Improvements in Refining and Separating Precious Metals.
Year: 1889

page_text: Date of Application, 11th Sept., 1889
Complete Specification Left, 28th May, 1890-Accepted, 28th June, 1890
PROVISIONAL SPECIFICATION.
Improvements in Refining and Separating Precious Metals.
I, EDOUARD DODE, of 99, Boulevard de Charonne, Paris, France, Chemist, do
hereby declare the nature of this invention to be as follows:-
The processes hitherto employed in refining and separating metals are slow and
costly and necessitate the use of a large plant.
According to my Invention the immediate separation of the gold, platinum, silver,
and other metals contained in the 'ingots from which the three precious metals are to
be extracted, is obtained by processes which avoid the above objections.
In carrying out my invention, I employ by preference the apparatus illustrated in
the accompanying drawing. I first dissolve in aqua regia an ingot composed of gold,
platinum, silver, copper, and tin, then evaporate about half the acids and add distilled
water to the solution in the proportion of three, times the weight of the quantity of
acids employed. I then collect the whole mixture in the vessel a and pour in 300
grammes of sulphuric ether or other analogous product such as for example chloro-
form, glycerines, etc., for every 100 grammes of metal treated. The apparatus is
oscillated upon its gudgeons b in order to thoroughly mix the ether with the solution.
The motion of the apparatus is arrested for a few moments and the ether rises to the
surface, carrying with it a great part of the gold. The progress of the operation is
indicated by the yellow color acquired by the ether. The vessel is then agitated a
second and third time after which the operation of separating the gold is complete.
The contents of the lower part of vessel a are run off at cock c into another and
similar vessel d placed immediately below it, care being taken to retain in vessel a the
There thus
ether containing the gold which is treated as hereinafter described.
remains in the solution the platinum, copper, tin. and a small portion of the silver,
the latter having been almost wholly precipitated as the solution in the aqua regia
progressed. In order to ensure that no silver remains in the solution, one kilogramme
of sea-salt is dissolved in three litres of water and a small portion is added to the
solution and if the latter becomes turbid more is added drop by drop stirring mean-
while. The precipitate is allowed to settle and the silver which is obtained by
decantation or filtration is washed in water containing a small proportion of liquid
ammonia for removing all traces of acid. The solution in the vessel d now contains
platinum, copper, and tin and said vessel is raised to the position occupied by vessel a
and turned on its gudgeons. The platinum is first treated, the other metals being of
minor importance. For this purpose essence of lavender is added to the solution (or
other essence such as that of turpentine. thyme, etc., or other essential oils may be
used) in the proportion of three times the weight of that of the metal treated the
operation being performed in the same manner as for gold and, although slower, with
the same certainty. The solution should be continually agitated until the essential
oil becomes of a fine deep brown color when it is allowed to rise to the surface of the
liquid charged with the platinum and the solution is run off at cock e. There then
remain in the acids the copper and tin which can be readily separated after previously
ascertaining that no platinum remains in the solution, by placing a small portion in
a test-glass, adding three times its volume of water. then a few drops of ammonia,
whereupon a precipitate is immediately formed. If it be of a yellow tint this is an
indication that the solution still contains platinum and if white that tin only is con-
tained. In the former event the operation is recommenced by treating with essential
To the
oil of lavender until the whole of the platinum is extracted in solution.
solution containing only copper and tin sufficient ammonia is then added to precipitate
the fin. The copper remaining in solution is recovered by evaporating. After the

