Extraction and Removal of Lithium by Adsorption onto Resin Amberlyst35 from Bayer Liquor Before Seed Decomposition

Abstract

Lithium present in Bayer liquor enters the alumina during the seed decomposition process, subsequently increasing energy consumption in the aluminum electrolysis process, which is environmentally unfriendly. Combined with the global demand for lithium and the alumina industry’s pursuit of high-quality alumina, it highlights the essential need for lithium recovery in the alumina production process. This study utilized Amberlyst35 resin as an adsorbent for the adsorption of lithium from Bayer mother liquor. Under experimental conditions consisting of a causticity ratio of 1.5 in sodium aluminate solution, lithium ion concentration of 6.8 mmol/L, and a reaction temperature of 70 °C maintained over a 240-min period, the resin exhibited a lithium adsorption capacity of 5.88 mmol/g and a removal efficiency of 69.18%. The adsorption process was fitted with the pseudo-second-order kinetic model and Langmuir isotherm model, and the theoretical saturation adsorption capacity of lithium was 6.485 mmol/g. The adsorption process is an endothermic process and occurs spontaneously. Analytical techniques, specifically Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, revealed the presence of sulfonic acid groups (–SO₃H) within the resin. A notable reduction in the peak intensities associated with these sulfonic acid groups post-adsorption suggested a direct interaction between the lithium ions and the sulfonic acid functionalities of the resin.