Semi-industrial test of vanadium extraction from stone coal vanadium ore by high-pressure roll-suspension roasting-solidification leaching process

Rich vanadium resources are stored in stone coal. Compared with the high temperature, high pressure, and high acid concentration conditions required by the direct leaching process, the roasting-leaching process demonstrates significant advantages. Roasting liberates and oxidizes the vanadium in the ore, allowing it to be recovered through a subsequent leaching process. This approach not only reduces the severity of the operating conditions but also broadens the application scope. The high-pressure roll-suspension roasting-solidification leaching process has been proposed to enhance vanadium leaching. Semi-industrial test results showed that qualified feed was obtained under the feed rate of 50 kg, the feed particle size of −15 mm, the roller surface pressure of 13–14 MPa, and the roller speed of 18 r/min. The suspension roasting system achieved stable and effective operation under the processing capacity of 90 kg/h, the air consumption of 28.0 m³/h, the CO₂ consumption of 8.0 m³/h, and the temperature of ≥ 890 °C in the primary and secondary reactors. Under the acid mixing temperature of 130 °C, acid dosage of 40 %, curing time of 6 h, and leaching time of 3 h, the V₂O₅ leaching rate of 83.79 % was obtained. After roasting, the cracks of the ore increase and elongate, the micropores enlarge and transform into open internal pores, the surface roughness of the ore undergoes further changes.