YU Jiangjiang, ZHENG Mianping, WU Qian, WANG Yunsheng, NIE Zhen, BU Lingzhong
Considering the huge impact of global warming on lakes on Qinghai-Tibet Plateau and the serious lake desalination resulting from expanded lake area, the research on carbonate-type desalinated saline lakes is of great significance. Taking the carbonate-type salt lake of Bangor Lake as the research object, the on-spot natural evaporation experiment has explored the pH changes in lake water and the effect of alkali metal elements content on mineral separation under the guidance of 298 K metastable phase diagram of quinary system of Na+, K+/Cl-, SO42-, and CO32--H2O, Experimental results show that mineral deposits from desalinated lake water would be developed in a longer period in the context of natural evaporation. After a slow reduction process, the pH value of lake water is increased rapidly in the late stage of evaporation, which is mainly related to and positively correlated with the contents of CO32-, HCO3- and OH- in the lake water. Among the main alkali metal elements that affect the acid-base property of desalinated lake water, the role of Na exceeds that of K, followed by Li. Their corresponding minerals are also changed from neutral to alkali property; and the order of separated minerals is mirabilite, halite, aphthitalite, burkeite and trona. Based on the separation characteristics of different minerals, they can be recovered and extracted by stages, which is practically significant in the development of the salt lake resources.
