硕士论文：常压下脱硫石膏的转晶、改性及溶解度研究.doc

摘 要 脱硫石膏是钙基湿法烟气脱硫过程中，通过烟气脱硫装置经石灰(石)浆液吸收SO2产生的一种工业副产品。实现脱硫石膏的资源化应用，是根本解决钙基湿法烟气脱硫工艺(FGD)中脱硫渣二次污染问题的有效途径。 本研究重点探索常压下利用脱硫石膏制备α-半水石膏过程中，脱硫石膏的转晶和改性的最佳条件。同时对该转化过程中试剂级二水硫酸钙和脱硫石膏的溶解度变化规律进行研究，并比较二者在单种盐溶液和复合盐溶液中溶解度变化的规律。 本实验以常压盐溶液水热法改性脱硫石膏(对脱硫石膏进行改性)，并利用间歇反应装置(三口烧瓶)模拟结晶反应器。本实验中主要探讨了不同温度及盐溶液种类和浓度对脱硫石膏晶体转化过程的影响，结合实验过程中样品的定性和定量分析，研究脱硫石膏转化生成α-半水石膏的过程，从而筛选出脱硫石膏常压盐溶液法晶体转化过程的最佳工艺条件。实验结果表明，温度、盐溶液种类和浓度是脱硫石膏转晶过程中最敏感的因素，得到结晶形态良好的α-半水石膏的最佳控制条件为温度95℃~98℃，盐溶液浓度25% 硫酸钙溶解度的研究结果显示，二水硫酸钙（AR）和脱硫石膏在单种盐溶液中的溶解规律性是一致的：在CaCl2溶液中由于Ca2+同离子效应的影响，盐溶液浓度越高，二水硫酸钙的溶解度越低；MgCl2溶液中，因Mg2+可与SO42-生成稳定的硫酸镁离子对，从而促进二水硫酸钙的溶解，促溶作用明显；KCl溶液中，KCl溶解产生的盐效应也具有促进二水硫酸钙溶解的作用，但KCl盐效应所产生的促溶效果低于MgCl2；在Ca-Mg-K的混合氯化盐溶液中，硫酸钙溶解度受到同离子效应的影响最为显著。 关键词：脱硫石膏；α-半水石膏；转晶控制；溶解度 Abstract Gypsum is an industrial by-products produced from the calcium-based wet flue gas desulfurization process (FGD). The practical utilization of FGD gypsum is an effective way and a fundamental solution to secondary pollution of the desulfurization residue of calcium-based wet FGD process. This study focuses on the optimum conditions of FGD gypsum conversion into α-calcium sulfite hemihydrate in salty solution at atmospheric pressure. At the same time, the change of solubility of reagent-grade calcium sulfate dihydrate and FGD gypsum are discussed and contrasted. The experiment is carried out in a batch reactor by using the method of hydrothermal mixed salt solution at atmospheric pressure. A 3-neck flask is used as the crystal reactor. In the experiment, the temperature and the concentration of salt solution which influence the transformation process are mainly discussed. With the samples analyzed by qualitatively and quantitatively, the progress of FGD Gypsum conversion into α-calcium sulfate hemihydrate is studied. HYPERLINK javascript:void(0) Sequentially??to select the optimum condition of FGD Gypsum conversion. The experimental results show that the temperature, species and concentration of salt solution are the most sensitive factors in the process of FG