THE EFFECT OF HYDROGEN SULFIDE ON THE IN-SITU LEACHING OF URANIUM FROM CARBONATE–SULFIDE-BEARING ORES

Abstract

This study investigates the influence of hydrogen sulfide (H₂S) on the in-situ uranium leaching process, with particular emphasis on its role in the reduction of hexavalent uranium to the tetravalent state, as well as the associated technological disruptions and severe equipment corrosion. The objective of the research was to determine the causes of H₂S formation, assess its impact on process stability, and develop effective neutralization methods. The research methodology included sampling of rock materials and productive solutions from production wells at the GTK-2 uranium deposit. Rock-forming and ore minerals were examined using scanning electron microscopy (SEM) and a Nikon ECLIPSE LV100N POL microscope at magnifications ranging from 40× to 1000×. In addition, the causes of hydrogen sulfide formation in the ore environment were investigated. The results showed that the H₂S concentration reached up to 320 mg/L in several production wells, whereas no hydrogen sulfide was detected in others. Productive solutions with elevated H₂S concentrations were analyzed at the Central Physicochemical Laboratory of the Zafarabad Mining Administration. Hydrogen peroxide (H₂O₂) was used to neutralize hydrogen sulfide, achieving a reaction efficiency of approximately 60%, with water and sulfuric acid as the reaction products. The scientific novelty of the study lies in the comprehensive analysis of the reducing effect of H₂S on uranium and the substantiation of hydrogen peroxide application for stabilizing the in-situ leaching process. The obtained results have significant practical importance for reducing corrosion damage, improving process reliability, and minimizing economic losses at uranium mining enterprises.