Effect of CaCO₃ on the Gaseous Reduction of Tin Oxide Under CO-CO₂ Atmosphere

ABSTRACT

Calcite (CaCO₃), one of the main impurities, has an uncertain effect on the volatilization behavior of tin oxide in the tin-bearing iron ore concentrates during the selective reduction volatilization process. In this study, natural calcite powders were added into the tin-bearing iron ore concentrates to investigate tin volatilization behavior affected by CaCO₃ under different roasting temperature, CO content, and roasting time. In addition, the effect of CaCO₃ on the phase transformation of SnO₂ was determined using XRD, SEM-EDS combined with thermodynamics calculation. The results indicated that CaCO₃ had a significantly adverse effect on the Sn volatilization ratio, because Ca₂SnO₄ was easily formed under CO-CO₂ atmosphere. It was also found from the study that the generation of SnO_(s) was the most critical intermediate for promoting the formation of Ca₂SnO₄.

KEYWORDS:

• Cassiterite
• Ca₂SnO₄
• gaseous reduction
• tin-bearing iron ore concentrates

Funding

The authors would express their heartful thanks to the National Natural Science Foundation of China (51574283), Co-Innovation Center for Clean and Efficient Utilization of Strategic Metal Mineral Resources and Hunan Provincial Innovation Foundation for Postgraduate (CX2015B054).

Additional information

Funding

The authors would express their heartful thanks to the National Natural Science Foundation of China (51574283), Co-Innovation Center for Clean and Efficient Utilization of Strategic Metal Mineral Resources and Hunan Provincial Innovation Foundation for Postgraduate (CX2015B054).