Evaluation of a green-sustainable industrialized cleaner production for FeV50 and FeV80 alloys from vanadium slag by calcification roasting–ammonia on-line cycle

Abstract

Conventional calcification roasting–ammonium precipitate for ferrovanadium preparation have been exposed many technical problems such as roasting temperature control, leaching kinetics problem, precipitating vanadium liquor loss, reducing-melting vanadium evaporation loss and smelting vanadium evaporation loss in the process of industrialization. Therefore, a green-sustainable industrialized cleaner production for FeV50 and FeV80 alloys from vanadium slag by calcification roasting–ammonia on-line cycle is discussed. This process involves several steps including vanadium pretreatment and Fe recycling, pre-calcified vanadium slag circulating roasting, two-step circulating leaching, continuous vanadium precipitating and wastewater recycling, reducing-melting and NH3 recycling, three-stage ferrovanadium smelting. According to the theoretical base about conventional chemical, thermodynamics principles, phase diagram, dissolution kinetics, solution state diagram, separation gravity, problems, challenges and reasons analysis, the several steps including six cycles of FeV50 and FeV80 preparation were designed and industrialized. Through before and after process optimization and heat discharge, TG–DSC, XRD, SEM–EDS analysis, the mechanisms from vanadium slag to ferrovanadium help understand the increasing of the whole process vanadium yield from 57.21% to 80.81%, including vanadium oxide yield increased from 59.90% to 82.88%, ferrovanadium yield increased from 95.50% to 97.50%, respectively. All results and conclusions had guiding significance and demonstration effect on vanadium industry.