Improvements in the Treatment of Cupreous Pyrites to Separate Gold, Silver, Copper, and Sulphur, and to Obtain Oxide of Iron, and in Apparatus Employed therein.
Year: 1887

page_text: Date of Application, 11th Mar., 1887
Complete Left, 12th Dec., 1887
Complete Accepted, 3rd Feb., 1888
Improvements in the Treatment of Cupreous Pyrites to Separate
Gold, Silver, Copper, and Sulphur, and to Obtain Oxide of Iron,
and in Apparatus Employed therein.
We JAMES HARGREAVES Chemist THOMAS ROBINSON Iron Founder and JOHN
HARGREAVES Chemist all of Widnes in the County of Lancaster do hereby declare
the nature of this invention to be as follows:-
The objects of our invention are to so treat pyrites that the copper silver and gold
(hereinafter referred to as valuable metals) and the sulphur therein contained are
obtained separately and the residual oxide of iron is left or formed into suitable
condition for use in blast furnaces. Our invention also relates to apparatus employed
and to improvements on the process covered to us by Patent No. 5681 of the
year 1886.
To render the valuable metals soluble under our patent of 1886 above referred to
we employ a series of converting chambers and provide each chamber with earthen-
ware or other refractory grids or perforated supports to carry the pyrites and we
fit each such chamber with sight pipes passing through the charge. The earthenware
grids or supports effectively resist the action of the corrosive gases and vapours.
To provide efficient apparatus in which to render the valuable metals soluble we
employ a tall vertical kiln constructed with special arrangements for inducting hot
gases and causing them to permeate the mass of pyrites. The hot gases enter the
Kiln under a lining hood placed within and near the bottom; apertures in the said
hood distribute the gases amongst the charge. The said gases evolved are conveyed
away from the side or top by a suitable passage or way.
To obtain an increased quantity of sulphur and an augmentation of sulphuric acid
vapour in the resulting sulphurous acid gas when burning pyrites in ordinary pyrites
burners, and to obtain the burnt pyrites in suitable condition for direct subsequent
treatment to separate the valuable metals, we admit hot air to the said burners mixed
with heated sulphuric or sulphurous acid gas. As a means of carrying the above

page_text: described treatment into effect we employ a flue lying between two lines of burners
and having convenient dampers for admission of the hot air to each burner
separately.
In treating pyrites to obtain directly therefrom sulphur sulphurous acid and sulphate
of copper as described in our before mentioned patent of 1886 we employ three
separate interchangeable series of burners. After charging the burners first yield
sulphur vapour and sulphurous acid gas. Afterwards sulphuric acid vapour, and
finally sulphate of copper. There is therefore one series giving off sulphur vapour
and sulphuric acid gas, another series giving sulphuric acid vapour, and the third
which receives the sulphuric acid vapour from the second series has the copper
contained in the pyrites converted into sulphate.
We render soluble the valuable metals contained in pieces of burnt and subsequently
further oxidized pyrites, by moistening such pyrites when cold with strong solutions
of chloride or sulphate of iron, or liquid hydrochloric or sulphuric acid and heating
the same in close chambers or vessels and passing hot gases or steam through or
amongst the said pieces. We condense and reuse the acid gases evolved.
We dry pieces of oxide of iron from which the valuable metals have been extracted
by passing such oxide when supported upon an endless iron band through an oven
heated to a temperature of about 400° F. To render finely divided oxide of iron
suitable for use in blast and other smelting furnaces we mix it with lime, stamp or
press, and subsequently dry it into cakes or lumps. The stamped or pressed mixture
is brought into direct contact with products of combustion. An iron band such as is
above described for pieces is suitable for the purpose.
In treating pyrites and obtaining sulphur vapour and sulphurous acid gas we for
the purpose of obtaining a large quantity of sulphur, first condense the sulphur
vapour and separate it as sulphur, and afterwards absorb the sulphurous acid by
passing the same through alkali waste or its solutions from which by the usual process
it is recovered as sulphur.
