Improvements in Furnaces for Treating Ores containing Precious Metals and other Ores.
Year: 1897

page_text: Date of Application, 24th June, 1897
Complete Specification Left, 23rd Mar., 1898-Accepted, 20th May, 1898
PROVISIONAL SPECIFICATION.
Improvements in Furnaces for Treating Ores containing Precious
Metals and other Ores.
A communication from abroad by JOSEPH CAMPBELL, M.A., F.G.S., F.C.S., of
Randwick, Sydney, New South Wales, and JOHN WILLIAM HENRY JAMES,
Engineer, of 52, Broad Street, New York, United States of America.
I, STEPHEN ALLEY, of the Sentinel Works, Polmadie Road, in the County of
Glasgow, North Britain, Engineer, do hereby declare the nature of this invention
to be as follows, that is to say:-
This invention comprises improvements in the construction of furnaces designed
for the treatment of ores, especially such as contain precious metals, with gases.
The gas or mixture of gases preferably employed in carrying out the invention
is what is known as water gas and consists of about equal volumes of hydrogen
and of carbon monoxide.
The main part of the improved furnace is a horizontal cylindrical vessel of
iron lined with firebrick, arranged in a building constructed with flues arranged
to apply the heat of ignited gas to the external cylindrical surface of the vessel,
the ends of which are just outside of the building. The ores to be treated are, in
a crushed or powdered state fed into one end of the vessel from a hopper, through
a rotating feeder; and when in the vessel are stirred and moved along it by
blades on a rotating shaft, some of which blades are inclined. The rotating shaft
which extends through stuffing boxes at the centres of the end plates of the
vessel, is made hollow and has water passed through it to prevent its becoming
overheated; and the shaft is, by preference, externally supported on bearing
rollers, and is driven by means of any suitable gearing from a motor. At the
further end from the feeding hopper there is a discharge duct or passage which
dips into a trough containing water which prevents the passage of gas; and
valved inlets and egress passages are provided for the gas.
By the combined action of the heat and the water gas or other gas on the ores
in the cylindrical vessel, base metals and other constituents such as sulphur,
arsenic, tellurium, antimony, bismuth, zinc, lead, iron and copper pyrites, and
iron oxide, are eliminated from the ores, and are either carried off by the water
gas as volatile compounds or altered in condition so that the precious metals can
be very easily obtained by subsequent amalgamation or other suitable known
process:
The volatile matters from the vessel are conveyed to closed condensing appara-
tus consisting of a series of water tanks and cooling plates, each water tank
having a weir over which a constant flow of water is maintained; and on striking
the cooling plates the volatile matters are deflected down upon the surface of

page_text: the water. The matters absorbed by the water in the tanks may be subsequently
separated and utilised in any suitable known way.
Dated this Twenty third day of June 1897.
EDMUND HUNT,
Applicant's Agent:
Improvements in Furnaces for Treating Ores containing Precious
Metals and other Ores.
A communication from abroad by JOSEPH CAMPBELL, M.A., F.G.S., F.C.S., of
Randwick, Sydney, New South Wales, and JOHN WILLIAM HENRY JAMES,
Engineer, of 52; Broad Street, New York, United States of America.
I, STEPHEN ALLEY, of the Sentinel Works, Polmadie Road, in the County of
Glasgow, North Britain, Engineer, 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, that is to say:-
This invention comprises improvements in the construction of furnaces designed
for the treatment of ores, especially such as contain precious metals, with gases.
The gas or mixture of gases preferably employed in carrying out the invention
is what is known as water gas and consists of about equal volumes of hydrogen
and of carbon monoxide.
The main part of the improved furnace is a horizontal cylindrical vessel of
iron lined with firebrick, arranged in a building constructed with flues arranged
to apply the heat of ignited gas to the external cylindrical surface of the vessel,
the ends of which are just outside of the building. The ores to be treated are, in
a crushed or powdered state, fed into one end of the vessel from a hopper, through
a rotating feeder; and when in the vessel are stirred and moved along it by
blades on a rotating shaft, some of which blades are inclined. The rotating shaft
which extends through stuffing boxes at the centres of the end plates of the
vessel, is made hollow and has water passed through it to prevent its becoming
overheated; and the shaft is by preference, externally supported on hearing
rollers, and is driven by means of any suitable gearing from a motor. At the
further end from the feeding hopper there is a discharge duct or passage which
dips into a trough containing water which prevents the passage of gas; and
valved inlets and egress passages are provided for the gas.
By the combined action of the heat and the water gas or other gas on the ores
in the cylindrical vessel, base metals and other constituents such as sulphur,
arsenic, tellurium, antimony, bismuth, zinc, lead, iron and copper pyrites, and
iron oxide, are eliminated from the ores, and are either carried off by the water
gas as volatile compounds or altered in condition so that the precious metals can
be very easily obtained by subsequent amalgamation or other suitable known
process.
The volatile matters from the vessel are conveyed to closed condensing appara-
tus consisting of a series of water tanks and cooling plates, each water tank
having a weir over which a constant flow of water is maintained; and on striking
the cooling plates the volatile matters are deflected down upon the surface of
the water. The matters absorbed by the water in the tanks may be subsequently
separated and utilised in any suitable known way,
The surplus water gas carried with any combustible vaporized matter is con-
veyed to the gas port of the furnace where it is mingled with the producer gas

