Hydraulic convey of iron ore slurry: Pipeline wear and ore particle degradation in function of pumping time

This paper reports and discusses the results of an experimental investigation on hydraulic transportation of iron ore concentrate and its effect on slurry wear, pure erosion and pure corrosion of a carbon steel pipe. For this, a specially designed test-loop was built to simulate long distance iron ore transportation, allowing also to determine pure erosion effects by means of a specially designed cathodic protection system. Pure corrosion damage was evaluated by linear polarization measurements in filtered ore concentrate, i.e., in the absence of particles. The results revealed that pure erosion and pure corrosion effects were much lower than the measured wear, evaluated as pipe thickness loss, indicating an important synergism between erosion and corrosion. Wear damage results in microcraters aligned in the flow direction, which merge with each other likely due to enhanced electrochemical activity fed by the erosion process. Evaluation of the effect of the pumping time on the ore concentrate characteristics revealed that particles sizes decreased while the sphericity factor increased leading to lower wear rates. Finally, a mechanism explaining the pipeline wear associating erosion, corrosion and the material microstructure as well as a methodology to forecast the pipelines thickness loss as a function of the ore concentrate travelling distance were also proposed.