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 industry. It also alleviates the shortage of potash resources of China. 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 these potash minerals is prepared with old bittern and water from Senie Lake, which contains average Mg2þ, Cl� , Kþ and Naþ 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 away from 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 ores, showing excellent ability to selectively dissolve Kþ-bearing saline minerals. After dissolution extraction experiments, the concentration of Kþ in the solvent increased from 0.23% 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.