Effect of oxygen enrichment on sintering behavior of high proportion vanadium–titanium magnesite concentrates

To achieve high-efficiency utilization of complex and unmanageable iron-containing minerals, the effects of oxygen enrichment on productivity, yield, flame front speed, exhaust gas peak temperature, and desulphurization reaction of the vanadium–titanium magnetite sintering process as well as sinter tumble index and mineralogy were clarified, with oxygen enrichment concentrations ranging from 21 to 29 vol.%. Results indicated that with increasing the oxygen enrichment concentration from 21 to 27 vol.%, the flame front speed increased from 30.3 to 40.0 mm min⁻¹, the yield enhanced from 72% to 77%, and the productivity augmented from 1.83 to 2.67 t m⁻² h⁻¹; in the meantime, the tumble index was improved from 73.7% to 77.9%, and the exhaust gas peak temperature rose from 376.4 to 484.8 °C. The main reason for the improvement in sintering properties was the increased combustibility of fuels and the generation of proper liquid phase that improved the permeability of the packed bed. The improved sinter strength is mainly due to the increase in the phase fraction of silico-ferrites of calcium and aluminium. In addition, oxygen enrichment sintering could significantly increase the desulphurization level of vanadium–titanium magnetite sinter and the rate of desulphurization reaction during sintering process.