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过程工程学报 ›› 2019, Vol. 19 ›› Issue (4): 817-825.DOI: 10.12034/j.issn.1009-606X.218328

• 材料工程 • 上一篇    下一篇

苦卤合成碱式硫酸镁晶须及后序分离工艺

白 雪1,2, 郭宏飞1,2, 陈学青1,2, 赵 斌1,2, 曹吉林1,2*   

  1. 1. 河北工业大学化工学院,天津 300130 2. 河北省绿色化工与高效节能重点实验室,天津 300130
  • 收稿日期:2018-12-10 修回日期:2019-01-11 出版日期:2019-08-22 发布日期:2019-08-15
  • 通讯作者: 曹吉林 caojilin@hebut.edu.cn
  • 基金资助:
    国家自然科学基金项目;河北省自然科学基金;广东省绿色化学产品技术重点实验室开放基金资助项目

Synthesis of magnesium oxysulfate whiskers from bittern and post-sequence separation process

Xue BAI1,2, Hongfei GUO1,2, Xueqing CHEN1,2, Bin ZHAO1,2, Jilin CAO1,2*   

  1. 1. College of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130, China 2. Hebei Provincial Key Lab of Green Chemical Technology and High Efficient Energy Saving, Tianjin 300130, China
  • Received:2018-12-10 Revised:2019-01-11 Online:2019-08-22 Published:2019-08-15
  • Contact: CAO Ji-lin caojilin@hebut.edu.cn

摘要: 用苦卤与工业液碱NaOH水热反应合成碱式硫酸镁(MOS)晶须,考察了原料配比、反应温度、液碱浓度及反应时间对液相组成和产品形貌的影响,用XRD和SEM等手段对产品进行表征,并对反应后母液进行钾盐和钠盐分离。结果表明,适宜的MOS合成条件为Mg2+与OH?摩尔比1:1.5及NaOH浓度4 mol/L、反应温度200℃、反应时间7 h。合成晶须后的母液按Mg2+与OH?理论摩尔比1:2反应,使母液中Mg2+完全转化为Mg(OH)2晶体。除镁后母液根据0和25℃时Na+, K+//Cl?, SO42??H2O四元体系相图、25和100℃时NaCl?KCl?H2O三元体系相图,通过蒸发浓缩结晶和低温结晶分离出NaCl, Na2SO4?10H2O和KCl。

关键词: 苦卤, 碱式硫酸镁, 水热反应, 相图, 结晶

Abstract: Based on the comprehensive utilization of bittern resources, the synthesis of magnesium oxysulfate whiskers from bittern and the separation of potassium salt and sodium salt in the subsequent process were studied. Magnesium oxysulfate whiskers were synthesized by hydrothermal reaction of bittern with NaOH. The effects of raw material ratio, reaction temperature, concentration of liquid alkali and reaction time on liquid phase composition and product morphology were investigated. The products were characterized by XRD and SEM. The optimum conditions were determined as follows: the raw material molar ratio of Mg2+ to OH? was 1:1.5, the concentration of liquid alkali was 4 mol/L, the reaction temperature was 200℃ and the reaction time was 7 h. The Mg2+ in the mother liquid was completely converted into magnesium hydroxide crystals with the theoretical molar ratio of Mg2+ to OH? of 1:2. According to the phase diagrams of Na+, K+//Cl?, SO42??H2O system at 0 and 25℃ and NaCl?KCl?H2O ternary system at 25 and 100℃, NaCl, Na2SO4?10H2O and KCl were separated from the remaining mother liquor by evaporation concentration crystallization and freezing crystallization.

Key words: bittern, magnesium oxysulfate, hydrothermal reaction, phase diagram, crystallization