Abstract:
This work evaluates the most time and cost-effective water treatment to prevent internal corrosion of iron-ore slurry pipelines. Water can be injected into the pipeline to separate iron-ore batches and ensure continuous pumping. The water was obtained from a reservoir containing a mixture of natural water from a river and the residual water from the ore production plant. The reservoir water has a typical pH of 7.7. During maintenance periods, the pumped water can be diverted to a dam. The dam water can then be re-injected. The dam water has a typical pH of 10.8 Both water sources must be treated before being injected into the pipeline to prevent corrosion problems. The treatment initially considered was to raise the pH with sodium hydroxide to values above 10.5 and to use sodium sulfite as an oxygen scavenger. The study was conducted with samples in its as-received condition and after the pH adjustment, with and without the addition of sodium sulfite. Linear polarization curves were obtained to estimate the corrosion rate, and anodic polarization curves were taken to evaluate the active/passive state. Dynamic immersion tests were conducted to get the corrosion rates. The results show that the correction of the pH alone and the correction of the pH with the addition of Na2SO3 seem to be interesting options for controlling the corrosivity of the reservoir water. Good results were obtained at pH 12.0 and 12.5 with and without Na2SO3 sufficient to consume the dissolved oxygen. Attention should be taken to the industrial use of Na2SO3, it took more than 2 h to consume the dissolved oxygen in the water studied.
Referência:
PASTRIÁN, Fabián Andree Cerda. Water treatment to prevent the internal corrosion in iron-ore slurry pipeline. In: RIO PIPELINE AND LOGISTICS, 2025, Rio de Janeiro. Palestra… 24 slides
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