摘要
研究了水热Ca Cl2溶液中可溶磷对Ca SO4·2H2O脱水形成α-半水石膏相以及晶形调控的影响,并从高强α-半水石膏相的晶体生长角度探讨了可溶磷的作用机理。结果表明：在98℃24%的水热Ca Cl2溶液中,p H的大小是决定二水石膏能否发生脱水相变反应形成α-半水石膏的主要因素;当p H不超过2.0时,可以得到针状的α-半水石膏,加入多元羧酸类媒晶剂NS后,可以得到长径比0.5~3.0的短柱状高强α-半水石膏,抗压强度超过20 MPa;可溶磷的存在可以降低体系的p H,增大α-半水石膏的过饱和度,降低晶体与液相界面的表面自由能,有利于α-HH相的形成;另一方面,酸根离子会影响到α-HH的结晶习性,减弱羧酸类媒晶剂的吸附效果。
The effect of soluble phosphorus on CaSO4·2H2O （DH） dehydration toα -calcium sulfate hemihydrate gypsum （α-HH） in hydrothermal CaCl2 solutions and the crystal shape regulation were investigated. The action mechanism of soluble phosphorus was studied by means of growth of hemihydrate crystal. The system pH was the main factor to determine whether DH could be dehydrated toα-HH in 24% CaCl2 solution at 98℃.Acicularα-HH crystal could be obtained when pH was less than 2.0. High-strengthα-HH crystal with aspect ratios from 0.5 to 3.0 could be observed when polycarboxylic crystal habit modifier NS was added. The corresponding compressive strength was more than 20 MPa. The presence of soluble phosphorus was favorable forα-HH formation by lowering system pH, increasing supersaturation degree and reducing interfacial energy. On the other hand, acid radical ions affectedα-HH crystallization behavior and adsorption results of medium crystal agent NS.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2015年第5期1983-1988,共6页
CIESC Journal
关键词
可溶磷
水热
相变
制备
高强α-半水石膏
soluble phosphorus
hydrothermal
phase change
preparation
high-strengthα-hemihydrates gypsum
