US1044295A - Process of producing silicon carbid. - Google Patents

Description

F. J. TONE. PROCESS OF PRODUCING SILICON CARBID.

-APPLICATION FILED JUNE14, 1907.

1,044,295, Patented Nov. 12, 1912.

FRANK J. TONE, OF NIAGARA FALL-S, NEW YORK.

PROCESS OF PRODIICING SILICON CABBID..

Specification of` Letters Patent.

Patented Nov. 1 2, 1912.

Application filed June 14, 1907. Serial No. 379,035.

T o all whom, it mayfconrn: i a

Be it known that I, FRANK J. TONE, al citizen of the United States, residing at-l Niagara Falls, in the county of Niagara and State of New York, have invented certain new and useful vImprovements in Processes of Producing Silicon Carbid, of which the following is a specification. v This invention relates to the manufacture of silicon carbid and has for its object the increasing of the efficiency of the process and the output of the furnace.

In the commercial manufacture of silicon, carbid almixture of silica and carbon is subjected to heat in an electric furnace, the heating means being a resistance-core ofgranular or pulverized carbon. This core offers resistance not only by reason of the specific resistance of the carbon but also on account of the numerous points of poor contact between the discrete particles of carbon.

I have discovered that the efliciency of. the process may be considerably increased by employing in place of the core of pulverized or granular carbon a continuous solid carbon corel consisting either of a .single shapedpiece Y"or a series ofl pieces joined together in a manner to form the equivalentof a single piece. l

Referring to the accompanying drawing, in which each of the figures is a horizontalv section of a charged furnacez-Figure l shows a straight core consisting of a single. long carbon rod; Fig. 2 shows a straight i' core built up of a series of joined pieces; and,

Fig. 3b shows azigzag core built up of a series of joined pieces.

The furnaces illustrated have end walls l and side walls 2, of fire brick. Carbon terminals 3 extend through the end walls.

The resistance core 4 shown in 'Fig'. l consists of a single long carbon rod, the section and length of the rod being proportioned to give the proper resistance for the voltage and current at which the furnace is to be operated. The ends of the core are connect cd to the inner ends of the carbon terminals by layers of pulver-ized carbon 5. The charge 6 completely fills the receptacle and surrounds the core.

It is difiicult to obtain carbon rods long. enough so thatthe proper resistance can be conveniently obtained without increasing the length of the furnace beyond practical limits. "I therefore show in Fig; 2 a modified core, which consists of a series of two ,in ahorizontal position and supported or more rods or pieoesfl joined end to end by means ofv closel -fitting carbon collars 7.. The resistances o the contacts are thus practically eliminated and the series of rods becomes the ractical equivalent of a single rod without joints.

The core shown in Flg. 3 consists of a series ofl pieces 4 disposed in a zigzag path from one termlnal to theother and joined end .to end'by'carbon blocks 8 into which the yends of the pieces are screwed. By this arrangement the length of the core is increased. without increasing the length of the furnace,- ythus making it possible to expend a. greateramount of energy in the saine space and obtain a corresponding increase in efiiciency.

The several cores are preferably arranged b r the charge,'as separate core-supports restinig lon the base of the furnaces afford direct jjpaths for the escape of heat and decrease f ythe current-eiliciency.

This process offers important advantages over that usin `the pulverized or granular core. These a vantages are due principally to the changed thermal conditions and will be apparent upon consideration of the fur! nace at the end of the run. cupyingthe central zone of the furnace, is

The core, oc-

then surrounded by a zone of silicon carbid whlch 1n turn 1s surrounded by a zone of partially reduced or unreduced charge-ma- --ter1als. The specific reslstance of granular or pulverized carbon is approXimatcly'fifty times that of solid carbon. The solid core therefore will occupy-much less space in the furnace and the same -volume of silicon carbid will hecomprised in a much smaller lzone in the case of the solid core than in Vthe case of the granular core, and the outer surface-in this zone, which is the surface of the non-productive heat diffusion, will be less.A In other words the losses by radiation will be reduced and the output will he correspondingly increased.v Another thermal radvantage is that the mass ofr core-material to he heated to the high temperature of reaction is much less in the case of the solid core than the granular core. Heat thus expend ed is non-productive'or lost heat, only the heat conducted from the core to the charge being` productive. Still another gain in thermal efficiency is that the heat expended in the mass of unrcduced charge surround` ingr the smaller silicon carbid zone of the solidcore furnace is less than that expended i inthe granular core furnace.

Thesolibd core is convenient to place in the furnace and does not Vcontaminatev the nished product as does pulverized o`r granular carbon. The product is better.-and more abundantly produced than with a granular core.

I claim: l

l. The process ofproduc'ing silicon carbid,'fWhich consists, in embedding in a charge 1 of silicious and carbonaceous materials a continuous solid resistance-core consisting of a] series o Jiolned shaped reslstanceieces and assin an electric current through said core.

2. The process of producingv silicon carbid, which consists inV embedding iny a charge of slliclous and. carbonaceous mate' rials a continuous solid resistance-core consisting off a series of joined shaped resistance-pieces` supported by the chargeL'and passing an electric current through said core.

43.The process'of producing silicon carbid, which consists in embedding ina charge of silicious and carbonaceous materials a continuous solid resistance-core consisting of a series of joined shaped resistance-pieces arranged in a circuitous path between the terminals, and passing an electric currentl through said conductor.

In testimony WhereofV/I aiix my signature in presence of two Witnesses.

FRANK J. TONE.

i Witnesses:

1 FRED I. Pinnen,

CHARLES CHORMANN.

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