Nonisothermal Carbothermal Reduction Kinetics of Titanium-Bearing Blast Furnace Slag

Abstract

The kinetics of carbothermal reduction of titanium-bearing blast furnace (BF) slag has been studied by thermogravimetric analysis and quadrupole mass spectrometry. The kinetic parameters (activation energy, preexponential factor, and reaction model function) were determined using the Flynn–Wall–Ozawa and Satava–Sestak methods. The results indicated that reduction of titanium-bearing BF slag can be divided into two stages, namely reduction of phases containing iron and gasification of carbon ( 1095°C). CO2 was the main off-gas in the temperature range of 530–700°C, whereas CO became the main off-gas when the temperature was greater than 900°C. The activation energy calculated using the Flynn–Wall–Ozawa method was 221.2 kJ/mol. D4 is the mechanism function for carbothermal reduction of titanium-bearing BF slag. Meanwhile, a nonisothermal reduction model is proposed based on the obtained kinetic parameters.