GB1157302A - Carbonization method - Google Patents

Abstract

1,157,302. Carbonization. HITCO. 14 July, 1966 [14 July, 1965], No. 31739/66. Heading C1A. Fibrous cellulosic material is carbonized by maintaining the material in an acidic oxidizing gas, which does not leave an appreciable residue on the carbonized product, at a temperature between 300‹ F. and that at which substantial degradation of the fibre structure occurs during its reaction with the gas, and then treating the fibre in the absence of oxygen by increasing the temperature to at least 1100‹ F. The acidic oxidizing gas may be chlorine, bromine or iodine, nitrous oxide, nitrogen pentoxide or hydrogen halides mixed with sufficient oxygen to convert the hydrogen halide to halogen and water. The gas may be diluted with an inert gas, e.g. nitrogen, helium or argon. The treatment at the higher temperature may be carried out in an inert gas, an alkaline gas (e.g. ammonia, methylamine, ethylamine, propylamine, dimethylamine, diethylamine, or methylethylamine), preferably diluted with an inert gas, or in an acidic oxidizing gas which does not contain oxygen and does not produce oxygen during the reaction (e.g. Cl, Br, I). The product may be further heated to at least 1800‹ F. in an oxygenfree atmosphere to remove further volatiles. The resulting fibre may be graphitized in an inert atmosphere at about 4000‹ F.