Nickel Recovery from Spent Ni/Al $_2$ O $_3$ Catalysts Using Nitric Acid Solution

This study investigates the possibility of recovering nickel from the spent catalyst (Ni/Al $_2$ O $_3$ ) used in the steam reforming process of a fertilizer industry. In the leaching process, nickel is recovered as nickel nitrate using nitric acid as a solvent The effects of acid concentration, temperature, solid to liquid (S:L) ratio and reaction time on nickel recovery were examined. The 95% leaching efficiency of nickel from the spent catalysts having size between 1–2 mm was achieved at optimized conditions: 40% acid concentration (v/v), temperature 90°C, solid:liquid ratio of 1:10 g/ml and leaching time 5 hour.