• 标题：The Effect of Solvent Chemistry on Potassium Dissolution Extraction from Low-Grade Solid Potash Ore in Qarhan Salt Lake, China
• 关键词：low-grade solid potash ore; solvent; geochemistry; dissolution extraction; Qarhan Salt
• 作者：Ruiqin Li, Chenglin Liu, Pengcheng Jiao, Wanping Liu, Shijun Wang, Deguo Tang

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Qarhan Salt Lake contains approximately 296 million tonnes of low-grade solid potash ores. The exploitation and utilization of this low-grade solid potash ore represents the fundamental framework for the sustainable development of Qarhan Salt Lake’s potash fertilizer. It also alleviates the shortage of potash resources. In this paper, we studied species and characteristics of the low-grade solid potash minerals from the Bieletan area in Qarhan Salt Lake and analyzed the solvent that affected the dissolution extraction of low-grade solid potash ore. The major potash minerals in the Bieletan Subbasin are polyhalite, carnallite and sylvite. An effective solvent for dissolving low-grade solid potash minerals is prepared with old bittern and water from Senie Lake, which contains average Mg2+, Cl- , K+ and Na+ values as 3.69%, 15.23%, 0.23% and 1.60%, respectively. Theoretically calculating by PHREEQC shows that the chemical composition of the solvent is nearly in equilibrium with halite and far from in equilibrium with polyhalite, carnallite and sylvite. This solvent does not significantly cause dissolution and precipitation of halite. Thus its influence on the porosity and permeability of the salt bed in the strata is minimum, which enables the solvent to flow to deeper and farther areas and dissolve more low-grade solid potash minerals, showing excellent ability to selectively dissolve K+ -bearing saline minerals. After dissolution extraction experiments, the concentration of K+ in the solvent increased from0.23% to 0.68%, showing the higher-dissolution effect of the solvent for the low-solid potash ores. Hence, the solvent plays an important role in developing of the low-grade potash ores.