无机盐工业
主管:中海油天津化工研究设计院有限公司
主办:中海油天津化工研究设计院有限公司
   中海油炼油化工科学研究院(北京)有限公司
   中国化工学会无机酸碱盐专业委员会
ISSN 1006-4990 CN 12-1069/TQ

无机盐工业 ›› 2020, Vol. 52 ›› Issue (11): 20-23.doi: 10.11962/1006-4990.2020-0033

• 研究与开发 • 上一篇    下一篇

氢氧根对半水硫酸钙晶体形貌的影响机理

王宇斌(),张鲁(),毛欣钰,王望泊,党炜犇   

  1. 西安建筑科技大学资源工程学院,陕西西安 710055
  • 收稿日期:2020-05-17 出版日期:2020-11-10 发布日期:2020-12-01
  • 通讯作者: 张鲁
  • 作者简介:王宇斌(1972— ),男,博士,副教授,主要从事矿物材料和资源综合利用研究;E-mail: wangyubin1972@sohu.com
  • 基金资助:
    国家自然科学基金项目(51974218)

Effect mechanism of hydroxide ions on morphology of calcium sulfate hemihydrate crystals

Wang Yubin(),Zhang Lu(),Mao Xinyu,Wang Wangbo,Dang Weiben   

  1. School of Resource Engineering,Xi′an University of Architecture & Technology,Xi′an 710055,China
  • Received:2020-05-17 Online:2020-11-10 Published:2020-12-01
  • Contact: Zhang Lu

摘要:

以二水硫酸钙为原料在氢氧化钠-水体系中水热合成不同形貌的半水硫酸钙晶体,并通过XRD、XPS和电导率等手段对水热产物进行表征,研究了OH-对水热产物晶体形貌的影响机理。结果表明,在碱性条件下可获得不同形貌的半水硫酸钙晶体,随着OH-浓度的增大,纤维状形貌水热产物的含量减小而短柱状形貌的含量增多,且当OH-浓度为1.0×10-2 mol/L时水热产物以短柱状形貌为主。OH-影响半水硫酸钙晶体形貌的原因:OH-会消耗溶液中的Ca2+,从而促进二水硫酸钙的溶解,而Ca2+浓度的减少不利于半水硫酸钙晶体的成核生长;同时,OH-对二水硫酸钙的促溶作用会增加溶液中SO42-的浓度,从而促进半水硫酸钙晶体沿(110)和(200)晶面的生长;此外,OH-在(002)晶面选择性吸附并与该晶面的Ca2+反应生成Ca(OH)+和Ca(OH)2,从而阻碍半水硫酸钙晶体沿该晶面的生长。在以上3种作用下半水硫酸钙晶体形貌由纤维状向短柱状转变。本研究可为碱性条件下生产不同形貌半水硫酸钙晶体提供一定的理论依据。

关键词: 半水硫酸钙, 氢氧根, 晶体生长

Abstract:

Calcium sulfate hemihydrate crystals with different morphologies were prepared in sodium hydroxide-distilled wa-ter system by hydrothermal method using calcium sulfate dihydrate as raw materials.The mechanism for influence of OH- on the crystalmorphology of hydrothermal products was investigated by XRD,XPS and conductivity etc..The results showed that calcium sulfate hemihydrate crystals with different morphologies can be prepared under alkaline condition.The content of fibrous hydrothermal products decreased and the content of short columnar hydrothermal products increased with the increase of OH- concentration.And when the concentration of OH- was 1.0×10-2mol/L,the morphology of hydrothermal products was mainly short column.The reason for the influence of OH- on the morphology of calcium sulfate hemihydrate crystals was as follow:the consumption of Ca2+ by OH- in solution promoted the dissolution of calcium sulfate dihydrate and the decrease of Ca2+ concentration was not conducive to the nucleation and growth of calcium sulfate hemihydrate crystals.Meanwhile,the promoting effect of OH- on the dissolution of calcium sulfate dihydrate can increase the concentration of SO42- in solution,thus promoting the growth of calcium sulfate hemihydrate crystals along(110) and(200) crystal planes.In addition,OH- selectively adsorbed on(002) crystal plane and reacted with Ca2+ on the crystal plane to form Ca(OH)+ and Ca(OH)2,which hindered the growth of calcium sulfate hemihydrate crystals along the crystal plane.Under the above three effects,the morphology of calcium sulfate hemihydrate crystals can transition from fibrous to short columnar shape.The study can provide theoretical basis for producing calcium sulfate hemihydrate crystals with different morphology under alkaline condition.

Key words: calcium sulfate hemihydrate, hydroxide ions, crystal growth

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