Hard granular activated carbon and preparation from a carbonaceous material a binder and an inorganic activating agent

Claim 1

A chemical activation process for the manufacture of granular activated carbon comprising the steps of forming a mixture having a consistency permitting the pelleting of granular shaped particles including the following: a ground solid raw carbonaceous starting material possessing an oxygen content of at least approximately 25 percent by weight on a moisture and ash free basis taken from a group consisting of wood, straw and low-rank brown coals, a carbonaceous binder material taken from a group consisting of lignosulphonates and polyvinyl alcohols which are soluble or emulsifiable in water or phosphoric acid solutions, the amount of the binder material being sufficient to contribute at least approximately 24 percent by weight of the total carbon present in the initial mixture formed, and an amount of phosphoric acid sufficient to form a ratio of 100 percent phosphoric acid to the dry basis mixture of the starting material and the binder material of at least 0.35 to 1; forming solid grnaular shaped particles of predetermined size from said mixture; heat treating said shaped particles for a predetermined time at a temperature no greater than approximately 650*C to form a granular activated carbon product having a ball-pan hardness value of approximately 85 percent or greater.