IMPROVEMENTS IN TREATING METALLIC ORES TO OBTAIN PRODUCTS, AND IN
Year: 1871

page_text: LETTERS PATENT to James Hargreaves, of Appleton-within-Widnes,
in the County of Lancaster, Chemist, and Thomas Robinson, of
Widnes, in the same County, Ironfounder, for the Invention of
"IMPROVEMENTS IN TREATING METALLIC ORES TO OBTAIN PRODUCTS, AND IN
Sealed the 19th January 1872, and dated the 21st July 1871.
PROVISIONAL SPECIFICATION left by the said James Hargreaves and
Thomas Robinson at the Office of the Commissioners of Patents,
with their Petition, on the 21st July 1871.
We, JAMES HARGREAVES, of Appleton-within-Widnes, in the County
of Lancaster, Chemist, and THOMAS ROBINSON, of Widnes, in the same
County, Ironfounder, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN TREATING METALLIC ORES TO OBTAIN PRODUCTS, AND IN
APPARATUS EMPLOYED IN THE SAID TREATMENT," to be as follows:-
The objects of this Inventions are,-
To completely oxydise or decompose sulnhides and to utilize the

page_text: And second. To convert the oxides and sulphides of certain of the
metals contained in the said ores, such as copper, zinc, tin, lead, silver,
and gold into chlorides, and to render them otherwise available by the
action of chlorine or hydrochloric acid gases at elevated temperatures.
Hereafter we refer to pyrites as the metallic ore to be operated upon, 5
but it will be obvious that the first part of our Invention is equally
applicable to other metallic sulphides, such as galena, blende, and blue
Anglesea stone. And we describe burnt or spent pyrites as the substance
to be operated on under the second part of our Invention.
In carrying the first part of our Invention into effect we proceed as 1
follows:-
A. We burn the pyrites in tall vertical or other retorts or burners until
the whole of the sulphur is oxidised. For this purpose we artificially
keep up the temperature of the pyrites after the greater bulk of the
sulphur is oxidised, and the heat evolved is insufficient of itself to keep
up the temperature. The sulphur may be oxidised either in the form
of sulphurous acid or of a sulphate of some constituent of the pyrites or
other ore which is being operated upon.
B. We then burn or treat the pyrites in retorts or burners arranged
in series or sets. The air, which may be heated, is made to pass into a
retort or burner containing nearly spent pyrites kept at a temperature
sufficiently high to oxidize the sulphur compounds still present. After
passing through the first retort or burner the air passes through another
retort or burner containing pyrites which is not so nearly spent or burnt,
and thence through any desired number of retorts or burners. Stoppers,
valves, and dampers are so arranged in the passages and connections
that each retort or burner becomes in its turn the first, intermediate, and
last of the set or series. We prefer that the air should be made to
enter at the retort or burner which contains the most nearly spent
pyrites, and the sulphurous acid produced should flow out of the
apparatus from the retort or burner which has last been charged with
fresh pyrites. After the pyrites ceases to give out sulphurous acid the
retort or burner is discharged if the pyrites is free from copper, zinc,
tin, lead, and other metals besides iron, but if metals other than iron
are contained in the pyrites, and it is desirable to obtain or utilize
them, we previously to discharging the said retort or burner treat the
spent pyrites in the method hereafter set forth in carrying the second
part of our Invention into effect.

