Processing of spodumene concentrates in fluidized-bed systems

•Successful calcination test work performed in fluidized bed systems.•Technical feasibility was proved for a wide range of spodumene concentrates.•High conversion rates of were achieved for all investigated materials.•Specific energy consumption can be significantly reduced. The production of lithium carbonate or lithium hydroxide out of lithium bearing ores requires a thermal activation for the phase transition in the mineral to enable an acid or soda leaching in the downstream hydrometallurgical section. In this paper, traditional processing of lithium ores in the lithium industry is reviewed and opportunities to improve product quality and recovery rate by simultaneously reducing energy consumption will be presented. The conventional process for pyro-processing is still based on rotary kiln, a technology in use since the early days of lithium ore processing, albeit not significantly further developed since. A new technology in this field is fluidized-bed calcination. A study of the major process parameters (temperature and residence time) was performed on laboratory and larger bench scale aiming for optimal product quality for subsequent processing. When converting α- to both β- and γ-spodumene, high conversion rates were achieved for all investigated materials. The conversion of α- to only β-spodumene varies significantly by concentrate. Preferential conditions were temperatures in the range of 1050–1070 °C with retention times of typically 25–40 min. Additional results include the characterization of granulometric properties, in particular the effect of defragmentation by decrepitation, elemental and mineral phase composition, and further aspects specifically related to the application of fluidized bed technology. After identifying optimal process conditions for calcination and proving general feasibility at laboratory scale, the technical feasibility was confirmed for a wide range of spodumene concentrates at bench and pilot scale (20 up to 500 kg/h feed) providing the basis for industrial process design. Thus, spodumene decrepitation through applying fluidized-bed technology is technically feasible for non-sticking material and high and homogenous product quality can be achieved.