Simulation of flow condition in circular pipe transporting Paragominas bauxite slurry in the presence of a viscosity modifier

ABSTRACT Ore pumping systems flowing through pipelines has attracted the interest of mining companies as it might become a very efficient alternative of transport. Friction factor estimation is believed to be one of the greatest challenges in such projects because it is affected by many variables. A 52 % (w/w) Paragominas bauxite slurry sample was characterized according to its physical, mineralogical, and rheological properties. The properties of the sample were 74 µm d50 size, 1455 kg/m3 specific gravity, and 0,011 Pa.s viscosity. Mineralogical composition of the sample was essentially bauxite, and it also contained other minerals such as goethite, hematite, kaolinite, anatase. Rheological tests revealed that the role of sodium hexametaphosphate was as deflocculant of the slurry. The concentration of the sodium hexametaphosphate in which viscosity values reached a minimum value was equivalent to 250 g of additive/ton of bauxite. The rheological behavior of bauxite samples studied was modeled according to Herschel-Bulkley equation. Friction factor of both samples with and without additive was estimated by applying Dodge-Metzner correlation, simulating the real flow conditions at the bauxite slurry pipeline in Paragominas. Results showed that friction factor values of samples containing additive reduced 12 % average compared to the samples without any additive.