Depressing Mechanism of Sphalerite in Hot Flotation and Behavior of Sphalerite Activated with Copper in the Subsequent Zinc Flotation

摘要

The mechanism of sphalerite depression in hot flotation (Pb flotation) and the flotation behavior of sphalerite activated with copper in the subsequent Zn flotation have been investigated.In single mineral flotation at pH 6 using potassium diethyl dithiophosphate as a collector, the floatability of sphalerite did not depend on pulp temperature (25 and 60 deg C . In the flotation of sphalerite and pyrite mixture at 60 deg C, the flotation recovery of sphalerite was significantly decreased as the mixing ratio of pyrite increased, However it was only slightly decreased at 25 deg C.The reaction product on sphalerite surface after conditioning in the pyrite Suspension or ferrous sulfate solution at pH 6 and 60 deg C was identified as a basic iron sulfate by means of X-ray photoelectron spectroscopy and diffuse reflectance infrared fourier transform spectroscopy. Collector adsorption did not depend on the pulp temperature and the presence of pyrite.From the above results, it is concluded that sphalerite depression was caused by deposition of hydrophilic basic iron sulfate on the surface, which was formed by oxidation and hydrolysis reactions of ferrous ions dissolved from pyrite surface.After hot flotation, sphalerite was activated by copper ion and easily floated by using potassium amyl xanthate as a collector. Collector adsorption on the sphalerite after hot flotation was increased by copper activation, hut the collector adsorption samples with and without copper activation did not differ so much to explain the difference in the fluatability.Accordingly, the different floatability of copper-activated and unactivated sphalerite may be explained by the difference in collector adsorption mechanism, i. e. hydrophobization. Namely, in the case of copper-activated sphalerite, it is supposed that hydrophobicity of potassium amyl xanthate overcomes that of basic iron sulfate which has been deposited on the surface during after hot flotation, resulting in enhanced floatability.