US861224A - Process of producing ferrosilicon. - Google Patents

Description

No. 861,224. I PATENTED JULY 23, 1907. 1-1. F. PRICE.

PROCESS OF PRODUCING FERROSILIGON. APPLICATION FILED NOV. 14, 1905.

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UNITED STATES PATENT OFFICE.

. EDGAR F. PRICE, OFNIAGARA FALLS, NEW YORK.

PROCESS OF PRODUCING FEBROSILICO'N.

Specification of Letters Patent.

Patented Jul 23, 1907.

Original application filed August 31, 1904, Serial No. 222,891. Divided and this application filed November 14, 190 5.

' Serial No. 287,346.

To all whom it may concern:

Be it known that I, EDGAR F. PRICE, a-citizen of the United States, residing at Niagara Falls, in the county of Niagara and State of New York, have invented certain new and useful Improvements in Processes of Producing Ferrosilicon, of which the following is a specification.

In my application 222,891, filed August 31, 1904,

which matured into-Patent 790,391 of May 23, 1905, I

described and claimed a process of smelting an electrically-conductive charge, specifically one containing chromite for the production of ferrochromium. The present application is a division of said earlier one and the claims are specifically directed to the productionof ferrosilicon.

A suitable. electric furnace-is shown in the accompanyingdrawing, in which the figure is a vertical axial section through the tap-holes, with the electrodes in elevation.

The furnace comprises a body 1 of firebrick or masonry, with a refractory lining 2 of magnesite, 'siloxicon or carbon. Lateral tap- holes 3, 4 for slag. and metal, respectively, extend from the lower part: of the fur- The electrodes 5,6 of opposite polarity, shown as carbon rods, depend into the furnace. In employing this furnace to carry out the process, an arc is established between the electrodes or each electrode and the carbon-lining 2, if used, and a small amount of the charge is fed into the bottom of the furnace. The charge may consist of a mixture of silica, iron or iron ore and coke, in which the ingredients are in such proportion as to make it a partial conductor plied to the electrodes, to largely prevent the electric current from shunting through the charge.' As the iron andsilicon are reduced, a layer 8 of the molten alloy collects in the bottom of the furnace and may be removed from time to time through the tap-hole 4. If the charge contains impurities, a layer of'slag may accumulate upon the metal, and is removed through the tap-hole 3.

It will be seen that the deep body of the charge 7 surrounding'the electrodes effectively retains the heat within the furnace, both increasing the production of metal and maintaining the contents in a moltencondition wlth out'especial attention. The use of this deep body is made possible by and necessitates the employment of a minimum electromotive force, since the voltage usually employed in furnaces of this character would cause excessive waste of current by shunting or short circuitingthrough the charge, if no current-regulator were employed, a commercially-impracticable mode of procedurey or would lift the'electrodes partially out of the charge if controlled by-a constant-cup.

rent regulator, thus raising the zone of'maximum temperature to the upper part of the furnace and causing excessive heatlosses by radiation from the charge, excessive oxidation of the hot exposed surfaces of the electrodes, and lossof a portion of the finely-divided chargeby the gases blowing violently out from the zone ,of reduction. The furnace is operated continuously, the metal and any slag beingdrawn off and fresh materials added as required. Thehot surfaces of the electrodes and furnace lining are therefore'never exposed to the oxidizing and cooling action of the atmosphere.

While-the furnace shown employs two..depending electrodes of opposite polarity, it' is obvious that the process may be ca'rriedout bythe use of a furnace inwhich the hearth surface is one electrode, the are being sprung between the hearth and a single depending electrode.

1. The process of producing ferrosilicon by smelting an electriwilly-conductive charge of'a silicon compound',.car'

bon-and a source of iron, which consists in establishing-an electric arc within the charge, surrounding the zone of reduction and protecting the electrodes from the oxidizing; and cooling effect of the atmosphere by a considerable body of the charge, and maintaining between the electrodes the minimum potential difierence requisite to effect reduc tion, thereby substantially preventing loss of electric cur-' rent by leakage through the churgeand heat radiation, as set forth.

2. The process of producing ferrosilicon by smelting an electrically-conductive charge of a silicon compound, carbon and a source of iron, which consists in establishing an electric arcwithin the charge, surrounding the zone of reduction and protecting the electrodes .from the oxidizing

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