Recovery of Silicon and Iron Oxides from Alumina-Containing Sweepings of Aluminum Production

The method of recovery of contaminating components from sweepings of the aluminum production for their further return into the electrolyzer is proposed. To concentrate the material, the following processing flowsheet is proposed: milling–classification–reverse flotation–thickening. For the most complete removal of silicon and iron oxides during the flotation of sweepings, the Flotigam 7266 flotation reagent produced by Clariant (Germany), which is a mixture of primary fatty alkyl amines, is used. To remove carbon particles, the combination of pine oil in a mixture with kerosene is used. Flotation is performed using a FML 0.3 flotation machine. The initial material, chamber product, and tails are analyzed for the content of carbon and aluminum, iron, and silicon oxides using X-ray spectral (XSA), X-ray phase (XPA), and chemical analyses. It is established that processing the total material mass does not make it possible to acquire a product with an acceptable content of silicon and iron oxides. Based on the XPA of various fractions of the initial material, it is proposed to process the material fractions containing the minimal amount of contaminating substances (carbon and silicon and iron oxides). Two fractions are selected for processing using the flotation method by the XRS results of various material fractions:–0.071 mm and +5.0 mm. When processing the first of them, the chamber product of the acceptable quality is acquired. A product with a high content of alumina and fluorinated components at low carbon and iron oxide concentrations but a considerable amount of silicon oxide is acquired from a coarse electrolyte-containing fraction (+5.0 mm). The further use of this product is possible to fabricate aluminum–silicon alloys.