Optimization of bioleaching of fluoride-bearing uranium ores by response surface methodology

The effect of four significant variables, namely, pH value, solid–liquid ratio, initial Fe²⁺, and inoculation percent, on uranium bioleaching was studied using a Box–Behnken design. The results showed that pH was the most effective parameter, followed by the solid–liquid ratio and the inoculation percent, whereas the effect of initial Fe²⁺ was minimal. The optimum variables for the maximum uranium bioleaching recovery (90.20% ± 0.70%) were as follows: pH, 1.80; solid–liquid ratio, 0.11 (w/v); inoculation percent, 19.20% (v/v); and initial Fe²⁺, 4.60 g/L. The maximum uranium recovery from the predicted models was 91.40%, which was reliable with the experimental value.