GB860342A - Improvements in or relating to processes for the production of graphite - Google Patents

Abstract

Substantially impermeable graphite used particularly for the manufacture of fuel support sleeves for nuclear reactors is produced by joining a dispersion of cellulose in which the fibrous structure of the cellulose is broken down in an aqueous medium, regenerating the cellulose from the dispersion, carbonizing the regenerated cellulose and graphitizing the carbon at 2500-3000 DEG C. Cellulose, e.g. blotting paper or cotton wool, may be beaten or milled until substantially non-fibrous to the naked eye and dispersed in water, preferably being beaten or milled during dispersion formation, or be dispersed without such treatment in water containing a chemical dispersing-agent, e.g. zinc chloride. The cellulose may be regenerated from the dispersion by removal of supernatant water by filtration or centrifugation and drying of the cellulose at, say, 15-40 DEG C. When chemical dispersing agents are employed the chemical is washed out of the dispersion before removal of the water. The regenerated cellulose mass may be formed and machined preferably before carbonization instead of after final graphitization. Alternatively, the dispersion of cellulose, preferably that formed without the aid of a chemical dispersing agent, or the regenerated cellulose may be employed as a binder instead of, say, pitch for admixture with coke prior to extrusion or moulding, firing and graphitization to form a substantially impermeable graphite mass or graphite masses produced by known processes may be made impermeable by impregnation with a dispersion of cellulose followed by carbonization and graphitization thereof.