A Method for Extracting Gold without the Use of Water by Means of a Combined Air Blast and Mercury, and Apparatus for Effecting same.
Year: 1894

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 18 of the Patents, &c. Act, 1883), as allowed by
the decision of the Comptroller General of the 30th day of July 1896.
Date of Application, 20th Dec., 1894
Complete Specification Left, 20th Sept., 1895-Accepted, 14th Dec., 1895
PROVISIONAL SPECIFICATION.
A Method for Extracting Gold without the Use of Water by Means
of a Combined Air Blast and Mercury, and Apparatus for
Effecting same.
WILLIAM HERBERT HYATT 1 Milton Road Herne Hill in the County of
Surrey, F.C.S. Chemical Engineer and Metallurgist, do hereby declare the nature
of this invention to be as follows:-
I cause an air-blast or air blasts to mix with sand, powdered quartz, earths,
minerals or substances containing gold, either in a pulverulent state or otherwise,
the blast containing these gold bearing materials is then forced or drawn over,
under, through, or against mercury. The mercury forms an amalgam with the
gold, at the same time the air-blast carries away the lighter particles of the gold
bearing materials, or otherwise displaces them, after the gold is extracted; and
allows the mercury to come in contact with fresh material, either intermittantly or
continuously. The air-blast or blasts generated in conjunction with the mercury,
may be effected by either forcing the air into contact with the gold-bearing
material, or by drawing the air into contact with the gold bearing material.
The air blast may be caused by rapidly revolving fans, bellows, or any suitable
means, and may be driven by hand, steam, water, or any other motive power. In
working the blast, advantage is taken of the very high specific gravity of mercury,
and its fluidity at ordinary temperatures, by means of which, sand, powdered quartz,
and many other materials can be blown under its surface, or through it, bringing
every particle into contact with the mercury, and on account of such gold bearing
materials being lighter than mercury, they will of themselves float to the surface,
and are either again subjected to mercury by the blast, or are exhausted, the heavier
gold having amalgamated with the mercury, and remaining bebind. To extract
the metallic gold, any ordinary process may be employed, such as pouring the
mercury & amalgam of mercury and gold into washleather or buckskin and
squeezing or pressing the fluid mercury through same, the amalgam remaining
behind, the amalgam is then distilled or sublimed, the mercury collected, and gold
in a metallic state remains in the retort or recepticle used. A suitable apparatus
for applying my principle for extracting gold by means of an air blast and mercury
conjointly, is as follows:-
A revolving fan is fixed horizontally into the end of a tube, which tube quickly
makes a bend downwards, and is continued in the form of a U shaped vertical tube;
immediately over the first downward turn of the tube, and in a vertical line with it,

page_text: is a feeding hopper, which allows the material to drop upon a perforated distributing
disc, fixed horizontally across the tube a little below the first downward bend.
The first U shaped tube is connected by an inverted U shaped tube to a second
U shaped tube, and so on until an undulating vertical tube is formed, having some-
what the appearance of a serpent bending up and down. Mercury is placed in the
bottom bends of each of the U shaped tubes, though not in sufficient quantities to
block a free passage for the blast containing material. The whole apparatus is
fixed in a light frame on wheels for easy movement, or can be quickly taken to
pieces and carried.
The tubes may be made in any proper material, such as light steel, gun
metal or any material combining the minimum of weight, with the maximum of
strength and durability. They are fitted together with flanges and screws,
connecting screws, or other means. The hopper has if necessary sieves fitted
over it to prevent larger particles entering than can be blown out by the air
blast, it is also fitted at the bottom with a flat, circular or other valve, to prevent
back pressure from the air blast and a slide if necessary to regulate the inlet of
material. The fan if so wished may be enclosed in a short tube which resembles a
funnel fitted into the end of the larger tube. This small tube has a gradually
decreasing diameter to concentrate the blast, and has its outlet in the middle of
the distributing disc. The motive power for the fan may be such as previously
indicated, or it may be driven by fixed or moveable pedals, treadles, or levers, by
making use of the legs and feet. In operation, gold bearing sand, quartz or other
· material drops into the tube from the hopper, mixes with the air blast, and is blown
to the mercury in the bottom of the first tube, then upwards, and over to the
bottom of the second tube, where it again comes in contact with mercury, over
again to the bottom of the third tube, where there is again mercury, and so on
through as many tubes as may be thought fit, the gold amalgamating with the
mercury, and leaving the treated material to be blown out, by means of and with
the blast as soon as it has passed through the last tube-the end of which tube may
be lengthened somewhat by adding a straight piece of tubing fitted at the top with
an adjustable nozzle, bent to a right angle with the vertical tube, to distribute the
sand or other material, in order that a heap may not too readily be formed to block
the exhaust; and also, such tube being longer than the others, it minimizes the
chance of mercury being blown out, there being practically little or no loss of
mercury, by using this apparatus.
By this up and down arrangement of the tube, or series of tubes, gold, being so
heavy has the tendency to be the first to fall downwards, and the last to rise
upwards from the bottom, its own weight assisting in bringing it into contact with
the mercury. The force of the blast can be regulated at will, to meet the require-
ments of the material treated, either for granular, fine dust or "float" gold. The
material can be passed through very rapidly and the refuse material exhausted in
a continuous stream.
As mercury dissolves large quantities of gold without losing fluidity, by means
of the air blast, the gold bearing material can be forced either over, under, or
through the mercury, the fluidity of which helps it to flow round or come in
-contact with the smallest particle. The same principle of an air blast or air
blasts in conjunction with mercury may be applied to my apparatus, such as a box
or chamber or series of boxes or chambers, with partitions having alternate
openings at the top and bottom with a removable air tight cover. There would be
openings to the outside, one for the admission of the material, one for the
entrance of the blast, and one for the exhaust. The sides, partitions and cover
to have copper plates amalgamated with mercury, and fluid mercury in the
-bottoms of such boxes or chambers.
Such apparati, which also might be made with horizontal partitions, riffles,
diagonal planes, shelves, spirals, or other means, the blast or blasts being worked
from above or below, across, through, or against the mercury with and in the
presence of gold bearing materials, would be suitable for stamp mills or gold

