Eng. sanit. ambient. 329Aval. da qualidade da água e autodepuração do Ribeirão do Meio, Leme (SP) Vol.13 -Nº 3 -jul/set 2008, 329-338

No abstract

22The two-dimensional fractal dimension (Df) of large aggregates of kaolin (> 540 μm) 23 during the shear flocculation process for kaolin solution was investigated using non-intrusive 24 in situ image-based acquisition system. Separate experiments were also carried out for three

The main constituents of red mud produced in Aluminio city (S.P., Brazil) are iron, aluminum, and silicon oxides. It has been determined that the average particle diameter for this red mud is between 0.05 and 0.002 mm. It is observed that a decrease in the percentage of smaller particles occurs at temperatures greater than 400 °C. This observation corresponds with the thermal analysis and X-ray diffraction (XRD) data, which illustrate the phase transition of goethite to hematite. A 10% mass loss is observed in the thermal analysis patterns due to the hydroxide–oxide phase transitions of iron (primary phase transition) and aluminum (to a lesser extent). The disappearance and appearance of the different phases of iron and aluminum confirms the decomposition reactions proposed by the thermal analysis data. This Brazilian red mud has been classified as mesoporous at all temperatures except between 400 and 500 °C where the classification changes to micro/mesoporous.