Magnetite dissolution and corrosion behavior in high temperature EDTA solvents

The effect of temperature on magnetite dissolution and corrosion behavior was evaluated in ethylenediaminetetraacetic acid (EDTA)-based solvents for iron oxide chemical cleaning of nuclear steam generators at temperatures ranging from 93 to 150 °C. Magnetite dissolution was drastically accelerated as the temperature was raised to 150 °C, while the amount of corrosion was controlled well within an allowable limit. Periodic venting and excessive EDTA concentration in the solvents were expected to be very effective in dissolving hard tube sheet sludge piles. The linear polarization (LP) method was also suitable to monitor the changes of corrosion rates and process conditions such as venting.