page_text: mines, to dispense with water in extracting either reef or alluvial gold as no
water at all is needed for extracting gold by this principle of an air blast and
mercury. My invention is also applicable to apparatus such as a horizontal tube,
bent into the shape of a coiled serpent, the hopper and fan at one end and the
exhaust at the other, with pockets, recepticles or a groove or grooves to hold
mercury; in this or any similar form of apparatus the material would be blown
round and round, and the gold being heavier than the sand, powdered quartz,
or other gold bearing material, it would tend to find its way to the bottom, and
amalgamate with the mercury. My invention applies to the extraction of gold
by the apparati already described, or any modification of same for use or
convenience provided they are worked on the principle of an air blast or air
blasts in conjunction with mercury, or to the application of causing mercury and
gold to come into contact by means of an air blast or air blasts.
Dated this 20th day of December 1894.
WILLIAM HERBERT HYATT.
COMPLETE SPECIFICATION (AMENDED).
A Method for Extracting Gold without the Use of Water by Means
of a Combined Air Blast and Mercury, and Apparatus for
Effecting same.
I, WILLIAM HERBERT HYATT, F.C.S., Chemical Engineer and Metallurgist,
of 1 Milton Road, Herne Hill in the County of Surrey, 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:―
According to my invention I effect the extraction of gold from gold bearing
material by the combined action of a strong current or currents of air and mercury,
whereby the air current is made to bring the gold into such intimate contact with
the mercury as to cause it to be effectually taken up thereby.
For this purpose I cause a strong current or currents of air acting either
continuously or intermittently to mix with gold-bearing material in a pulverulent
state, and I then cause such mixture of air and gold-bearing material to pass in
intimate contact with mercury, whereby the mercury amalgamates more rapidly
with the gold particles, while the exhausted residuum is carried off by the air
currents, so as to leave the mercury free to come in contact with farther quantities
of gold bearing material. The said air currents may be produced either by forcing
the air in the form of a blast into contact with the gold-bearing material or by
drawing the air into contact by suction or exhaust.
The air blast may be caused by rapidly revolving fans, bellows, or any suitable
means, and driven by hand, steam, water, or any other motive power. In working
the blast, advantage is taken of the very high specific gravity of mercury, and its
fluidity at ordinary temperatures, by means of which, sand, powdered quartz, and
many other materials can be propelled either under or over its surface, or through
it, so as to bring every particle into contact with the mercury and on account of
such gold-bearing materials being lighter than the mercury, they will of them-
selves float to the surface and are either again subjected to mercury by the blast,
or are removed, the heavier gold having amalgamated with the mercury, and
ren:aining behind. To extract the metallic gold, any ordinary process may be
employed, such as pouring the mercury and amalgam of mercury and gold into
wash leather or buckskin and squeezing or pressing the fluid mercury through the
Fame, the amalgam remaining behind; the amalgam is then distilled or sublimed,
the mercury collected, and gold in a metallic state remains in the retort or
receptacle used.
Various arrangements of apparatus may be employed for carrying my said

