Corrosion Behavior of Q235 Steel in Coal Leaching Solution

The composition of a long-flame coal leaching solution was analyzed by ion chromatography. The effects of ion concentration and temperature on the corrosion behavior of Q235 steel in coal leaching solution were investigated by electrochemical impedance spectroscopy and polarization curves. The corrosion behaviors of Q235 steel in different stirring rates and various solutions were analyzed through weight loss experiments. Results show that the main cations are Na+ and Ca2+ and the main anions are SO42- and Cl- in the coal leaching solution. The increase of ion concentration and temperature can reduce the corrosion resistance of Q235 steel in coal leaching solution. The corrosion rate of Q235 steel was accelerated with increasing stirring rate. When the stirring rate was 60 r/min, the corrosion rate reached 0.304 7 mm/a that was about 2.3 times higher than that in static state. Increasing concentration of Cl- or SO42-, or both existence of SO42- and Cl- in solution could promote corrosion of Q235 steel.