A Comparative Study of Different Columns Sizes for Ultrafine Apatite Flotation

The desliming operation to discharge ultrafine particles less than 20 mu m prior to concentration by flotation is a common practice in phosphate ores beneficiation plants. The first industrial application for the beneficiation of the phosphate material with particle sizes <44 mu m in Brazil was in the Araxa plant concentrator in the beginning of the 1980s. This work shows the comparative flotation results with two different phosphate slime samples (<40 mu m) obtained from the Copebras (CMOC International) industrial plant located in Catalao (Goias state, Brazil), considering a circuit with rougher/cleaner configuration with different columns sizes, as follows: Circuit 1 (rougher-4" diameter column; cleaner-2" diameter column) and circuit 2 (rougher-6" diameter column; cleaner 4" column). The results indicate that better flotation apatite recovery results were achieved for the circuit with higher size columns (6" and 4"). The results can be explained by the application of a cavitation tube in the rougher stage in the 6" column. The improved flotation performance can be attributed to increased probabilities of collision and attachment and the reduced probability of detachment by the small size bubbles generated by the cavitation tube in comparison with the bubbles produced by the porous tube of the 4" column flotation.