Keywords: solid waste management, nickel recovery, spent catalyst, single leaching, multiple leaching, sulphuric acid
Recovery of nickel from spent catalyst by single- and multi-stage leaching process
Nickel-supported catalyst is used in petroleum, fertiliser and iron industries. This research studied the possibility of recovering nickel by leaching the ground catalyst with sulphuric acid. The leaching was done in single stage and multi-stages. The results obtained in single-stage leaching showed that the percentage recovery of nickel increased with increasing acid concentration used up to 25% and then the percentage recovery of nickel decreased. Also, the percentage recovery of nickel increased as the time of leaching increased. The optimum time was 3 h with three stages, each stage for 1 h. Using multi-stages gave 82% recovery while using two stages with the same acid concentration for 2 h gave 84% recovery. Increasing the number of stages leads to the use of lower acid concentration.