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:
Jun. 28, 1977
Filed:
Jun. 11, 1975
Hari N Murty, Grand Island, NY (US);
The Carborundum Company, Niagara Falls, NY (US);
Abstract
Granular activated carbon is manufactured from sub-bituminous coal by crushing and screening the as received coal containing 17% moisture by weight to produce 8/30 mesh granules which are treated by mixing with about 5% by weight of concentrated inorganic acid (H.sub.2 SO.sub.4, H.sub.3 PO.sub.4 or HCl), without the addition of a carbonaceous binder. The so treated granules are ground to more than 65% by weight -325 mesh powder, preferably 75 to 85% by weight -325 mesh, which powder has a moisture (including acid) content of about 21% by weight, as a temporary binder, and which powder is compressed into pellets of 0.5 inch diameter and 0.5 inch long under a pressure of 40,000 to 80,000 psi, and then granulated to obtain 6/20 mesh granules. These granules are devolatilized by heating to 450.degree. C at 300.degree. C/hour in an atmosphere of N.sub.2 and the volatiles and by maintaining the temperature for 1 hour, and then activated by heating to 800.degree. to 900.degree. C in an atmosphere of N.sub.2 and steam and by maintaining the temperature for 4 to 5 hours. The overall yield of granular activated carbon is 25 to 35% by weight of the dry coal, and the activated granules have a surface area of 900 to 1050 m.sup.2 /gram, an iodine number of 900 to 1100, an ash content of 10 to 12%, an abrasion number of 80, and an apparent density of 0.48 to 0.50 gram/cc, which properties make them suitable for use in waste water treatment and other applications.