FACTORS AFFECTING THE PREPARATION OF ALUMINUM FLUORIDE BY THE WET PROCESS FROM FLUOSILICIC ACID PRODUCED FROM PHOSPHATE FERTILIZERS INDUSTRY

Abstract

This thesis deals with studying some of the factors affecting the preparation of anhydrous aluminum fluoride fit for several uses by the wet process. Different parameters were optimized along the preparation scheme, namely; kaolin particle size, acid concentration, temperature, reaction time and kaolin to acid ratio. Leaching reaction kinetics was studied using the isothermal technique and two models were found to best fit the obtained data, namely, the unreacted core model (diffusion through product layer controlled) and the progressive reaction model. Filtration process was performed under constant pressure using both vacuum and pressure filtration whereby the specific cake and filter medium resistances were obtained. Crystallization process was performed using the evaporative method with optimization of time and seeds type. Finally, the calcination step was carried out to obtain the final anhydrous product with purity more than 98%.