西藏当雄错碳酸盐型盐湖卤水自然蒸发析盐规律研究

盐湖卤水中蕴藏有许多重要的无机盐资源,是多种无机化学品的重要来源。当雄错盐湖是我国藏北高原典型的碳酸盐型盐湖,卤水中蕴藏有丰富的锂、钾、硼等盐类,当地气候条件非常适宜采用盐田相分离技术进行盐湖卤水的综合开发和利用。本文以Na+,K+/CO32-,SO42-,Cl--H2O五元体系(25℃)介稳相图为指导,通过对当雄错盐湖卤水在湖区现场开展自然蒸发实验研究,考察了卤水中Li、K、B等元素的浓缩富集规律,获得了卤水夏季自然蒸发结晶路线及析盐次序为石盐、水碱、天然碱、钾石盐、钾芒硝、硼砂和碳酸锂,同时分析了夏、冬季卤水自然蒸发浓缩析盐规律的区别,为指导西藏当雄错碳酸盐型盐湖卤水的综合开发利用提供了盐田工艺设计基础和理论依据。

Natural Evaporation and Crystallization Regularity of Dangxiongcuo Carbonate-Type Salt Lake Brine in Tibet

The salt lake brine contains a lot of inorganic salt resources,and it is an important source for the inorganic chemicals.Dangxiongcuo salt lake is a typical carbonate-type salt lake in Tibet of China,which is rich in Li,K and B.The local climatic condition is very suitable for the exploitation and utilization of salt lake brine by using the salt field phase-separation technique.In this paper,the natural evaporation experiment of Dangxiongcuo salt lake brine has been operated in the lake-district.The concentrating behaviors of Li,K,B with their separated conditions were analyzed in detail.According to the quinary system Na+,K+/CO32-,SO42-,Cl--H2O(25 ℃) metastable diagram,the crystallization path of salts has been drawn and the precipitation sequence is halite(NaCl),thermonatrite(Na2CO3.H2O),trona(Na2CO3.NaHCO3.2H2O),sylvite(KCl),aphthitalite(Na2SO4.3K2SO4),borax(Na2B4O7.10H2O) and zabuyelite(Li2CO3).The comparison of brine concentration and crystallization regularity between summer and winter has also been listed.All these can provide the technology foundation for the comprehensive exploitation and utilization of the carbonate-type salt lake brine such as Dangxiongcuo.