Preparation of high purity MoO3 through volatilization of technical-grade Mo calcine in water vapor atmosphere

Comparative experiment on MoO3 preparation from a technical-grade Mo calcine by volatilizing in water vapor atmosphere and air atmosphere was investigated. MoO3 deposition in the forms of strip-like α-MoO3 and spherical β-MoO3 were obtained at varying condensing temperatures. By adjusting the carrying gas from air to water vapor, MoO3 separating rate and product purity were remarkably improved, which is attributed to the selectively intensified evaporation of MoO3 from melted calcine. Specifically, MoO3 purity was over 99.99% and its corresponding recovery reached 70.6% when the calcine was evaporated at 1050 °C within 10 min in the water vapor atmosphere. Mechanisms of MoO3 separation from polynary system were furtherly explored and impurities including calcium, iron molybdates and silica were found to exert negative influence on MoO3 separation.