Determination of Optimal Preparation Conditions of Iron-Containing Coagulants by Oxidation of Spent Solutions Using Sodium Hypochlorite

Abstract

Optimal oxidation conditions of spent etching solutions of steel-rolling plants using sodium hypochlorite are established. It is shown that it is reasonable to fabricate iron-containing coagulants with the molar ratio (Fe2+ : NaOCl) = 1 : 0.36 and oxidation time of three days, which corresponds to the 70 % conversion of Fe2+ into Fe3+. The performance of oxidation under these conditions will make it possible to reduce the oxidant consumption by 29 % and to decrease the amount of the NaCl side product by 32 % without activity lowering of the prepared coagulant.