Selective Recovery of Cadmium, Cobalt, and Nickel from Spent Ni-Cd Batteries Using Adogen ® 464 and Mesoporous Silica Derivatives.

Spent Ni-Cd batteries are now considered an important source for many valuable metals. The recovery of cadmium, cobalt, and nickel from spent Ni-Cd Batteries has been performed in this study. The optimum leaching process was achieved using 20% H 2 SO 4 , solid/liquid (S/L) 1/5 at 80 °C for 6 h. The leaching efficiency of Fe, Cd, and Co was nearly 100%, whereas the leaching efficiency of Ni was 95%. The recovery of the concerned elements was attained using successive different separation techniques. Cd(II) ions were extracted by a solvent, namely, Adogen ® 464, and precipitated as CdS with 0.5% Na 2 S solution at pH of 1.25 and room temperature. The extraction process corresponded to pseudo-2nd-order. The prepared PTU-MS silica was applied for adsorption of Co(II) ions from aqueous solution, while the desorption process was performed using 0.3 M H 2 SO 4 . Cobalt was precipitated at pH 9.0 as Co(OH) 2 using NH 4 OH. The kinetic and thermodynamic parameters were also investigated. Nickel was directly precipitated at pH 8.25 using a 10% NaOH solution at ambient temperature. FTIR, SEM, and EDX confirm the structure of the products.