Leaching Kinetics of Calcium Aluminate Slag

Leaching calcium aluminate slag by Na2CO3 solution is solid?liquid reaction generating solid product. A study on the leaching kinetics of calcium aluminate slag was carried out. The effects of reaction temperature, concentration of reagents, particle size and agitation rate on the leaching rate were deterimined. The results show that the leaching process can be modeled with the shrinking core model of the first order reaction. An empirical equation for the leaching kinetics was established as 1+2(1?xB)?3(1?xB)2/3= 1.108exp(?1906/T)t. The apparent activation energy is 15.84 kJ/mol. The leaching rate is controlled by diffusion of reacting reagents in a porous solid product layer. The leaching mechanism is fairly explained by the model. A higher leaching rate of calcium aluminate slag is obtained by higher leaching temperature and/or with smaller particle size.