High mixing enhancement for continuous uniformity Li/Al-LDHs in lithium extraction from low grade salt lakes

Abstract

The enhancement of lithium extraction from low grade salt lake through the development of advanced adsorbents has become a primary focus in current research. A new method was developed in this work for the continuous fabrication of ultra-highly uniform lithium-aluminum layered double hydroxides (H-LDHs), used as lithium adsorbents, through a high mixing reactor. These H-LDHs featured a more consistent particle size distribution, which facilitated an enhanced vibrational density. This not only significantly increased the powder content in granules but also improved lithium adsorption efficiency. Computational fluid dynamics (CFD) modeling showed that the reactor reached peak mixing efficiency with a minimal gap size of 1 mm. The analysis further indicated that a Reynolds number of 75 led to enhanced mixing effects and stronger flow dynamics. Experiments with Qarhan salt lake brine demonstrated that the H-LDHs powders reached a lithium adsorption capacity of up to 7.27 mg/g, while the volumetric adsorption capacity of these H-LDHs granules exceeded that of traditional granules by 1.179 times. Subsequent desorption and cycling experiments verified the material’s enduring lithium adsorption efficacy and structural integrity, underscoring its considerable potential for industrial use.