Management and valorisation of delithiated β-spodumene and its processing stream

Abstract

In many regions including Australia and South America (Lithium Triangle), lithium mining needs to thrive without compromising natural ecosystems. In particular, extracting lithium from pegmatites produces significant amounts of Delithiated β-spodumene (DβS) or equivalent materials. In this paper, an approach is proposed to solidify and stabilise both the solid and liquid streams of lithium processing, which is safer than the disposal of slurries in tailings dams. Alternatively, the obtained solid phase can be used for construction or geotechnical amelioration. The characterisation of DβS revealed that it belongs to the “silt loam” textural class with irregularly shaped and sharply edged particles. It has low basicity and hydration activity, which means that ground-granulated blast-furnace slag (GGBS) is required to make adequate solid products at ambient condition. In addition, it loses more mass than GGBS and fly ash (FA) as temperature increases, likely due to the decomposition of leached pyroxene and gypsum, dehydroxylation of hydrated aluminosilicates and quartz, and marginal losses of carbon dioxide. It was found that as opposed to common precursors of geopolymer or alkali activated materials, DβS increases workability and setting time.