Improvements in the Extraction of Gold. from Sea-water by Chemical Means and Apparatus to be Employed in connection therewith
Year: 1899

page_text: Date of Application, 8th July, 1899
Complete Specification Left, 4th Apr., 1900-Accepted, 7th July, 1900
PROVISIONAL SPECIFICATION.
"Improvements in the Extraction of Gold. from Sea-water by
Chemical Means and Apparatus to be Employed in connection
therewith."
We, HENRY CLAY BULL, of No. 15, West Square, Lambeth, Engineer, and
ARTHUR WATLING, of Nos 59. and 60., Chancery Lane, Land Agent, both in
the County of London, do hereby declare the nature of this invention to be as
follows:
It is well known that gold exists in sea-water in the form of iodide of gold;
and the object of this invention is to extract such gold in a simple and economical
manner, so that notwithstanding the large volume of water to be dealt with and
the minute quantities in which the gold is found, the desired. object can be
effected with commercial success.
For the purpose of this invention, the sea-water is collected in a tank or
reservoir and is rendered alkaline by the addition of milk of lime in a caustic
state which combines with the iodine of of the iodide of gold forming iodide of
calcium and the gold being set free settles to the bottom: after a sufficient time
has been allowed for settlement, the water is syphoned off or otherwise removed
and the gold is separated or extracted from the sludge by any suitable known
means.
The apparatus employed for the purpose of this invention may consist of a
series of chainbers preferably round and each fitted with a central pipe about
one quarter of the diameter of the chamber. The said central pipe descends about
three fourths of the height of the chamber.
These chambers are arranged vertically, each one being slightly below the level
of the next adjacent one so that the whole series is stepped and the sea-water in
passing through the series will flow swiftly downward through the comparatively
small area of the central pipe in each chamber and rise comparatively slowly
through the larger area of the chamber, overflowing to the central pipe of the
next chamber below and so on throughout the series
The effect of the swift downward flow through the central pipe of each chamber
and the slow rise within the chamber causes the matter held in suspension in
the water to settle and remain at the bottoms of the chambers.
In practice, the water is first allowed to pass, through one or more of the
series of chambers to free it from sedimient; sufficient milk of lime to render the
sea-water alkaline is then added to the water through the central pipe in the
next chamber, this effects the decomposition of the iodide of gold held in
the sea-water, forming iodide of calcium and metallic gold in a fine state of
division.
The finely divided gold or a large portion thereof, in the passage of the water
through the remaining chambers is deposited on the bottoins thereof together

page_text: with any carbonate of lime which may have been formed by the lime introduced
as above stated and the carbonic acid in the sea-water.
The gold and carbonate of lime are removed from the chambers from time to
time and a sufficient quantity of sand and soda is added thereto to form a fusible
slag which may then be melted down and the gold separated or the gold may be
collected in mercury or it may be recovered by any other suitable means.
After the water has passed through the series of chambers above described it
may be passed through a quantity of finely pulverised sulphide, preferably
galena. The effect of this filtration is to retain the finely divided gold which
may not have been precipitated in passing through the chambers. The galena
will also act chemically and extract the metal from any compound of gold which
may have escaped the chemical action of the milk of lime.
The milk of lime put into the water as above described may if desired be
recovered as chemically pure carbonate of lime in a fine state of division by
treating the water with carbonic acid.
Although we have herein before described the successive treatment of the sea-
water by the addition of the milk of lime and the filtration through sulphides,
we would have it understood that we may employ either the milk of line or
the filtration through sulphides aloue in the manner described.
Dated this 8th day of July 1899
VAUGHAN & SON
Agents for the Applicants.
"Improvements in the Extraction of Gold from Sea-water by
Chemical Means and Apparatus to be Employed in connection
therewith "
We, HENRY CLAY BULL, of No: 15, West Square, Lambeth, Engineer, and
ARTHUR WATLING, of Nos. 59 and 60, Chancery Lane, Land Agent, both
in the County of London, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
lained in and by the following statement:-
-
This invention relates to the extracting of gold from sea-water.
It is well known that gold exists in sea-water and it is believed that it exists
in the form of iodide of gold; the object of this invention is to extract such gold
in a simple and economical manner so that notwithstanding the large volume of
water to be dealt with and the minute quantities in which the gold is found, thic
desired object can be effected with commercial success.
For the purpose of this invention, the sea-water is collected in a tank or
reservoir and is rendered alkaline by the addition of lime, preferably in the form
of milk of lime in a caustic state, which combines with the iodine of the
iodide of gold forming iodide of calcium and the gold being set free settles to the
bottom after a sufficient time has been allowed for settlement, the water is
syphoned off or otherwise removed and the golil is separated or extracted from
the sludge by any suitable means.
Suitable apparatus for carrying out our invention is illustrated in the accom-
panying drawing in which:-
Figure 1 is a sectional elevation of such apparatus; and
Figure 2 is a plan.
In these figures a indicates a tauk or reservoir which is built up or, arranged in
any suitable and convenient manner and preferably near the sea-shore in such

