US943290A - Electric furnace. - Google Patents

Description

G. E. WILSON.

ELECTRIC FURNACE.

Arrmoumx rum) rm. 1, 1909.

Patented 14 1909.

i a large amount of high-grade ferro-tungsten CHARLES E. WILSON, or HOOD RIVER, oimeoxt.

ELECTRIC FURNACE.

Specification of Letters Patent.

Patented Dec. .14, 1909.

Application filed February 1, 1909. Serial No. 475,493.

To all'whom it may concern:

Be it known that I, CHARLES E. VILSON,

a citizen of the United States, residing at- Hood River, in the county of Hood River and State of Oregon, have mvented a new and useful Improvement in Electric Furnaces, of which the following is a, specification.

My invention relates to improvement in the construction of electric smelters for use in reducing ores carrying certain highly refractory metals, or metal alloys. and more especially for reducing wolframite to obtain What is known as high-grade ferrotungsten. By high-grade ferro-tungsten is meant a productover seventy per cent. pure. a

The higher the grade of ferro-tungsten the'more refractory it becomes, and while ferro tungsten .of a comparatively low grade, say, for example, only fifty per cent. pure, may be melted in an electric furnace and tapped therefrom, this metal-alloy when ever, say, seventy per cent. pure is so refractjory and chills so quickly, that unless the temperature to which it is subjected is high enough to volatilize a large proportion of the metal, it cannot be run out successfully. It is necessary, therefore, in the production of ferro-tungsten above, say, seventy per cent. pure that the ore be subjected to a temperature capable of driving off the oxygen constituents and of fusing, to the fluid state, any slag-makingconstituents. The temperature should at the same time be high enough to render the ferro-tungsten constituent sufficiently plastic to agglomerate in a distinct mass.

In furnaces hitherto provided for the production of a high-grade ferro-tungsten it has been usual to treat but a limited quantity of ore in a single furnace-run and permit it after reduction to cool in the furnace. As -the high-grade ferro-tungsten would tend to adhere tenaciously to the furnacelining it had to be chiseled out by slow, la-

borious means.

My ob ect is toprovide an electr c furnace of novel and lmproved construction in which may be ,pr aged in a single run or operation and pe 't the removal of the reduced mass with facility and with comparatively little, if any, injury to thefu'rn'ace.

In carrying out my invention I provide a urnace chamber, in the form of a crucible,

with removable and replaceable s'ides,;lined' with refractory material, and with a bottom of graphite, or other suitable carbonaceous material, forming one of the electrodes; Extending dow nward through the open top of the furnace 1s an electrode in the form of a pencil of graphite, or -other suitable carbonaceousmaterial, means being provided for raising and lowering the furnace with reference to the carbon pencil. In practice the ore to be treatedis fed into the furnace around the pencil and the slag-making constituents of the ore form the heat-generating material. Sufiicient heatis generated by the passage of the electric current from one electrode to the other through theresistance material, to reduce to a plastic state the ferro-tungsten, drive off the oxygen, and melt, to a fluid state, the less refractory gangue which forms the slag-making constituent of the ore. As the ferro-tungsten is reduced it agglomerates between the electrodes and settles upon the carbon base. A

core of ferro-tungsten is thus gradually built up enveloped in slag, and as it increases in height the carbon electrodes are separated. as required, to maintain the heat-generating arc. The operation is continued until a core of the ferro-tungsten of the desired height,

whichmay approximate the depth of the furnace, is formed, when the electric current is shut off and the contents of the furnace allowed to solidify, after which the walls of the furnace are removed from thecontained mass. 'Thereafter the slag enveloping and .adhering to the ferro-tungsten may be readily broken away, leaving a column of finished high-grade ferro-tungsten.

In the accompanying drawing, I show the furnace structure I prefer to employ for the production of ferro-tungsten from Wolframite, and, wherein the furnace carrying the lower electrode is vertically adjustable with reference to the upper elect-rode. v

Figure I is a broken, sectional elevationshowing in full lines the furnace raised to initial position, and in dotted lines the position of the furnace at the end 01 a run; and

Fig. 2, a broken, fragmentary plan view of a corner portion of the furnace, illustrating the means for holding'the sides removably in place.

