半晶态硅酸钙材料结晶状态对过滤分离的影响
Effect of the Crystalline State of Semi-Crystalline Calcium Silicate Materials on Filtration Separation

XRD 和 SEM 等技术手段对合成样品的结晶状态进行表征，并利用自组装过滤性能测试装置对合成样品的 过滤性能进行分析．研究了硅酸钙类材料结晶状态对其过滤性能的影响．结果表明，在 200,℃条件下，经过 8,h 的 合成反应结晶过程基本完成，反应的历程为：C―S―H 凝胶→结晶 C―S―H→硬硅钙石晶体．随着反应时间的延 长，硅酸钙产品的晶体结构由团絮状向纤维状结构转化．4,h 样品过滤性能最好，其平均过滤速度比结晶过程完成 时提高了 40％,，滤饼含水率下降了 4％,
Calcium silicate samples with different degrees of crystallinity were synthesized from sodium sili- cate(Na 2 SiO 3 ？9H 2 O)and calcium oxide(CaO)using the hydrothermal method under a variety of synthesis time con- ditions．The crystalline state of each sample was characterized by X ray diffraction(XRD) and scanning electron mi- croscopy(SEM)．Filtration properties of each product were analyzed using self-designed filtration testing equip- ment．The effects of the crystalline state on the samples’ filtration properties were studied．The results show that the crystallization process of calcium silicate is completed after 8,h at reaction temperature of 200,℃．The reaction prod- uct progresses as C―S―H(gel)→ C―S―H(crystal)→xonotlite．The morphology of the product changes from amorphous aggregated structure to a fibrous crystalline structure with the lengthening of reaction time．The perform- ance of product is peaked after 4,h reaction time，with 40%, increase in average filtration flux and 4%, decrease in filtration cake’s moisture content compared with the product after 8,h