Application of response surface methodology and central composite rotatable design for modeling and optimization of sulfuric and nitric leaching of spent catalyst

摘要

The optimization of leaching parameters for the Ni recovery of the used catalyst was developed using response surface methodology. The relationship between the Ni recoveries, and four main leaching parameters, temperature, acid concentration, leaching time and particle size were presented as empirical model equations. The predicted values of nickel recoveries were found to be in a reasonable agreement with the experimental values, with R-2 as correlation factor being 0.9669 and 0.9869 for sulfuric and nitric acids, respectively. The model equations were then optimized using the quadratic programming method to maximize nickel recovery. The optimum conditions were found to be 103.4A degrees C temperature, 246.5 min leaching time, 4.9 mol/L acid concentration and 30.6 mu m particle size to achieve the maximum Ni recovery (73.51%) for sulfuric leaching. Similarly, the conditions for maximum nickel recovery were found to be 104.1A degrees C temperature, 199.5 min leaching time, 4.45 mol/L acid concentration and 96.6 mu m particle size to achieve the maximum Ni recovery (99.76%) for nitric leaching.