For the rotary kilns for spodumene calcination and cooling as well as for the acid roasting and cooling Metso can rely on the experience of over one thousand rotary kiln installations worldwide, e.g. for coke calcining, lime calcination, iron ore indurating and many other processes. The heating can be tailored to the specific requirements of the project, with direct or indirect heating, radiative, conductive or convective heat transfer and all different heat sources like gas, oil and coal, hydrogen or biomass or electrical with IR elements of even plasma torches.
The main features for the calcination kiln are high flexibility to feed variability, which accommodates wide particle size distributions, stable reaction zone and uniform drying, increased lithium yield, high thermal efficiency with approx. 15% reduced fuel consumption and smaller footprint for kiln, material handling and gas cleaning.
For the acid roast kiln Metso is following the concept of an efficient natural gas fired kiln with effective heat recovery. The furnace provides convective and radiative heat transfer, with waste heat recovery for preheated combustion air. Accurate temperature control results in lower probability to overheat material, less H2SO4 evaporative loss, lower OPEX and low fuel consumption rate.
