关键词: 气候变化, 碳酸盐型, 自然蒸发, 析盐规律

Abstract: Salt lake expansion is one of the most direct geological responses to the global change on the Qinghai-Tibet Plateau,and the subsequent desalination poses challenges to the exploitation of salt lake resources. For these dilute salt lake,understanding the behavior of enrichment of elements and mineralization has become increasingly important. We carried out natural evaporation experiment on the water of Dujiali salt lake,a representative of dilute carbonate-type salt lake,at a nearby science station. On the basis of the 298K metastable phase diagram for the Na⁺,K⁺/Cl^-,SO₄^2-,CO₃^2--H₂O quinary system,the concentration behavior of Na,K,B and Li was investigated,and the precipitation conditions and precipitation sequence were reported. Our experiments showed that the precipitation sequence through natural evaporation was mirabilite (Na₂SO₄·10H₂O) the first,carbonate containing alkaline salts the second,and finally B and K bearing minerals. The brine did not reach the stage for the precipitation of Li bearing minerals in our evaporation experiments,and Li⁺ was enriched in the residual brine.

Key words: climatic change, carbonate-type, natural evaporation, crystallization law