INFLUENCE OF SOLIDS CONCENTRATION, PARTICLE SIZE DISTRIBUTION, pH AND TEMPERATURE ON YIELD STRESS OF BAUXITE PULP

In Northern Brazil, bauxite pulp is transported through pipelines to the plant where alumina is produced. In slurry transportation through pipelines, knowing the yield stress value is essential for the pumps and pipeline design. Yield stress is the minimum shear stress and corresponds to the first evidence of flow. This rheological property is influenced by factors, such as: particle form, temperature, particle size distribution and interaction among the particles. Within the context above, the objective of this work is to verify the influence of solids concentration, particle size distribution produced by different grinding time, temperature and pH on the yield stress of bauxite pulp. It was verified that the yield stress of bauxite slurry increases as solids concentration and grinding time go up and decreases with temperature and pH.