National University of Science and Technology “MISIS”, Moscow, Russia:

E. V. Bogatyreva, Assistant Professor, e-mail: Helen_Bogatureva@mail.ru

A. G. Ermilov, Former Collaborator of a Chair, Chair of Non-ferrous Metals and Gold

This work demonstrates the possibility of forecasting of efficient mechanical activation conditions for scheelite concentrate from X-ray diffraction (XRD) data with the aim of accelerating subsequent soda leaching. There is presented the XRD data for unmilled and milled low-grade scheelite concentrate. From the XRD data, there were evaluated the contributions of ΔЕ_d, ΔЕ_s, and ΔЕ_ε to ΔЕ_Σ (where ΔЕ_Σ is the energy stored during mechanical activation (MA), ΔЕ_d is the energy spent for changing of interplanar spacings in the crystal lattice, ΔЕ_s is the energy stored in the form of freshly formed crystallite surfaces, and ΔЕ_ε is the energy stored in the form of microstrain). This approach is unique because it offers the possibility of evaluating of energy stored in the system and, accordingly, predicting the reactivity of materials from XRD data, without chemical or physical characterization, which typically leads to disintegration of the sample and requires significant amounts of activated material. The activation energy change is shown to depend on the type of energy stored during MA. Process tests confirmed the foregoing that the degree of extraction depended not on the total stored energy but on the kind of energy. Our results confirm that the energy stored during mechanical activation in the form of surface energy makes an influence on leaching behavior of the concentrate. There was studied the effect of the surface energy stored in the scheelite phase during mechanical activation on the tungsten extraction into solution through low temperature soda leaching. Evaluation of the reactivity of milled scheelite concentrate from XRD data made it possible to optimize MA conditions and reach tungsten extraction into solution at a level of 99%.

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