Microstructure and properties of Fe₂(MoO₄)₃ prepared by sintering recovery products from waste MoSi₂

MoO₃ was recovered from waste MoSi₂ after oxidation roasting by thermal evaporation method, and Fe₂(MoO₄)₃ was prepared by reaction sintering method using the recovered MoO₃ and Fe₂O₃ as raw materials. The time and temperature for the complete oxidation of MoSi₂ were discussed, and the microstructure, linear shrinkage, volume density, spectral properties of the prepared Fe₂(MoO₄)₃ materials were studied. The results show that, the waste MoSi₂ powders can be completely oxidized after calcination at 500 ℃ for more than 120 min. During the reaction sintering process of MoO₃ and Fe₂O₃, the higher the sintering temperature, the more complete the reaction between MoO₃ and Fe₂O₃; the void of the prepared Fe₂(MoO₄)₃ materials increases, the line shrinkage rate increases, and the volume density decreases. Fluorescence spectrum analysis shows that, the photogenerated electron-hole pairs of the Fe₂(MoO₄)₃ and MoO₃ composite materials are more difficult to be recombined than those of the pure Fe₂(MoO₄)₃, showing the higher photocatalytic activity for the composites. Using methylene blue as dye, the pure Fe₂(MoO₄)₃ has the good adsorption performance, while the Fe₂(MoO₄)₃ and MoO₃ composites show the excellent photocatalytic performance, and the mixture of Fe₂(MoO₄)₃ and MoO₃ composites has the best photocatalytic degradation cycle stability.