IMPROVEMENTS IN THE TREAT- OBTAIN THE SILVER AND GOLD
Year: 1883

page_text: LETTERS PATENT to Frederic Claudet of Coleman Street in the City of
London Metallurgist, for an Invention of
MENT OF COPPER MATTES IN ORDER TO
THEREFROM"
IMPROVEMENTS IN THE TREAT-
OBTAIN THE SILVER AND GOLD
PROVISIONAL SPECIFICATION left by the said Frederic Claudet at the
Office of the Commissioners of Patents on the 10th October 1883.
FREDERIC CLAUDET of Coleman Street in the City of London Metallurgist
"IMPROVEMENTS IN THE TREATMENT OF COPPER MATTES IN ORDER TO OBTAIN
THE SILVER AND GOLD THEREFROM
"
This Invention relates to the treatment of what are known as Argentiferous
Copper Mattes that is to say Copper Mattes containing either Silver or Silver and
Gold and consists in firstly submitting the Mattes to a process of grinding or of
disintegration and then to a Roasting or Calcining process in order that certain
constituents contained therein may be rendered soluble in Hydrochloric Acid and
then after separation of the solution of the dissolved metals precipitating the Silver
and Gold by means of a soluble Iodide--The solution containing Copper after
separation from the deposited Iodides of Silver or of Gold is then submitted to the
action of Iron or is separated by any other well known means and the precipitated
metallic Iodides are then reduced by means of Iron or zinc or otherwise treated.
In carrying out this Invention the ore should be finely ground and the roasting
continued until the Sulphur is expelled and the metals of the mattes oxidized If
the roasted mass should have become lumpy it must be sifted and the lumps ground
fine to be again roasted before proceeding with solution in Hydrochloric Acid-
This may be effected in octagonal or other stone or stone ware tanks similarly
constructed to those used in Alkali works for generating Chlorine fitted with a
perpendicular revolving shaft to which arms are affixed for the purpose of keeping
the metallic Oxides and Acid in motion. The tank is now partially filled with
Hydrochloric Acid of about 25° Twaddle (1·125 sp: gr), the arms set in motion and
the finely ground calcined matte gradually introduced until sufficient has been

