A study of the effect of lime addition on the behaviour of the concentrate of iron ore from the Aiegria Complex along the pipeline of Samarco Mineragao S. A.

摘要

The pipeline of Samarco Mineracao S.A. started its operations with slurry of iron ore from the Germane Mine in 1977. Since 1992 it started operating with ores originating in the Aiegria Complex. Plug potential formation was then observed for this material, which led to the study of rheology modifiers. The use of lime as a coagulant reagent was the best solution found for controlling the slurry physico-chemical properties, a necessary measure to ensure safe pumping. This paper describes the study of the lime effect on the potential pipe blockage and the particles compaction, which reflect the difficulty level of restart operations. The Theological parameters viscosity and yield stress were also evaluated using a rotational rheometer of the concentric cylindrical type. The results obtained through the tests showed that the rheological behaviour was that of a Bingham Plastic for the samples with lime, unlike the samples without lime that showed Newtonian behaviour after agitation. Furthermore, when lime was added the sediment became less compact and there was no evidence of plug formation. It was also verified that the slurry physico-chemical properties were directly affected by time.