page_text: method of operating into practice; thus according to one arrangement I employ &
tube or passage of a vertically undulating or serpentine form, in the lower bends of
which is contained mercury. One end of the tabe being connected with a
supply of air blast mixed with pulverulent or granular gold-bearing material;
this is projected downward in the first branch of the tube onto or into the
mercury in the bottom bend, which takes up a portion of the gold from the
material as it passes over or through it on its way up the next vertical limb;
the air blast and material then pass through the upper bend and down the next
limb and onto or into the mercury in the next lower bend, and so on, as often as
may be required until the whole of the gold is extracted from the material which is
then conveyed away by the air blast through the open end of the tube either into
the open air or into an exhaust chamber. By thus causing the air with the gold-
bearing material to travel alternately upward and downward in the channel, the
advantage is gained that the gold being specifically heavier than the other materials
will be the first to descend into the mercury by its own weight assisted by the
impetus imparted thereto by the air, and also the last to ascend from the mercury,
the finely dispersed gold being caught by the spray of mercury which is produced
by the air current or blast. If necessary, the motion of the air and materials
through the successive limbs of the tube or passage can be accelerated by
introducing farther jets of air at one or more of the upper bends thereof.
The accompanying drawing shews by way of example some of the various
arrangements by means of which my said invention can by carried out. Fig. 1
shews a longitudinal section of an arrangement similar to that above described.
It consists of a serpentine tube A, the lower bends A'A' of which are made
detachable by means of a screw or other joint at B, and which each contain a
quantity of mercury C. At the top of the first limb of the tube is a feed
hopper D into which the granular or pulverulent gold bearing material to be
treated is introduced and from which it descends through a pipe E on to the
mercury. The hopper D is provided with a regulating valve which may be
arranged as shown to an enlarged scale at Fig. 2. The lower end of the hopper is
provided with a balance valve F situated in an enlargement E¹ of the pipe E, the
greatest extent of opening of the valve being regulated by a screw so that the
material will only flow downwards at a determined rate.
The end a of the tube is connected to any suitable supply of air blast, such as a
rotary fan, Root's blower, or the like, which may either be driven by a motor
engine or by manual power by treadles or crank handles. The air blast passing
down the limb of the serpentine tube A, meeting the material issuing from the
pipe E propels it against the mercury C in the lower bend A, so as to bring the
particles of gold into intimate contact therewith, causing it in great measure to be
taken up thereby, while the material together with the remaining gold is carried
on by the blast up the next limb of the tube A, and down the following one, at the
bottom of which it again impinges upon the mercury C, and so on, until the gold
has been entirely exhausted from the material, which is eventually expelled by the
air blast at the end a' of the tube.
When by this means the mercury C has become sufficiently amalgamated with
gold, the bends A¹ are removed and emptied and a fresh supply of mercury is
introduced.
In order to insure that only material of a sufficient degree of fineness shall be
supplied to the apparatus, it inay be screened either separately, or screens may be
combined with the hopper as shewn at G G Fig. 3, the coarser material being
caught by the troughs HH. In this construction of the hopper the regulation of
the quantity passing down the pipe E is effected by a slide I separate from the
balance valve F.
Fig. 4 shews a longitudinal section of a modification in which the serpentine
passage is formed by means of partitions JJ' projecting alternately from top and
from the bottom of a rectangular casing K, mercury being introduced into the
bottoms of the compartments thus formed.

page_text: The gold bearing material is supplied to the hopper D through a shoot Land'
falls thence through a regulating valve down the first passage where it is caught
by the blast issuing from the pipe M and propelled down on to the mercury as
before described.
In this arrangement the partitions and sides of the casing may have copper
plates coated with amalgam for taking up a portion of the gold.
Fig. 5 shews a construction in which the passage is formed as a helically coiled
tube N, in the lower bends of which mercury C is placed.
It will be evident that a great variety of other apparatus may be designed for
carrying my method of operating into practice, those above described merely
serving to indicate the arrangemente which I employ by preference. But it will
be observed that, in all the arrangements above described, there is a free passage
of air through the apparatus, and unless this is maintained there is considerable
loss of mercury and risk of choking, and I do not claim any method of working in
which such free air passage is not maintained.
The main advantages of my method of operating are, firstly, that I entirely
dispense with the more or less expensive cyanide processes, as by my method not
only the coarse gold such as is alone taken up by the ordinary amalgamating
process, but also the fine or float gold is extracted; secondly the great advantage
is gained that the use of water is entirely dispensed with.
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 subject
to the above disclaiming note what I claim is :-
1. The method of extracting gold from gold bearing material wherein such
material is mixed in a more or less finely divided state with strong air currents.
which bring it into intimate contact with mercury, the said air currents being made
to carry the exhausted material away from the mercury after this has taken up the
gold therefrom, substantially as described.
2. Apparatus for carrying out the method of operating referred to in the first
claim, consisting in a passage or pipe of a vertically undulating or zigzag or
serpentine form, in the bottom bends of which is contained mercury while the one
end is combined with means for supplying air blust mixed with gold bearing
material, the other end being either open to the atmosphere or in connection with
an exhaust arranged and operating substantially as described with reference to
Figs. 1 to 3 of the drawings.
3. Apparatus for carrying out the method of operating referred to in the first
claim, consisting of a casing containing partitions extending alternately from the
upper to near the lower side and from the lower side to near the upper side
thus forming a zig-zag passage, in the bottom bends of which is contained mercury,
while the one end of the casing is made to communicate with an apparatus for
producing air blast and a hopper supplying gold-bearing material, arranged and
operating substantially as described with reference to Fig. 4 of the drawings.
4. For carrying out the method of operating referred to in the first claim, the
use of a coiled tube with mercury contained in the lower bends, arranged and
operating substantially as described with reference to Fig. 5.
Dated this 20th day of September 1895
ABEL & IMRAY,
Agents for the Applicant.