Lithium sorption from natural brine

The study aims to investigate the efficiency of lithium extraction from highly mineralized calcium chlo ride brine of the Siberian Craton using a synthesized sorbent based on layered aluminum-lithium hydroxide. The re search into the sorbent properties (swelling characteristics, mechanical strength) was conducted in accordance with GOST 51641-2000 using an ELMI S-3L.A20 orbital shaker and a high-precision analytical balance CAS CAUW-220D. The sorption kinetics was studied under static conditions. The total dynamic capacitance and dynamic exchange ca pacity (before “breakthrough”) at brine flow rates from 1 to 3 column volumes per hour were determined in dynamic experiments. 100 continuous sorption-desorption cycles were carried out. The analysis of solutions for the element content was performed by the ICP-AES method with an iCAP 7400 Radial inductively coupled plasma atomic emis sion spectrometer. According to the conducted research, the swelling capacity of the sorbent was 19%, grindability equaled 1.72%, and abrasion amounted to 0.27%. The time to reach semi-equilibrium during lithium sorption under static conditions was 3 minutes. The total static capacitance equaled 5.5 mg/g; the total dynamic exchange capacity amounted to 5.5–5.7 mg/g. At a brine flow rate of 2 column volumes per hour, 95% lithium extraction was achieved. For commercial lithium recovery at a level of 95% at a flow rate of 1–2 column volumes per hour, 2 columns are re quired (or 3 columns at a flow rate of 3 column volumes per hour). It is shown that the sorbent capacity is maintained at a level of 5.6 mg/g throughout 100 sorption-desorption cycles. The concentration ratio (Ca2++Mg2+)/Li⁺ in the eluate is reduced 682-fold compared to the original brine. Thus, the sorbent demonstrates high efficiency for lithium extraction from brines with extremely high calcium ion content. The high values   of the rate of reaching semi-equilib rium, capacity, mechanical strength, as well as operational stability over 100 sorption-desorption cycles confirm the industrial potential of sorption extraction of lithium from highly mineralized calcium chloride brines.

sorption, lithium, layered double hydroxides, lithium extraction, brine