| 摘要 |
{PG,1 Granular activated carbon is manufactured from briquettes of about 1{33 2{41 {0 mesh formed from brown coal from which iron material has been extracted and which has a moisture content of about 15% by weight, by crushing and screening the pre-treated coal briquettes to produce 8/30 mesh granules, which are treated by mixing with about 5% by weight of concentrated inorganic acid (H{HD 2{L SO{HD 4{L , H{HD 3{L PO{HD 4{L , or HCl), without the addition of a carbonaceous binder such as coal tar pitch. The so treated granules are ground to form fine powder of more than about 65% by weight {31 325 mesh powder, more preferably 75 to 85% by weight {31 325 mesh, which powder has a moisture (including acid) content of about 21% by weight, as a temporary binder, and which powder is compressed into shapes such as pellets of 0.5{41 {0 diameter and 0.5{41 {0 long under a pressure of 40,000 to 80,000 psi, and then granulated to obtain 6/20 mesh granules. These granules are devolatilized, without charring, by directly heating to and at a temperature higher than the charring temperature in an oxygen-free atmosphere, and then activated by heating to and at a temperature higher than the devolatilizing temperature in an atmosphere containing a gaseous activating agent. The overall yield of granular activated carbon is not less than about 22% by weight, dry basis, and the activated granules have a surface area of not less than about 900 m{hu 2{l /gram, an iodine number of not less than about 900, an ash content of not more than about 6% by weight, an abrasion number of not less than about 70, an {pg,2 apparent density of not less than about 0.48 gram/cc, and a Molasses number of not less than about 200; which properties make them suitable for use in water and waste water treatment and in other applications.
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