Formation kinetics of Na2SnO3 from SnO2 and Na2CO3 roasted under CO-CO2 atmosphere

- Formation kinetics model of Na2SnO3 under different temperatures and CO contents are clarified.
- The reaction rate controlling step for SnO2 + Na2CO3 = Na2SnO3 + CO2 is determined.
- Morphology transformation of Na2SnO3 is used to explain the kinetic model matching.

A novel method for Na2SnO3 preparation from SnO2 and Na2CO3 roasted under CO-CO2 atmosphere in a solid state has been successfully developed. In this study, the formation kinetics of Na2SnO3 was investigated. The formation of Na2SnO3 was controlled by the first-order interfacial chemical reaction at 800 °C under 10 vol% CO content; as the temperature increased to 850 °C-900 °C, it was controlled by the three-dimension (Ginstling and Brounshtein) diffusion through the product layer at the early reaction stage. The rate constant increased with the increasing of temperature. Furthermore, the rate controlling characterizations of three-dimension diffusion were also discussed.

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