Abstract: A water absorbent cross-linked, carboxyalkylated cellulose-containing material is produced by impregnating a cellulose-containing material with an aqueous reaction solution including a carboxyalkylating agent, an alkali metal hydroxide, and a cross-linking agent dissolved in water in an initial content of 50 to 90% by weight, the molar ratio of the carboxylating agent to glucose groups of cellulose being 0.7 to 2.0; adjusting the water content of the aqueous reaction solution impregnated in the cellulose-containing material to 20 to 60% by weight and of at least 5% by weight below the initial water content by evaporating a portion of water; and subjecting the water content-adjusted cellulose-containing material to a simultaneous cross-linking and carboxylating reaction procedure at 50.degree. to 110.degree. C., while maintaining the water content at 20 to 60% and of at least 5% by weight below the initial water content.

Abstract: Disclosed is a process for simultaneously drying mechanical wood pulp and improving the mechanical strength and brightness of the wood pulp by mixing mechanical wood pulp with an aqueous solution of at least one sulfonating compound, the resultant mixture having a dry solid consistency of 20 to 50% of the wood pulp, based on the weight of said mixture and; bringing the mixture into contact with a heating gas having a temperature higher than 100.degree. C. to cause the dry solid consistency of the wood pulp in the mixture to be increased to a range of from 65 to 90% by weight.