Effect of Salt Roasting Factors on Water Leaching of Vanadium Concentrate by Design of Experiment

We investigated the effect of salt roasting conditions on vanadium concentrate's water leaching by Design of Experiment (DOE). The experiments were done by a random sequence using the design of 2-level and three repetitions with a central point. The factors and their levels were roasting temperature 1000, 1200 °C, sodium sulfate ratio in sodium salt 30, 70 %. The change in factor level did not give a statistically meaningful effect on the vanadium leaching ratio based on T-test and ANOVA with a significance level of 0.05, and the vanadium leaching ratio was between 80 and 90 % in 30 minutes. In contrast, the factors and interaction had a statistically significant effect on the aluminum leaching ratio. Higher temperature and sodium sulfate ratio produce a higher aluminum leaching ratio, whereas the interaction of factors showed the opposite. Water leaching of roasted vanadium concentrate at 1000 °C/sodium sulfate ratio of 30 % and 1200 °C/70 % resulted in 8.96 % and 0 % of aluminum leaching ratio, respectively. A regression analysis produced an aluminum leaching model equation with an R-squared of 0.9960.