Effect of the solution ionic composition upon the precipitation kinetics and self-organization processes in basic iron sulfate precipitates

A possibility is shown for the control over self-organization processes in multi-phase precipitates at oxidative-hydrolytic precipitation of Fe (III) ions (oxidized from Fe(II) state) from sulfate solutions. A decrease in the degree of the system non-equilibration and precise optimization of the onset conditions afforded the elimination of the concentration self-oscillations, estimation of the process kinetic parameters and obtaining basic iron sulfates of a definite composition and dispersity at high degrees of Fe ions precipitation from the solutions. In order to dissolve an oxide-hydroxide layer on the surface of the initial goethite precipitate the solutions were supplied with chloride ions forming surface complexes and behaving as modification activators thus affecting the heterogeneous oxidation. The seeming activation energy of the studied processes (129.9...41.9 kJ/mol) was evaluated at different process stages and various temperatures and pressures according to the heterogeneous reaction formal kinetics (particularly. Praut-Tomkins equation) and the reaction order (2.2...0.65) was calculated according to Vant-Hoff method.