Production of Dissolving Grade Pulp From Rice Straw

Abstract

In this study, two stage treatement was used to produce the dissolving grade pulp from rice straw which contains the high alpha-cellulose content and high brightness. In first stage rice straw was treated with distilled water at different bath ratios at a temperature of 165˚C for 60 min reaction time. The suitable bath ratio found for prehydrolysis is 1:8 in which the yield of material is 72.10%( over dry rice straw) and alpha cellulose content 51.85%( over pre-hydrolyzed rice straw). After pre-hydrolysis, the hydrolyzed material was treated with sodium hydroxide solution combined with sodium sulphide having sulfidity maintained at 25% with active alkali dosage of 14%(w/w) (% over pre-hydrolyzed rice straw, 0.05% anthraquinone(w/w) (% over pre-hydrolyzed rice straw) at different bath ratio at a temperature of 165˚C for 30 minutes reaction time. The suitable bath ratio found to be 1:7. After optimizing the bath ratio of kraft pulping, again pulping of the pre-hydrolyzed rice straw was done at different active alkali dosage. The yield of cellulosic pulp obtained after optimization has yield of 41.82% (w/w) was obtained in kraft pulping which contains alpha cellulose content of 80%. The pulp obtained after pulping was bleached by D0ED1P sequence which produces bleached pulp having yield of 31.25% over dry rice straw, ISO Brightness of 85% and alpha cellulose content of 89.38%.