GRANULAR ACTIVATED CARBON MANUFACTURE FROM SUB-BITUMINOUS COAL MIXED WITH CONCENTRATED INORGANIC ACID WITHOUT PITCH

摘要

GRANULAR ACTIVATED CARBON MANUFACTURE FROM SUB-BITUMINOUS COAL MIXED WITH CONCENTRATED INORGANIC ACID WITHOUT PITCH Granular activated carbon is manufactured from subbituminous 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 (H2SO4, H3PO4 or HC1), 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" diameter and 0.5" 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 N2 and the volatiles and by maintaining the temperature for 1 hour, and then activated by heating to 800 to 900.degree.C in an atmosphere of N2 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 m2/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.