Title

EVALUATION OF COARSE PARTICLE FLOTATION PROCESSES

EVALUATION OF COARSE PARTICLE FLOTATION PROCESSES

Authorship

Lima, Neymayer Pereira

Lima, Neymayer Pereira

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DOI

10.5151/2594-357x-0032

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Abstract

Flotation is a very successfull concentration process, and is employed for many types of minerals (sulphides, oxides, etc.) as well as for diverse particle sizes. Previous works show that flotation can be applied successfully for particle sizes between 10 to 300μm. The flotation selectivity drops dramatically out of these size limits, as the system hydrodynamic conditions cannot keep at suitable levels for the flotability of these particles. Some flotation systems use a wide range of particle sizes, which can very often reduce the process selectivity due to distinct behaviors of the several size classes, and corresponding specific surface areas, hydrophobicity and weight. Along the course of this work a mechanical industrial flotation process for itabirite iron ore with high grade of coarse particles was evaluated. The results show low selectivity (Gaudin) for coarse (+0.500mm) and fine (-0.045 mm) size fractions. Positive results were obtained with 25% of particles greater than 0.150mm with the top size of 0.300mm and about 13% of particles smaller than 0.045mm. The available literature shows high probability of non-collection during flotation for coarse particles, thus requiring greater collector dosages aimed at increasing the hydrophobicity level for these particles. Bench scale flotation assays were conducted using a -1.0+0.15mm size fraction for an itabirite iron ore. The results showed the possibility to obtain a flotation concentration with SiO2 degre below 1% and metalic recovery close to 90%. Additional tests must be carried out to confirm these results.

Flotation is a very successfull concentration process, and is employed for many types of minerals (sulphides, oxides, etc.) as well as for diverse particle sizes. Previous works show that flotation can be applied successfully for particle sizes between 10 to 300μm. The flotation selectivity drops dramatically out of these size limits, as the system hydrodynamic conditions cannot keep at suitable levels for the flotability of these particles. Some flotation systems use a wide range of particle sizes, which can very often reduce the process selectivity due to distinct behaviors of the several size classes, and corresponding specific surface areas, hydrophobicity and weight. Along the course of this work a mechanical industrial flotation process for itabirite iron ore with high grade of coarse particles was evaluated. The results show low selectivity (Gaudin) for coarse (+0.500mm) and fine (-0.045 mm) size fractions. Positive results were obtained with 25% of particles greater than 0.150mm with the top size of 0.300mm and about 13% of particles smaller than 0.045mm. The available literature shows high probability of non-collection during flotation for coarse particles, thus requiring greater collector dosages aimed at increasing the hydrophobicity level for these particles. Bench scale flotation assays were conducted using a -1.0+0.15mm size fraction for an itabirite iron ore. The results showed the possibility to obtain a flotation concentration with SiO2 degre below 1% and metalic recovery close to 90%. Additional tests must be carried out to confirm these results.

Keywords

Flotation; Coarse particles; Selectivity.

Flotation; Coarse particles; Selectivity.