转晶剂对磷石膏制备无水硫酸钙影响的研究  

Study on effect of crystallizer on preparation of anhydrous calcium sulfate from phosphogypsum

作　　者：王明顺 敖先权[1] 袁兴 董文燕 陈前林[1] WANG Mingshun;AO Xianquan;YUAN Xing;DONG Wenyan;CHEN Qianlin(College of Chemistry and Chemical Engineering,Guizhou University,Guiyang 550025,China)

机构地区：[1]贵州大学化学与化工学院,贵州贵阳550025

出　　处：《无机盐工业》2024年第5期101-107,共7页Inorganic Chemicals Industry

基　　金：国家重点研发计划项目(2018YFC1903500)。

摘　　要：磷石膏(PG)产生量大、资源化利用困难,严重影响磷化工行业的发展。为提高PG应用附加值,以除杂后的PG为原料,以NaCl和乙二胺四乙酸二钠(EDTA-2Na)为转晶剂,采用常压盐溶液法制备高白度无水CaSO_(4)。通过SEM、XRD、FT-IR、粒度分析仪等分析方法研究转晶剂对无水CaSO_(4)制备的影响。结果表明:当NaCl质量分数为15%、EDTA-2Na质量分数为0.5%时,PG结晶水脱水时间由120 min缩短至40 min,脱水效果显著;同时,无水CaSO_(4)晶体粒度分布均匀,颗粒表面完整,D_(50)为5.26μm,白度值为92.5%,P_(2)O_(5)质量分数仅为0.045%。这主要是因为非晶格Na^(+)降低了体系中水的活度,促进PG脱水转晶及杂质脱除;EDTA-2Na中羧基基团与石膏晶体表面的Ca^(2+)发生配位形成的配位离子层可调控无水CaSO_(4)晶体生长,修饰晶面。The production of phosphogypsum(PG)is large,and its resource utilization is difficult,which seriously affects the development of phosphorus chemical industry.In order to improve the added value of PG application,anhydrous CaSO_(4) with high whiteness was prepared by normal pressure salt solution method with PG as raw material,NaCl and EDTA-2Na as crystallization agents.The effect of crystal transition agent on the preparation of anhydrous CaSO_(4) was studied by SEM,XRD,FT-IR and particle size analyzer.The results showed that when the mass fraction of NaCl was 15%and the mass frac-tion of EDTA-2Na was 0.5%,the dehydration time of PG crystal water was shortened from 120 min to 40 min,and the dehy-dration effect was remarkable.At the same time,the particle size distribution of anhydrous CaSO_(4) crystal was uniform,the particle surface was complete,the D_(50) was 5.26µm,the whiteness was 92.5%,and the P_(2)O_(5) content was only 0.045%.It was mainly because non-lattice Na^(+)reduced the activity of water in the system,and promoted the dehydration,crystallization and impurity removal of PG.The coordination ion layer formed by the coordination between carboxyl groups in EDTA-2Na and Ca^(2+) on the surface of gypsum crystal could regulate the growth of anhydrous CaSO_(4) crystal and modify the crystal face.

关 键 词：磷石膏 转晶剂 无水CaSO_(4) 常压盐溶液法 

分 类 号：TQ177.3[化学工程—硅酸盐工业]