page_text: and burnt in the combustion chamber thereby increasing the temperature and
Bo effecting a saving in fuel.
Another improvement, where it is necessary to treat large quantities of ore,
consists in constructing such furnaces with two or more closed chambers placed
either side by side or superposed.
Though the improved treatment as hereinbefore described has particular
reference to dealing with refractory auriferous ores, yet it is also applicable to
ores or to compounds containing only the commoner metals, the treatment effect-
ing such a satisfactory roasting of the ores that there is no difficulty in smelting
them.
And in order that my said invention and the manner of performing the same
may be properly understood I hereunto append two sheets of explanatory draw-
ings to be hereinafter referred to and showing my improvements in furnaces
for treating ores.
Figure, 1, on Sheet, 1, of the accompanying drawings is a longitudinal section
of the improved furnace, Figure, 2, shows two half transverse sections of the
furnace, as taken at right angles to Figure, 1, Figure, 3, shows two half hori-
zontal sections, and Figure, 4, an end elevation of the furnace. Figures, 5, and 6;
on Sheet, 2, are respectively a transverse and a longitudinal section of details
drawn to an enlarged scale and Figure, 7, is a longitudinal section of condensing
apparatus used in connection with the improved furnace. The same reference
letters and numerals are used to mark the same or like parts wherever they are
repeated.
On Sheet 1, Figure, 1, a is the closed hopper for the reception of ore, al is the
mechanically driven feeding drum or rotary feeder, a 2 is the shoot for conveying
the ore to the closed or sealed horizontal cylindrical vessel or ore treating chamber,
A, and a 3 is the pipe for the admission of water gas to the closed chamber. By
preference I force this water gas or its equivalent into the closed chamber at a
greater pressure than that of the atmosphere to prevent inward leakage of atmo-
spheric air.
b is the hollow spindle or shaft, passing at each end of the furnace through
stuffing boxes b1 62, packed with asbestos for exclusion of air, and upon the
spindle are fastened discs c fitted with rakes or stirrers c 1 for turning over and
keeping the ore in constant agitation. Blades c2 on the discs c are set at the
required angle for moving the ore from end to end of the furnace at the desired
apeed, each of the discs being fitted with two rakes c 1 and one blade c 2.
The ends of the spindle 6 are carried upon roller bearings d, d1 running in
brackets 2 fastened to girders e apart from the furnace so as to prevent distur-
bance of the brick work by vibration, motion being given to the spindle by spur
gearing driven by pulley g from a motor (not shown). The spindle 6 is made
hollow, water being circulated through it by pipes, c3, c4 for the purpose of keeping
it cool, h is the hopper for the discharge of ore from the closed chamber into
water trough for sealing the back end of the chamber, A, and for carrying the
treated ore to the amalgamators.
On Sheet, 2, Figure, 7, B is the condensing apparatus, or precipitating chamber,
is the connecting pipe between the ore treating chamber, A, and precipitating
chamber for carrying off the surplus water gas and volatile matter, k, k 1, k2, k 3, k4,
are the precipitating tanks, 1, 11, 12, 13, 14 are the baffle or cooling plates for deflect-
ing the volatile matter on to the surface of the water in the tanks, m is the water
supply pipe to the tanks, and n is the overflow from the precipitating chamber, B,
to the settling tank, o with overflow o 1. In the side wall of the precipitating
chamber B, opposite to each tank are fitted' doors p, p 1, p 2, p 3, p 4, to give access
to the tanks when necessary and to empty them of the by-products. q is a chimney
for carrying off the waste gases, when air roasting is resorted to, but when water
gas or other gas is employed a damper q 1 is closed and a valver is opened, and
the surplus water gas is returned through pipes to the gas box or port of the
furnace and burnt therein.

