Application of PVC as Novel Roasting Additive in Vanadium Extraction from Stone Coal

Abstract

In order to search for a more economical and effective roasting additive for extracting vanadium from stone coal and solve the question of the disposal of PVC waste, PVC waste was proposed as a novel roasting additive to enhance extraction of vanadium from stone coal and realize the comprehensive utilization of resources. By adding this roasting additive, the leaching rate of vanadium reached 94.5% under the conditions that the PVC waste addition was 10\xa0wt%, the roasting temperature was 800\xa0°C, the roasting time was 1\xa0h, the sulfuric acid concentration was 15\xa0vol%, the liquid-to-solid ratio was 1.5\xa0cm3/g, the leaching temperature was 95\xa0°C, and leaching time was 4\xa0h, which increased by 8.4% compared with that of blank roasting. The thermodynamics calculation showed that the decomposition reaction of mica was performed easier with the participation of HCl produced by pyrolysis of PVC. Meanwhile, The SEM-EDS and aperture test analyses demonstrated that more cracks and voids appeared in the roasted sample by roasting with PVC waste, which could facilitate the release and extraction of vanadium. Additionally, the TG-DSC analyses indicated that PVC could provide large amounts of heat for the roasting process to promote the decarbonization and roasting efficiency of stone coal because of its high calorific value.