A novel process for extracting bismuth from high iron content copper smelting dust by magnetic separation and leaching process

Abstract

In this study, an efficient method for extracting bismuth from copper smelter flue dust with high content of iron was proposed. In this method recovery of bismuth from copper flue dust was carried out after copper and iron separation. To separate copper from dust, this material was leached with water and dilute sulfuric acid (0.6 M). Magnetic separation was performed with field intensities of 0.1 T and 0.4 T to separate iron in the leaching residue. 70 % of bismuth is placed in the non-magnetic fraction. The non-magnetic fraction of this separation was leached with (1.4 M) H2SO4 + (1 M) NaCl solution to recover bismuth. In optimal conditions, more than 98 % of bismuth in the non-magnetic fraction is leached. Bismuth precipitation from this solution was done by adjusting the pH to 2.5 with the ammonia solution. Impurities such as; Pb, Fe, As, and Cu were precipitated with bismuth in this condition. Lead was removed as a PbCl2 compound by leaching the precipitate with 6 M hydrochloric acid. Other elements were leached in this chloride environment and entered the solution phase. Bismuth was separated from this leaching solution by hydrolysis in the form of BiOCl. The purity of the BiOCl product was about 95 %. This substance can be used in photocatalyst and solar cell industries.