Iron sulphates production being polarized by the direct and alternating currents

Abstract

The process of iron oxidation in the sulfate electrolytes was studied by the method of electrochemical polarization by the steady and transient currents. Initially, in the first electrolyzer, the iron electrodes were oxidized under the influence of alternating current. The results of iron oxidation in the first electrolyzer were monitored by determining the weight loss of the iron electrodes. An almost rectilinear increase in the mass of iron is established to be observed, which passed into the solution in the form of Fe2+ ions when the current density changes in the range of 80-400 A / m2. The current efficiency is close to 100%, and sometimes exceeds 100%, since the chemical dissolution of iron in sulfuric acid also occurs simultaneously. The iron sulfate (II) can be obtained by evaporation of the solution. After that, the sulfate solution containing iron ions (II) was sent to the second electrolyzer, in which the oxidation of iron (II) to iron (III) was carried out under the direct current. The electrode spaces were separated by an MA-40 anion exchange membrane. Over 90% of iron (II) was demonstrated to be transfers into the trivalent state within 1 hour in the second electrolyzer at a current density of 120 A / m2. A change in the current density to 600 A / m2 leads to an increase in the oxidation state to 97.5%, i.e. iron ions (II) are almost completely oxidized under the specified conditions. As a result of the experiments, an electrochemical method for producing iron sulfate (III) was developed.