A Novel Approach to Lithium Extraction From Spodumene by Combining Maleic Acid Leaching and Cyanex 936P Solvent Extraction

Abstract

This paper explores a novel approach to lithium recovery from spodumene, a lithium-bearing mineral. Instead of traditional sulfuric acid leaching, organic acids—specifically maleic acid—are investigated for efficient lithium extraction. The study examines the effects of various parameters on leaching efficiency, including maleic acid concentration, solid-to-liquid ratio, time, and temperature. The results show that using 2 mol L⁻¹ maleic acid, despite being less acidic than sulfuric acid, demonstrates promising leaching performance at 110°C with a solid-to-liquid ratio (S/L) of 80 g/L. After neutralization at pH 13 with sodium hydroxide to remove impurities (Mg, Mn, Fe, Si, and Al), solvent extraction using 30% (v/v) Cyanex 936P diluted in kerosene—a highly selective extractant for lithium—was performed to further purify the lithium-containing leachate and extract lithium. Following stripping with 2 mol L⁻¹ HCl, the resulting stripping solution containing lithium can undergo classical precipitation steps to remove calcium and precipitate lithium as lithium carbonate.