| Abstract Scope |
Kaolinite directly impacts alumina production costs (soda consumption). In Brazil, kaolinite is removed from Amazonian bauxite through stages of scrubbing, milling, screening, and cycloning. Typically, on Amazonian bauxite processing plants in Brazil particles below 38 µm tend to follow the tailings streams. Analyzing its granulochemical profile, the fraction between 38 and 10 µm has approximately 42% of available alumina grade and 6% of reactive silica grade. Meanwhile, the fraction below 10 µm has available alumina grade of 19% and a reactive silica grade exceeding 20%. Therefore, the study aimed the use of column flotation to recover the ultrafine fraction of bauxite (between 38 and 10 µm), with a focus on increasing alumina recovery in the beneficiation plant. Different types of collectors, washing water flow, and air flow in the column were evaluated. After pilot tests and process simulations, the potential increase in metallurgical alumina recovery was approximately 3 percentage points. |