FREMGANGSMAATE FOR FREMSTILLING AV SILISIUMKARBID

A mixt. of powdered SiO2 and carbon is pressed into pellets to give a min. apparent density of 1.0 g/cm3 and min. compressive strength of 6.5 kg/cm2; the pellets are then mixed with non-reacted or partly reacted reclaimed matl. as a furnace packing and heated in an electric furnace with a min. remaining air space of 10%. The reclaimed material comprises 50% SiO2, 30% C, 20% SiC, with particle size distribution 47.5% 9-1 mm sieve with 52.5% passing through a 1 mm sieve; the use of this material and the controlled density of the pellets prevents the blow-ups, smoke and bad odours from mercaptans, which arise when sawdust is used as a furnace packing.