GB1503007A - Process for converting pitch into crystalloidal pitch - Google Patents

Abstract

1503007 Treatment of pitch; carbonization; graphitization KUREHA KAGAKU KOGYO KK 20 June 1975 [24 June 1974] 26400/75 Heading C1A [Also in Division C5] Crystalloidal pitch is produced by (1) treating solid pitch particles having a maximum dimension of the minimum projected area of not more than 5 mm. to render them resistant to mutual fusion and then (2) contacting the particles with a non- oxidative gas at 350-550‹ C. while maintaining a void ratio of not less than 30% by volume. The treatment (1) can be carried out by (a) coating the particles with a metal (e.g. Cu, Cr, Ni or Ag), or a metal salt (e.g. a chloride of Ni, Fe or Al) or with a phenol, furan or epoxy resin; (b) forming an oxidized coat on the particles by immersing the particles in a solution of hydrogen peroxide, a chlorate, a hypochlorite, a perchlorate, nitric acid, ferric chloride, a dichromate, a mixed acid, a permanganate or a peracetate or by treating the particles with an oxidizing gas (e.g. oxygen, ozone, an oxide of sulphur or nitrogen or a halogen) which can be diluted with an inert gas (e.g. nitrogen, argon, hydrogen, steam or combustion gas) or (c) removing low boiling point or low melting point components by extracting the particles with a solvent such as acetone, methylethyl ketone, benzene, toluene, hexane, heptane, cyclohexane, methanol, chloroform or carbon tetrachloride. The softening point of the particles treated by extraction can be increased by heating between the softening and flow points of the pitch. The particles can be globular, filamentary or other shapes and can be composed of petroleum pitch, coal pitch (optionally containing 3 wt. per cent iron chloride) or pitch derived from by-product tars produced by thermal cracking of crude oil or naphtha. The heating can be carried out in a fluidized bed, fixed bed or rotary kiln. The crystalloidal pitch can be carbonized and graphitized, e.g. by heating in argon at up to 2400‹ C.