SYNTHESIS OF COBALT FERRITE BY ELECTROGENERATED REACTANTS

This study demonstrates the possibility of obtaining ferrites from solutions containing nitrate ions and Ba2+ and Co2+cations using an electrochemical method based on the anodic dissolution of a steel electrode in a coaxial electrolyzer followed by heat treatment of the poorly soluble electrolysis products. The following parameters were determined experimentally: solution acidity (pH) before and after electrolysis, anode current yield (BTa), and anode oxidation rate (Va). It was shown that the anode current yield exceeds 100% due to the electrode dissolution process proceeding by both electrochemical and chemical mechanisms. Intensive hydrogen evolution at the cathode contributes to the organization of a specific hydrodynamic regime that ensures intensive mixing. The generation of OH- ions at the cathode contributes to a more complete precipitation of hydroxide compounds. The phase composition of the electrolysis products was determined by X-ray diffractometry. It was established that at 1000C, cobalt ferrite and iron (III) oxide (hematite) are formed in a ratio of ~ 1:1. High-temperature treatment (1100°C) slightly increases the cobalt ferrite content in the sample (up to 64%) and promotes the formation of barium hexaferrite in insignificant amounts. The average crystal size of cobalt ferrite also increases, reaching 43 nm. Undesirable phenomena occurring during electrolysis were noted, associated with the precipitation of cobalt on the cathode in the form of hydroxides and oxides, as a result of which the concentration of Co2+ ions in the solution decreases, as well as passivation of the anode metal, in some cases up to complete cessation of its dissolution due to the presence of nitrate ions in a sufficiently high concentration.