Efficient separation and recovery of barium from barium slag via hydrometallurgical approach: Process design, thermodynamics research and mechanism investigation

The accumulation of barium slag (Bs) not only presents significant environmental challenges but also results in the inefficient utilization of resources. The present study investigates the scientific problems of hydrometallurgical methods for converting compounds containing barium in Bs into desired barium salts, with a specific focus on acid treatment, flocculation and precipitation of soluble barium from the leaching solution, as well as heavy media separation in the Bs residue. The experimental findings demonstrate that over 98.5% of the compounds containing barium undergo successful conversion into BaCO₃ and BaSO₄, achieving high purities of 98.7% and 79.4%, respectively. A crucial aspect of the mechanism lies in the interaction among ions, which facilitates the conversion of compounds containing barium into the desired barium salts. Additionally, the utilization of flocculants significantly enhances the efficiency and rate of flocculation for the BaCO₃ turbid fluid, wherein PAM and C-PAM exhibit superior effects in comparison to A-PAM. The reduction in the thickness of the electrical double layer, achieved through the application of flocculants, plays a pivotal role in expediting particle precipitation. Moreover, thermodynamic analysis illuminates the energy changes and the transformation processes during the recovery of barium from Bs. The study concludes by presenting a strategy for cleaner production to recover desired barium salts with Bs.