A Novel Mode of Obtaining Gold from Sea Water or other Solutions containing the same and means for the purpose.
Year: 1899

page_text: Date of Application, 16th June, 1899
Complete Specification Left, 16th Mar., 1900—Accepted, 21st Apr., 1900
A Novel Mode of Obtaining Gold from Sea Water or other Solutions
containing the same and means for the purpose.
1, JOHN FREDERICK DUKE, of 160, Rosendale Road, West Dulwich, in the County
of London, Chemist, do hereby declare the nature of this invention to be as
follows:-
It is a well known fact that sea water contains a certain amount of gold, generally
from 2 to 5 grains per ton. Repeated attempts have been made to precipitate this
gold by the decomposition of metallic bodies such as zinc, and amalgamating the
precipitate with mercury from which the gold was ultimately recovered by distilla-
tiou. The expense of this process however has been so great that although gold was
obtained it was not in sufficient quantity to repay the cost of extraction.
Now I have discovered that gold even in extremely dilute solutions is precipitated
by those calcic or aluminic earths which are decomposed by either chlorine or
bromine; one eminently suitable earth is the carbonate of calcium in the form of
chalk.
My invention therefore consists in obtaining gold from sea water or other solutions
containing it by precipitating it by means of carbonate of calcium or other calcic or
aluminic earth of the kind above referred to.
For the purpose of carrying out my invention as applied to sea water in an
economical manner I preferably proceed as follows:-
:-
In calcic or aluminic strata such as chalk cliffs at or near the sea shore 1 dig out a
shallow reservoir having its top edge about 6 feet above the highest water mark and
its outlet slightly above low water mark. The sides of the reservoir preferably slope
towards the middle where there is a sump extending from end to end. Supported in
this sump
free from the botton is an inlet pipe perforated along its under side. This
pipe is fitted with a ball or other automatic valve preferably so arranged as not to
open until the tide has risen about 18 feet (assuming the normal rise to be 20 feet).
There is an outlet pipe at a short distance above the sump and this outlet pipe is also
fitted with an automatic valve, the edge of this outlet pipe extending beyond the face
of the tank..
The mode of working is as follows:-As the tide rises no water enters the reservoir.
until the rise has reached the prescribed limit of say 18 feet. The inlet valve then
opens and the water rushes with great force through the perforated pipe and scours
all the lower part of the reservoir, stirring up the sludge and thoroughly mixing it
with the body of water let it, the outlet pipe being during this time closed. The
water is then allowed to rise in the reservoir until the tide reaches its full. The
water should be retained in the reservoir until the turn of the tide; it is then run off
through the outlet pipe which ought not to be large enough to cause a sufficiently
great efflux of the water to stir up the sludge. The sludge which will consist mainly
of chalk mixed with metallic gold remains in the sump from which it can be removed
periodically. The gold can be subsequently obtained from the sludge by fusion with
any suitable flux or by dissolving the chalk with an acid.
Dated this 16th day of June 1899
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.

page_text: A Novel Mode of Obtaining Gold from Sea Water or other Solutions
containing the same and means for the purpose.
I, JOHN FREDERICK DUKE, of 160, Rosendale Road, West Dulwich, in the County
of London, Chemist, 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:-
It is a well known fact that sea water contains a certain amount of gold, generally
from say 1 to 5 grains per ton. Repeated attempts have been made to precipitate
this gold electrically and also by the decomposition of metallic bodies such as zine,
and amalgamating the precipitate with mercury from which the gold has been ulti-
mately recovered by distillation. The expense of these processes has however been
so great that although gold was obtained it was not in sufficient quantity to repay
:
the cost of extraction.
Further, it is well known that gallic and tannic acids and albumenous bodies and
in fact most organic substances will decompose salts of gold and thereby reduce the
gold to the metallic state. This method however in view of the extremely small
quantity of gold in sea water and the fact that whatever solution is added to the sea
water is run off afterwards with the water, is too costly.
Now I have discovered that gold, even in extremely dilute solutions is precipitated
by those calcic, aluminic or other earths or compounds which by forming a haloid
with the halogen of the gold salts will thereby reduce the gold to the metallic
One eminently suitable earth is the carbonate of calcium in the form of
.state.
chalk.
My invention therefore consists in obtaining gold from sea water or other solutions
containing it by reducing it to the metallic state by means of carbonate of calcium or
other calcic, aluminic or other earth or compound of the kind above referred to and
in the manner explained.
For the purpose of carrying out my invention as applied to sea water in an
economical manner I may make use of chalk cliffs at or near the sea shore and I
preferably proceed as follows:-
In calcic or aluminic strata such as chalk cliffs at or near the sea shore I dig out a
reservoir having its top edge about 6 feet above the highest water mark and its out-
let slightly above low water mark. The sides of the reservoir preferably slope so that
the top area is somewhat smaller than the bottom area. There is a sump at the
middle extending from end to end. Supported in this sump free from the bottom is
an inlet pipe perforated preferably along its under side. This pipe is fitted with an
automatic or other valve preferably so arranged as not to open until the tide has risen
about 18 feet (assuming the normal rise to be 20 feet). There are one or more out-
let pipes at a somewhat higher level than the sump and these outlet pipes are also
fitted with valves preferably automatic.
Figure 1 of the accompanying drawings is a longitudinal section and Figure 2 a
transverse section illustrating the means or apparatus by which my invention may be
carried into effect in the manner above described.
a represents a chalk cliff at or near the sea shore and b a reservoir dug out of the
cliff. The top edge of this reservoir is about feet above the highest water mark
which is indicated at c. The bottom of the reservoir is slightly inclined from the
two sides to the middle where there is a sump & extending from end to end.. In this
sump is a sea water inlet pipe e of comparatively large diameter and perforated along
its under side. The outer end of this pipe leads to or communicates with the sea and
is fitted, with an automatic inlet valve. This may be of any suitable form. The
drawings show it as a flap valve f binged to the pipe e at g and connected by rods hi

