Distribution of minor elements between calcium ferrite slag and copper matte at 1523 K under high partial pressure of SO2

Abstract

As a fundamental study for the oxygen-blowing copper smelting, the distribution ratio of some minor elements such as Ag, Pb, As, Sb and Bi between calcium ferrite slag and copper matte was investigated at 1523 K under the partial pressures of SO2 with 10.1, 50.7 and 101.3 kPa, using the sulfur reservoir for controlling the partial pressure of S2. When the distribution ratio, LXs/m, is defined as (mass%X in slag)/{mass%X in matte}, LXs/m was found to change considerably with matte grade {mass%X in matte}. LAss/m and LSbs/m decreased remarkably in the range of high matte grade while LBis/m increased. LAgs/m and LPbs/m decreased gradually with increasing matte grade up to 75-77 mass% and increased abruptly in the range of higher matte grade. It was clarified that the distribution ratios of Pb, As, Sb and Bi increased remarkably with pSO2 and that the proportion of these elements in the slag phase increased with increasing oxygen-enrichment. The results obtained were analyzed successfully by assuming a mutual reaction between a metallic species in the matte and an oxide species in the slag for As, Sb and Bi, while for Ag and Pb the equilibrating of mutual reaction between the metallic species in the matte and sulfide species in the slag at the low matte grade was suggested.