Dissolution Kinetics Studies of Nigeria Gypsum Ore in Hydrochloric Acid


Dissolution kinetics studies of gypsum ore sourced from Postikum, Northern Nigeria, was conducted using hydrochloric acid as the leachant. The study was done with the aim of establishing possibility for the development of hydrometallurgical route for the production of highly pure gypsum. The effects of the experimental variables investigated were contact time, acid concentration, temperature, particles size and solid-liquid ration. The energy of activation of the dissolution reaction estimated from experimental data is 9.6kJ mol-1. Leaching in 6 M HCl solution, at temperature of 80oC, stirring speed of 400 rpm and using -90 + 63 µm particles size resulted in 99.7% dissolution of the ore within 120 min. The ore and the leached residue were characterized using X-ray Fluorescence (XRF), X-ray Diffraction (XRD), and Scanning Election Microscope (SEM) coupled with energy dispersive spectroscopy techniques (EDS) for chemical composition, phase and morphology. Statistical analysis of the kinetic dissolution data show that the chemical controlled model best describes the gypsum dissolution in hydrochloric acid.



gypsum ore, hydrochloric acid, dissolution kinetics, chemical controlled model