The, furnace-shown is rectangular in crosssection and formed of four sides, co sisting eaclrof an outer plate 3 and an inner refractory lining 4. The. plates have percarrying counter-weights 16.

' proper the lower electrode.

suitable electric current leads. The baseplate 7 carrying the furnace is suspended upon cables 10, runnin over pulleys 11 and carrying counter-weig ts 12. Fitting into the top of the furnace is a suitable raising and lowering heat-confining cover 13, of highly refractory material, or of waterjacketed construction, suspended upon cables 14, running over pulleys-I15, and frallixtending downward from a support 17 ari brackets 18 forming retaining guides for an electrodeholder 19, which is connected by a lead 20 with the electric-current supply. The holder -is formed with a dove-tail socket to fit over and receive the upper dove-tail end of a carbon pencil or electrode 21. the pencil is formed in sections, each of comparatively short length, the sections being dove-tailed together and fastened, as indu cated, by means of gra hite bolts 22.

The ore to be treats may be fed through openings 23 in the cover. Initially the fur-. nace would be raised to bring the electrode 8 close to the lower end of the electrode 21, and a layer of ore and coke, in proper proortions, would be placed between them to orm the heat-generating resistance material. The palssageof the current from one electrode to theother soon raises the temperature in the furnace to the melting point of the ore, thus generating the heat necessary for the reductlon of the ore. The core or colunin 24 indicates the zone of highest temperature in .which the form-tungsten constituent of the ore will be reduced to a state sufficiently soft and plastic to separate from the slag and a 'glomerate into a mass or core which settles y gravity initially upon the surface of the electrode 8, becoming an extension thereof. As the column or core 2& of i form-tungsten forms, the molten slag will surround and overlie the same, tap-holes d counter-weighted suspending means for the E furnace, an'upper stationary electrode ex- 25, with removable. plugs, being provide through which the slag is drawn off from time to time.

as the column 24 electrode.

furnace is shown in its extreme lowered po- The base-plate 7 has means, as shown at 9, for its connection with As indicated,

Care should be employed during the operation to lower the furnace as fast E grows, to maintain the distance between it and; the upper.

The operation may be continued until the core rows to the proportions indicated by the dotted lines 26, wherein the sition. At the end of the run described, the 65 connected with tie current-supply by means of a flexible insulated cable, The cable,

being above the furnace, its insulation is very apt to become charred and to break ofi, leaving the wires exposed so that, in the event they contact with the top of the furnace, a short circuiting results. In mypresent construction heavy stationary lead may be employed without insulation to hold the electrode with great steadiness while the furnace is being raised and lowered. This construction renders it necessary to connect "the base-plate at 9 to flexible conductors, in

the form of cables, but these are not in positlon-to be injured by the furnace-heat.

' W'hatyI claim as new and desire to secure by Letters Patent islfylil'an electric smelter for reducing ore containing ferro-tungsten, or a like refractoi y: metal, the combination of a furnace formed with'an electrode-carrying base and removable and replaceable sides, means for raising and lowering the furnace, and a stationary electrode extending downward into the furnace.

.2. In an electric smelter for reducing ore containing ferro-tungsten, or a like refractory metal, the combination of a furnace formed with an electrode-carr ing base and removable and replaceable si es, means for raising and lowerin the furnace, a stationary electrode extending downward into the furnace, and a heat-resistingl cover surround-- ing the upper electrode wit means for raising and lowering the cover.

3. In an electric smelter for reducing ore containing ferro-tun sten, or a like refractory metal, the com ination of a furnace Y formed with a base-plate, removable and replaceable sides with means for securing them together and an electrode on the base-plate,

tending downward into the furnace, a heatresisting cover surrounding the upper electrode in the Iurnace, and counter-weighted suspending means for the cover.

CHARLES E. WILSON. in the presence 0ii- H. F. DAVIDSON, F. H. Burrow.

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