A Review of Fatty Acid Collectors: Implications for Spodumene Flotation

Increasing demand for lithium-ion batteries has led to the development of several new lithium mineral projects around the globe. Some major mineral processing challenges these projects face are similarities in gangue and value mineral behaviour and poor selectivity in froth flotation. Unsaturated anionic fatty acids are the primary spodumene flotation collectors, known to be strong collectors with poor solubility and selectivity. Fundamental flotation research consensus is that spodumene flotation is driven by a fatty acid–anion complex adsorbed at cationic aluminum sites. However, many small-scale studies result in poor recoveries, prompting several researchers to investigate cationic activators or mixed anionic/cationic collectors to improve flotation performance. Testwork with real spodumene ore is rare in recent literature, but older publications from several deposits prove that fatty acids can successfully concentrate spodumene. The process generally includes alkaline scrubbing, high-density fatty acid conditioning, and flotation at pH 7.5–8.5 with 500–750 g/t fatty acid collector. The collector speciation behaviour is notably sensitive to pulp conditions around this pH; possibly resulting in unstable flotation circuits and inconsistent results. This paper reviews fatty acid collector properties and the available industrial and fundamental spodumene flotation research. We aim to provide new insight for understanding particle-collector interactions in spodumene flotation and help bridge the gap between fundamental and industrial processes which will be needed to de-risk projects in the growing lithium mineral industry.