RECOVERY OF LITHIUM FROM WASTE MATERIALS

In this study, processes based on roasting-leaching-crystallization steps and condensation-precipitation steps for Li2CO3 separation from spent Li/MnO2 batteries and lithium-containing wastewaters were developed and verified on a laboratory scale. Spent Li/MnO2 batteries were roasted under reduced pressure at 650°C, which split the castings and deactivated the batteries by reduction of LiMnO2 and MnO2 with residual lithium metal and graphite to form MnO and Li2CO3. The resultant lithium carbonate was selectively solubilised in water with manganese remaining in the leach residue. Li2CO3 of 99.5 % purity was obtained after evaporation of 95 % water. Processing of lithium-containing alkaline wastewaters from the production of liquid rubber comprises condensation up to lithium concentration of 12-13 g/l Li and a two-step precipitation of lithium carbonate using CO2 as a precipitation agent. Sparingly soluble Li2CO3 was produced in the second step at 95°C, whilst most impurities remain in the solution. Obtained lithium carbonate products contained on average more than 99.5 % Li2CO3. The lithium precipitation efficiency was about 90 %.