New Probes Into The Way To Reinforce Hydrogen Peroxide Bleaching Of Pulp

Hydrogen peroxide is an important chlorine free bleaching agent, which is widely used in the bleaching of pulp. The key to bleach pulp by hydrogen peroxide is how to improve the efficiency of bleaching. One effective way of improving bleaching efficiency is adding stabilizer in bleaching liquid. But the stabilizer, such as sodium silicate, which is commonly used recently have still some disadvantages. So it is very necessary to improve its using effect or probe more effective stabilizer.In the article the way of improving the using effect for the stabilizer is investigated from two aspects: on one hand the surfactant is added into the bleaching liquid which contain sodium silicate and its influence in the bleaching process is studied; on the other hand zeolite is modified, then the using effect of zeolite, modified zeolite and sodium silicate as stabilizer is compared. The bleaching technology of CTMP and deinked pulp is optimized when modified zeolite is used as stabilizer, then the proper temperature, time and quantity of sodium hydrogen is determined. The conclusions drown from experimental data were followed as:1 when the surfactant is used in the hydrogen peroxide bleaching of pulp, the brightness of pulp is improved at the same time the consumption of hydrogen peroxide decreases.2 In the bleaching of wheat straw pulp, the effect of zeolite is poorer than that of sodium silicate. After zeolite is modified, its stabilizing effect is obviously better not only than zeolite, but also than sodium silicate3 when zeolite is used as stabilizer of wheat straw pulp, the optimum bleaching conditions are followed: the modified zeolite charge 3% (based on oven dry pulp), temperature 70C, time 60 min and sodium hydrogen charge 2%.4 In the bleaching of deinked pulp, the effect of modified zeolite is better than zeolite, but its effect is comparable with sodium silicate. So the modified zeolite can become supplement of sodium silicate and reduce the dirt phenomenon in the process of the use of sodium silicate.5 when modified zeolite is used as stabilizer of deinked pulp ,the optimum bleaching conditions are followed: the modified zeolite charge 2% (based on oven dry pulp), temperature 60C, time 45min and sodium hydrogen charge 1.5%.The stabilizing ability of hydrogen peroxide bleaching is probed, we hope it canbecome the base of future study.