The foundation for the efficient utilization of potassium resources in Salt Lake brine is to reveal the structural characteristics of the solution, analyze the crystallization behavior process, and its correlation. This study investigated ionic hydration and binding structures in K2SO4-MgSO4 mixed solutions using synchrotron X-ray scattering. Meanwhile, the crystallization behavior of mixed solution droplets was further studied using in situ Raman spectroscopy technology. Research has shown that as the mass fraction of MgSO4 increases, the hydrogen bond network structure is disrupted in the solution. In the mixed solution, Mg2+ competes with K+ for SO42-, promoting the transformation of the K+-SO42- binding form from a bidentate contact ion pair to a monodentate contact ion pair, forming multi-ion clusters such as K+-SO42--Mg2+. Under low humidity (RH 2+-SO42- chain MCIP, resulting in a 60-92% decrease in water loss rate (k = 0.0059-0.0179 s-1) compared to pure K2SO4 (k = 0.0741 s-1). In addition, the colloidal interfacial layer in the mixed droplets significantly delayed the nucleation and crystallization of K2SO4. This study provides a theoretical basis for extracting potassium sulfate from sulfate-type Salt Lake brine.
Du et al. (Thu,) studied this question.