Abstract

The most important factors' effects on the kinetics of leaching Nigerian chromite ore with sulfuric acid were thoroughly investigated. The shrinking core model was used to assess the impact of H2SO4 concentration, leaching temperature, and particle size on the rate of chromium leaching. On the other hand, as H2SO4 concentration, temperature, and particle size decrease, the rate of leaching dissolution accelerates. The ideal conditions were found to be a 3M H2SO4 concentration, 80°C system temperature, particle size range of +110-75m, and moderate churning. Under these circumstances, over 78% of the chromium was completely recovered. The dissolving process is regulated by a diffusion controlled mechanism, according to the kinetic analysis. In terms of concentration, the reaction order is 0.334, with a 28.43kJ/mol activation energy. Finally, to explain the process, a dissolving rate equation is derived: 1-2/3α-(1-α) kd[H+]0.336(S)0.179ro 0.023 e-2843/RT t = 2/3 = kd[H+]0.336(S)0.179ro 0.023 e-2843/RT t. Under optimum conditions, X-ray diffraction spectroscopy (XRD) and scanning electron microscopy (SEM) were utilized to analyze the residual product. These revealed that the raw sample's primary peaks of chromium containing ore had been degraded, leaving peaks such as flurite, brown millerite, and sellaite.

Key words: Chromite; Kinetics; Leaching; Lixiviant; Nigerian