HORNIFICATION OF PULP AND MEANS OF ITS REVERSAL

Pulp treatment in order to reverse hornification has to be evaluated i n closed recycling loops according to its potential improvement of the functional paper properties as well as in terms of a sustained revers ion of hornification to increase the number of possible recycling loop s. Hornification profiles were used to study the course of hornificati on of chemical pulp in terms cia decrease in the water retention value . The hornification point and the hornification gradient were introduc ed as new parameters. Results showed a possible compensation of hornif ication by beating, which in turn modifies fibres causing additional h ornification during a consecutive drying cycle. Higher fibrillation by beating in the PFl-mill seemed to impair fibres less than low-consist ency beating in the valley beater Hot disintegration after alkali addi tion caused little but sustained hornification reversion of bleached p ulp. A hornification reversion of 55% is gained by alkali cooking. Fin ally, results were presented showing the influence of salt on hornific ation.