| 摘要 |
Granular activated carbon is manufactured from briquettes formed from brown coal, from which iron material has been extracted, by crushing and screening the pretreated coal briquettes to produce ganules, treating the granules with a dilute aqueous solution of inorganic acid (H2SO4, H3PO4 or HCl) at a concentration of about 1 to about 10% by weight ro reduce the volatile content and thereby increase the fixed carbon content comprising: mixing the granules with the acid, washing off the acid, and drying the granules. In one case the washed granules are dried partially without the addition of a binder. In the other case the granules are dried and mixed with about 5 to about 15% by weight of coal tar pitch. The so treated granules are ground to form fine powder which is compressed into shapes such as pellets, and then granulated. These reformed 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 activated granules have a surface area of not less than about 900 m<2>/gram, an abrasion number of not less than about 70, and an apparent density of not less than about 0.46 gram/cc, which properties make them suitable for use in water and waste water treatment and in other applications. |
