盐种类对常压盐溶液法制备半水石膏的影响
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摘要
常压盐溶液法制备半水石膏与盐介质、温度、pH等有关,盐介质的选择是常压盐溶液法制备半水石膏的基础。研究了常压盐溶液法制备半水石膏过程中不同阴阳离子及其组合的几种盐介质体系对转晶速率和晶体形态的影响。结果表明,阴阳离子对二水石膏转晶速率的影响分别按Cl-≈NO3-、SO42-顺序和NH4+、Ca2+、K~+、Na~+、Mg~(2+)顺序递增。在氯化镁、氯化钙、硝酸钙3种体系中,二水石膏转晶速率随着盐浓度的降低而减小,但存在不同的浓度阈值,低于该阈值转晶过程在4 h内无法进行;在一定的盐浓度范围内,盐介质都能较好地控制半水石膏的晶形。
The process of preparing hemihydrate gypsum by atmospheric salt solution method is related to salt medium,temperature and p H etc..The selection of salt medium is the basis of preparation of hemihydrate gypsum by atmospheric salt solution method.The effects of anions,cations and composition of salt on the conversion rate and crystal morphology were studied.The results showed that the effect of ion on the crystallization rate of dihydrate gypsum was increased by the following anions Cl-≈NO3-and SO_4~(2-),and cationic NH4+,Ca~(2+),K~+,Na~+and Mg~(2+).In the three systems of MgCl_2,CaCl_2 and Ca(NO_3)_2,the conversion rate of dihydrate gypsum decreased with the decrease of salt concentration,but there were different concentration thresholds,which can not be carried out below these values within 4 h.In a certain salt concentration range,the salt medium could control the crystal form of hemihydrate gypsum better.
The process of preparing hemihydrate gypsum by atmospheric salt solution method is related to salt medium,temperature and p H etc..The selection of salt medium is the basis of preparation of hemihydrate gypsum by atmospheric salt solution method.The effects of anions,cations and composition of salt on the conversion rate and crystal morphology were studied.The results showed that the effect of ion on the crystallization rate of dihydrate gypsum was increased by the following anions Cl-≈NO3-and SO_4~(2-),and cationic NH4+,Ca~(2+),K~+,Na~+and Mg~(2+).In the three systems of MgCl_2,CaCl_2 and Ca(NO_3)_2,the conversion rate of dihydrate gypsum decreased with the decrease of salt concentration,but there were different concentration thresholds,which can not be carried out below these values within 4 h.In a certain salt concentration range,the salt medium could control the crystal form of hemihydrate gypsum better.
引文
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[14]刘光启.化学化工物性数据手册[M].北京:化学工业出版社,2002.
[2]陈燕.石膏建筑材料[M].北京:中国建材工业出版社,2003.
[3]茹晓红,马宝国,黄赟.磷石膏制高强α半水石膏研究进展[J].新型建筑材料,2011(11):15-18.
[4]彭家惠.有机酸对α半水脱硫石膏晶体生长习性的影响与调晶机理[J].硅酸盐学报,2011,39(10):1711-1718.
[5]吴世琴,李军,金央,等.Ca Cl2-HCl-H2O体系中铁、镁、铝对二水硫酸钙转晶过程影响研究[J].无机盐工业,2015,47(4):30-32,42.
[6]胥桂萍,童仕唐.从FGD残渣制备α型半水石膏过程晶形的控制[J].吉林化工学院学报,2002,19(2):3-6.
[7]张巨松.转晶剂对脱硫石膏制备α-半水石膏形貌及强度的影响[J].沈阳建筑大学学报:自然科学版,2009,25(3):521-525.
[8]岳文海,王志.α半水石膏晶形转化剂作用机理的探讨[J].武汉工业大学学报,1996,18(2):1-4.
[9]刘先锋.盐溶液浓度对常压水热法制备α-半水脱硫石膏的影响[J].科学技术与工程,2012,12(16):3877-3879.
[10]郭会宾,张兴儒.Na Cl盐溶液制备半水石膏的工艺条件研究[J].青海大学学报:自然科学版,2013(2):24-31.
[11]Wu X Q,Wu Z B.Modification of FGD gypsum in hydrothermal mixed salt solution[J].Journal of Environmental Science,2006,18(1):170-175.
[12]何伟.常压下脱硫石膏的转晶、改性及溶解度研究[D].武汉:武汉科技大学,2009.
[13]马宪法,官宝红.常压KCl溶液中α-半水石膏的脱水过程[J].硅酸盐学报,2009,37(10):1654-1659.
[14]刘光启.化学化工物性数据手册[M].北京:化学工业出版社,2002.