苛化工艺对草浆碱回收白泥结构性质的影响

Effect of Causticizing Conditions on the Lime Mud's Structure Properties in the Straw Pulp Alkali Recovery

在消化苛化同时进行的条件下,通过四因素三水平的正交试验探讨了绿液浓度、搅拌速度、硅酸钠的浓度及石灰与绿液的摩尔比对白泥碳酸钙结构性质的影响。结果表明,绿液中硅含量对于白泥结构性质的影响最大,硅含量越高,白泥的面积加权平均粒径越大,比表面积越大,吸油值越高,这也充分说明了绿液除硅的必要性。若硅含量不变的情况下,可改变影响其次的因素,石灰与绿液的摩尔比对于比表面积影响较大;而搅拌速度对于白泥面积加权平均粒径及吸油值影响较大。硅酸钠含量为50g/L时,白泥碳酸钙大部分呈蜂窝状;含量为25g/L时白泥碳酸钙为蜂窝与块状交叠;不加硅时,白泥碳酸钙呈块状或片状堆叠。

Under the condition that slaking and causticizing went on simultaneously, the experiment was designed ac- cording to four factors and three levels orthogonal table. The effects of the green liquid concentration, stirring speed, the concentration of sodium silicate along with the molar ratio of green liquor to lime on the lime mud＇s structure properties were discussed. The results showed that the silicon content had the largest impact. The higher the silicon content in the green liquor, the higher the specific surface area , the area weighted average particle size and the oil absorption value of the lime mud. If the silicon content was invariable, the specific surface area of white mud was af- fected by the molar ratio of green liquor to lime largely, besides, the area weighted average particle size and the oil absorption were influenced by the stirring speed largely. When the content of the sodium silicate was 50 g/L, 25 g/ L and 0 g/L, most of calcium carbonate were alveolate, overlapped with the massiveand stacked together,respectively.