Kinetic study on the leaching of calcined magnesite in gluconic acid solutions

A kinetic study on the leaching of calcined magnesite in aqueous gluconic acid solutions was investigated in batch reactor employing the parameters of particle size, temperature, stirring speed, solid–liquid ratio and acid concentration. A mathematical model was evaluated for the rate increased with decreasing particle size and increasing temperature and initially, the leaching in terms of acid concentration and then fell with increasing concentration. It was found in the study that stirring speed was not effective on leaching rate. The leaching rate decreases as solid–liquid ratio increases. It was shown that the mathematical model for calcined magnesite particle was:−1.9041 ln((1−XB)1/3+1.157)+0.952 ln((1−XB)2/3−1.156(1−XB)1/3+1.338)−3.298 arctan(0.577(1.73(1−XB)1/3−1))=3bkSCA0ρBRtDissolution curves were evaluated in order to test shrinking core models for fluid–solid systems. Consequently, it was determined that the leaching rate is controlled by surface chemical reaction. In addition, the fact that dissolution was controlled by the surface chemical reaction was also supported with the relationship between the rate constant and the particle radius. The activation energy of the process was determined to be 32.88 kJ mol−1.