西藏杜佳里盐湖湖水的自然蒸发及析盐规律

湖泊面积扩大和湖水淡化是青藏高原盐湖在响应全球气候变化过程中最直接的一种表现形式,这给青藏高原盐湖资源的开发带来了诸多挑战,探索淡化湖水中可利用元素的富集成矿规律在新形势下越趋重要。本文现场自然蒸发实验以杜佳里淡化碳酸盐型盐湖为研究对象,根据Na⁺、K⁺/Cl^-、SO₄^2-、CO₃^2--H₂O五元体系298K介稳相图,获得了淡化湖水在蒸发过程中Na、K、B、Li元素的富集浓缩规律以及各盐类矿物在蒸发过程中的析出规律。实验结果显示,杜佳里盐湖湖水在自然蒸发过程中最先析出芒硝矿物,其次为含CO₃^2-的碱类矿物,最后析出含B和K的矿物。直至实验结束,未见任何含Li矿物的析出,Li⁺仍处于浓缩富集过程中。

Natural evaporation and crystallization of Dujiali salt lake water in Tibet

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.