Co-extraction of Vanadium Titanium and Chromium from Vanadium Slag by Oxalic Acid Hydrothermal Leaching with Synergy of Fe Powder

To co-extract vanadium, titanium, and chromium from vanadium slag, a cleaner process featuring oxalic acid hydrothermal leaching with synergy of Fe powder was proposed in this paper. With the leaching temperature of 125 degrees C, oxalic acid concentration of 25 wt pct, liquid-to-solid mass ratio of 8:1, leaching time of 90 minutes, and iron powder addition of 3.2 wt pct, the leaching extents of vanadium, titanium, and chromium can reach up to 97.9, 98.4, and 93.3 pct, respectively. The non-toxic residue is mainly composed of FeC2O4 center dot 2H(2)O, MnC2O4 center dot 2H(2)O, and amorphous SiO2. Compared with the traditional sodium roasting-water leaching and calcification roasting-acid leaching processes, this novel process is possessed of two prominent advantages. Firstly, without the roasting step, the process is simplified significantly and the energy consumption is reduced greatly. Secondly, the valuable components titanium and chromium which cannot be extracted by the traditional processes are leached synchronously and efficiently.