Hydrometallurgical processing of molybdenum middlings from Shatyrkul-Zhaysan cluster ore

Abstract

This research investigates the hydrometallurgical processing of molybdenum middlings extracted from copper-molybdenum ore in the Shatyrkul-Zhaysan cluster in Kazakhstan. A molybdenum intermediate obtained after selective flotation of the copper-molybdenum concentrate was used, with a recovery of 0.07%, a molybdenum content of 22.23% and an extraction of 74.91%. The mineralogical analysis shows molybdenite and chalcopyrite as the main minerals. In experiments, atmospheric leaching with nitric acid in single-stage and two-stage countercurrent processes was investigated to optimize molybdenum extraction and reduce acid consumption. The optimum conditions obtained were: 300 g/L nitric acid, 100 g/L sulfuric acid, 90?C temperature and 2 hours leaching time in the single-stage leaching, which extracted 98.8% molybdenum. The two-stage leaching under optimized conditions allows the extraction of 94.3% molybdenum in solutions with lower residual acidity (0.89 g-eq/L) and redox potential (550 mV) without reducing the extraction of valuable component. Molybdenum extraction reaches 94.3% in the subsequent solvent extraction stage from two-stage leaching solutions. The final product, calcium molybdate with a molybdenum content of 46.83%, meets commercial grade specifications. This research demonstrates an effective process for hydrometallurgical production of commercial grade calcium molybdenite from copper-molybdenum ore, with high molybdenum recovery, reduced acid consumption through two-stage leaching, and minimal hazardous discharges.