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Abstract

Ultra-clean isotropic coke is obtained from bituminous coal by extracting such coal following the extraction procedure described in U.S. Pat. No. 4,272,346, issued Jun. 9, 1981, to Stiller et al., using, for example, N-Methyl Pyrrolidone as the extraction solvent, and subjecting the extracted solids after separation of the solvent to a conventional coking heat treatment. The isotropic coke thus obtained can be ground, mixed with conventional binder pitch and shaped into carbon products which can be used directly, e.g. as carbon electrodes, or can be subjected to a graphitizing heat treatment under the usual conditions to produce isotropic graphite structures of high purity and high quality. The graphitization can be a multi-stage procedure and the porous intermediate stage products can be impregnated with a conventional impregnating pitch for increased density, the impregnating pitch being graphitized in the subsequent stage.

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First Claim