GB1107836A - Graphite body - Google Patents

Abstract

A graphite body having a relatively high and substantially isotropic coefficient of thermal expansion is produced from a coking charge by maintaining it above its melting point, mixing the molten charge with from 2 to 20% by weight of the charge of a carbon black having a particle size not exceeding 350 millimicrons and a surface area of 8 to 850 square meters per gram, coking the resulting mixture at 450 DEG to 650 DEG C. calcining the coke at 900 DEG to 1500 DEG C., comminuting the calcined coke, mixing the comminuted coke with a carbonizable aromatic binder, forming the mixture in a desired shape, carbonizing the resulting bond in an inert atmosphere and graphitizing the body at 2600 DEG to 3000 DEG C. The coking charge is preferably admixed with 2 to 10% of the carbon black. The coking may be carried out at 450 DEG to 525 DEG C. and the carbonization at 750 DEG to 1000 DEG C. The "coking charge" consists of (1) petroleum residues obtained from the atmospheric or vacuum distillation of crude oils; or (2) heavy catalytic cycle oils; or (3) catalytically or thermally cracked distillate stock residues. Suitable carbon blacks are thermal black, acetylene black, gas furnace black, channel black and oil furnace black. Coal tar, petroleum and wood pitches are suitable binders.ALSO:A graphite body having a relatively high and substantially isotropic coefficient of thermal expansion is produced from a coking charge by maintaining it above its melting point, mixing the molten charge with from 2 to 20% by weight of the charge of a carbon black having a particle size not exceeding 350 milli-microns and a surface area of 8 to 850 square meters per gram, coking the resulting mixture at 450 to 650 DEG C., calcining the coke at 900 DEG to 1500 DEG C., comminuting the calcined coke, mixing the comminuted coke with a carbonizable aromatic binder, forming the mixture in a desired shape, carbonizing the resulting bond in the shaped body in an inert atmosphere and graphitizing the body at 2600 DEG to 3000 DEG C. in an inert atmosphere. The coking charge is preferably admixed with 2% to 10% by wt. of the carbon black. The coking is preferably carried out at 450 DEG to 525 DEG C. and the binder carbonized at 750 DEG to 1000 DEG C. The "coking charge" consists of (1) petroleum residues obtained from the atmospheric or vacuum distillation of crude oils; or (2) heavy catalytic cycle oils or (3) catalytically or thermally cracked distillate stock residues. Suitable carbon blacks are thermal black, acetylene black, gas furnace black, channel black and oil furnace black. Coal tar, petroleum and wood pitches are suitable binders.