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:
May. 14, 1985
Filed:
Jun. 20, 1983
Thomas D Wheelock, Ames, IA (US);
Iowa State University Research Foundation, Inc., Ames, IA (US);
Abstract
Pyritic sulfur, organic sulfur, and ash-forming minerals are removed from coal by a 2-stage alkaline treatment, using sodium carbonate or bicarbonate as the reagent. The first stage is an alkaline oxidation at moderate temperatures (130.degree.-150.degree. C.), and the second stage is a non-oxidizing alkaline treatment at a much higher temperature (250.degree.-330.degree. C.). The alkaline treated coal is extracted with an aqueous mineral acid, preferably hot aqueous sulfuric acid (H.sub.2 SO.sub.4) followed by washing with hot water. The resulting low-ash, low-sulfur coal can be used as a fuel in oil-firing boilers, and for similar applications where minimal-ash content is a basic requirement.