Kinetics of Reductive Dissolution of a Magnetite Specimen Using Oxalic Acid

Abstract

The removal of radionuclides from the primary coolant system of nuclear power plants occurs with the dissolution of corrosion metal oxide layers deposited with the radionuclides. Kinetic dissolution experiments were conducted with a synthetic magnetite specimen in the form of a thin plate using an aqueous solution of oxalic acid as a reducing agent. The effects of acid concentration and temperature were investigated on the kinetics of the reductive dissolution of a magnetite specimen. In particular, the kinetic experiments were performed in a wide temperature range from low (57 °C) to high (120 °C), above the normal boiling point of water. The dissolution of magnetite increased with increasing acid concentration and temperature. The acid concentration dependence of the dissolution reaction rate of Fe at a given temperature was correlated with the nth power of the oxalic acid concentration. Additionally, the temperature dependence of the dissolution reaction rate of Fe at a fixed oxalic acid concentration was studied with an Arrhenius-type equation.

Demulsification of Pickering Emulsions by Chemical Dissolution of Stabilizers

“…The ability to facilitate electron transfer makes oxalic acid an effective reducing agent. Thereby, reducing hematite from a +3 to +2 oxidation state to form ferrous oxalate acting as an autocatalyst and oxalate ligand on the iron oxide surface In contrast, the reaction between hydrochloric acid and hematite is a simple acid–base reaction where no reduction occurs which results in the formation of metal salts, i.e., ferric chloride and water .…”