Abstract: Extraction of lignin from sulfite pulping waste liquor was investigated. The extraction rate of lignin from black liquor by desulfonation increased in comparison with that without desulfonation. Then the influence of 15% H2SO4，precipitation time，precipitation temperature on the separation of lignin from black liquor by desulfonation was studied through 53 orthogonal experiments. The result indicated that the optimal condition of purifying lignin was as follows：the proportion of black liquor and 15% H2SO4 was 1∶2 and cooking at 90℃ for 1.5h. Lignin obtained from desulfonation of black liquor，had high purity，high molecular weight，good-heat stability and plasticity through the analyses of IR spectrum，GPC，TG-DSC and Torque curve.

摘要： 以亚硫酸盐法制浆废液为原料，经脱磺处理后木质素的提取率显著提高，并通过（53）正交实验深入探讨经脱磺处理的黑液中硫酸用量、沉淀时间、沉淀温度等反应条件对木质素提取纯化的影响，得到高纯木质素提取纯化最佳条件为：黑液与15%硫酸体积比为1∶2，沉淀温度90 ℃，沉淀时间1.5 h。红外光谱、凝胶色谱、差热和流变特性分析结果表明，脱磺处理的木质素具有纯度高、分子量大、热稳定性和塑化性好等特点。