Obtaining lithium carbonate from the black mass of lithium-ion batteries

The article explores the possibility of obtaining lithium carbonate from the black mass – an intermediate product of lithium-ion batteries recycling. X-ray phase analysis and inductively coupled plasma atomic emission spectrometry of the black mass revealed that it contains 3 % lithium. It has been established that during water leaching, 40 % to 70 % of lithium can be selectively extracted from the black mass into the aqueous phase at L/S ratios ranging from 10 to 200. During water leaching, kinetic curves were recorded at temperatures of 25 °C and 80 °C. To remove Al ions from the leaching solution, we studied the sorption of aluminate ions on weaky basic (AN-31, CRB05) and strongly basic (A500) anion exchangers under static conditions using a model Li–Al solution. It was demonstrated that in an alkaline environment, strongly basic anion exchangers with quaternary amino groups are not able to adsorb Al ions, while AN-31 and CRB05 with hydroxyl clusters in their functional groups have a capacity of 2 to 3 g/dm 3 in terms of aluminum ions. The sorption of aluminum from the model Li–Al solution was conducted under dynamic conditions using the CRB05 anion exchanger (N-methylglucamine) at specific flow rates of 2 and 4 column volumes per hour. Elution sorption curves were plotted, and both the dynamic exchange capacity and the total dynamic exchange capacity were determined. Additionally, we showed that aluminum ions can be removed by sorption so that their residual concentration in the raffinate drops below 0.5 mg/dm 3 . Sorption purification of the solution after water leaching of the black mass was performed using a weaky basic anion exchanger Diaion CRB05 and a chelate cation exchanger Purolite S950. After evaporation of the purified solution, we obtained lithium carbonate with a main substance content of 98.2 %.