitable means. The amalgam is then added to the mercury employed
for the purposes of amalgamation, the proportions varying according to the
quantities of precious metal contained, and the state in which it occurs in the
ore or matrix; but as in the process the beneficial effects of the sodium are
gradually removed, the action should be maintained, if needed, by occasionally
introducing fresh supplies of the amalgam into the charge of mercury con-
tained in the machine employed. The quantity must, however, be regulated"
and determined by the skill and judgment of the operator, as no definite and
absolute proportion can be laid down as being necessary. If, however, the
proportion of the alkali metal exceeds that of one part to from one hundred
and twenty to one hundred and fifty parts of mercury, the amalgam becomes
viscid, and its manipulation may be inconvenient. The effect of thus com-
bining the sodium with the mercury is to impart to the latter a greater
affinity for or power of adhesion to the precious metal under treatment than

page_text: .it possesses in its simple and uncombined condition, so that it will readily
amalgamate with the gold or silver, even when the latter metals are soiled by
grease or other extraneous matter. Although I prefer that the amalgamation
shall be conducted in the presence of water, as in the usual processes, the
operation, if desirable, may be performed in a dry manner. I should here
state that the amalgam above mentioned should be stored in air-tight vessels,
or under naphtha, such as metallic sodium is usually kept in. Instead of
using the amalgam as herein-before mentioned, the sodium may be combined
directly with the mercury employed, care being taken that the proportions
shall remain substantially as already indicated.
I may
This Invention can be used in conjunction with any machine or apparatus
for performing the amalgamating process, and, in cases where amalgamating
vessels or receptacles or plates constructed of iron or other metal employed,
an additional advantage arises from the fact that the mercury combined as
before mentioned with sodium forms a thin film over the surface of the iron
or other metal, thus aiding in the collection of any minute quantities of the
precious metal under treatment. The subsequent extraction of the gold or
silver from the mercury may be conducted in any desirable manner.
mention that I do not find in actual practise that a small quantity of sodium,
if accidentally allowed to remain in the mixture of gold or silver and mercury,
affects the subsequent treatment in any appreciable degree. In cases where,
from the nature of the ores or substances under treatment, the mercury used
for amalgamation becomes divided into minute globules, technically known as
flouring" or "granulating," there is frequently a difficulty in separating the
globules from the heavy particles of the powdered ore or substance containing
the precious metal; the addition of the sodium amalgam to such a mixture
is found to induce the coalescence of the liquid or viscid metallic particles, so
that a mechanical separation of the gold or silver amalgam from the gangue
may be readily effected. The employment of sodium in combination with
mercury will especially be found beneficial in cases where gold or silver occurs
with pyrites, sulphurets, or minerals containing arsenic, antimony, tellurium,
or bismuth.
The process of amalgamation with ordinary mercury is difficult
to perform in the presence of such minerals without great loss both of mercury
and of the precious metal under treatment, owing to the surfaces of the
latter being in such a tarnished or soiled state that mercury alone will not
touch them (as, for instance, when gold exists in pyrites), and also owing to
the mercury becoming what is technically termed "sick" or "floured," in
which state its power of uniting with the precious metals is much diminished; in
these cases the addition of sodium amalgam will be found highly advantageous.

page_text: I should here also observe that whenever the mercury has become "floured "
or powdered by the result of distillation, or from any other cause, it is readily
restored to the liquid or bright metallic state by the addition thereto of
sodium, either in its simple metallic condition, or as an amalgam with
mercury.
Although I have herein-before mentioned sodium as being used in the
processes above described, other alkali metals, such as potassium and lithium,
and other metals strictly analogous thereto in their chemical and physical
characters, may be employed in lieu thereof in combination with mercury for
the purposes of this Invention.
Having thus fully declared and ascertained the nature of my said Invention,
and the manner in which it is to be performed, I would observe, in conclusion,
that what I consider novel and original, and therefore claim as constituting my
said Invention is, the employment of an amalgam of sodium, or such other
alkali metal as aforesaid, in treating ores or substances containing gold or
silver for the extraction and separation therefrom of the precious metals,
as herein-before substantially set forth and described.
In witness whereof, I, the said William Crookes, have hereunto set my
hand and seal, this Eleventh day of August, in the year of our Lord
One thousand eight hundred and sixty-five.
Witness,
E. P. H. VAUGHAN,
54, Chancery Lane,
Agent for the Patentee.
WILLIAM CROOKES. (L.s.)