Kinetic Study in Atmospheric Pressure Organic Acid Leaching: Shrinking Core Model versus Lump Model

• Main Authors: Kevin Cleary Wanta, Widi Astuti, Indra Perdana, Himawan Tri Bayu Murti Petrus
• Format: Article
• Language: English
• Published: MDPI AG 2020-07-01
• Series: Minerals
• Subjects: citric acid; kinetics; leaching; lump model; nickel laterite; shrinking core model
• Online Access: https://www.mdpi.com/2075-163X/10/7/613

The kinetics study has an essential role in the scale-up process because it illustrates the real phenomena of a process. This study aims to develop a mathematical model that can explain the mechanism of the leaching process of laterite ore using a low concentration of the citric acid solution and evaluate that model using the experimental data. As a raw material, this process used powder-shaped limonite laterite ores with a size of 125–150 µm. The leaching process is carried out using 0.1 M citric acid solution, F:S ratio of 1:20, and a leaching time of 2 h. The temperature parameter was varied at 303, 333, and 358 K. The experimental results showed that the higher the operating temperature, the higher the extracted nickel. The results of this experiment were used to evaluate the shrinking core kinetics model and the lumped model. The simulation results for both models show that the lumped model can provide better simulation results. Quantitatively, the percentage of errors from the shrinking core model is around 3.5 times greater than the percentage of errors from using the lumped model. This result shows that in this leaching process, the process mechanism that occurs involves the reactant diffusion step and the chemical reactions step; those steps run simultaneously.