Ferrite Process; Heavy Metal Ions Treatment System

Abstract

The principle of the “Ferrite Process”, heavy metal ions treatment system, and the practically operated systems are presented. In the “Ferrite Process”, the heavy metal ions are incorporated into the lattice points of the ferrites in the course of the formation of the spinel structure by the oxidation of the Fe(II) ions. The ferrite formation reaction proceeds in two paths depending on the reaction pH; 1) the green rust path (pH 7-10), and 2) the γ-FeO(OH) path (pH 10.5-11). The mole ratio of the heavy metal ions incorporated into the lattice points to the Fetotal in the ferrites depends on the reaction pH and the mol ratio of the heavy metal ions in the reaction solution and to the Fe(II) ions added to the reaction solution. Ferrite Process is now practically adopted to the treatment of the laboratory waste waters at the universities and the institutes in Japan, to the treatment of the plating waste waters, and to the treatment of branching mine drainage waters. Since the ferrite sludge has a strong magnetic property, it is reused as a useful magnetic material.