Regeneration of Sn⁴⁺ from Sn²⁺ solution during electrowinning process using anion exchange membrane

ABSTRACT

Electrowinning process to regenerate Sn⁴⁺ from Sn²⁺ in HCl solution using an electrowinning cell with anion exchange membrane was proposed to suggest a novel recycling process to recover Sn. During the tests, the effects of initial Sn²⁺ concentration on the regeneration of Sn⁴⁺ were investigated under the following condition; 7,000 mg/L, 10,000 mg/L, and 13,000 mg/L of Sn²⁺, 1 M HCl, 250 A/m² of current density, graphite anode, titanium cathode, room temperature, and 2 h. Electro-deposited Sn on the cathode showed dendritic structure regardless of the Sn²⁺ concentration and no change of Sn concentration was observed in the anolyte. Leaching tests were performed using the anolyte, obtained from the electrowinning tests, to examine the amount of regenerated Sn⁴⁺ concentration during electrowinning process. Based on the results of Sn leaching tests, it was found that 84.44%, 81.03%, and 79.43% of Sn⁴⁺ were regenerated from 7,000 mg/L, 10,000 mg/L, 13,000 mg/L initial concentration of Sn²⁺ solution, respectively. Consequently, it was found that the regeneration of Sn⁴⁺ can occur during the electrowinning process at the same time with Sn recovery and Sn⁴⁺ can be reused as an oxidant to leach Sn successfully.

KEYWORDS:

• Sn leaching
• Sn⁴⁺ regeneration
• electrowinning
• anion exchange membrane
• electro-deposited Sn

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No.2017R1A2B1008174).