Why TiO2 powder earnd from sulfate process turns yellow after anealing?

Tio2 powder is earned after sulfate process by solving illmanite in the sulfuric acid and a purity of up 95% of TiO2 is gained . why the color of Tio2 turns yellow after 2h annealing in 900 oC...

08 February 2020 5,895 3 View