Study on the high-efficiency separation of Fe in extracted vanadium residue by sulfuric acid roasting and the solidification behavior of V and Cr

[Display omitted] •A lower roasting temperature is 320 °C.•93.74% V and 98.18% Cr in extracted vanadium residue is recovered.•V and Cr are fixed in ammonium jarosite and petroleum proppant.•Petroleum proppants have the advantages of both α-Al2O3-3Al2O3·2SiO2 dual-phase. The large accumulation of extracted vanadium residue not only causes waste of resources but also causes environmental pollution. In this work, 96.8% Fe in extracted vanadium residue is efficiently and selectively leached by sulfuric acid roasting process at a lower temperature. Petroleum proppant is prepared from iron removal waste slag and low-grade bauxite, and V and Cr in extracted vanadium residue are solidified. Specifically, under the conditions of reaction temperature of 95 °C, pH of 2.5, and time of 6 h, 86.8% of Fe in the iron-rich leaching solution is converted into flower-like ammonium jarosite. After the thermal decomposition of ammonium jarosite, the product Fe2O3 still has a flower-like morphology. The microstructure of the petroleum proppant is that corundum crystals are filled in the gaps of the network structure of the mullite columnar crystals to form a staggered skeleton structure, which combines the advantages of two-phase materials. The total recovery rates of V and Cr in extracted vanadium residue are 93.74% V and 98.18% Cr, respectively. This study provided a cleaner production approach to recycle industrial waste, reduce the hazards of V and Cr, and reduce the cost of preparing α-Al2O3-3Al2O3·2SiO2 dual-phase structure petroleum proppants.