| 摘要 |
<p>ACl-l GRANULAR ACTIVATED CARBON MANUFACTURE FROM SUB-BITUMINOUS COAL LEACHED WITH DILUTE INORGANIC ACID Granular activated carbon is manufactured from subbituminous coal by crushing and screening the as received coal containing about 17% moisture by weight to produce 8/30 mesh granules, which are treated by leaching with a dilute aqueous solution of inorganic acid (H2S04, H3P04, or HCl) at a concentration of about 6.5% by weight and at an aqueous solution to coal ration of about 10/1 by weight, by washing off the acid, and by drying. In one case the granules are dried partially to a moisture content of about 15% by weight without the addition of a carbonaceous binder. In the other case the granules are dried thoroughly and mixed with about 10% by weight of coal tar pitch. The so treated granules are ground to more than 65% by weight -325 mesh powder, preferably 75 to 85% by weight -325 mesh, which is compressed into pel lets 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 33% by weight of the dry coal, and the activated granules have a surface area of 900 to 1100 m2/gram, an iodine number of 1000 to 1100, an ash content of 5 to 7%, an abrasion number of 70 to 80, and an apparent density of 0.46 to 0.50 gram/cc, which properties make them suitable for use in waste water treatment and other applications.</p> |