page_text: C. The retorts or burners which we prefer to use consist of vertical,
circular, elliptical, or square tubes with bearers or false bottoms to
support the pyrites, and perfectly heated on the outside. The said
retorts or burners may be connected together so as to form a series or
may be fed in the ordinary way, and the gas from each retort or burner
be made to flow directly from each retort or burner without passing
through another.
The retorts or burners may be of iron or clay or other suitable
material.
In carrying the second part of our said Invention into effect, we
proceed as follows, that is to say :—
We keep the above or other spent pyrites at suitable temperature, or
we take pyrites which has already been burnt and heat it; the temperature
which we have so far found to be suitable is one from 700° to 900°
Fahrenheit. Through, once, or amongst the said spent or burnt pyrites
we pass a current of chlorine or of hydrochloric acid gas or vapour
whereby any oxide of copper, zinc, lead, tin, or other metals present are
converted into chlorides or otherwise made available.
If the pyrites or other ores contain sulphides, but in too small a
quantity to afford a separate treatment for the oxidation of the said
sulphides, we mix atmospheric air or oxygen with the chlorine or
hydrochloric acid gas used so as to oxidise the sulphides and to form
chlorides at one operation.
The pyrites after being treated with chlorine or hydrochloric gas as
aforesaid is then crushed (if not already in a sufficiently minutely
divided state) and lixiviated with water to dissolve out any soluble salts
such as those of copper, zinc, and tin, and the oxide of iron remaining
is then fit for use in iron manufacture and for other purposes. If salts
which are insoluble in water are present, such, for instance as sulphate
of lead, we submit the ore to any suitable treatment to obtain the said
lead or other metal in the form of a salt or metal.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Hargreaves and Thomas Robinson in the
Great Seal Patent Office on the 20th January 1872.

page_text: First. To completely oxidize or decompose sulphides and to utilize
the greatest possible quantity of sulphur contained in metallic ores.
And second. To convert the oxides and sulphides of certain of the
metals contained in the said ores, such as copper, zinc, tin, lead, 35
silver, and gold into chlorides, or to render them otherwise available

page_text: by the action of chlorine or hydrochloric acid gases at elevated
temperatures.
Hereafter we refer to pyrites as the metallic ore to be operated upon,
but it will be obvious that the first part of our Invention is equally
applicable to other metallic sulphides, such as galena, blende, blue
Anglesea stone, and we describe burnt or spent pyrites as the substance
to be operated on under the second part of our Invention.
In carrying the first part of our Invention into effect we proceed as
follows:-
A. We burn the pyrites in tall vertical or other retorts or burners
until the whole of the sulphur is oxidized. For this purpose we
artificially keep up the temperature of the pyrites after the greater
bulk of the sulphur is oxidized, and the heat evolved is insufficient of
itself to keep up the temperature. The sulphur may be oxodized either
in the form of sulphurous acid or of a sulphate of some constituent of
the pyrites or other ore which is being operated upon.
(B.) We burn or treat the pyrites in retorts or burners arranged in
series or sets. The air, which may be heated, is made to pass into a
retort or burner containing nearly spent pyrites kept at a temperature
sufficiently high to oxidize the sulphur compounds still present. After
passing through the first retort or burner the air passes through another
retort or burner containing pyrites, which is not so nearly spent or
burnt, and thence through any desired number of retorts or burners.
Stoppers, valves, and dampers are so arranged in the passages and
connections that each retort or burner becomes in its turn the first,
intermediate, and last of the set or series. We prefer that the air
should be made to enter at the retort or burner which contains the most
nearly spent pyrites, and the sulphurous acid produced should flow out of
the apparatus from the retort or burner which has last been charged
with fresh pyrites. After the pyrites ceases to give out sulphurous acid
the retort or burner is discharged if the pyrites is free from copper, zinc,
tin, lead, and other metals besides iron, but if metals other than iron
are contained in the pyrites, and it is desirable to obtain or utilize them,
we previously to discharging the said retort or burner treat the spent
pyrites in the method hereafter set forth in carrying the second part of
our Invention into effect.
The retorts or burners which we prefer to use consist of vertical,
circular, elliptical, or square tubes with bearers or false bottoms.to

page_text: support the pyrites, and preferably heated on the outside. The said
retorts or burners may be connected together so as to form a series, or
may be fed in the ordinary way, and the gas from each retort or burner
be made to flow directly from each retort or burner without passing
through another.
The retorts or burners may be of iron or clay or other suitable
material.
In carrying the second part of our said Invention into effect we
proceed as follows, that is to say :-
We keep the above or other spent pyrites at a suitable temperature,
or we take pyrites which has already been burnt, and heat it; the tem-
perature which we have so far found to be suitable is one from 700° to
900° Fahrenheit. Through, over, or amongst the said spent or burnt
pyrites we pass a current of chlorine or of hydrochloric acid gas or
vapour, whereby any oxide of copper, zinc, lead, tin, or other metals
present are converted into chlorides, or otherwise made available.
If the pyrites or other ores contain sulphides, but in too small a
quantity to afford a separate treatment for the oxidation of the said
sulphide, we mix atmospheric air or oxygen with the chlorine or bydro-
chloric acid gas used so as to oxidize the sulphides and to form chlorides
at one operation.
The pyrites after being treated with chlorine or hydrochloric acid gas,
as aforesaid, is then crushed (if not already in a sufficiently minutely
divided state), and lixiviated with water to dissolve out any soluble
salts, such as those of copper, zinc, and tin, and the oxide of iron
remaining is then fit for use in iron manufacture, and for other purposes.
If salts which are insoluble in water are present, such, for instance, as
sulphate of lead, we submit the ore to any suitable treatment to obtain
the said lead or other metal in the form of a salt or metal.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 is a vertical longitudinal section, and Fig. 2 a horizontal section
at the line A, B, of vertical burners or retorts illustrative of the first
part of our Invention.

