Nickel Extraction from Fuel Oil Ash Using Sonoleaching Process

Ash produced by fuel-oil combustion in power plants contains nickel as one of the valuable metals. Ni recovery from the ash is very important in both economic and environmental aspects. In this study, leaching with assisted ultrasonic (sonoleaching) is used to extract Ni from the fuel oil ash. Response Surface Methodology (RSM) was used to optimize the effective factors including solid/liquid ratio (S/L ratio), sulfuric acid concentration and ultrasound power. Moreover, the kinetics of process was investigated using a modified shrinking core model to better understand the mechanism of the leaching reaction. Finally, the model predictions indicated that the diffusion step controls the overall dissolution kinetic. Also, the thermodynamic parameters of the process were investigated, and according to the obtained results, activated energy was 9.57 kJ.mol-1, and diffusion control the process.