Investigation of dissolution kinetics of natural magnesite in gluconic acid solutions

In this study, the dissolution of magnesite particles in aqueous gluconic acid solutions was investigated in a batch reactor employing the parameters of stirring speed, particle size, temperature, solid/liquid ratio and acid concentration. The shrinking core model was evaluated for the rate increased by decreasing particle size and increasing the temperature and initially, the dissolution in terms of acid concentration and then fell with the increasing concentration. No important effect of stirring speed was observed and the dissolution rate decreased as solid/liquid ratio increased. It was shown that the model is: -2.0 In((1 - X-B)(1/3) + 1.63) + 1.0 In((1 - X-B)(2/3) - 1.63(1 X-B)(1/3) + 2.66) - 3.47 arctan(0.58(1 - X-B)(1/3) - 1)) = 3bk(s)Cao/rho R-B t Dissolution Curves were evaluated in order to test shrinking core models for fluid-solid systems. Consequently, it was determined that the dissolution rate is controlled by surface chemical reaction. The activation energy of the process was determined to be 61.7 kJ mol(-1). (c) 2006 Elsevier B.V. All rights reserved.