CIESC Journal ›› 2016, Vol. 67 ›› Issue (S1): 296-301.DOI: 10.11949/j.issn.0438-1157.20151808

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Influence of Al3+, Na+ and Mg2+ on crystallization of calcium sulfate dihydrate

LIU Tonghai1, DOU Yan1, FANG Yang1, CUI Peng1, SHEN Hao2, ZHENG Zhiyin2, LIU Rong2   

  1. 1 School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009, Anhui, China;
    2 Anhui Liuguo Chemical Co., Ltd., Tongling 244000, Anhui, China
  • Received:2015-12-01 Revised:2015-12-11 Online:2016-08-31 Published:2016-08-31

Al3+、Na+和Mg2+对二水硫酸钙结晶的影响

刘同海1, 窦焰1, 方羊1, 崔鹏1, 沈浩2, 郑之银2, 刘荣2   

  1. 1 合肥工业大学化学与化工学院, 安徽 合肥 230009;
    2 安徽六国化工股份有限公司, 安徽 铜陵 244000
  • 通讯作者: 崔鹏,cuipeng@hfut.edu.cn

Abstract:

The system, including CaHPO4·2H2O-H2SO4-H3PO4-H2O, is utilized to simulate wet process for phosphoric acid production. Based upon the slurry composition of phosphate mineral analysis, according to single factor experimental demands, the influence of Al3+, Na+and Mg2+ on crystallization and washing rate of CaSO4·2H2O were investigated. The result indicated that, it is beneficial for the size of CaSO4·2H2O crystals when adding Al3+into the system. Na+as the form of 0.9% (mass) Na2O in the slurry also caused agglomeration of CaSO4·2H2O crystals. We also found that it is helpful for the washing rate. But when Mg2+ was added into the system, the unfavorable impact such as increasing the viscosity of solution, seriously influencing crystal growth and washing rate. For our target production, CaSO4·2H2O crystal, XRD, SEM were adopted to characterize the products during the process. The results showed that crystal growth conforms to Burton-Cabrera-Frank model. The impurity ions change the reaction rate and crystal plane growth rate.

Key words: reaction, crystallization, ions, preparation, calcium sulfate dihydrate

摘要:

采用CaHPO4·2H2O-H2SO4-H3PO4-H2O体系模拟湿法磷酸生产过程,以磷矿浆成分为依据,在单因素条件下分别研究Al3+、Na+和Mg2+对结晶和CaSO4·2H2O水洗速率的影响。研究发现:添加Al3+有利于CaSO4·2H2O晶体粒径增加;添加Na+使得0.9% Na2O含量的Na+引起CaSO4·2H2O晶体团聚,有利于水洗;Mg2+增加溶液黏度,严重影响晶体生长和水洗速率。通过X射线衍射、扫描电子显微镜对CaSO4·2H2O进行表征,发现其晶体生长符合非完整光滑突变界面模型,杂质离子影响反应速率和晶面生长速度。

关键词: 反应, 结晶, 离子, 制备, 二水硫酸钙

CLC Number: