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. 24, 1978
Filed:
Jul. 18, 1977
Edgel P Stambaugh, Worthington, OH (US);
Battelle Memorial Institute, Columbus, OH (US);
Abstract
A method of treating a solid carbonaceous material comprising essentially lignite or bituminous or subbituminous coal to provide therefrom finely dispersed solid particles substantially free of ash and sulfur, by mixing the solid material with a liquid aqueous alkaline solution comprising essentially a sodium, potassium, or ammonium hydroxide, hydrosulfide, or carbonate, or a plurality thereof; dissolving the material by heating the resulting mixture to a temperature in the range of about 125.degree. C to the critical temperature, at a pressure of at least about 25 psig, while maintaining a substantial portion of the mixture in the liquid state; separating from the resulting solution any undissolved coal, ash, and other solids; reducing the pH of the solution to less than about 9 to precipitate therefrom a powder comprising the carbonaceous material, with a substantial proportion of the ash and sulfur that had been in the starting material now remaining in solution; and separating the precipitated powder from the solution. Typically either the pH of the solution is gradually reduced to less than about 2 during a time of at least about 5 minutes, or the precipitated powder is washed with an acid solution having a pH of less than about 2.