锂铝层状吸附剂超低品位卤水提锂冲洗和解吸过程

锂铝层状氢氧化物对Li⁺具有高吸附选择性，能够有效地从高镁锂比（质量比）盐湖卤水中进行锂资源提取，具有工艺简单、经济环保等特点。本文使用球形锂铝层状吸附剂GLDH作为吸附柱填充物，系统研究了流速、温度和Li⁺初始浓度对铝盐锂吸附剂盐湖提锂工艺中冲洗、解吸的影响。试验结果表明，低温快速冲洗能有效降低冲洗过程中的Li⁺损失率。当冲洗液中Li⁺的浓度为200mg/L，冲洗液以12.0BV/h的速度在0℃下通入吸附柱时，Li⁺损失率可降低到17.8%。在解吸过程中，高温、低速和低初始Li⁺浓度的条件有利于Li⁺从吸附剂中脱出。但鉴于吸附剂的循环稳定性，采用初始Li⁺浓度为300mg/L的解吸液以2BV/h的流速在40℃下对吸附柱进行解吸，3BV时停止解吸，此时锂解吸量可达3.76mg/g，解吸液中Li⁺的平均浓度为590.83mg/L，Mg/Li比仅为0.13，可有效实现镁锂分离和锂元素集浓。循环30个周期后吸附剂的吸附容量没有明显下降，表明锂铝层状吸附剂GLDH具有良好的循环稳定性。

Washing and desorption procedures research on granulated lithium aluminum layered double hydroxides for lithium recovery from low-grade brine

Lithium/aluminum layered double hydroxides (Li/Al-LDHs) was an effective adsorbent with high lithium selectivity for lithium extraction from old brine with ultrahigh Mg²⁺/Li⁺ ratio and low Li⁺ grade. The effects of flow rate, temperature, and initial lithium concentration on the washing and desorption processes of lithium recovery with granulated lithium aluminum layered double hydroxides (GLDH) had been investigated in this study. A lower temperature, higher flow rate, and initial lithium concentration could increase the Li⁺ deintercalation resistance during washing, but be negative to the Li⁺ unloading from GLDH during desorption. The Li⁺ loss rate could be reduced to 17.8% when the initial Li⁺ concentration of 200mg/L had been applied with the flow rate of 12.0BV/h at 0℃. The Li⁺ desorption amount could reach to 3.76mg/g when the initial lithium concentration of 300mg/L went through the column at a flow rate of 2BV/h at 40℃ for 3BV. The average lithium concentration in collected strip solution was 590.83mg/L with an Mg/Li ratio of 0.13, which could perfectly achieve the separation of magnesium and lithium and the lithium concentration. The Li⁺ adsorption capacity of GLDH was immobile in 30 adsorption-washing-desorption cycles, proving the good adsorption performance stability.