Graphitisation of pitch-impregnated carbon articles - in Acheson furnace using lower layer of pitch-impregnated and upper layer of unimpregnated articles

摘要

The furnace pref. is charged with 50-70% pitch-impregnated and 50-30% unimpregnated articles, the mats. depending on the gas concn. and contact time in the hot zone. Owing to the higher electrical resistance of the impregnated articles, the upper zone reaches a temp. of ca. 1000 degrees C before marked coking of the impregnant begins. The gas from the lower zone is cracked in the upper zone so that it ignites and burns with a clear, almost smokeless flame to H2O and CO2 on leaving the furnace. The method eliminates the need for precoking in a round down-draught kiln, and gives better control and reproducible resistance values.