Thermodynamic Calculations and Kinetics Study on Direct Alloying Process of Abandoned Denitration Catalyst

The thermodynamic software Factsage 7.1 was used to calculate the effects of reduction temperature and aluminum amount of the TiO₂-CaO-CaF₂-Na₂O-SiO₂ slag system during the direct alloying process of the abandoned denitration catalyst.When the reduction temperature reaches 1 550 ℃,titanium in the steel almost no longer rises,but the content of titanium oxides continues to increase with the increase of temperature.At 1 600 ℃,titanium content in the steel increases with increase of the amount of aluminum.When the ratio of aluminum to slag is about 0.4,the titanium content can reach to maximum 4.25%.The reaction for reduction of the abandoned denitration catalyst by aluminum occurs at around 923 ℃ and belongs to a liquid-solid reaction.The kinetics parameters of the direct alloying reduction process were calculated by Freeman-Carroll method,with the obtained apparent activation energy E=243.33 kJ/mol and the reaction order n=0.13.