Formation Of Spinel Iron Oxide In Solution

Abstract

ABSTRACTThe alkalizing of aqueous mixtures Fe111 + xFe11 has been investigated at pH ≈ 8 for 0≤x≤0.5. Three composition zones have been observed. At x<O.l goethite was the only stable product. At 0.1≤x≤0.25 the early stage, characterized as mixed-valent protoferrihydrite, spontaneously transformed into nonstoichiometric magnetite. At x>0.25 the system, made of spinel particles, was homogeneous during all the evolution.