Effect of Fe/SiO2 and CaO/SiO2 mass ratios on metal recovery rate and metal content in slag in oxygen-enriched direct smelting of jamesonite concentrate
(School of Metallurgical and Environment, Central South University, Changsha 410083, China)
Abstract: The oxygen-enriched direct smelting of jamesonite concentrate was carried out at 1250 °C by changing the slag composition. The effects of Fe/SiO2 and CaO/SiO2 mass ratios on the metal recovery rate as well as metal content in slag were investigated. Experimental results indicated that the metal (Pb+Sb) recovery rate was up to 88.30%, and metal (Pb+Sb) content in slag was below 1 wt.% under the condition of slag composition of 21-22 wt.% Fe, 19-20 wt.% SiO2 and 17-18 wt.% CaO with Fe/SiO2 mass ratio of 1.1:1 and CaO/SiO2 mass ratio of 0.9:1. The microanalysis of the alloy and slag demonstrated that the main phases in the alloy contained metallic Pb, metallic Sb and a small amount of Cu2Sb and FeSb2 intermetallic compounds. The slag was mainly composed of kirschsteinite and fayalite. Zinc in the raw material was mainly oxidized into the slag phase in the form of zinc oxide.
Key words: jamesonite concentrate; metallurgical process intensification; slag type; pyrometallurgy; oxygen-enriched direct smelting