The black liquor (BL) obtained by straw pulping can hardly be applied to conventional alkali recovery systems because of its high concentration of silicon and viscosity. Soda-oxygen pulping can synchronously deposit silica on the surface of the cellulose to reduce the silicon content and viscosity of BL remarkably. In this paper, the BLs of wheat straw soda-oxygen pulping obtained at different end points (pH < 10, 11.5 < pH < 12) and conventional soda-anthraquinone (soda-AQ) were obtained. The extent of silicon removal and viscosity reduction before and after centrifugation or membrane filtration as well as the thermodynamic properties of the BLs were investigated. Compared with that achieved by soda-AQ, over 45% silicon was removed from BL after soda-oxygen cooking at a similar delignification level. The total solid (TS) concentration of the soda-oxygen BL was easily concentrated by up to approximately 50%. SiO₂ can be further removed by simple centrifugation and membrane filtration, and its TS could be increased to 60% at 300 mp s. With cooking end point further decreased pH < 10, the centrifugated BL had the lowest silica content, the highest volumetric isothermal expansivity (VIE) value, and the lowest pyrolysis temperature.

秸秆制浆得到的黑液（BL）硅含量高、粘度大，难以应用于常规碱回收系统。苏打氧制浆可以同步将二氧化硅沉积在纤维素表面，显着降低BL的硅含量和粘度。本文获得了麦草苏打-氧气制浆在不同终点（pH < 10, 11.5 < pH < 12）和常规苏打-蒽醌（soda-AQ）的BLs。研究了离心或膜过滤前后硅去除和粘度降低的程度以及 BL 的热力学性质。与苏打-AQ 实现的相比，在类似的脱木素水平下，苏打-氧蒸煮后 BL 中的硅去除率超过 45%。苏打氧 BL 的总固体 (TS) 浓度很容易浓缩至约 50%。二氧化硅₂可以通过简单的离心和膜过滤进一步去除，在 300 mp s 时其 TS 可以增加到 60%。随着蒸煮终点进一步降低 pH < 10，离心后的 BL 具有最低的二氧化硅含量、最高的体积等温膨胀率 (VIE) 值和最低的热解温度。