Improvements in the Extraction of Lead with Silver, Gold, or other Metals from Ores Blended with Sulphide of Zinc or otherwise.
Year: 1895

page_text: Date of Application, 12th Jan., 1895
Complete Specification Left, 12th Oct., 1895-Accepted, 4th Jan., 1896
PROVISIONAL SPECIFICATION.
Improvements in the Extraction of Lead with Silver, Gold, or other
Metals from Ores Blended with Sulphide of Zinc or otherwise.
HENRY ROBERT ANGEL 7. St. Helen's Place London E.C. Ship Owner do
hereby declare the nature of this invention to be as follows:-
Into a revolving furnace oval shaped (or a V shaped one with a bearing in
the centre and a screw at each end for tilting) and lined with fire bricks
secured by a cement composed of volcanic dust and iron oxide, which renders
it impervious to both heat and alkali, I force an ignited mixture of air & gas,
or an ignited mixture of oil or tar with steam, which can be so regulated that
it causes no damage to the iron shell or lining of the furnace and at the same
time it produces a uniform heat throughout.
When the furnace is brought up to a red heat caustic alkali with coarsely.
ground ore is placed in the furnace and well mixed together by the action of
revolving, or with scrapers if the V shaped furnace is used. In a few minutes
after the charge is introduced the ore is reduced and the bullion is first drawn:
off into moulds, followed by the zinc slag into water which dissolves it into fine
powder and produces a solution of sodium sulphide, which is converted back into
caustic alkali by leaching through ferrite of soda, and is used over and over
again, or the solution of sulphide can be used to separate the metals from the
raw ore by being mixed with it, placed in a furnace, brought up to a red heat,
and then concentrated.
The slag from the first operation, after being drawn from the furnace, is
passed through a mill, ground very fine, and then concentrated over vanners -
which brings the zinc up to a high grade and recovers any lead or bullion
left in it.
The action of tilting the V shaped furnace is for the purpose of bringing the
molten bullion down to one end for tapping, and then to the other end for
drawing off the slag.
COMPLETE SPECIFICATION.
Improvements in the Extraction of Lead with Silver, Gold, or other
Metals from Ores Blended with Sulphide of Zinc or otherwise.
HENRY ROBERT ANGEL 7 St. Helen's Place London E.C. Ship Owner 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:-
I construct a furnace ✓ shaped with a screw at-each end for tilting and lined
with fire-bricks secured by a cement composed of volcanic dust, or fire clay, with
iron oxide, mixed with silicate of soda, which renders it impervious to the action of
caustic alkali.
The ore to be treated is coarsely ground and roasted, or it can be treated without
roasting.

page_text: Into the furnace described as above I force an ignited mixture of steam with
petroleum tar or other combustible matter, or an ignited mixture of gas with air
under pressure which can be easily regulated and at the same time produces a much
stronger flame than coal, therefore the smelting can be done in much less time,
which prevents the caustic alkali from turning into carbonate, or sulphide, so that
it can be used over again without regenerating.
In order that my invention may be more fully understood, I have annexed
drawings herewith, similar parts are correspondingly lettered. Fig. is a
longitudinal section, and. Fig. 2 is a transverse section of the furnace, which is
formed of firebricks C C, enclosed within an iron casing. D. D, and supported upon
the rocking bearing J, which allows the furnace to be tilted upon the foundation h,
by means of the screws F. and G, for the purpose of drawing off the molten lead
and bullion by means of the aperture N, and the molten slag by means of the
aperture P. The furnace is charged by the door in the roof T, and the charge is
reduced by means of the flame from the jet L Fig. 2. passing over the coke fire M
through the apertures k. k, in the brick lining. The openings C. C in the chamber a. a,
are for the purpose of inserting instruments for rabbling the ore during the process
of reduction.
When the furnace is brought up to a good heat of a ton of caustic alkali of
70% strength is poured hot into the furnace, or when a weaker strength of caustic
is used, a larger quantity is poured in, in the same proportion, followed by one ton
of ore, and in a few minutes the charge is reduced, and the furnace. tilted to bring
the bullion down to one end N, to be tapped off. The furnace is then tilted back
again and the zinc slag tapped from the aperture P in the other end into cold
water which disintegrates the molten slag into fine particles.
The receiving tank is provided with a wooden platform to prevent the concussion
from throwing the solution over the top..
The powdered slag is then passed through a fiue mesh seive which separates the
finer grained zinc from the coarser grained silicate, and leaves the former at a high
grade.
Sulphide of sodium may also be placed in the furnace in lieu of the caustic
alkali and the process conducted in the same manner as.described above..
The cement used in constructing my furnace is composed of 90% volcanic dust
or fire clay and 10% of iron oxide brought to the consistency of cream by means
of silicate of soda in a liquid form..
Having now fully described and ascertained the nature of the said invention and
the manner in which the same is to be performed what I claim is
1st. The reduction of sulphide ores by means of a tilting furnace as herein shown
or described.
2nd. The cement used in the construction of the furnace as herein described.
3rd. An ignited mixture of steam & petroleum, tar or other combustible matter,
or gas with air under pressure for the reduction of sulphide ores.
4th. Recovery of the zinc by passing it through a fine sieve after coming from
the furnace all as herein described.
5th. Reducing the metals contained in sulphide ores by placing sulphide of
sodium in the furnace along with the ore herein described.
6th. The wooden platform for saving the solution as herein described.
H. R. ANGEL.