page_text: metals have been thus perfectly separated; the treatment of the gold and platinum
solutions is next proceeded with.-
The auriferous solution is poured into, a porcelain capsule which is placed in a still
of glass or enamelled iron, porcelain, etc., heated by a water bath and in communi-
cation by means of a condensing worm with a receiver for the ether which is driven
off from the gold by a very moderate heat leaving only pure gold in the capsule. The
operation is similar for the platinum but greater heat is necessary in order to volatilize
the essence of lavender which is recovered and can like the cther be used over again,
the loss being insignificant.
DL: L
1000
++
COMPLETE SPECIFICATION.
Improvements in Refining and Separating Precious Metals.
I, EDOUARD DODE, of 99, Boulevard de Charonne, Paris, France, 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:
The processes hitherto employed'in refining and separating metals are slow and
costly and necessitate the use of a large plant.
According to my Invention, the immediate separation of the gold, platinum, silver,
and other metals, contained in the ingots from which the three precious metals are to
be extracted, is obtained by processes which avoid the above objections.
In carrying out my invention I employ by preference the apparatus illustrated in
the drawing accompanying my Provisional Specification. I first dissolve in aqua
regia an ingot composed of gold, platinum, silver, copper and tin, then evaporate
about half the acids and add distilled water to the solution in the proportion of three
times the weight of the quantity of acids employed. I then collect the whole mixture
in the vessel a and pour in 300 grammes of sulphuric ether or other analogous
product, such as, for example, chloroform, glycerines, etc., for every 100 grammes of
metal treated. The apparatus is oscillated upon its gudgeons b. in order to thoroughly
mix the ether with the solution. The motion of the apparatus is arrested for a few
moments and the ether rises to the surface carrying with it a great part of the gold,
the progress of the operation being indicated by the yellow color acquired by the
ether. The vessel is then agitated a second and third time after which the operation
of separating the gold is complete. The contents of the lower part of vessel a are
run off at cock c into another and similar vessel d placed immediately below it, care
being taken to retain in vessel a the ether containing the gold which is to be treated,
as hereinafter described.
There thus remains in the solution the platinum, copper, tin, and a small portion of
the silver, the latter having been almost wholly precipitated whilst the solution in the
aqua regia was effected. In order to ensure that no silver remains in the solution,
one kilogramme of sea-salt is dissolved in three litres of water and a small portion is
added to the solution and if the latter becomes turbid more is added drop by drop
agitating meanwhile. The precipitate is allowed to settle and the silver which is
obtained by decantation or filtration is washed in water containing a small proportion
of liquid ammonia for removing all traces of acid. The solution in the vessel d now
contains platinum copper and tin, and said vessel is raised to the position occupied by
vessel a and rocked on its gudgeons. The platinum is first treated the other metals
being of minor importance. For this purpose, essence of lavender is added to the
solution (or other essence such as that of turpentine, thyme, etc., or other essential oils
may be used) in the proportion of three times the weight of that of the metal treated,

page_text: the operation being performed in the same manner as for gold, and, although slower,
with the same certainty. The solution should be continually agitated until the
essential oil becomes of a fine deep brown color when it is allowed to rise to the
surface of the liquid charged with the platinum and the solution is run off at cock e.
There then remain in the acids the copper and tin, which can be readily separated,
after previously ascertaining that no platinum remains in the solution, by placing a
small portion in a test-glass, adding three times its volume of water, then a few drops
of ammonia, whereupon a precipitate is immediately formed. If it be of a yellow
tint, this is an indication that the solution still contains platinum and if white that tin
only is contained. In the former event the operation is recommenced by treating
with essential oil of lavender until the whole of the platinum is extracted in solution.
To the solution containing only copper and tin sufficient ammonia is then added to
precipitate the tin. The copper remaining in solution is recovered by evaporating.
After the metals have been thus perfectly separated, the treatment of the gold and
platinum solutions is next proceeded with.
The auriferous solution is poured into a porcelain capsule which is placed in a still
of glass or enamelled iron, porcelain, etc.. heated by a water bath and in communi-
cation by means of a condensing worm with a receiver for the ether which is driven
off from the gold by a very moderate heat leaving only pure gold in the capsule.
The operation is similar for the platinum, but greater heat is necessary in order to
volatilize the essence of lavender which is recovered and can, like the ether, be used
over again the loss being insignificant.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1st. The herein described series of operations for the direct separation of the
precious metals, gold, silver, and platinum, which consist essentially in dissolving the
metals in aqua-regia and then separating the gold by means of sulphuric ether
chloroform or their equivalent; the platinum by means of essence of lavender or other
essence or essential oil; and the tin by means of ammonia, all substantially as herein-
before described for the purpose specified.
2nd. The employment of sulphuric ether chloroform glycerines or other analogous
products for separating out the gold contained in any auriferous liquid or solution.
3rd. The employment of essence of lavender or other essence or essential oil for
separating platinum from liquids or solutions containing the same.
4th. The separation of gold and platinum held in solution from the ethers or
essences in which they are dissolved by distillation, as specified.
Dated this 28th day of May 1800
Dated this 28th day of May 1800
By A. M. & Wm. Clark,
E. DODE.
53, Chancery Lane, London, Patent Agents.