Abstract:The influences of temperature, H₂SO₄ concentration, CuSO₄ concentration, reaction time and SO₂ flow rate on the reduction of arsenic(V) with SO₂ were studied and the deposition behavior of arsenic (III) under the effect of concentration and co-crystallization was investigated in copper electrolyte. The results indicate that reduction rate of arsenic (V) decreases with increasing temperature and H₂SO₄ concentration, but increases with increasing SO₂ flow rate and reaction time, and it can reach 92% under appropriate conditions that reaction temperature is 65 °C, H₂SO₄ concentration is 203 g/L, CuSO₄ concentration is 80 g/L, reaction time is 2 h and SO₂ gas flow rate is 200 mL/min. To remove arsenic in the copper electrolyte, arsenic (V) is reduced to trivalence under the appropriate conditions, the copper electrolyte is concentrated till H₂SO₄ concentration reaches 645 g/L, and then the removal rates of As, Cu, Sb and Bi reach 83.9%, 87.1%, 21.0% and 84.7%. The XRD analysis shows that crystallized product obtained contains As₂O₃ and CuSO₄·5H₂O.

Key words: copper electrolyte; arsenic (V); reduction; sulfur dioxide; concentration; arsenic trioxide