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A selective reduction volatilization (SRV) process developed by the authors could remove excessive tin from the complex tin-bearing iron concentrates. But it was especially noteworthy that the volatilization ratio of Sn and the residual tin content were obviously influenced by the variation of roasting parameters during the SRV process. Hence, the existence form of residual tin in the roasted products and the possible reactions between SnO 2 and Fe 3 O 4 need to be further determined. In the present study, the effect of roasting parameters on the reduction of SnO 2 in the tin-bearing iron concentrates was first investigated. Then, samples with diverse cassiterite/magnetite (C/M) mass ratios were used to determine the effect of magnetite on phase transformation of SnO 2 by using XRD, SEM–EDS, etc. The results indicated that magnetite markedly affected the tin volatilization and phase transformation of SnO 2 under CO–CO 2 atmospheres. Fe–Sn spinel was easily formed during the reduction process, and higher roasting temperatures promoted the formation of Fe–Sn spinel, which had an adverse effect on the Sn volatilization ratio. [ABSTRACT FROM AUTHOR]

Quartz (SiO 2 ), one of the main gangue minerals in the tin-bearing iron concentrates, has an uncertain effect on the volatilization behavior of tin during the selective reduction volatilization (SRV) process. In this study, high purity quartz was added into the tin-bearing iron concentrates to investigate the tin volatilization behavior affected by SiO 2 under CO–CO 2 atmosphere of 10–70 vol.% CO at 900–1100 °C. In order to eliminate the interference of iron oxide in the iron concentrates, the reduction behavior of natural cassiterite and the mixture (20 wt.% cassiterite and 80 wt.% quartz) was also determined. Effect of SiO 2 on the phase transformation of SnO 2 was conducted using SEM–EDS, chemical phase analysis, etc. [ABSTRACT FROM AUTHOR]