page_text: to the lever j of a float k.
level than the sump d.
is an outlet pipe from the tank at a somewhat higher
Although only one outlet. pipe is shown more may be
employed. The outlet pipe (each outlet pipe when more than one) is fitted with an
automatic valve. This may be of any suitable form. The drawings show it as a flap
valve m operated by a float and lever p.
The mode of working is as follows:-
Into this reservoir is introduced a suitable quantity of calcium carbonate con-
veniently in the form of whitening and in the proportion of say 1 lb. per ton of sea
water to be treated. The quantity however will depend upon the length of time
intended to be allowed to elapse between the clearings of the reservoir. As the tide
rises no water enters the reservoir 6 until the rise has reached the prescribed limit of
say 18 feet. The inlet valve f then opens and the water rushes with great force through
the perforated pipe e and scours all the lower part of the reservoir, stirring up the
sludge and thoroughly mixing it with the body of water let in, the outlet pipe
being during this time closed by the valve m. The water continues to rise in the
reservoir until the tide reaches its full. The water should be retained in the reservoir
until the turn of the tide so that there may be ample time say 10 hours for the
carbonate of calcium in the sludge and on the walls and bottom of the reservoir to act
on the salts of gold. The sludge having settled, the water is then allowed to run off
through the outlet pipe which ought not to be large enough to cause a sufficiently
great efflux of the water to stir up the sludge. The sludge which will consist mainly
of chalk mixed with metallic gold remains in the sump from which it can be removed
periodically. The gold can be subsequently obtained from the sludge by fusion with
any suitable flux or by dissolving the chalk with an acid.
Instead of acting upon the sea water by allowing it to run into a reservoir dug in
a cliff as above described so that the chalk or carbonate of calcium may decompose
the salts of gold, it is obvious that gold can be obtained from sea water or other solu-
tions containing gold by adding the chalk or other earth or compound to the sea
water of other solution in any suitable tank or reservoir..
1
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. The process of obtaining gold from sea water or other solutions containing the
same which consists in precipitating the gold by a calcic or other earth or compound
which will forn a haloid with the halogen of the gold salt and thereby reduce the
gold to the metallic state substantially as described.
2. The process of obtaining gold from sea water or other solutions containing the
same which consists in precipitating the gold by carbonate of calcium, substantially
as described.
3. The process of obtaining gold from sea water which consists in allowing sea
water to flow by the natural rise of the tide into a reservoir at or near the shore, in
which reservoir it comes in contact with a calcic or other compound of the kind
specified in Claim 1, allowing the water to remain in said reservoir for some hours,
and then after the settling of the sludge running off the sea water, substantially as
set forth.
4. For the purpose of obtaining gold from sea water the combination of a reservoir
dug at or near the shore, a sea water inlet pipe to said reservoir near the bottom of
same and in communication with the sea, an inlet valve in said pipe, an outlet pipe
from said reservoir and a valve on said outlet pipe substantially as set forth and
shown.
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, W.C., Chartered Patent Agents.