Direct reduction of ammonium molybdate to elemental molybdenum by combustion reaction

Self-sustaining reduction of ammonium molybdate tetrahydrate (AMT) by mixture of zinc and magnesium is investigated. It is shown that utilizing mixtures of metallic reducers is an attractive methodology to control the reduction conditions and product characteristics. Optimal intervals of key parameters, e.g. composition of reducing mixtures and pressure of inert gas are determined. Analysis of combustion temperature profiles, XRD, SEM/FESEM, DTA, microanalysis, and quenching techniques are applied to investigate the reduction mechanism. Based on the obtained fundamental knowledge, for the first time, highly crystalline molybdenum powder with particle sizes in the range 0.1–1 μm is produced by direct reduction of AMT in a single-stage and energy saving process. Proposed combustion-based approach of Mo production has high potential to become an alternative to the conventional hydrogen reduction processes.