When gold and silver are precipitated from copper solutions by means of Iodides
we hasten and more completely settle the precipitate by adding thereto a hot solution
of chloride of lead, or finely divided sulphide or sulphate of lead.
We reduce the quantity of metallic iron necessary to precipitate copper contained
in solutions resulting from the treatment of pyrites by passing sulphuretted hydrogen
or equivalent sulphides previous to precipitating the copper, into, through, or amongst,
the hot acid solution of copper until per salts of iron are reduced to proto salts.
We obtain sulphide of copper in suitable condition comparatively pure to make
therefrom oxide or sulphate of copper, by treating solutions of copper obtained from
pyrites as herein, or under the hereinbefore mentioned 1886 patent, first with iodides
to precipitate and separate the gold and silver. We afterwards precipitate the copper
with sulphuretted hydrogen whilst the solution is agitated in a series of covered
vessels, or whilst falling down a suitable packed tower maintained under slight
vacuum. The resulting precipitated sulphide of copper is settled, the solution of
free acid decanted, the precipitate washed with water and subsequently treated with
an alkaline solution to remove arsenic and antimony. We free the precipitated
copper from moisture by a centrifugal machine or filter press. The decanted solution
of free acid is utilized in generating sulphureited hydrogen from alkali waste and is
used as set forth to precipitate copper, or the acid solution is oxidized and used in
dissolving the valuable metal in the pyrites.
To convert precipitated sulphide of copper into oxide or sulphate of copper and
obtain the sulphur we form the precipitated sulphide of copper into lumps or pieces
and oxidize the same in suitable chambers. We oxidize by passing hot air preferably
mixed with aqueous vapour through or amongst the sulphide at a temperature of
about 900° F. The powdered sulphide may be treated in suitable shelf burners.
The sulphurous acid gas and sulphuric acid vapour evolved during treatment as
above is passed over previously oxidized heated sulphide to form sulphate.
To obtain oxide of copper we employ a higher temperature than when it is desired
to form sulphate of copper.

page_text: We recover the sulphuric acid in useful form and the iron in suitable condition
for use as pigment from solutions of sulphate of iron resulting from the method of
obtaining precipitated metallic copper described in our before mentioned 1886 patent,
by evaporating the solution of sulphate of iron forming the sulphate into pieces and
roasting the said pieces in a covered chamber or series of chambers by passing
therethrough hot air or products of combustion preferably mixed with steam, or we
roast the sulphate of iron in suitable shelf burners giving sufficient area of sulphate
of iron to evolve sulphuric acid sufficiently concentrated, to form sulphate of copper
as herein or described in our before mentioned 1886 patent or to be otherwise useful
in the arts.
We wash and dry the resulting oxide of iron,

page_text: Improvements in the Treatment of Cupreous Pyrites to Separate
Gold, Silver, Copper, and Sulphur, and to Obtain Oxide of Iron,
and in Apparatus Employed therein.
We JAMES HARGREAVES, Chemist, THOMAS ROBINSON, Ironfounder, and Jons
HARGREAVES, Chemist, all of Widnes in the county of Lancaster, 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 objects of our invention are to so treat pyrites that the copper silver and gold
(herein referred to as valuable meals) and the sulphur are obtained separately and
the residual oxide of iron is left by the treatment in suitable condition for use in
blast furnaces.
Our invention has also for its object to improve the treatment and apparatus
covered to us by patent No. 5681 of the year 1886.
For convenience we will describe our improvements under the heads following.
First. To render the valuable metals soluble under our patent of 1886 above
referred to we employ a series of connected chambers and provide each chamber
with earthenware or other refractory grids or perforated supports to carry the pyrites
and we fit each such chamber with sight pipes passed through or into the charge of
pyrites.
