Abstract: The possibility of modified opal as the stabilizer in hydrogen peroxide bleaching was investigated.Results showed that modified opal in place of sodium silicate as the stabilizer in hydrogen peroxide bleaching is feasible.At the same dosage, more than 3%(ISO) of brightness can be increased for both wheat straw pulp and deinked pulp.The stabilizing ability of modified opal in hydrogen peroxide bleaching of pulp is improved markedly.It is favorable for bleaching to increase temperature and time within a permissive extent.Suitable process conditions are 10% of pulp consistency, 3% of hydrogen peroxide, 1.5% of sodium hydroxide, 3% of the modified opal, 60 min and over 70℃ when modified opal is used as the stabilizer in hydrogen peroxide bleaching.Under these conditions, the brightness gain can reach more than 16%(ISO) for wheat straw pulp.In addition, it is favorable for bleaching to add a little amound of magnesium sulfate when the modified opal is used as the stabilizer in hydrogen peroxide bleaching, the brightness of pulp can increase 1%(ISO) if 0.05% of magnesium sulfate is added.

Key words: hydrogen peroxide, pulping bleaching, modified opal, stabilizer