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Chin. J. Process Eng. ›› 2015, Vol. 15 ›› Issue (6): 954-961.DOI: 10.12034/j.issn.1009-606X.215268

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Water Leaching Kinetics and Recovery of Potassium Salt from the Roasted Product of Potassium Slate-FGD Gypsum-Calcium Carbonate System

CHEN Pan-ze ZHONG Yi-wei GUO Zhan-cheng,   

  1. State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing Academic of Metallurgical and Ecological Engineering，University of Science and Technology Beijing
  • Received:2015-07-13 Revised:2015-09-01 Online:2015-12-20 Published:2015-12-20
  • Contact: CHEN Pan-ze

富钾板岩-脱硫石膏-碳酸钙焙烧产物钾盐的回收及其水浸动力学

陈攀泽 钟怡玮 郭占成   

  1. 北京科技大学钢铁冶金新技术国家重点实验室 北京科技大学钢铁冶金新技术国家重点实验室 北京科技大学生态与循环冶金教育部重点实验室
  • 通讯作者: 陈攀泽

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Abstract: Aiming at utilization of poorly soluble potassium slate, recovery and water leaching kinetic of potassium salt in the roasted product of potassium slate-FGD gypsum-calcium carbonate system were studied. The results showed that the main components in the roasted product were Ca2SiO4, CaO, K2SO4 and Ca3Al2O6. K2SO4 in the roasted product could be separated and recovered by water leaching under stirring and fractional crystallization. When the ratio of liquid to solid was 2 mL/g, K+ concentration of the leaching solution 14.98 g/L and K2SO4 content of the crystallized substance was 91.28%. On-line monitoring of specific electrical conductivity of the leaching system verified the prediction that leaching kinetics of K2SO4 from the roasted product fit to the dissolution model. Higher temperature, higher stirring speed and smaller particle size of roasted product could increase the leaching rate. On this basis, by multiple linear regression, the leaching rate was expressed as dc/dt=(9.567′10-3T-1.699′10-3d+7.561′10-4r-2.668)(0.0722-c).

Key words: potassium slate, FGD gypsum, calcium carbonate, roasting, potassium sulfate, water leaching, kinetics

摘要： 针对难溶性钾岩的利用问题，研究了富钾板岩-脱硫石膏-碳酸钙体系焙烧产物中钾盐的回收及其浸出动力学. 结果表明，焙烧产物主要是Ca2SiO4, CaO, K2SO4, Ca3Al2O6等，其中K2SO4可通过水浸分离提取，在液固比2 mL/g的条件下搅拌浸出，浸出平衡时的钾离子浓度为14.98 g/L，浸出液蒸干结晶物K2SO4含量为91.28%. 提高温度(T)、增大搅拌速率(r)和减小焙烧产物粒度(d)可提高浸出速率，水浸出过程符合扩散控制的溶解过程模型，通过多元线性回归得到钾盐浸出动力学方程为dc/dt=(9.567′10-3T-1.699′10-3d+7.561′10-4r-2.668)(0.0722-c).

关键词: 富钾板岩, 富钾板岩, 碳酸钙, 焙烧, 硫酸钾, 水浸, 动力学

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