Loading patent…
OwnerAlfred H. Stiller, John W. Zondlo +1inventors
InventorsAlfred H. Stiller, John W. Zondlo, Peter G. Stansberry
Estimating the term…
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.
A method of producing from bituminous coal an isotropic coke essentially free of inorganic matter and adapted to undergo graphitization to yield isotropic graphite, which comprises the steps of extracting a finely divided bituminous coal comprising organic matter and inorganic matter in an extraction medium with which said coal does not soften or undergo chemical reaction, the extraction medium consisting essentially of a solvent of the general formula R.sub.(n) --M(.dbd.O) (--R.sup.1)--N--R.sup.2 R.sup.3, where M is a carbon, sulfur, or phosphorous atom, R.sup.2 and R.sup.3 are each a hydrogen atom or a lower alkyl group, R and R.sup.1 are each a lower alkyl group, another --N--R.sup.2 R.sup.3 group, or together R.sup.1 and R.sup.2 represent the atoms necessary to close a 5-membered heterocyclic ring, or R.sup.1 can be a R.sub.n --M(.dbd.O)(--R.sup.X)--N--R.sup.2 --group where R, n, R.sup.2 are as before and R.sup.X is a lower alkyl group, another --NR.sup.2 R.sup.3 group or together with R.sup.2 can represent the atoms to close a heterocyclic ring, and n is unity where M is phosphorous and otherwise zero, to dissolve in said medium a substantial fraction of said organic matter of the coal equal to from about 25% to about 80% by wt of said coal, separating said extraction medium containing the dissolved fraction of organic matter therein from undissolved material comprising said inorganic matter, recovering said dissolved fraction from the medium as a solid, and subjecting the solid recovered fraction to a coking heat treatment to yield an isotropic calcined coke which is adapted to undergo graphitization to yield a substantially isotropic graphite.
Dependencies are inferred from the claim text.