Improvements in Oxidizing and Calcining Retort Furnaces.
Year: 1891

page_text: Date of Application, 4th July, 1891
Complete Specification Left, 31st Mar., 1892-Accepted, 25th June, 1892
PROVISIONAL SPECIFICATION.
Improvements in Oxidizing and Calcining Retort Furnaces.
WILLIAM OSWALD TAYLOR Elm Lodge Riverside Mortlake Surrey Civil
Engineer do hereby declare the nature of this invention to be as follows:-
This invention has for its object the calcining and oxidizing of metalliferous
ores particularly what are known as refractory gold and silver ores and other
material and in order to more perfectly and economically accomplish this object
I construct my retort furnace in the following manner.
I construct a vertical chamber of suitable height and dimensions with one or
more suitable furnaces either for coal, wood, oil, gas or any other fuel. Inside
this vertical chamber I construct another chamber which I call the retort. The
space between the outside of the retort and the inside of the walls of the outer
vertical chamber forms the flues in connection with the furnace or furnaces which
are the means of heating the retort to the required temperature.
The flues have no connection with the interior of the retort and therefore the
products of combustion do not mingle with the ore or material being treated.
At the top or in any suitable position of the retort I arrange a suitable hopper
through which the material to be calcined or oxidized in a finely powdered state
is continuously fed into the retort.
In the retort may be arranged inclined shelves on which the ore or other
material falls on its way and is retarded in its descent to the bottom, thus giving
longer time to complete the calcination and oxidation desired.
I also provide special flues or passages for the admission of atmospheric air
needed for the oxidation of the ore or other material operated upon and pre-
ferentially these air flues or passages are constructed in the walls of the furnaces
and in the annular space between the outer casing of the vertical tower and the
retort, these flues being surrounded by the flames and heated gases, the products
of combustion, the air is brought to a high temperature in which condition it is
admitted by suitable openings and at suitable positions and in suitable quantities
into the interior of the retort and meeting the heated ore or other material in its
descent thereby accomplishes the oxidization the sulphur, arsenic, antimony and
other rebellious or deleterious elements being expelled or volatilized by the heat
supplied as previously stated.
Tarrange a suitable chamber with hopper at the bottom of the retort with door
through which the ore or material that has been treated is withdrawn.
I also arrange one or more settling chambers connected by an opening with the
lower portion of the retort for collecting the finer dust.
The settling chamber being also connected with a chimney of suitable height and
dimensions to furnish the necessary draught.
The entire structure is built so far as necessary of firebricks or other suitable
material and where not so required of ordinary brick or stone as may be most-
convenient properly braced with necessary iron bracing with suitable doors for
inspection cleansing &c.
Dated this 3rd day of July 1891.

page_text: COMPLETE SPECIFICATION.
Improvements in Oxidizing and Calcining Retort Furnaces.
I, WILLIAM OSWALD TAYLOR, of Elm Lodge, Riverside, Mortlake, in the
County of Surrey, Civil Engineer, do hereby declare the nature of my said
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
The object of my invention is to provide a new and improved retort furnace for
calcining and oxidizing metalliferous ores, particularly what are known as refractory
gold and silver bearing ores, and other materials.
The invention consists of an outer vertical chamber, built of ordinary bricks or
other suitable material, and lined, where necessary, with fire brick and one or
more heating furnace or furnaces adapted for consuming or using coal, wood, oil,
gas, or other fuel. Also an internal vertical retort chamber, constructed of fire
brick, or other refractory and fire resisting material. An annular or equivalent
surrounding space, approximating to the sectional form of the retort, is provided
between the outer chamber and the retort; such surrounding space acting as a
fluo or flues, by means of which the retort is heated, and raised to the requisite
temperature.
The flue or flues, communicating with the furnace or furnaces, have no con-
nection with the interior of the retort, and therefore the products of combustion of
the fuel are entirely separated, and prevented from mingling with the ore or other
material under treatment.
Separate passages or flues are provided for heating and admission of atmospheric
air into the retort, for the special purpose of oxidizing the materials under treat-
ment; suitable doors being fitted for regulating the supply of air. Air for the
purpose of combustion of the heating fuel being supplied through separate and
special openings.
The materials to be operated upon are continuously and automatically fed into
the retort, in a dry and finely pulverized condition, through a hopper fitted at the
top of the retort.
Inclined shelves may be fitted inside the retort, upon which the ore or other
material falls, on its way to the bottom of the retort, and is thereby retarded in
its descent; thus affording additional time for the operations of calcination and
oxidation, as required; the calcined ore or material being continuously discharged
from the hoppers at the bottom, without any cessation of operations.
And in order that my said invention may be particularly described and ascertained,
reference is hereby made to the accompanying drawings, in which similar letters of
reference indicate corresponding parts.
Fig. 1 is a longitudinal vertical section, on the line A, B, of Fig. 3.
Fig. 2 is a transverse vertical section, on the line C, D, of Fig. 3.
Fig. 3 is a sectional plan through the furnaces, flues, retort and settling
chambers.
Fig. 4 is a section on the line E, F, of Fig. 3.
Fig. 5 is a section on the line G, H, of Fig. 3.
Fig. 6 is a section on the line J, K, of Fig. 3.
Fig. 7 is a vertical section, showing a modification of Fig. 1, arranged for a
downcast flue.
Fig. 8 is a vertical section, showing another modification, also arranged for a
downcast flue.
L, L, are the walls of the outer vertical chamber, constructed preferably of
common brick work, lined internally with fire brick. M, M, is the internal
vertical retort, constructed of fire brick, or other suitable fire resisting material.
N, N, are the upcast and heating flues from the furnaces O, O. P, P, is the
chimney to which all the flues of the furnace are connected. Q, Q, are the settling

