Acid roast process, spodumene

Figure 1.86 The initial flowsheet for LCA s production of lithium carbonate from spodumene by the acid roast process (after Hader et al, 1951).

A detailed laboratory study has been presented by Dresler et al. (1998) on the Roast, Acid-Leach Process that exactly follows the process previously used by the LCA (now EMC) at their North Carolina deposit. It is reviewed here because of the additional details that it supplies on this very effective spodumene process. Their ore was from Wekusko Lake, Manitoba, which as at LCA s deposit was an unzoned and low-grade (0.79% Li) spodumene ore, but with a very small crystal size. Electron micrographs showed that each of the minerals in the ore (Table 1.18) was present as discrete crystals, but the liberation size was quite small. Consequently, they ground the ore to a —212 p,m (—65 mesh) size, and made into a 23% slurry to be agitated and conditioned with 2 kg of sodium hydroxide/mt of ore for 20 min. 

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