Research on removal of iron and copper from low-grade molybdenum calcine in strong acid system.

The presence of iron (Fe) and copper (Cu) negatively impacts molybdenum (Mo) recoveries in existing metallurgical processes. This study investigated the speciation of Mo in highly acidic solutions, exploring the removal of Fe and Cu from low-grade molybdenum calcine through acid washing. The species distribution diagram for the Mo-H 2 O system indicated that Mo predominantly existed as a monomeric and dimeric species at pH < 0. Acid washing experiment results indicated that 92 % of Fe and 97 % of Cu were removed, and the Mo loss rate remained <4 %. Furthermore, optimized conditions included 3 M H 2 SO 4 , 150 min, 90 °C, and a liquid–solid ratio of 2:1. Characterization through X-ray diffraction (XRD) and scanning electron microscopy- energy dispersion spectrum (SEM-EDS) analysis of the acid washing residue indicated that Mo existed in the form of MoO 3. Furthermore, solvent extraction successfully recovered over 97 % of Mo from the acid washing solution. Recycling the raffinate into the acid washing process was found to reduce overall process costs. This study offered a practical and economical approach, optimizing the utilization of Mo resources by addressing challenges associated with Fe and Cu contents in existing processes. [ABSTRACT FROM AUTHOR]