| 摘要 |
<p>AC1-6 GRANULAR ACTIVATED CARBON MANUFACTURE FROM SUB-BITUMINOUS COAL TREATED WITH DILUTE INORGANIC ACID: DIRECT ACTIVATION METHOD Granular activated carbon is manufactured from subbituminous coal by crushing and screening the as received coal containing about 10 to about 25% moisture by weight to produce 8/30 mesh granules, treating the granules with a dilute aqueous solution of inorganic acid at a concentration from about 1 to about 25% by weight to reduce the volatile content and thereby increase the fixed carbon content, the particular concentration being selected to provide the desired activity and porosity of the activated carbon, comprising: mixing the granules with the acid, washing off the acid, and drying the granules at least partially to a moisture content below about 25% by weight. The granules are mixed with from 0 to about 15% by weight of coal tar pitch. The so treated granules are ground to form fine powder of not less than about 60% by weight -325 mesh, preferably more than about 55% by weight -325 mesh, which is compressed into shapes, such as pellets or thin corrugated sheets under high pressure and then granulated to reform 6/20 mesh granules. These reformed granules are then directly activated, without prior charring and devolatilization, by directly heating to and at a temperature higher than the devolatilizing temperature in an atmosphere containing a gaseous activating agent. To produce hard granular activated carbons suited for water and waste water applications where the preferred properties are 900 minimum Iodine number, 200 minimum Molasses number, more preferably, 950 Iodine number, 220 Molasses number or higher and Abrasion number of at least 70 or higher, a lower acid concentration from about 1 to about 12% by weight, preferably from about 2 to about 5% by weight, is employed for acid treatment in the process. To produce hard granular activated carbons suited for gas and air purification applications where the preferred properties are 1,000 minimum Iodine number, a very low Molasses number, i.e., less than 200, more preferably 1,050 Iodine number and Molasses number of about 180 and a minimum carbon tetrachloride number of 50, more preferably 60, a relatively high acid concentration from 12 to about 25% by weight, preferably about 15 to about 25% by weight, is employed for acid treatment in the process.</p> |