page_text: The gaseous fuel or producer gas is conveyed direct from the gas generators
to the gas box or port t through pipe t 1 and regulating valve t2 the surplus water
gas from the precipitating chamber, B, being admitted to the furnace port through
pipe s. u, u 1, 2, 3, 4, 5, 6, u 7, are channels or ducts for air, which is drawn
in by the chimney draught through holes of which some v4, v5, v6, v7, are shown in
Figure, 3; the air becomes heated in its passage beneath the combustion cham-
ber, C, and unites with the gas in the port or gas box, passing into the combustion
chamber, C, and annular flues, C1, where it is burnt with the gases, such products
of combustion being carried beneath the ore treating chamber, A, to the rear of
the furnace, returning over the top and escaping through chimney, D.
When treating ores, where it becomes unnecessary to recover the by-
products and therefore dispensing with the precipitating chamber the surplus
water gas is returned direct to the gas port t through pipe to shown in dotted lines
in Figure, 4, or if air roasting is in such cases resorted to, it is led to the
chimney, D, through pipe, z.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare, that what
I claim is:-
1. The improved treatment of refractory gold and silver and other metal bear-
ing ores and compounds, consisting in or characterized by the subjection of the
ore or compound while being roasted to the action of water gas preferably under
a pressure greater than that of the atmosphere in a closed or sealed furnace,
retorts or chambers substantially as and for the purposes herein before described.
2. The improved treatment of refractory gold and silver, and other metal bear-
ing ores and compounds consisting in and characterized by the subjection of the
ore or compound while being roasted to the action of water gas in a closed or
sealed furnace, retorts, or chambers, in conjunction with a sealed mechanical ore
feeding hopper substantially as and for the purpose hereinbefore described.
3. The improved treatment of refractory gold and silver and other metal bear-
ing ores and compounds consisting in and characterized by the subjection of the
ore or compound while being roasted to the action of water gas in a closed or
sealed furnace, retorts, or chambers, in conjunction with a sealed mechanical ore
feeding hopper a combined rake or agitator and conveyor, working in said closed
ore treating chamber substantially as and for the purposes hereinbefore described.
4. The improved treatment of refractory gold and silver and other metal
bearing ores and compounds consisting in and characterized by the subjection
of the ore or compound while being roasted to the action of water gas in a closed
or sealed furnace, retorts or chambers in conjunction with a sealed mechanical ore
feeding hopper, a combined rake or agitator and conveyor working in said closed
ore treating chamber, an hydrostatic precipitating chamber, with a series of pre-
cipitating tanks, cooling plates or deflectors substantially as and for the purposes
hereinbefore described."
5. The improved treatment of refractory gold and silver and other metal
bearing ores and compounds consisting in or characterized by the subjection of
the ore or compounds while being roasted to the action of water gas in a closed
or sealed furnace, retorts or chambers, in conjunction with a sealed mechanical
ore feeding hopper a combined rake or agitator and conveyor working in said
ore treating chamber, an hydrostatic precipitating chamber, with a series of
precipitating tanks, cooling plates or deflectors, the return of the surplus water
gas to the combustion chamber of the furnace substantially as and for the pur-
poses herein before described.
6. The improved treatment of refractory gold and silver and other metal bear-
ing ores and compounds consisting in or characterized by the subjection of the
ore or compounds while being roasted to the action of water gas in a closed or
sealed furnace, retorts or chambers, in conjunction with a sealed mechanical ore

page_text: feeding hopper a combined rake or agitator and conveyor working in said ore treat-
ing chamber, an hydrostatic precipitating chamber,, with a series of precipitating
tanks, cooling plates or deflectors, the return of the surplus water gas to the
combustion chamber of the furnace, the burning in combustion of producer and
water gas and superheated air in flues, channels, and chambers in one furnace
structuro substantially as and for the purposes hereinbefore described.
loted this Twenty first day of March 1898