The effect of conditioning pH behaviour on spodumene flotation with fatty acids

Spodumene - the primary lithium mineral - is often concentrated by flotation with fatty acid collectors. However, producing high-grade concentrates at high recoveries is challenging and a risk for future operations. Poor spodumene selectivity is largely driven by the sensitive properties and poor solubility of fatty acids and requires high-density conditioning for desired flotation performance. This study related pH behaviour and operating parameters during fatty acid conditioning to flotation performance. The best pH characteristics for >85% lithium recovery at >5.25% Li2O were a minimum pH 6.5-6.8, final pH 6.7-7.1, and a pH change rate of 0.07 Delta pH/min. Regression analysis predicted optimizated conditions of initial pH 8.2, 30 W/L power density, 8 min conditioning and 550 g/t collector. Follow-up testing confirmed a higher W/L improved grade, and recovery was maintained when combined with decreased residence time and pH. Better defining these relationships can improve process control n developing industrial spodumene flotation circuits.