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In this paper, thermal decomposition process of molybdenum concentrate in vacuum was thermodynamically analyzed, and decomposition mechanism of Mo S system in molybdenum was mainly studied. To further investigate and analyze the electronic properties in different temperature, the simulation calculations of MoS 2 (0 0 1) surface and Mo 2 S 3 (0 0 1) surface density of states, electron density difference, electronic orbital and Mulliken overlap population were carried out by density functional theory(DFT) formalism. The dynamics simulations results of MoS 2 (0 0 1) surface and Mo 2 S 3 (0 0 1) surface were obtained the temperature range of phase transforming are 1573 K–1673 K and from 1473 K to 1573 K at 20Pa, respectively. The interaction of MoS 2 and Mo 2 S 3 shows that thermal-decomposition of MoS 2 and Mo 2 S 3 does react, when new S S bonds and Mo Mo bond are formed instead of Mo S bond fracture. The experimental results of the thermal decomposition of MoS 2 and Mo 2 S 3 were in accordance with the thermodynamics theoretical calculation results and ab-initio molecular dynamics simulation results.

Vacuum decomposition process of molybdenite concentrate was investigated under pressure of 5–35 Pa for 15–120 min at the temperature range 1473 K–1973 K. The theoretical and experimental results showed that Gibbs free energy of vacuum decomposition reactions and evaporation rate of pure sulfur provided the theoretical calculation basis for temperature and heat preservation time selection in vacuum decomposition experiments of molybdenite concentrate. Melting points and saturated vapor pressures of pure substances and compounds predicted the evaporation behavior of impurity elements and its compounds during the experimental process. Both Cu and Fe could partly evaporate into condensate and Cu had better evaporation ability than Fe. MoO3 could easily and Al2O3, SiO2 could partly evaporate into the condensate. Kilo-scale experiment was performed based on the small experiments and its results showed that the Mo content of molybdenum metal product was 92.38% and the S content of sulfur product was 96.28%, and the molybdenum recovery rate reached to 95.94%. Both the theoretical and experimental results proved that it was feasible to produce crude molybdenum and sulfur from molybdenite concentrate through vacuum decomposition.

AlN chlorination route, in the present work, was proposed to extract Aluminum from aluminum nitride under vacuum. Density functional theory (DFT) were implemented to study the interaction of AlCl 3 molecule and AlN ( 10 1 ¯ 0 ) surface. The results of DFT indicate that chemisorbed AlCl 3 adsorption configuration was observed on the clean AlN ( 10 1 ¯ 0 ) surface after structure optimization, and adsorbed AlCl molecules were generated after 1 ps dynamic simulation time. The phase and composition of condensate were examined by means of XRD and EDS. It was found that 97.76 wt% of Al metal was obtained in the experiment B (in the presence of AlCl 3 ), however, no condensate was collected in the experiment A (without AlCl 3 ) at 1760 K under pressure of average 60 Pa. The results show that AlN chlorination route is an alternative Al production method from aluminum nitride.