The earthenware grids or supports effectively resist the action of the corrosive
gases and vapours.
Second. To provide efficient apparatus in which to render the valuable metals
soluble we employ a tall vertical kiln constructed with arrangements for permitting
the passage thereinto of hot acid gases and causing them to permeate the mass of
pyrites by allowing or causing the gases to enter the kiln under a lining hood as
illustrated in figures I and 2 and be distributed through the charge. Figure 1 is a
vertical section and Figure 2 a horizontal section of a kiln constructed according to
the second part of our invention a walls of kiln & charging holes c discharging way
dair passage formed with holes e through which air is forced into the charge of pyrites
in the kiln, outlet for acid gases, y passage leading from the gas outlet f to the air
supply d. A portion of the acid gases evolved from the burning charge is drawn
through the passage g and mixing with the air in the way d is passed into the
charge of pyrites in the kiln.
When green pyrites is under treatment gases evolved from the lower strata are
returned as from Z to the bottom of the kiln and admitted with air and when
previously burnt pyrites is being treated the gases found at the top are returned to
the bottom.
Third. By the method set forth in our 1886 patent for burning pyrites and at the
same operation rendering the valuable metals therein contained soluble we there
described burning the pyrites in long columns contained in a series of two or more
chambers or burners by admission to the first chamber of hot air and acid gases
heated to about 1000° Fahrenheit obtaining thereby sulphurous acid necessarily
free from sulphuric acid because of being mixed with a large amount of sulphur
vapour which latter was subsequently burned with excess of air in a combustion
chamber.

page_text: In practice we now find it preferable to employ ordinary pyrites burners whereby
we directly obtain during the burning, sulphurous and sulphuric acid gases, and, these
gases being returned with hot air render soluble the valuable metals contained in the
pyrites.
It will be evident that when all the sulphur is burned in the mass of pyrites the
hot air and acid gases entering the burners may be of lower temperature than is
required when sulphur is distilled from the pyrites as in our said 1886 patent.
To obtain an increased quantity of sulphur and an augmentation of sulphuric acid
vapour in the resulting sulphurous acid gas when burning pyrites in ordinary pyrites
burners and to obtain the burnt pyrites in suitable condition for direct subsequent
treatment, to separate the valuable metals we admit hot air mixed with heated
sulphuric, or sulphurous acid gas to the said burners. As a means for carrying the
above described treatment into effect we employ a flue lying between the two lines of
burners having convenient dampers for the admission of the hot air and sulphur
acid gases to each burner separately.
To more easily adapt the process to existing pyrites burners without material
alteration of existing brick work two flues may be employed one flue being placed
under each line of burners. We find it advantageous to vary the depth of pyrites
under treatment in the burner. Thus when the percentage of copper is high and
sulphur low the depth is increased. On the other hand when the percentage of
copper is low and sulphur high the depth is reduced-A fan or other appliance may
be used to force or aspirate air through an air heater-We prefer however to employ
for this purpose a steam jet and to utilize the steam to regulate the temperature of
the pyrites to prevent fusion thereof.
Figure 3 is a cross section and figure a longitudinal section of pyrites burners
constructed according to the third part of our invention 1 burners formed with two
crowns 2. 3 so as to leave a space between them. 5. Steam jet for forcing air
into the space 4 where it becomes heated and thence through the flue 6 to the flue 7
underneath the burners-A division plate $ is placed in the flue so that each burner
receives air at about the same temperature-The air passes first along underneath the
plate and then backwards above the plate, 9 openings provided with doors 10 leading
from the flue 7 to each burner. 11 rods for opening and closing the doors 10.
12 passage through which sulphurous acid gas is drawn by the action of the steam
jet 5 and forced along with the air through the space and flues 6 and 7 to the
burners. 13 damper for regulating the opening of the passage 12 Figures 5 and 6
are views showing different methods of arranging the flue 7. In figure 5 two vertical
division plates are used and the air passes first through the central space 14 and then
back through the two side passages 15. 9 openings to the burners.
