改进沉淀法对高镁锂比卤水进行锂镁分离研究

Study on the Separation of lithium and Magnesium from High Mg/Li Ratio Salt Lake Brine by the Improved Precipitation Method

高镁锂比盐湖卤水中锂镁分离提锂是一项需要攻克的技术难题。采用改进沉淀法进行锂镁分离,来解决我国高镁锂比盐湖卤水提锂的工艺难题。配制高镁锂比卤水(ρ(Mg^(2+))=110 g/L,ρ(Li^+)=2.5 g/L,Mg/Li=44),加入氢氧化镁晶种;以氢氧化钠为主沉淀剂,以吐温-80、聚丙烯酰胺为辅助沉淀剂,进行沉淀除镁反应。结果表明,沉淀反应生成的氢氧化镁易于过滤,锂损失率低于2%。通过对得到的沉淀进行SEM、LPSA表征,其沉淀的结构和形态发生了很大的变化,得到了颗粒大而完整的沉淀。

At present, the separation of magnesium and lithium in salt lake containing high magnesium- lithium ratio is a key technical problems in the development of salt lake brine. The improved precipitation method is used to solve the problems that lithium is extracted by means of separation of the high ratio of magnesium lithium from salt lake brine. High Mg/Li ratio salt lake brine （ρ（ Mg ^2＋） =110 g/L;ρ（ Li ^＋） =2. 5 g/L;Mg/Li =44 ） is prepared , adding the magnesium hydroxide crystal seed, and precipitation reaction for magnesium hydroxide was proceeded by using sodium hydroxide as the main precipitat-ing agent, tween -80 and poly（ acrylamide） regard as auxiliary precipitant. The results showed that the resulting precipitate of magnesium hydroxide was easy to filter, lithium-ion adsorption loss rate of less than 2% . Using SEM, LPSA, the results showed that the morphology and structure of magnesium hydrox-ide precipitate have been changed effectively and the large granu-lar and solitary precipitate could be got by using the improved precipitation method.