The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 10, 1978
Filed:
May. 21, 1976
Michael David Gray, Cheltenham, GB;
Geoffrey Michael Kimber, Cheltenham, GB;
Coal Industry (Patents) Limited, London, GB;
Abstract
A low-impurity coke suitable for the production of electrodes for aluminium manufacture is prepared by extracting coal volatile matter content greater than about 28% by weight on a dry ash free basis with a highly aromatic hydrocarbon extractant of which the middle 90% boils in the range 250.degree. to 350.degree. C at a temperature of about 380.degree. to 450.degree. C, in the liquid phase, insoluble matter is separated off and the extract is heated to remove distillable oil and coked wherein the residence time of coal in the extraction step is controlled and the weight ratio of extractant to coal during extraction is maintained greater than 3:1 to maintain a substantially constant specific resistivity of the filter cake.