Comparison between simulated evaporation and natural evaporation of inter-crystal brine in Yiliping salt lake

Abstract

The simulated and natural evaporation processes of Yiliping inter-crystal brine were completed in the laboratory and in the field, respectively. (1) The different salts and precipitation sequence in different evaporation environment were achieved by XRD results, and the crystallization path of simulated evaporation is basically in conformity with the meta-stable diagram of Na⁺, K⁺, Mg²⁺//Cl⁻, SO₄ ²⁻–H₂O quinary system at 25 °C. (2) The natural evaporation path should have been described by equilibrium system at 25 °C due to the existence of Kainite, but in fact does not. However, the late stage of natural evaporation could be explained by the meta-stable system at 35 °C. (3) Carnallite precipitated in advance no matter what the evaporation condition was. (4) There exists a certain regularity between water loss rate and salt crystallization rate during the simulated evaporation process in laboratory. Namely, there is an abrupt change of water evaporation and salt precipitation rate when minerals enter the next precipitation stage. (5) The rare elements of boron and lithium that Yiliping lake features present similar enrichment rule for the two evaporation methods, even though their concentrated times are far lower than that of brine.