Comparative analysis of molybdenite concentrate thermochemical activation by magnesite and brucite

Abstract

The purpose of the paper is to establish physico-chemical regularities and technological parameters of molybdenite concentrate thermochemical decomposition with the use of various magnesium minerals (brucite Mg (OH)₂, magnesite MgCO₃) in the oxidizing medium. The compositions and physico-chemical properties of initial materials and interaction products are studied by atomic absorption spectrometry, photocolorimetry, differential scanning calorimetry and x-ray phase analysis. Physical and chemical modeling of the systems MoS₂-MgCO₃-O₂ and MoS₂-Mg(OH)₂-O₂ is carried out by means of the universal program for determining the equilibrium parameters of multicomponent heterogeneous systems "Terra" and the Temkin-Schwarzman method. It is shown that magnesium molybdate (MgMoO₄) formed in the process of interactions is stable within the range of the studied temperatures from 300 K to 1150 K. We have determined the technological parameters of molybdenite concentrate sintering with each of the additives providing directed transformation of the refractory mineral form into the soluble molybdate phase MgMoO₄ and sulfur oxide into non-volatile magnesium sulfate: temperature 600°C, firing duration 60-90 min, consumption of brucite or magnesite is 100-110% of stoichiometrically required for complete binding of molybdenum and sulfur into a cinder. The developed method of molybdenite concentrate thermochemical activation makes it possible to reduce the cost of the thermochemistry process by using magnesium minerals as a raw material additive and promotes the effective interaction of decomposition products with the formation of soluble compounds MgMoO₄ and MgSO₄.