从烟气脱硫残渣中制取α-半水石膏的研究

Study on α-Form Calcuim Sulfate Hemhydra from Flue Gas Desulfuriza Scrubbing Sludge Waste

对溶液法从烟气脱硫残渣中制取α半水石膏进行了进一步的研究。 FGD残渣在碱土金属盐类的盐溶液中 ,在丁二酸、丙三醇等结晶改良剂的作用下 ,与大气压下加热脱水生成α半水石膏。研究中发现 p H值和盐溶液浓度是影响FGD石膏脱水速度最敏感的因素 ,固液比虽然对脱水速度影响不大 ,但固液比增大对晶体生长和习性改良不利。 p H值愈接近中性范围 ,愈能增强α半水石膏结晶在液相中的稳定性 。

Some study are done for the new process for conversion of flue gas desulfurization scrubbing sludge waste.FGD gypsum further into α form calcium sulfate hemihydrate by heating in an aqueous solution consisting of some alkail earth metal salts and sulfuric acid or chlorhydric acid at the atmospheric pressure has been studied in this subject.It is found that the concentration of sulfuric acid in liquid and the reaction temperature are the most sensitive factors for this process.Increasing the ratio of solid to liquid is disadvantageous for growth of crystals even though it does not effect obviously for the rate of dehydration of FGD gypsum.On the other hand,the more closed to the neutral range of pH value the liquid is adjusted,the better stability of the α form calcium sulfate hemihydrate appear,the more favorable for modification of crystal habit the process is made.