Formation of Metallic Iron and Disproportionate Reaction of Iron (II)

Abstract

A new reaction was carried out in a quasi-static way through an analytical filter paper (No.5 C) between 1 mol/l ferrous chloride and 1N sodium hydroxide solutions at room temperature for 24 hours. The reaction product of apparent density 3.15 g/cm3 was precipitated on the filter paper at the side of ferrous solution.It has been found that metallic iron was contained in the resultant product with ferrous hydroxide, green rust-I, magnetite and gethite. The metallic iron was identified by means of X-ray diffractometry, thermomagnetic analysis and chemical analysis. Needle-like metallic iron particles could be separated from resultant precipitate by dissolving in hydrochloric acid. By determination of consumed reagents due to the reaction in both solutions and of total iron contained in the resultant precipitate, it was proved that the reaction proceeded stoichiometrically.State analysis of iron was undertaken for obtaining the iron valences in the resultant precipitate. In spite of contamination of the solution with air during the reaction periods, the proportional relation between metallic (Fe0) and ferric (FeIII) iron could be observed. In proportion as these iron contents in the resultant preceipitate increased, the quantity of ferrous (FeII) iron decreased.It was considered from above experiments that the metallic iron was formed by the following disproportionate reaction of ferrous iron.3FeII Fe0 2FeIII