Effect of dissolved copper ions on erosion-corrosion synergy of X65 steel in simulated copper tailing slurry

Erosion-corrosion is studied in the context of carbon steel pipelines transporting copper tailings with focus on the influence of dissolved copper ions present in the slurry. API 5L X65 steel is exposed to flow of slurry in rotating cylinder electrode (RCE) simulating flow conditions typical of a slurry pipe. Degradation is evaluated by means of electrochemical and gravimetric techniques, and the worn surfaces are analyzed by scanning electron microscope equipped with focused ion beam. It is found that 500 ppm of dissolved copper ions increases the total weight loss by at least 30% and the increase is attributed to the combined contributions of corrosion and the erosion-corrosion synergy, with the underlying mechanism being galvanic coupling of steel with the reduced copper ions deposited on steel surface.