有机转晶剂对常压盐溶液法制备的α-半水石膏晶体形态的影响

以山东华能电厂烟气脱硫石膏为原料,采用常压盐溶液法制备α-半水石膏(α-HH)。分别以己二酸、柠檬酸、EDTA、丁二酸、草酸为转晶剂,考察其对合成α-HH晶体形态的影响。结果表明,当盐溶液浓度为20%、料浆浓度为20%、p H值为自然p H、反应温度为95℃、反应时间为3 h时,5种有机酸转晶剂对α-HH晶体形态均有影响;但以己二酸、柠檬酸、草酸为转晶剂时,获得的α-HH晶体形态均不理想;添加0.04%的丁二酸或0.07%的EDTA时,获得的产品较佳。XRD分析结果验证了获得的产品为α-HH,TEM分析表明,添加0.04%的丁二酸时获得的α-HH晶体质量较添加0.07%的EDTA时的晶体质量好。

Effect of Organic Crystal Modifier on Crystal Morphology of α-Hemihydrate Gypsum by Salt Solution Method at Atmospheric Pressure

The α-hemihydrate gypsum(α-HH) was prepared by aqueous salt solution method at atmospheric pressure u-sing flue gas desulfurization gypsum from Shandong Huaneng Power Plant. Effect of crystal modifier type,such as adipic acid, citric acid,ethylenediaminetetraacetic acid(EDTA),succinic acid,oxalic acid,on the crystal morphology of α-HH was stud-ied. The results show that when NaCl salt solution concentration of 20%,gypsum slurry concentration of 20%,natural pH,reac-tion temperature is 95 ℃,optimum reaction time is 3 h,the crystal morphology is change by five organic acid crystal modifier . The crystals morphology is unsatisfactory with adipic acid,citric acid and oxalic acid as crystal modifier,but the crystals mor-phology is perfect with the succinic acid dosage is 0. 04% and EDTA dosage is 0. 07%. XRD analysis results showed the products is α-HH,and TEM analysis results indicated the quality of crystal is better when adding 0. 04% succinic acid than 0. 07% EDTA.