Objective Oil-based solid waste is a secondary resource containing barite. From the perspective of process mineralogy, this study investigates the distribution and enrichment patterns of barite in oil-based solid waste of different particle sizes and explores the process flows for barite recovery.

Method X-ray diffraction (XRD) and X-ray fluorescence (XRF) tests were conducted, combined with electron probe and energy-dispersive spectrometer (EDS) analysis, to study the occurrence state of barite and its intergrowth relationships with gangue minerals. Magnetic separation, gravity separation, and flotation separation methods were applied to recover barite from the oil-based solid waste.

Result The oil-based solid waste contained 41.37% barite, indicating significant recovery value. The main gangue minerals include limestone, quartz, feldspar, and hematite-limonite. The liberation of barite with more than 38 μm and maximum of 200 μm fraction was insufficient, and it mainly bound with calcium-containing minerals in the form of complex aggregates. By using weak magnetic separation, strong magnetic separation, and shaking table gravity separation, a barite concentrate with a yield of 7.25%, a grade of 92.59%, and a density of 4.29 g/cm³ was obtained. The liberation of barite with more than 5 μm and maximum of 38 μm fraction was relatively complete. Through a "one rougher and three cleaner" flotation process, a barite concentrate with a yield of 30.50%, a grade of 85.38%, and a density of 4.03 g/cm³ was achieved.

Conclusion The combined magnetic-gravity-flotation separation process effectively recovers barite resources from oil-based solid waste, achieving a comprehensive recovery rate of 79.18%. The concentrate products meet the industrial standards for chemical-grade barite. The research results can provide scientific guidance for barite resources from oil-based solid waste.