MINERALOGICAL AND IRON RECOVERY FROM CCS FLOTATION TAILS BY PHYSICO-INTERFACIAL SEPARATION: SEPARATION OF MAGNETITE AND IRON SILICATES

摘要

Copper converter slag (CCS) discharge causes significant environmental problems. In this work, on the basis of a study of mineralogical characteristics, the recovery of iron from CCS flotation tails using a combined process of magnetic separation and reverse flotation was investigated. The study revealed that CCS flotation tails are primarily composed of magnetite (21.49%) and iron silicates (72.52%). The iron content of CCS flotation tails is as high as 49.60%, while only 30.31% of the iron distributed in the magnetite and ferroalloy shows significant magnetic properties. Zeta-potential studies of magnetite, quartz and fayalite samples have shown that amines are well adsorbed, both on the surfaces of the magnetite and also on the surfaces of the iron silicates, within a pH range of 5-10. The iron content of CCS flotation tails can be effectively upgraded to 59.61% using magnetic separation Amines with different molecular structures performed different selectivity for iron silicates when reverse flotation was used to remove iron silicates from the magnetic concentrate. The use of mixtures of cationic and anionic collectors provided a formation of a stable hydrophobic adsorption layer on the surface of the iron silicates and magnetite silicate aggregates; this improved the flotation of these mineral particles, even in the presence of a starch, which acted as a depressant of Fe oxides. The scheme of combining magnetic separation and reverse flotation is a promising method to use to (a) recover iron and (b) produce iron concentrates with SiO2 content of 6.59% and Fe content of up to 63.35% from CCS flotation tails with SiO2 content as high as 36.40%.