Extraction Potential of Tantalum from Spent Capacitors Through Bioleaching

Abstract

Tantalum (Ta) is the one of the most critical elements according to the European Commission. Research on tantalum recovery from secondary sources such as waste electrical and electronic equipment (WEEE), bottom ash and by products of the industrial activities, however, is limited. In this study, the recovery potential of tantalum from spent tantalum capacitors was tested using bioleaching. Three different kinds of microorganisms were tested for tantalum recovery, which were Pseudomonas putida (DSM No. 6125), Bacillus subtilis (DSM No. 1088532), and Penicillium simplicissimum (DSM No. 1078). It turned out that P. simplicissimum has the ability to leach tantalum from wasted tantalum capacitors with a maximium leaching rate of 1.25 g Ta per kg sample. An unknown species achieved the highest leaching rate (9.88 g Ta / kg sample) but isolation and identification failed. The potential of tantalum recovery by bioleaching is demonstrated, however, further research needs to be carried out.