Mark G. Aylmore, Kelly Merigot, William D. A. Rickard, Noreen J. Evans, Bradley J. McDonald, Enej Catovic, Peter Spitalny
With the impetus for less reliance on fossil fuels and cleaner environments, the ability to be able to
extract lithium used in rechargeable batteries for portable electronic devices from ores economically,
is essential. However a comprehensive understanding of the deportment of lithium and associated
minerals in some ore bodies is limited. To facilitate further process development, a comprehensive
understanding of the deportment of Li and associated minerals in ore bodies is essential to
allow the industry to predict the response of ore reserves to metallurgical treatment options.
To quantify the different lithium bearing minerals in the ore, the chemistry and structural characteristics
of a suite of Li mineral phases were examined and defined prior to examining ore material.
The mineralogy, mineral associations and liberation characteristics of both ore-bearing and gangue
minerals were characterised using a Tescan Integrated Mineral Analyser and X-ray powder diffraction
studies. The Li content and distribution within minerals were defined in both ore and mineral
standards using LA-ICPMS and FESEM with ToF-SIMS capabilities. The Al:Si ratio, Mn, Na, Fe
and F contents were used to classify and group the different Li mica minerals.
Analysis of a micaceous pegmatite from Lepidolite Hill (400,000 t, 1.5 wt-% Li, Resource ~ 6 kt)
indicated the ore is predominately lepidolite composite particles, with moderate to minor amounts
of liberated trilithionite, albite, quartz, polylithionite and muscovite. Minor amounts of topaz, elbaite
and beryl also occur. The lepidolite particles consist of fine textured intergrowths of Li muscovite-
muscovite, lepidolite, polylithionite and trilithionite. A calculated theoretical grade-recovery
for minerals lepidolite and combined trilithionite and polylithionite indicated that optimum Libearing
mineral recovery occurs in the sieve fraction − 355 to +180 μm with rejection of quartz and
albite that make up ~ 20 % of the sample. However, further grinding of lepidolite particles to
particle size < 90 μm is required to breakup and expose fine grains of polylithionite, trilithionite and
possibly reject some muscovite, before applying a process for leaching and extracting lithium. Liberation
and leaching of F from micas also has to be managed.