扎布耶盐湖卤水碳酸锂恒温平衡浓度和结晶规律初步研究

The Preliminary Study on the Equilibrium Solubility and Crystallization Laws of Lithium Carbonate Based on the Composition of Zhabuye Salt Lake Brine

文章采用化学反应法和恒温法首次探索研究了-5℃、5℃、15℃、30℃、40℃、55℃、70℃情况下扎布耶盐湖卤水介质环境中碳酸锂的恒温平衡浓度和结晶规律。研究结果表明在扎布耶盐湖卤水中,由于大量碳酸根和其它离子的存在,碳酸锂的恒温平衡浓度较纯水中的浓度小,最大差别达1.2 g/L(以锂离子浓度表示),其逆溶解度的特性不变。升温过程中不同组成卤水碳酸锂结晶规律基本一样,温度越高,碳酸根浓度越高的卤水在升温过程中达平衡时间越短,析出的碳酸锂也越多,最高碳酸锂析出率达39.5%。相同温度下,卤水中碳酸根浓度在30 g/L以下时,碳酸根对碳酸锂的恒温平衡浓度影响较大,碳酸根高过30 g/L以后影响变小;不同组成卤水40℃以下需要120 h以上才可达到平衡,55℃以上只需24 h。

The Equilibrium solubility and crystallization of lithium carbonate based on the composition of Zhabuye Salt Lake Brine were primarily studied in this work with chemical reaction method isothermal method at -5 ℃ , 5 ℃ , 15 ℃ , 30 ℃ , 40 ℃ , 55 ℃ , 70 ℃. It was found that the solubility of the lithium carbonate with the composition of Zhabuye Salt Lake brine was quite different with pure lithium carbonate solution. The most difference is about 1.2 g/L （ Li ^＋ ）. The crystallization process of lithium carbonate for different composition brine was similar at different temperatures. The higher the crystallization temperature is, the higher the concentration of sodium carbonate in the solution is, the shorter the crystallization time is, and the higher the recover rate of lithium carbonate from Zhabuye Salt lake brine. The highest recover ratio of lithium carbonate is about 39.5%. The solubility of the lithium carbonate was strongly affected by the concentration of the carbonate ion in the brine at the same temperature when the concentration of carbonate ion was lower than 30 g/L. The solubility of lithium carbonate was not influenced much when carbonate ion excess 30 g/L. The crystallization time was about 120 hours when crystallization temperature is lower than 40 ℃. When crystallization temperature is higher than 55 ℃, the crystallization time was only 24 hours.