Stability of [BMIM]HSO4 for using as additive during zinc electrowinning from acidic sulfate solution

The stability of ionic liquid additive 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM]HSO 4 ) during zinc electrowinning from acidic sulfate solution was investigated by cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy. Compared with the traditional industrial additives, gelatine and gum arabic, [BMIM]HSO 4 has more excellent chemical and thermal stabilities. The inhibition effects of gelatine and gum arabic on the zinc electrocrystallization are observed to markedly weaken due to their part degradation after 12 h longtime successive electrolysis and high temperature (90 °C) treatments. In contrast, the activity of [BMIM]HSO 4 is practically unaffected after 24 h longtime successive electrolysis and high temperature treatments. These results are corroborated with the corresponding morphological analysis of the cathodic deposits.