Comparative Study of Various Kinetic Models on Leaching of NCA Cathode Material

Abstract

The kinetics study of NCA leaching in the HCl system was proposed. Various kinetic models such as shrinking core, logarithmic rate law, and Avrami equation were used to find out the most appropriate kinetic models for this process. The effect of HCl concentrations, leaching temperatures, solid to liquid (S/L) ratio, and leaching duration were observed. The optimum conditions of NCA leaching were at HCl concentration of 4 M, temperature of 80 °C, S/L ratio of 100 g/L, and leaching time of 1 h. The result shows that shrinking core model with diffusion control process of residue layer describes well the leaching mechanism in this research, which is indicated by the good fitting of coefficient values of correlation (R2) and confirmed by the activation energy values of Ni, Co, Al that were less than 40 kJ/mol.

High-Performance Recovery of Cobalt and Nickel from the Cathode Materials of NMC Type Li-Ion Battery by Complexation-Assisted Solvent Extraction

“…Figure 11 indicates the extraction percentages of cobalt and nickel by different complexing reagents. Separation factors of cobalt and nickel were 2, 42,18,25,525,162,372,72 for citric acid, sodium citrate, succinic acid, sodium acetate, ammonium acetate, sodium thiocyanate, ammonium thiocyanate and blank (no complexing reagent added). We proposed ammonium thiocyanate as the best complexing reagent because of its better cobalt extraction capability, low nickel extraction percentage and a good separation factor.…”

“…Nevertheless, the metal extraction percentage in some organic acid solution systems is not high enough for the recovery and separation of different metals from ternary metal oxide, i.e., NMC. As shown in Table 2, there are also some studies using inorganic acid leaching solution [24][25][26][27][28][29][30][31][32][33]. Among them, acid leaching solution added with reducing agent has higher efficiency for cathodic metals.…”