In figure 6 the air passes first through the pipe 16 and back through the
surrounding way 17. 9 openings to the burners. Figure 7 is a view shewing a
method of arranging the flue 7 to suit existing burners. Here two pipes 18 are
used one on each side of the dividing wall. The air passes first through the pipes 18
and then back through the covered way 19. 9 opening to the burners.
In plans 3 and 4 we describe an arrangement for the admission of hot gases to the
burners and method of working which we prefer to employ for carrying into operation
the process described under this head-Each burner may have separate openings into
the sulphurous acid flue, or the gas may be conducted over the line of burners as
shown, or other convenient conduit used for taking away the sulphurous acid.
Fourth. In treating pyrites to obtain directly therefrom sulphur sulphurous acid
and copper in the form of sulphate as described in our before mentioned patent
of 18SG. We employ 3 separate interchangeable series of burners such burners
and connections being of brick or other refractory material capable of resisting the
action of the corrosive gases and vapours, each series is preferably arranged similar
to the well known cylinder apparatus employed in the Hargreaves & Robinson
sulphate of soda process-After charging the burners sulphur vapour and sulphurous
acid gas are first given off, next sulphuric acid vapour and finally sulphate of copper
is formed. There is therefore one series giving off sulphur vapour and sulphurous

page_text: acid gas another series giving sulphuric acid vapour mixed with more or less
sulphurous acid gas, and the third which receives the sulphuric acid vapour from the
second series has the copper and silver contained in the pyrites converted into
sulphates.
Fifth. We render soluble any valuable metals contained in pieces of burnt and
subsequently further oxidized pyrites by moistening such pyrites when cold with
strong solutions of chloride or sulphate of iron or liquid hydrochloric or sulphuric
acid and heating the same in close chambers or vessels and passing hot air gas or
steam through or amongst the said pieces. We condense and reuse the acid gases
evolved.
Sixth. We dry pieces of oxide of iron from which the valuable metals have been
extracted as herein described or as described under our before mentioned 1886 patent
by passing such oxide when supported upon an endless iron band through an oven
heated to a temperature of about 400° Fahrenheit-To render finely divided oxide of
iron suitable for use in blast or other smelting furnaces we mix it with lime and
stamp or press the mixture. Both the pieces of oxide of iron and the finely divided
oxide with lime are subjected to the action of the products of combustion passing
through the heated oven.
Seventh. In treating pyrites under our invention to obtain a large quantity of
sulphur and sulphurous acid gas and to render the pyrites suitable for treatment by
acid gases as herein or in our 1886 paient described we condense out and collect in a
fine state of division the sulphur vapour given off from the pyrites in the burners
and afterwards absorb the sulphurous acid by passing the same through alkali waste
or its solutions from which by a well known process it is recovered as sulphur. By
collecting the sulphur in a fine state of division the arsenic if any can be easily
separated.
Eighth. When gold and silver are precipitated from copper solutions obtained as
described in our before mentioned 1886 patent by means of iodides we hasten
precipitation and more completely settle the precipitate by adding thereto a hot
solution of chloride of lead or finely divided sulphide or sulphate of lead.
Ninth. We reduce the quantity of metallic iron necessary to precipitate copper
resulting from the treatment of pyrites as herein and also in our before mentioned
1886 patent by passing sulphuretted hydrogen or equivalent sulphides previous to
precipitating the copper into through or amongst the hot, acid solution of copper
until per-salts of iron are reduced to proto salts.
Tenih. We obtain sulphide of copper in suitable condition to make therefrom
comparatively pure oxide or sulphate of copper by treating solutions of copper
obtained from pyrites as herein or under the herein before mentioned 1886 patent by
first precipitating the gold and silver present with iodides and afterwards precipitating
the copper with sulphuretted hydrogen whilst the solution is agitated in a series of
covered vessels or whilst falling down a suitably packed tower each such vessel or
tower being maintained under slight vacuum. The resulting precipitated sulphide of
copper is sealed the solution of free acid decanted the precipitate washed with water
and subsequently treated with an alkaline solution to remove arsenic and antimony.
