Influence of Sulfur Anions on Corrosion of 16Mn Low-Alloy Steel in Sulfide-Containing Bayer Solutions

The influence of sulfur anions known to exist in sulfide-containing Bayer solutions on the corrosion of 16Mn low-alloy steel was investigated by laboratory tests. The high-temperature weight-loss tests, means of anodic polarization curves, and cyclic voltammetry were conducted to characterize the influence of sulfur anions on Bayer solution corrosiveness and to examine the origins of the corrosion acceleration or deceleration that was observed. Results indicate that the sulfide was found to increase significantly the corrosion rate of the steel and impair the ability of the steel to passivate, and, hence, could be described as corrosion activators. Thiosulfate had no effect on the corrosion of the steel in Bayer solutions without sulfide. Furthermore, it could decrease the corrosion rate and anodic current density of the steel in Bayer solutions in the presence of sulfide, and could be described as sulfide corrosion inhibitors. Sulfite and sulfate had no effect.