page_text: chambers. R, R, are the air heating chambers and passages, receiving heat by
conduction, through the walls, from the furnaces O, O, and Hues N, N. "S, S, are
inlets for admitting heated air into the interior of the retort for oxidizing the ore
or material being treated. T, is the hopper for admitting a continuous supply of
dry ore, or other material, in a finely powdered state. U, U, are inclined shelves,
which may be fitted in the retort for the purpose of retarding the descent of the
ore or other material to be operated upon. V, V, are openings fitted with doors
for the purpose of inspection of the interior of the retort, and for cleansing the
shelves. W, W, are hoppers with suitable doors for the purpose of withdrawing
the calcined and oxidized material. X, X, is a furnace and X, X', is a flue for
further heating the bottom of the retort M, and the settling chambers Q, Q.
Y, Y, are flues connecting the settling chambers Q, Q, and the furnace X, X,
with the chimney P, P. Z, Z, are manhole doors and openings into various parts
of the furnace and flues, for convenience in cleansing the same. Dampers are
fixed in suitable positions to control the draught of the heating furnaces; also for
the hot air supply, and the outlet for the fumes from the retort and settling
chambers.
The arrangement illustrated in Fig. 7, shows the retort chamber M surrounded
on all sides by the heating flues N, N, from which the products of combustion are
led to the downcast flue P¹. From this flue the products of combustion are carried
to the horizontal flue P, from whence they may be carried.to a chimney.
The arrangement illustrated in Fig. 8 shows another construction, in which the
heating flues N, N, are connected by a downcast shaft P³, with the horizontal
flue P; from which the products of combustion may be carried away, as last above
described.
The operation is as follows:-The retort chamber is first raised to the required
temperature by means of the furnaces and heating flues shown on the drawings.
The ore or other material to be operated upon (after being reduced by suitable
machinery to a finely powdered and dry condition) is fed automatically and con-
tinuously through the hopper T into the interior of the retort M. It then falls
upon the inclined shelves in succession, whereby its descent is retarded, such
retardation affording more time for the material to become heated by the heat
passing through the walls of the retort. The ore or material being treated, is met
at intervals in falling through the retort by currents of heated air, admitted to the
interior of the retort by the passages S, S. The material thus becomes thoroughly
calcined and oxidized; the sulphur, arsenic, antimony, and other deleterious
elements contained in the ore being expelled or volatilized by the action of the
heat. The base metals contained in the ore are, at the same time, oxidized,
leaving the gold and silver contained in the ore in a free and metallic state, or in
a state suitable for easy recovery by amalgamation with mercury, or by other
well known methods.
The products of combustion from the heating furnaces do not come into contact
with the ore or material under treatment, or enter into the interior of the retort,
and therefore the oxygen of the heated air, carried inwards by the special air
passages, is all available to be utilised in the oxidation of the ore or material being
treated.
The operation is continuous. The calcined and oxidized ore falls into the
hoppers W, W, from which it is withdrawn for further treatment (preferably by
amalgamation with mercury) for the recovery of the gold and silver; of which, by
this process, fully 95 per cent. of what is contained in the ore can be economically
recovered.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a retort furnace for calcining and oxidizing metalliferous ores, particularly
what are known as refractory or rehellious cold and silvar beeving ave and other

page_text: minerals and materials: the combination of a heating furnace or furnaces with a
vertical chamber enclosing a vertical retort; also with a continuous and automatic
feed into the retort, of the material to be treated; also with a continuous and
automatic discharge at the bottom of the retort for withdrawing the material
after treatment; the retort being so constructed that the products of fuel com-
bustion arising from the heating furnaces are prevented from mingling with the
ore or other material being treated, while passing through the retort; and whereby
the atmospheric air (specially heated in the chambers and passages R, R,) admitted
into the interior of the retort, for the purpose of oxidizing the ore or material
being treated is kept separate from the heating furnaces and flues to prevent its
oxygen being consumed therein, and to render it available in the oxidation of the
ore or other material, substantially as herein before described and illustrated by
the drawings.
:
2. The improvements in oxidizing and calcining retort furnaces, substantially as
herein before described and illustrated by the drawings.
Dated 21st March 1900
GEO.
DOWNING,
8, Quality Court, London, W.C., Agent.