Separation of Cd(II), Cu(II) and zinc sulfate from waste produced in zinc hydrometallurgy cementation

ABSTRACT

This study aims to evaluate the feasibility of applying aqueous two-phase systems (ATPS) to process the zinc hydrometallurgical cementation residue, seeking to extract the Cu(II) and Cd(II) in the top phase, while zinc is concentrated in the bottom phase. Initially, leaching conditions were optimized. After evaluating several polymers, the optimum conditions of ATPS formation were: poly(ethylene glycol) 4000 g.mol⁻¹ at 18 wt% and pH = 2.0. After two extraction steps, high values of %E for Cu(II) (%E = 90.1 ± 3.1%) and Cd(II) (%E = 99.1 ± 4.0%) were obtained, while Zn(II) was predominantly retained in the bottom phase.

KEYWORDS:

• Metal separation
• hazardous waste
• aqueous two-phase system
• metal recuperation
• environmentally safe technique

Acknowledgements

The authors are grateful for the financial support provided by Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) (APQ-01308-18), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (425913/2018-0) and Federal University of the Jequitinhonha e Mucuri Valleys. AWV and CSA received an undergraduate scholarship from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. This work was part of a collaborative research project with members of Rede Mineira de Química (RQ-MG), supported by FAPEMIG (Project: CEX-RED-0010-14.)

Declaration of interest statement

Declaration of interest statement: none

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Additional information

Funding

This work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico [425913/2018-0]; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior [Financial Code - 001]; Fundação de Amparo à Pesquisa do Estado de Minas Gerais [APQ-01308-18].