Selective Extraction of Molybdenum from the spent HDS catalysts using Cyanex۲۷۲ extractant

Selective extraction of Mo from the spent HDS (Hydrodesulfurization) catalysts was studied using Cyanex۲۷۲ extractant. The required experiments were designed by RSM (Response Surface Methodology) method according to CCD (Central Composition Design), and four independent parameters were examined, including Cyanex۲۷۲ concentration, H+ concentration of leach solution, temperature, and Mo concentration in the leach solution. A quadratic equation was derived for the prediction of Mo recovery with R۲ equal to ۰.۹۸, which verified this equation for fitting the experimental results. The value of Mo recovery in different conditions showed that the effect of the leach solution acidity is insignificant at a low concentration of Cyanex۲۷۲. The optimum value for Cyanex۲۷۲ concentration, H+ concentration of leach solution, temperature, and Mo concentration was obtained at ۰.۲۷ M, ۳.۴ M, ۳۰ ˚C, and ۲۷۹.۷۴ mg/L, respectively. The Mo recovery was ۹۹.۰۵% in these conditions, which had a ۰.۷۴ error from the software predicted value.