从FGD残渣制备α型半水石膏过程晶形的控制

对从烟气脱硫残渣制备α型半水石膏的结晶形态进行了研究 .研究结果表明 :pH值、温度和盐溶液是影响α型半水石膏产品性能的最重要的因素 ,当 pH值从 3～ 6变化时 ,晶体的长径比从 10∶1～ 1∶1,在适当浓度的盐溶液中 ,加入结晶习性改良剂、结晶稳定剂和表面活性剂可以使α型半水石膏的晶体向粗大、短柱状的方向发展 ,同时 ,碱土金属盐离子的种类不同 ,对晶形的影响也不同 .

Control of crystal shape of flue gas desulfurization sludge waste into α-form calcium sulfate hemihydrate

The crystal shape of flue gas desulfurization sludge waste into α form calcium sulfate hemihydrate is studied. The study results show that the PH value, the reaction temperature and the aqueous solution consisting of some alkali earth metal salts are the most important factors for this process. The more closed to the neutral range of PH value the liquid is adjusted, the better stability of the α form calcium sulfate hemihydrate appears. The aspect of crystals is varied from 10∶1 to 1∶1 with change of PH from 3 to 6. The effects of adding crystal habit modifiers, stabilizing agent and surfactant on the formation of ideal α form hemihydrates are investigated experimentally. Meanwhile, it is noticed that the type of cationic ions in the media influences the shape of crystals.