Effect of lithium impurity upon aluminum hydroxide crystallization

In this study, the nucleation behavior of sodium aluminate solutions having different modulB values were investigated. For this aim, induction period measurements were carried out for different maximum allowable temperature (33,35-18,35) and different lithium concentrations (5-20 ppm). As a result of experimental studies, critical free energy exchange, critical nuclei radius, critical nuclei number in molecule and nucleation rate were calculated. It was determined that the induction time for the pure sodium aluminate solution varied between 100-400 minutes for different supersaturation ratio. In the presence of lithium ranging from 5 to 20 ppm, the highest induction time was determined as 20 min. for 10 ppm lithium. According to the classical nucleation theory, it was determined that in the presence of lithium, the critical nuclei radius decreased, the number of molecules in the critical nuclei decreased and the nucleation rate increased compared to the pure solution. For the 5 ppm Li additive, it was determined that the increase in nucleation rate increased approximately 100 times and the increase of 20 ppm Li increased approximately 39 times compared to the pure solution. It has been found that the induction times of sodium aluminate solutions in different module B values vary in the range of 6-7 minutes for low and high modulus solutions in the presence of lithium. For modules 1,49 and 1,8, a maximum of 10 minutes of induction times were obtained.