page_text: heating flues; 9, escape flue for heating gases. The fire-place 7 and
up-take flues 8 serve to artificially maintain the temperature of the
pyrites after the greater bulk of the sulphur is oxidized; 10 are teasing
holes. Air, heated or otherwise, is admitted past the regulating slides 11
in the discharge doors 4.
In illustration of head B, under which the retorts or burners are so
arranged as to become the first, intermediate, and last of the series, and
the evolved gases pass from one to the other, the references, given above
in describing head A, apply. Four retorts or burners are here shown, that
marked 1 being the first of the series. Air enters past the regulating
slide 11, the discharging doors 4 and slides 11 in the others being
closed, and the evolved gases and air pass from 1 through the passage
12 down the pipe 13 into the bottom of retort 1', thence through the
passage 14, down the pipe 15, up the retort 1" through the passage 16,
down the pipe 17, and into the retort 1, from which latter the said gas
passes through the outlet way 5" into the main gas pipe 6.
It will be evident that dampers are placed in all the outlet ways
except the one marked 5 which is the last of the series. A damper
is provided in the connecting passage opening into the bottom of each
retort, and the one here marked 18 at the bottom of the retort which
is the first of the series is closed so as to prevent the air from passing
direct to the outlet way 5 leading into the gas main 6 without passing
through the whole series.
It will be evident that by opening any particular damper in the
outlet ways 5, 51, 51, 5¹¹¹, and closing the corresponding damper 18 in the
ash-pit that any of the chambers can be made the first, intermediate,
and last of the series.
It will also be evident that as herein-before mentioned the chamber
which is the first of the series and to which air is admitted should be
the one containing the most nearly spent pyrites, and that the one which
is the last of the series should contain fresh pyrites.
Under the second part of our Invention we prefer to proceed as
follows: We admit chlorine or hydrochloric acid gas with or without
atmospheric air, either after or during oxidation of the sulphur, into
the retorts or chambers, and allow it to pass through the burnt pyrites
contained in the series of retorts or burners. The burnt pyrites should
be maintained at from 700° to 900° Fahrenheit. When the whole
of the oxides of copper, zinc, lead, tin, or other metals present, iron

page_text: excepted, are converted into chlorides, the mass is to be withdrawn
and heated by ordinary and well-known means as herein mentioned
to separate the metals. The condition of the metals, such as copper,
zinc, lead, and tin, can be ascertained by withdrawing samples from
time to time.
Having now described the nature of our said Invention, and par-
ticularized the same, we claim,—
I. Oxidizing or decomposing metallic sulphides by means of vertical
retorts or burners heated externally, substantially as described.
II. Oxidizing or decomposing metallic sulphides by means of a
set or series of retorts or burners so arranged and connected that each
retort or burner may be made the first, intermediate, and last of the
series, substantially as described.
III. Passing chlorine or hydrochloric acid gas with or without atmo-
spheric air through a set or series of retorts or burners containing
heated pyrites, such retorts or burners being so arranged that each
may be made the first, intermediate, and last of the series, substantially
as described.
In witness whereof, I, the said James Hargreaves, have hereunto
set my hand and seal, the Eighteenth day of January, in
the year of our Lord One thousand eight hundred and seventy-
two.
In the presence of
J. T. KING,
Patent Agent,
Liverpool.
JAMES HARGREAVES. (L.S.)