We free the precipitated copper from moisture by a centrifugal machine or filter
press. The decanted solution of free acid is utilized in generating sulphuretted
hydrogen from alkali waste which sulphuretted hydrogen is used as mentioned above
to precipitate copper or the said acid solution is oxidized and used in dissolving the
valuable meials in the pyrites.
Eleventh. We oxidize precipitated sulphide of copper obtained under our present
invention or under our 1886 patent into oxide or sulphate by passing hot air preferably
mixed with acqueous vapour through or amongst the sulphide at a temperature of
about 900° Fahrenheit. This treatment applies to lumpy and also to finely divided
sulphide. These or either of them are or is placed on suitable shelf burners and the
sulphurous acid gas and sulphuric acid vapour evolved during the treatment is passed
over previously oxidized heated sulphide. A higher temperature is employed to form
oxide of copper than is necessary to form sulphate of copper.

page_text: Twelfth. We recover the sulphuric acid in useful form and the iron in suitable
condition for use as pigment from solutions of sulphate of iron resulting from the
method of obtaining strong copper solutions and precipitated metallic copper there-
from as described in our before mentioned 1886 patent by evaporating the resulting
solution of sulphate of iron to dryness, forming the sulphate into pieces and roasting
the said pieces in a covered chamber or series of chambers by passing there through
hot air or products of combustion preferably mixed with steam, or we roast the
sulphate of iron in suitable shelf burners giving sufficient area of sulphate of iron to
evolve sulphuric acid sufficiently concentrated to form sulphate of copper as herein or
described in our before mentioned 1886 patent or the sulphuric acid may be condensed
and recovered We wash and dry the resulting oxide of iron.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is
First. With a series of chambers, perforated grids and sight pipes under the first
head for the purpose set forth.
Second. Kilns constructed substantially as described and illustrated for the purpose
sei. forth.
Third. Admitting to pyrites in ordinary pyrites burners hot air and sulphurous or
sulphuric acid gas when such air and acid gas or gases is or are admitted to the
lower part of the burners to act on the pyrites and render the valuable metals soluble
substantially as herein described.
Third A. A flue with dampers placed between two lines of burners for conducting
and regulating the admission of hot air and acid gases to ordinary pyrites burners for
the purpose set forth.
Fourth. The three series of burners operating substantially in the manner and for
the purpose set forth.
Fifth. Saturating pieces of burnt pyrites after oxidation with liquid acids or
salts and subsequently passing through or amongst the mass heated air or gas for the
purpose herein set forth.
Sixth. Subjecting oxide of iron obtained after treatment with acid gases and
finely divided iron mixed with lime to the action of products of combustion when they
are being carried on an endless band as described.
Seventh. Condensing out sulphur vapour as sulphur and absorbing sulphurous acid
in alkali waste substantially as described.
Eighth. Obtaining gold and silver from copper solutions by adding to such solutions
chloride or sulphide of lead substantially as described.
Ninth. Reducing persalts of iron contained in copper solutions to proto salts by
passing sulphuretted hydrogen through such solution substantially as set forth.
Tenth. Treating solutions of copper with iodides to separate gold and silver and
subsequently subject such solution to the action of sulphuretted hydrogen in covered
vessels all substantially as described.
Eleventh. Obtaining sulphate of copper from sulphide of copper by subjecting the
latter to hot air and sulphur acid gases substantially as described.
Twelfth. Recovering from solutions of sulphate of iron sulphuric acid in useful
form and iron as pigment substantially by the means and appliances described herein
under this head.
ملف 1 . Dard
Draan 1887
JAMES JOHNSON,
Agent.