Reduction in adsorbent granule dimensionality to strengthen lithium adsorption in low‐grade salt lakes

Abstract Sluggish internal mass transfer within granulated adsorbents constrains the efficiency of Li + extraction from low‐grade salt lakes. In this study, Li + diffusion behavior simulations using finite element analysis indicated that reducing the granule dimensionality enhanced Li + transfer in aluminum‐based lithium adsorbents, with ionic strength as the driving force. Hence, low‐dimensional aluminum‐based adsorbent granules (LD‐LDHs) with fast transport channels and highly accessible adsorption sites were directionally prepared via a wet‐spinning method. Adsorption kinetics suggested LD‐LDHs with reduced internal diffusion resistance achieved equilibrium in less than 30 min, which was significantly shorter than the 36 h required for larger granules prepared by conventional extrusion molding, while maintaining the performance of the encapsulated active components. During continuous lithium extraction from low‐grade Qarhan old brine, LD‐LDHs reached adsorption saturation in 60 min, with a 1.8‐fold increased working capacity, and the desorption solution was of higher quality, favorable for subsequent lithium carbonate production processes.