Ammoniacal Dissolution of Polymetallic Alloy Produced from Waste Electroscrap

Resumo

The paper reports spontaneous and electrochemical dissolution of polymetallic alloy obtained from electrowaste. Effectiveness of chloride, carbonate and sulfate ammoniacal solutions was compared. Leaching process was conducted with and without addition of cupric ions. It resulted in the transfer of primarily copper (over 90%) and negligible amounts of zinc, lead, nickel and iron to the electrolyte, but the rate of the spontaneous dissolution was low. The best condition of the alloy leaching was obtained in the presence of Cu²⁺ ions in ammonium-carbonate solution. Anodic dissolution of the alloy led to unfavorable distribution of metals among the slime, electrolyte and cathodic deposit, but the highest dissolution rate in the chloride bath was found. Copper can be selectively recovered on the cathode from all electrolytes.