Synthesis Thermodynamic and Kinetics of

This study investigates the synthesis, thermodynamics, and kinetics of rubidium jarosite decomposition in calcium hydroxide solutions. The objective was to analyze the properties of synthetic rubidium jarosite and its behavior under alkaline conditions. The methodology involved synthesizing rubidium jarosite through precipitation from an aqueous solution, followed by characterization using X-ray diffraction and scanning electron microscopy. A thermodynamic analysis was conducted using FACTSage to model the decomposition process under varying pH levels at 298 K. Experimental decomposition studies were performed in alkaline solutions with different concentrations of Ca(OH)2. Results indicated the formation of goethite and release of Rb+ and SO4 2- ions during the decomposition, with the process exhibiting an induction period followed by progressive conversion. Kinetic analysis revealed that the decomposition process is modeled by the shrinking core model, showing a reaction order of 0.4342 with respect to Ca(OH)2 and an activation energy calculated at 98.70 kJ mol-1. These findings contribute to understanding the reactions involved in the decomposition of jarosite-type compounds and their implications in hydrometallurgical processes.