Concentration of bauxite fines via froth flotation (

Companhia Brasileira de Alumínio (CBA) has bauxite processing plants at Poços de Caldas and Itamarati de Minas, and a new processing plant at Miraí that has been operating since June, 2008; all of them are in the State of Minas Gerais. The plants haveunits for the crushing, scrubbing and screening operations. The screened oversize is the concentrate or washed bauxite. At Itamarati de Minas, the fines are de-slimed and concentrated by gravity separation of the iron-titanium minerals in Reichert spirals followed by HIWMS. The tailings still contain bauxite, which can be separated by reverse froth flotation (flotation of the quartz and depression of the bauxite), using starch as a depressant and amine as a promoter; the pH must be around 10.0. The iron and titanium bearing minerals are depressed with the bauxite and an additional magnetic separation operation is necessary on the depressed bauxite. This paper describes the work performed on Itamarati de Minas’ samples on a bench scale at Escola Politécnica, University of S. Paulo.