ON THE MECHANISM OF CRYSTAL-FORMATION IN THE FESO4-H+/OH--H2O-O2 SYSTEM

On the basis of the available literature data the main factors affecting the phase and dispersion composition of poorly soluble Fe(III) compounds which form on oxidation of FeSO4 aqueous solutions or Fe(II) hydroxide suspensions have been studied: pH of the reaction medium, temperature, the oxidizing agent feed rate and its reactability, the presence of seed crystals. An analytical method is proposed to determine the composition of crystal-forming complexes. The method is based on the crystal chemistry data on the structure of the forming phases, the data on the ionic state of Fe(II) and Fe(III) in solution and accepted notions about chemical reactions during polycondensation of crystal-forming complexes. In the framework of this model, an explanation of the experimental data about the phase and dispersion composition of the forming Fe(III) compounds on the synthesis parameters has been given.