Reduction of SnO<SUB>2</SUB> with Hydrogen

Abstract

This study deals with the reduction of tin oxide by hydrogen in the temperature range of 773∼1023 K and the hydrogen partial pressure of 30.4∼101.3 kPa. It aims to investigate the kinetics of the reaction between tin oxide and hydrogen. The hydrogen reduction of tin oxide is to be related with the efforts to extract tin metal with decreasing the emission of carbon dioxide which causes global warming. The experiments were carried out under isothermal condition in hydrogen atmosphere using TGA equipment. The reduction rate of tin oxide to tin metal by hydrogen was found to be relatively fast under the whole conditions until the reduction ratio of SnO2 approaches to about 0.95. As an example, at 1023 K under a hydrogen partial pressure of 101.3 kPa, almost 100% of tin oxide was reduced to tin metal in 10 min. The nucleation and growth model yielded a satisfactory fit to these experimental data. The reaction was first order with respect to hydrogen partial pressure and had an activation energy of 62.5 kJ/mol (15.0 kcal/mol).