Formation and Inhibition Mechanism of Na8SnSi6O18 during the Soda Roasting Process for Preparing Na2SnO3

Zijian Su; Shuo Liu; Benlai Han; Yuanbo Zhang; Tao Jiang

doi:10.3390/ma15248718

Formation and Inhibition Mechanism of Na₈SnSi₆O₁₈ during the Soda Roasting Process for Preparing Na₂SnO₃

Materials (Basel). 2022 Dec 7;15(24):8718. doi: 10.3390/ma15248718.

Authors

Zijian Su¹, Shuo Liu¹, Benlai Han¹, Yuanbo Zhang¹, Tao Jiang¹

Affiliation

¹ School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China.

Abstract

To produce Na₂SnO_3, which is widely used in the ceramics and electroplating industries, a novel process for the preparation of sodium stannate from cassiterite concentrates was developed successfully by the authors' group. It was found that sodium stannosilicate (Na₈SnSi₆O₁₈) was easily formed due to the main gangue of quartz in cassiterite concentrates, which was almost insoluble and decreased the quality of Na₂SnO₃. The formation and transitions of Na₈SnSi₆O₁₈ in the SnO₂-SiO₂-Na₂CO₃ system roasted under a CO-CO₂ atmosphere were determined. The results indicated that the formation of Na₈SnSi₆O₁₈ could be divided into two steps: SnO₂ reacted with Na₂CO₃ to form Na₂SnO₃, and then Na₂SnO₃ was rapidly combined with SiO₂ and Na₂CO₃ to form low melting point Na₈SnSi₆O₁₈. In addition, Na₈SnSi₆O₁₈ can be decomposed into Na₂SiO₃ and Na₂SnO₃ by using excess Na₂CO₃.

Keywords: Na2SnO3; Na8SnSi6O18; TG-DSC analysis; phase transformation.

Abstract

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