Flotation Separation of Cu-Pb-Zn Polymetallic Ore Based on Sulfuric Acid as Regulator

The main valuable elements of a Cu-Pb-Zn polymetallic ore in Laos are Cu, Pb, Zn and associated Ag. Aiming at the characteristics of the close association and fine dissemination of the valuable minerals, on the basis of exploratory experiments, the condition tests of preferential flotation of copper, lead and zinc successively and the structural optimization tests of the circuit were carried out. Through H₂SO₄ used as regulator to create a weak acidic medium in the slurry, and the new process of flash copper flotation and its middlings return to Pb flotation circuit was carried out. When the feed assays 2.07% Cu , 5.76% Pb, 2.95% Zn and 443 g/t of Ag, results in closed-circuit test show that the copper concentrate contains 20.18% Cu, 10.32% Pb and 1.52% Zn, at Cu recovery of 82.40%, and silver in the concentrate is as high as 2738 g/t at Ag recovery of 52%; lead concentrate assays 45.35% Pb, 2.43% Cu and 3.34% Zn at Pb recovery of 71.54%; zinc concentrate contains 42.21% Zn, 0.07% Cu and 2.55% Pb at Zn recovery of 70.15%.The efficient separation of Cu, Pb and Zn minerals and the recovery of associated silver have been successfully realized, which provides a technical reference for the development and utilization of this resource.