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191

In order that my improved system and apparatus and the manner, or substantially so, in which I purpose constructing the latter may be fully understood, reference is hereinafter made to the accompanying drawings, in which the furnace and certain of its conduits are shown in section. In carrying my invention into effect I prefer to construct the furnace proper A of circular formation in plan, and slightly coned or tapered from the bottom to the top, and I may provide the said furnace wholly of firebricks or other suitable material, or with an outer casing of iron lined with firebricks or other material, but preferably the former; and in any convenient part of the said furnace I may provide an opening and door, or openings and cloors (not shown), through which the fuel may be fed, when solid fuel is used, but when petroleum or other liquid fuel is employed this may be fed into the furnace by other means hereinafter explained. By preference the said furnace would rest upon any number of suitable blocks B, and between and within these the bottom of A would be provided with a central aperture C, surrounded by a conical or tapered chamber D, standing up within the furnace, and provided with any number of perforations or holes E, inclined in an upward direction from the outer to the inner surface. The said chamber may conveniently be of the same material as A, when the latter is constructed without a metallic casing, and may be either fixed in position by any suitable means or formed integrally with A, preferably the latter, as shown. The upper end of a furnace is closed by a fireclay or other diaphragm F, having a central opening G, and upon the said diaphragm rests the funnel-shaped mouth of a fume and dust conduit or exhaust 11, which may bend and extend in any direction, its final end H 1 leading to a suitable condenser (not shown), and in a direct line above the opening G in F the said conduit H is provided with a branch H 2 ,leading to the atmosphere, in which a suitable damper J is provided, by means of which the said branch may be opened or closed a4will. In any suitable position adjacent to the furnace and convenient for operation by any available power I provide a suitable blower X, the air-current from which is conveyed by a pipe L to surround or partly surround the furnace A, and at suitable intervals in this I provide any number of depending branches M, each connected to a suitable fireclay or other nozzle or tuyere N leading through apertures in the wall of A into the fire-space 0, and, by means of the said conduit and nozzles, the whole or part of the said blast may be employed, when needed, for imparting extra draught to the furnace, suitable throttle or other valves being provided in any part of the conduit L, when necessary, for opening and closing this at will. The conduit Lis provided with a branchpipe P, which terminates in a nozzle E within the chamber D, and at any convenient part of the said branch-pipe P a suitable adjustable hopper T is provided, which receives the finely pulverised ore to be treated, and anywhere between the said hopper and the conduit L the said pipe P is provided with a screw-down or other suitable valve, such as S, by means of which the passage through P may be wholly or partly closed or opened at will, to regulate the force of the blast. The manner of operation is as follows : Given that the, fire in the furnace has been lighted and in a condition for work, the air-blast through L may be wholly or partly closed, when the ore, in a finely pulverised condition, would be fed into the hopper T, and the valve S be opened, when the current of air passing through P would convey with it the pulverised ore, which would be thereby forced up through the nozzle E and out at the top of the chamber D, and this forced draught through D would create an up-draught of superheated air through the perforations E in D, thus superheating the powdered ore, which would be caused to impinge upon the point a of the undersurface of a coned plate or diaphragm V, suspended beneath the diaphragm F, and now white hot or incandescent from the heat of the furnace; and this being now the hottest part of the furnace, such impact with V would vapourise or atomize the pulverised ore, and deflect this in all directions from the centre of the furnace, when the metallic portions would be melted and fall into the fire at 0, and pass out through suitable outlets b, while the fumes, dust, and more volatile portions would, by the aid of convection (and, maybe, by assisted draught through the nozzles N), pass upwardly through apertures c in V, and through the opening G in F, into the conduit H, and, by opening the damper J, be allowed to pass out through H 2 into the atmosphere, or, by closing the said damper, to pass along the conduit H and H 1 into a suitable condenser, according to the constituents of the fumes; or, as the ore under treatment is known to contain metal of greater or lesser density, and for the purpose of recovering from the said fumes such metallic portions as may be valuable, I may, in lieu of or in addition to the use of a condenser in the usual way, provide a water-curtain at the end of the conduit H (shown by dotted lines at c), by the means of a water-conduit d, having suitable perforations through which the water may fall. 1 may find it convenient to employ petroleum or other liquid fuel in lieu of ordinary fuel, in which case I may employ means by which such liquid fuel may be conveyed into the furnace 0 by the use of certain of the nozzles or tuyeres N, which, for this purpose, may be perforated at their final ends, so as to emit the said liquid fuel in the form of a spray, suitable valves or taps being provided where necessary to regulate the flow of the said liquid fuel. Having now particularly described and ascertained the nature of my said invention, and iii what manner the same is to be performed, I declare that what I claim is,— 1. The improved method of and apparatus for treating refractory ores, substantially as herein described and shown. 2. In the treatment of refractory ores the combination of a reducing-furnace, and means for conveying the said ores in a finely powdered condition thereinto by the use of a powerful air-blast, substantially as herein described and shown. .3. In the treatment of refractory ores the combination of a furnace A, having diaphragms F and V, and chamber D, with perforations E, with means for conveying a blast of air to the said furnace from a suitable blower, and by means of a conduit such as P, and nozzle E, for utilising the said blast for conveying finely pulverised ore from a hopper such as T to the said furnace, and means such as a conduit H, H l , and H 2 , and water-curtain c, for exhausting the fumes from the furnace and recovering volatile metallic particles therefrom, substantially as herein set forth and shown. Dated this 4th day of February, 1898. J. E. Preston,