用H_(2)TiO_(3)型锂离子筛从盐湖卤水中提锂试验研究

Extraction of Lithium from Salt Lake Brine by H_(2)TiO_(3)Lithium Ion Sieves

针对西藏碳酸型盐湖,采用吸附法进行连续离子交换提锂试验研究,考察了H_(2)TiO_(3)型锂离子筛在盐湖卤水提锂的吸附—解吸过程,采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)对吸附前后锂离子筛的晶型和形貌进行了表征。结果表明:造粒后H_(2)TiO_(3)锂离子筛表面颗粒分散性良好,孔道疏松,晶体结构稳定,循环使用后结构未发生明显变化;在连续离子交换系统中,按吸附—洗料—解吸—洗酸4段工序将30柱分配为6∶1∶2∶1,H_(2)TiO_(3)型锂离子筛在吸附进料流速12 BV/h、三级吸附、吸附时间3 h、洗料流速10 BV/h、冲洗时间30 min、解吸过程盐酸为0.1 mol/L、解吸温度30~40℃、循环解吸1 h、洗酸流速8 BV/h、冲洗时间30 min条件下连续吸附卤水运行30个周期,吸附性能稳定,吸附量约6.67 mg/g,吸附率约80%,富锂解吸液中Li^(+)质量浓度约为1.2 g/L,ρ(Li^(+))/ρ(Na^(+))约为1。该法具有一定工业化推广应用价值。

The adsorption—resolution process of H_(2)TiO_(3)lithium sieves for lithium extraction from salt lake brine was investigated.The crystal shape and morphology of the screen before and after adsorption were characterized by X-ray diffraction(XRD)and scanning electron microscopy(SEM).The results show that the surface of H_(2)TiO_(3)lithium ion screen has good particle dispersion,loose pores and stable crystal structure after granulation,and the structure does not change significantly after recycling.In the continuous ion exchange system,the 30 columns are divided into 6∶1∶2∶1 according to the four steps of adsorption—washing material—desorption—acid washing,under the optimal conditions of the adsorption feed flow rate of 12 BV/h,the adsorption time of 3 h,the washing flow rate of 1 BV/h,the rinsing time of 30 min,the hydrochloric acid in the analytical process of 0.1 mol/L,analytical temperature of 30~40℃,the cyclic analytical time of 1 h,the acid washing flow rate of 8 BV/h,the washing rate of 30 min,the continuous operation of 30 cycles,the adsorption performance is stable,the adsorption capacity is about 6.67 mg/g,the adsorption rate is about 80%,and the Li-rich analytical liquid Li^(+)mass concentration is about 1.2 g/L,ρ(Li^(+))/ρ(Na^(+))is about 1.The method has a certain value of industrial popularization and application.