Study on Deactivation of Sphalerite with Sulphuric Acid and Ferric Ion Solutions

Abstract

The separation of Cu/Zn ores in the flotation treatment of complex sulphide ores is very difficult because of copper activation. Therefore, the deactivation of copper-activated sphalerite is one of the most important subjects in the flotation operation of complex sulphide ores. In this study, the deactivation of copper-activated sphalerite has been investigated in a series of laboratory experiments. Firstly, the effects of sulphuric acid and ferric ions in the presence of sulphuric acid on the deactivation of copper-activated sphalerite were examined from the flotation tests by the Hallimond tube. From the results obtained, it was found that the deactivation of copper-activated sphalerite could be attained to some degree by a 3～5 vol. % H₂SO₄ solution, and could be attained very well by a 500～l, 000 mg/1 Fe⁺⁺⁺ solution containing H₂SO₄. In this case, oxygen gas accelerated the deactivation of the sphalerite in the treatment of both the above solutions. Temperature was also one of the important factors for the deactivation. Secondly, the dissolution of the copper-activated film formed on the sphalerite was investigated. From the results obtained, it was found that copper-activated film could be dissolved completely by the Fe⁺⁺⁺ solution containing H₂SO₄, and could be dissolved to some degree by the H₂SO₄ solution. The dissolution rate of the activated film was measured as a function of the concentration of Fe⁺⁺⁺ and H₂SO₄ and of the temperature. The dissolution rate is shown by a linear equation. Using a flotation machine, a series of differential flotation tests of Cu/Zn sulphide ores was carried out. From the results obtained, it was confirmed that the flotation separation of Cu/Zn sulphide ores was successful by the deactivation treatment for the Cu/Zn sulphide ores.