Abstract:Stone coal was direct acidic leached and roasting acidic leached respectively. The effects of introducing fluoride into leaching systems on vanadium extraction were investigated. The results show that it is reasonable to adopt direct leaching with fluoride and solvent extraction. The leaching rate of vanadium is 92.39%, pre-treatment loss efficiency of vanadium is 1.12%, CaO consumption is 6.38 t per ton V2O5, and a three-stage counter-current solvent extracting efficiency of vanadium is 98.05% with stable procedures. Furthermore, the choice between the two processes and introduction of fluoride into leaching system had significant effects on solvent extraction of vanadium. Direct acidic leaching may introduce organics from stone coal into aqueous solution. The organics form interfacial membrane during solvent extraction, which is an important factor to produce emulsification. Blank-roasting can remove influence of organics, but increase contents of various elements other than vanadium, which may also contribute to emulsification. Existing in the form of [AlF5]2- and [SiF6]2-, fluorine can facilitate solvent extraction by hindering production of silicon-bearing colloids, fine particles and interfacial membrane. However, emulsification may occur again with content of various elements other than vanadium reaching to a maximum value.