Release kinetics of vanadium from vanadium titano-magnetite: The effects of pH, dissolved oxygen, temperature andforeign ions
Xingyun Hu , Yuyan Yue , Xianjia Peng
DOI:10.1016/j.jes.2017.07.001
Received March 08, 2017,Revised July 03, 2017, Accepted July 03, 2017, Available online July 11, 2017
Volume 30,2018,Pages 298-305
As part of a broader study of the environmental geochemistry behavior of vanadium (V), the release kinetics of V from the dissolution of natural vanadium titano-magnetite under environmentally relevant conditions was investigated. In both the acidic and basic domains, the V release rate was found to be proportional to fractional powers of hydrogen ion and dissolved oxygen activities. The dependence of the rate on dissolved oxygen can also be described in terms of the Langmuir adsorption model. The empirical rate equation is given by: r (The formula is in PDF)where, α = 0.099–0.265, k′ = 3.2 × 10-6–1.7 × 10-5, K = 2.7 × 104–3.9 × 104 mol/L in acid solution (pH 4.1), and α = - 0.494 - (- 0.527), k′ = 2.0 × 104–2.5 × 10-11, and K = 4.1 × 103–6.5 × 103 mol/L in basic solution (pH 8.8) at 20°C. Based on the effect of temperature on the release rate of V, the activation energies of minerals at pH 8.8 were determined to be 148–235 kJ/mol, suggesting that the dissolution of vanadium titano-magnetite is a surface-controlled process. The presence of Na+, Ca2+, Mg2+, K+, NO3-, Cl-, SO42- and CO32- was found to accelerate the V release rates. This study improves the understanding of both the V pollution risk in some mine areas and the fate of V in the environment.
