HLS Testwork on Spodumene and Lepidolite Samples to Determine Maximum Achievable Lithium Upgrade

Abstract

There is a growing demand for lithium as it is primarily used in the production of batteries. Two lithium bearing ores, namely spodumene and lepidolite, underwent gravity separation via heavy liquid separation (HLS) laboratory tests to determine the amenability of each ore to upgrade by gravity processes, such as dense medium separation (DMS). Each sample was crushed to −20 mm, and the −1 mm fraction was screened out to produce a −20 + 1 mm feed for HLS testwork. A 50/50 composite sample was also created to determine the performance when both ores are treated simultaneously. At a cut point of 2.9 g/cm3, lepidolite, spodumene and the composite achieved %Li2O grades of 4.28%, 3.38% and 4.59%, at recoveries of 24.6%, 2.77% and 10.1%, respectively. The grade of the composite samples is greater than the theoretical calculated grade, which may be due to the nugget effect of spodumene. At a cut point of 2.8 g/cm3, recoveries are significantly improved (>73%); however, the grade is then compromised.