IMPROVED PROCESS OF AND COMPOUND FOR REMOVING PRECIOUS METALS FROM ORES AND METALLURGICAL PRODUCTS
Year: 1884

page_text: I EDWARD HUBBARD RUSSELL of Park City in the County of Summit and
Territory of Utah in the United States of America gentleman, do hereby declare
the nature of my Invention for "IMPROVED PROCESS OF AND COMPOUND FOR
REMOVING PRECIOUS METALS FROM ORES AND METALLURGICAL PRODUCTS and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
.
In the ordinary process of leaching or lixiviating ores or metallurgical products
with a hyposulphite solution, water is first turned onto the mass of material and
allowed to filter down through it. This dissolves out and removes the base salts
which are soluble in water.
After these salts have been dissolved out, a solution containing a hyposulphito of
an alkali or alkali earth is turned on and caused to filter through the material.
This dissolves out and carries down with it the chloride of silver a portion of the
gold and some copper.
The resultant solution is then conducted into precipitating tubs or tanks where
the metals contained in it are precipitated usually as sulphides. The solution is
then ready for use again.
While this solution takes out the chloride of silver and a portion of the gold and
copper contained in the ore or metallurgical product being treated it attacks but
slightly or not at all metallic silver, sulphide of silver and gold and compounds of
silver with antimony or arsenic.
The metallic silver and these compounds which are often contained in ores or
metallurgical products are then but imperfectly or not at all separated therefrom
by the leaching process in which the hyposulphite solution alone is used but remain
in the material containing them and are thrown away with the tailings.
The object of my Invention is to thoroughly remove them all from the ore or
product and so save them.
This I do by leaching said ore or product with a new leaching solution which I
have invented for the purpose and which has the property of dissolving said metals
and metallic compounds.

page_text: This solution is preferably applied to the mass of material after the chloride has
been leached out by the ordinary process but can be used successfully and effectively
directly upon the ore without the latter being first subjected to the ordinary
leaching process with the simple hyposulphite solution as it also has the property
of dissolving chloride of silver."
The ore or product can be subjected to the dissolving action of the solution or
solutions in any of the well known ways instead of by the leaching method.
The leaching solution which I have invented consists of an ordinary hyposulphite
solution to which has been added a soluble compound or salt of copper of which the
most available, effective and suitable one, is the sulphate usually called bluestone.
The other compounds or salts of copper which I contemplate using are the
by posulphite, chloride nitrate, carbonate and acetate, cuprous carbonate ammoniated
copper and hydrate of copper.
I have named them in the order of their effectiveness, the hydrate being the least
effective.
The sulphate or other soluble salt of copper renders the solution capable of
attacking and dissolving out metallic silver, sulphide of silver and gold and
compounds of silver with antimony and arsenic.
When the sulphate of copper is added to a hyposulphite solution the double salt
of cuprous hyposulphite and sodium hyposulphite is formed in the solution. That
such is the case is shown by the fact that the above named double salt is precipi-
tated as a canary-yellow powder if concentrated solutions are mixed this double
salt being much less soluble in water than either of the reagents alone.
It is this. double salt having the forinula Cu̟, S, O̟,, Na, S, O, which acts with
such energy and brings metallic silver, sulphide of silver and gold and the metallic
compounds referred to hereinbefore into solution. In effecting this no mictallic
silver or chloride of silver is formed. The cuprous hyposulphite double salt
changes to an argentic hyposulphite double salt. An equivalent of copper is
replaced by an equivalent of silver while the copper combines with those elements
with which the silver was originally associated.
This reaction is not only new to chemistry but of the greatest utility and
importance in the extraction of silver from ores and metallurgical products by
hyposulphite solutions.
The solving energy of the solution for metallic silver and silver sulphide becomes
greatest when the solution contains for an equivalent of sulphate of copper, two
equivalents of sodium hypósulphite
4 Na, S, 0, +2 Cu SO, = Cu, S, O₁
Na, S. O, +2 Na, SO, + N₁₂ S. O
I have found that the double salt of cuprous hyposulphite and sodium hypo-
sulphite will also be formed in a hyposulphite solution when any one of the soluble
salts or compounds of copper set forth above besides the sulphato is added to said
solution.
.
In practice I make my solution by adding to a solution containing from one to
five percent. of hyposulphite of an alkali or alkali carth, one to three percent. of
one of such compounds or salts of copper. Where as indicated above as being
preferable the ore or product is first leached in the ordinary manner with the
simple hyposulphite solution to dissolve out the chloride of silver, the solution after
passing through the ore is subjected to the ordinary process of precipitation so that
the metal held in the solution is separated therefrom and said solution is realy to
be used again.
The mass of ore or product is then subjected to the action of my new solution
which is turned on and allowed to filter down through it.
By this the metallic silver, compounds of silver or gold with sulphur and of silver
with arsenic and antimony are dissolved out and removed The resultant solution
is then subjected to the usual and well known precipitating process to precipitate
the metals therefrom in the form of sulphides.

page_text: My solution as described can be used successfully in treating roasted or unroasted
ores, ores that have been subjected to chlorine gas and various metallurgical
products.
The preliminary washing or leaching of the ore or product with water can
obviously be dispensed with if desired as it is not necessary in order to make
successful the action of the simple hyposulphite solution and. my new solution.
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 what
I claim is
1. The process of removing precious metals from ores and metallurgical products
which consists in first dissolving out therefrom with water the salts soluble therein,
then subjecting the mass to the dissolving action of a hyposulphite solution and
finally to the dissolving action of a hyposulphite solution to which has been added
a soluble salt or compound of copper substantially as described.
2. The process of removing precious metals from ores and metallurgical products
which consists in subjecting the mass of material to the dissolving action of a
byposulphite solution and then to the dissolving action of a hyposulphite solution
to which has been added soluble compound or salt of copper substantially as
described.
3. The process of separating precious metals from ores and metallurgical products
which consists in leaching the mass of material with a hyposulphite solution and
then leaching it with a hyposulphite solution to which has been added a sulphate
of copper substantially as described.
4. The process of removing precious metals from ores and metallurgical products
which consists in subjecting the ore or product. to the dissolving action of a
hyposulphite solution to which has been added a soluble salt or compound of
copper substantially as described.
5. The process of removing precious metals from ores and metallurgical products
which consists in subjecting the ore or product to the dissolving action of a solution
containing the double salt of cuprous hyposulphite and sodium hyposulphite
substantially as described.
6. The leaching solution for removing precious metals froin ores and metallurgical
products which consists of a hyposulphite solution to which has been added a soluble
salt or compound of copper substantially as described.
7. The leaching solution for separating precious metals from ores and metal-
lurgical products which consists of a solution containing the double salt of cuprous
hyposulphite and sodium hyposulphite substantially as described.
Tisted the 21 doy of Tanum 100.