Ionic Liquid-Based Process Development for Cobalt Recovery from Aqueous Streams

Using the ionic liquid [P8888 +][Oleate-], liquid-liquid extraction has been studied to recover Co2+ from water. Extractionregeneration experiments were followed during five consecutive cycles with Na2CO3(aq) as regeneration solution. Over 99% of Co2+ was extracted and using 0.7-1 M Na2CO3(aq) the extracted Co2+ was recovered for 99% in the form of CoCO3(s). Co2+ transfer shifted from ion-pair extraction in the first cycle to ion-exchange in the successive cycles. Thus, the measurement of a single extraction–regeneration cycle is not sufficient to perceive conclusive information about the steady-state conditions of the process. In the context of the feasibility of the technology, four key aspects are addressed: extraction efficiency, recovery of the IL, loss of the IL, and the end product. Synopsis Cobalt extraction from aqueous using ionic liquid [P8888 +][oleate-] and cobalt recovery applying Na2CO3 solution as an efficient and sustainable regeneration strategy since it provides interesting end product for market with high regeneration efficiency.