Mechanism of stibnite volatilization at high temperature

The volatilization of stibnite (Sb 2 S 3 ) in nitrogen from 700 to 1000 °C was investigated by using thermogravimetric analysis. The results indicate that in inert atmosphere, stibnite can be volatilized most efficiently as Sb 2 S 3 (g) at a linear rate below 850 °C, with activation energy of 137.18 kJ/mol, and the reaction rate constant can be expressed as k =206901exp(−16.5/ T ). Stibnite can be decomposed into Sb and sulfur at temperature above 850 °C in a nitrogen atmosphere. However, in the presence of oxygen, stibnite is oxidized into Sb and SO 2 gas at high temperature. Otherwise, Sb is oxidized quickly into antimony oxides such as Sb 2 O 3 and SbO 2 , while Sb 2 O 3 can be volatilized efficiently at high temperature.