page_text: added to saturate the Acid. A considerable elevation of temperature takes place
and the saturation at first proceeds rapidly steam or hot air may after a time be
injected or other means may be employed to maintain the heat of the liquors to
about from 160° to 190° Fahrenheit in order to facilitate complete saturation-
When the Acid will take up no more of the metallic Oxides the arms are stopped
in order to allow the suspended particles to subside and the clear solution is run
off to the desilverizing tanks. The dissolving tank is now again charged with
Acid more calcined matte added and the same operation repeated several times.
until a certain amount of deposit has accumulated which is then treated by itself
with fresh Acid so as to exhaust all the metallic Oxides which are soluble in the
residue and the solution is then run into a settler. The clear Acid liquor from
this is again put back in the dissolving tanks to become saturated with the copper
and the deposit is washed and put on one side in case it should contain any Silver
or Gold in which case it is mixed with the reduced Silver precipitate and smelted
along with it for silver and gold-If necessary the residues in the bottom of the
dissolving tanks may be re-roasted previous to being again treated by Hydrochloric
Acid.
The nearly saturated Acid liquors containing Copper, silver Gold and other
metals in the form of Chlorides having been run into stone or stone ware tanks
of known capacity may be assayed for silver in the way described by me in the
final Specification of my Letters Patent N° 282-1870 and the quantity of Iodine
in the form of a soluble Iodide necessary to precipitate the exact amount of silver
present in each tank is added diluted with water, the liquors well mixed and the
whole allowed to settle until the precipitated Iodide of Silver together with the
gold (when the metal is present) has entirely subsided. The clear supernatant
Copper liquors are then run off to other tanks where the Copper is precipitated by
iron or any other well known means-The copper is found to be practically free
from Silver and Gold those metals being separated in the Iodizing process.
The Silver precipitate which consists chiefly of Iodide of Silver with some Gold
is carefully collected washed from all soluble salts and then decomposed by Iron or
Zinc which reduces the silver and Gold and yields a soluble Iodide of Iron or Zinc
to be used in a future operation.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Frederic Claudet in the Patent Office on the 8th April 1884.
"
FREDERIC CLAUDET of Coleman Street in the City of London Metallurgist
IMPROVEMENTS IN THE TREATMENT OF COPPER MATTES IN ORDER TO OBTAIN
THE SILVER AND GOLD THEREFROM'
"
This Invention relates to the treatment of what are known as Argentiferous
Copper Mattes that is to say Copper Mattes containing either Silver or silver and
Gold and consists in submitting the mattes to a process of grinding or disintegration
and to a roasting or calcining process in order that certain constituents contained
therein may be rendered soluble in Hydrochloric acid to which the ground and
roasted mattes are afterwards added the solution of the dissolved metals from the
undissolved residue being subsequently separated and the silver or silver and gold
precipitated therefrom by means of a soluble Iodide. The solution containing
Copper after separation from the deposited Iodides of silver or of silver and gold
may then be submitted to the action of iron or any other well known means for
the separation of the copper whilst the precipitated metallic Iodides are reduced
by means of iron or zinc or otherwise treated.
And in order that my said Invention may be fully understood. I shall now
proceed to describe a system mode or manner in or under which the same may be
carried into practical effect.
The mattes should be finely ground and the roasting continued until the Sulphur
is expelled and the oxidisable metals therein contained oxidised. If the roasted
mattes should have become lumpy they must be sifted and the lumps ground fine
to be again roasted before proceeding with solution in Hydrochloric acid. This
solution in hydrochloric acid may be effected for example in octagonal or other
stone or stone ware tanks which may be similarly constructed to those used in
Alkali works for generating chlorine or in other suitable vats and preferably fitted
with a revolving shaft to which arms or stirrers are affixed for the purpose of
keeping the metallic oxides and acid in motion. The tank is partially filled with
the hydrochloric acid which should by preference be of about 28° Twaddle
(1.140 specific gravity). The arms or stirrers being set in motion the finely ground
and calcined matte is gradually introduced until sufficient has been added to
saturate the acid. A considerable elivation of temperature takes place and the
saturation at first proceeds rapidly, steam or hot air may be injected or other
means may be employed to maintain the heat of the liquors to about 190° Fahrenheit
in order to facilitate complete saturation of the acid. When the acid will take up
no more of the metallic oxides the arms are stopped in order to allow the suspended
particles to subside and the clear solution is run off to the desilverizing tanks. The
dissolving tank is now again charged with acid and more calcined matte is added
the same operation being repeated until a certain amount of deposit has accumulated
in the dissolving tank which deposit may then be treated by itself with fresh acid
so as to take up all the remaining soluble metallic oxides from the deposit and the
solution is then run into a settler. The clear acid liquor from this may be again
put back in the dissolving tanks to become saturated with copper and the deposit
is washed and put on one side, in case it should contain any silver or gold, in which
case it may be mixed with the reduced silver precipitate and smelted along with it
for silver and gold but if it contains Copper it may be smelted with Copper ore
mattes or other ore containing Sulphur in order to produce a fresh matte which
may then be treated in the manner above described. If necessary the residues in
the bottom of the dissolving tanks may be re-roasted previously.to being again
treated by hydrochloric acid.

page_text: The nearly saturated acid liquors containing Copper, Silver, Gold and other
metals in the form of Chlorides having been run into suitable tanks of known
capacity may be assayed for silver in the way described by me in the final
Specification of my Letters Patent N° 282 of 1870 and the quantity of Iodine in
the form of a soluble Iodide necessary to precipitate the exact amount of Silver
present in each tank is diluted with water and added and the liquors are then well
mixed and the whole allowed to settle until the precipitated Iodide of Silver
together with the gold (when that metal is present) has entirely subsided. The
clear supernatant Copper liquors are then run off to other tanks where the Copper
may be precipitated by iron or any other well known or suitable means. The
Copper thus obtained is found to be practically free from Silver and Gold as those
metals have been practically all separated in the Iodising process.
The silver precipitate which consists chiefly of Iodide of Silver (possibly with
some Gold) is carefully collected, freed from all substances soluble in hydrochloric
acid by treatment with that acid and water, and then decomposed by iron or zinc
or otherwise which reduces the silver (or silver and Gold) and yields a soluble
Iodide of Iron or Zinc which may be used in a future operation. Instead of
decomposing the Iodide of Silver by Iron or Zinc an Alkaline Sulphide may be
employed for that purpose.
Having now described and particularly ascertained the nature of my said:
invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is :-
The treatment of copper mattes containing silver or Silver and Gold for the
purpose of obtaining the silver or Silver and Gold therefrom by grinding or
disintegrating the mattes and roasting or calcining them and afterwards treating
them with hydrochloric acid so as to obtain a solution of metals including silver or
Silver and Gold therefrom and afterwards separating the silver or silver and Gold
from this solution by means of a soluble Iodide substantially as herein before
described.
In witness whereof I the said Frederic Claudet have to this my Specification set
my hand and seal this fourth day of April One thousand eight hundred and
eighty four.