Li Ruiqin, Liu Chenglin, Jiao Pengcheng, Hu Yufei, Liu Wanping, Wang Shijun
MNR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing, 100037, China.
School of Earth and Space Sciences, Peking University, Beijing, 100871, China.
Sci Rep. 2021 May 18;11(1):10539. doi: 10.1038/s41598-021-88818-z.
The output and grade of liquid potash minerals in Qarhan Salt Lake are decreasing year by year, which has become the main problem restricting the sustainable production of potassium fertilizer. The exploitation and utilization of low-grade solid potash ore, which is in the strata of the Qarhan Salt Lake, represents the fundamental framework for the sustainable development of Qarhan Salt Lake's potash fertilizer. PHREEQC is a simulation software for hydrogeochemistry. In this paper, PHREEQC was applied to simulate temperature, pH value and solvent chemical characteristics which affect the dissolution process of low-grade solid potash minerals. The simulation results indicate that the optimum temperature for ore dissolution is around 25 °C, because, around this temperature, the dissolving ability of solvents to low-grade solid potash minerals is enhanced, while the dissolving ability to halite remains basically unchanged, which is conducive to selective dissolution of low-grade solid potash. It is recommended the temperature is between 20 and 30 ℃. The simulation results show that, when the pH value of solvents is more than 9, although it is advantageous to selective dissolution of low-grade solid potash minerals, the solvent becomes strong alkali solution, which will cause environmental pollution and seriously corrode materials and equipment in actual production, so it is recommended the pH value of the solvent is adjusted between 6 and 8. The simulation results show that, when the values of K, Na, Mg, Ca, Cl and SO in the solvent are 0.1%, 2.9%, 3.77%, 0.05%, 15.72% and 0.13% respectively, the solubility of low-grade solid potash ores is stronger, which is more conducive to selective ore dissolution. It is suggested that in actual production, the chemical composition of solvents prepared with old brine and fresh water should be as close as possible to the above chemical composition characteristics.
察尔汗盐湖液态钾矿的产量和品位逐年下降，已成为制约钾肥可持续生产的主要问题。察尔汗盐湖地层中低品位固体钾矿的开发利用是察尔汗盐湖钾肥可持续发展的基本框架。PHREEQC是一款水文地球化学模拟软件。本文应用PHREEQC模拟了影响低品位固体钾矿溶解过程的温度、pH值和溶剂化学特性。模拟结果表明，矿石溶解的最佳温度约为25℃，因为在此温度附近，溶剂对低品位固体钾矿的溶解能力增强，而对石盐的溶解能力基本不变，有利于低品位固体钾矿的选择性溶解。建议温度在20至30℃之间。模拟结果表明，当溶剂的pH值大于9时，虽然有利于低品位固体钾矿的选择性溶解，但溶剂变成强碱性溶液，会造成环境污染，在实际生产中严重腐蚀材料和设备，因此建议将溶剂的pH值调整在6至8之间。模拟结果表明，当溶剂中K、Na、Mg、Ca、Cl和SO的值分别为0.1%、2.9%、3.77%、0.05%、15.72%和0.13%时，低品位固体钾矿的溶解度更强，更有利于矿石的选择性溶解。建议在实际生产中，用老卤和淡水配制的溶剂的化学成分应尽可能接近上述化学成分特征。
