INVESTIGATION OF THE MECHANISM OF MOLYBDENITE OXIDATION BY NITRIC ACID

This paper provides a detailed examination of the oxidation of molybdenite (MoS₂) by nitric acid. It explains how molybdenite interacts with the acid, which chemical reactions occur at different stages of the process, and which substances are formed as a result. Particular attention is paid to the conversion of sulfur, which is part of molybdenite, into oxidized compounds, as well as to changes in the chemical state of molybdenum during the reaction. The influence of the main technological parameters on the oxidation rate is also analyzed. The paper considers how changes in nitric acid concentration, process temperature, and ore particle size affect the completeness of reagent interaction and the degree of molybdenum extraction. In general, an increase in temperature and a decrease in particle size accelerate the reaction because they improve the conditions for interaction between the acid and the mineral surface. However, the specific effect depends on the ore composition and process conditions. The formation of intermediate compounds that appear during oxidation and may affect the subsequent course of the reaction is also considered. In addition, the passivation of the molybdenite surface is examined. This phenomenon involves the formation of a layer of reaction products on the particle surface, which hinders access of nitric acid to the unreacted mineral and slows its further oxidation.