page_text: a position that it can be filled and emptied by the rise and fall of the tide. b is
the pipe through which the water enters the tank, the flow through the said pipe
being controlled by means of a valve c, which, as shewn, is arranged to be operated
from a bridge which spans the tank. e is the pipe through which the water is
discharged from the tank. This discharge pipe, on the tank end, is provided
with a movable mouth piece which is adapted to be supported by a float at some
little distance below the level of the water, so that the water which is discharged is
drawn from the top of the tank and not from the bottom, whereby the sediment
which is left upon the floor of the tank will not be disturbed. As shewn in the
ав being
drawing the portion of the pipe e within the tank is represented
collapsable and attached to a Hoat f working between guides g, which may
form some of the supports of the bridge. The collapsable portion of the discharge
pipe e is arranged to drop into a pit e so as to permit the mouth of the discharge
pipe to descend to nearly the level of the floor. is a valve also operated from
The bridge and which serves for preventing the discharge of the water from the
tank when desired. is a pit which is connected with the tank a by a tunnel j,
the said pit serving to receive the sludge which, after the discharge of the water,
remains upon the floor of the tank, the tunnel j. being, as shewn, high enough
to allow the workmen to push the sludge before them into the pit i k is a
watertight door or sluice gate which serves for preventing the water from
flowing from the tank into the pit the said door or sluice gate is operated
from the bridge d. is an elevator which raises the sludge from the pit i and
delivers it either into trucks m, by which it can be transported to any suitable
is a tank for
place for treatment, or directly into apparatus for treating it.
containing the milk of lime for treating the sea water, from which tank a
pipe o leads to a point adjacent to the delivery point of the inlet pipe band
valve for regulating the flow of the milk of lime.
sea water.
is a
The mode of carrying out the process by means of the apparatus hereinbefore
described is as follows: The floor of the tank a being clean and the discharge
valve and door being closed, the valve is opened to admit the sea water
through the pipe b, and at the same time the valve p is opened to allow the milk
of lime from the tank to flow through the pipe and mix with the incoming
When the tank is filled to a certain point, for instance, that of high
water (if the tank is directly filled and emptied by the rise and fall of the tide),
the valve e is closed as also is the valve and then the contents of the tank are
allowed to settle, with the result that a sludge or mud containing the gold
deposits on the floor of the tank. When this deposit has taken place the
valve is opened so that the water from the tank will flow out through the
pipe c. It will be noticed that by means of the Hoating discharge nozzle f the
discharge takes place from tlie surface of the water, so that the sludge which is ·
lying upon the floor is not disturbed, as would be the case if the discharge took
place from the bottom of the tank. When practically all the water has been
discharged the collapsable portion of the pipe e, having sunk down into the
pit e, the valve his closed and the door opened and the sludge which is upon
the floor, together with the small remaining quantity of water, is discharged by
workmen into the pit i by means of squeegees or other suitable means, and from
this pit the sludge is lifted by the elevator and delivered into the waggons m.
The Hoor having been thus cleaned the door is again closed as also is the
valve h, whilst the inlet valve and the milk of lime valve are opened and the
tank is refilled as hereinbefore described. ·
It is advisable that the amount of sludge which has to be treated should be as
small as possible. In practice we have found it advantageous to mix the milk of.
lime and sea water in the proportion of 1 part of unslaked lime (to which water
is subsequently added to, make milk of lime) to 4500 parts of sea water, although
a greater or lesser proportion of lime may be used.
As hereinbefore stated any suitable means may be employed for extracting the
metallic gold from the sludge. A very advantageous arrangement consists in
-

page_text: passing the sludge through anialgamators whereby an amalgam is obtained, the
separation of the gold from which can be effected in a well known manner.
.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we wish it to be
understood that we are aware that it has been proposed to precipitate gold from
sea water by barium chloride, or by calcium carbonate, or by calcic or other
carths or compounds, and we make no general claim to such processes, but we
declare that what we claim is:-
1. The method of extracting gold from sea water consisting in adding to
and mixing with the sea water to be treated a quantity of lime sufficient
to precipitate the gold which it contains in a metallic condition, substantially
as described:
:
2. The method of extracting. gold from sea water consisting in allowing the
sea water to flow into a tank and at the same time mixing therewith a proportion
of milk of lime which reacts upon the iodide of gold contained by the sea waler
to form iodide of calcium and liberate the gold, the sludge formed by the
reaction being allowed to settle and the water from the tank being then drawn
off and the sludge collected for treatment to extract the metallic gold there-
from, substantially as described.
3. Apparatus for the extraction of gold from sea water by the methods claimed
in the preceding claiming clauses comprising a water tank, means for intro-
ducing sea water into the said tank, means for allowing the water to be
discharged from its surface, a lime tank and means for adding to the sea water
as it enters the water tank a proportion of milk of lime and a pit or well into
which the deposit resulting from the reaction of the milk, of lime upon the sea
water can be introduced, substantially as described.
Dated the 4th day of Anrili 1900.
G. F. REDFERN & Co.
.4, South Street, Finsbury, London.
Agents for the Applicants..