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Given that particle and bubble size, as well as their surface properties, are pivotal in froth flotation, surfactants have been extensively employed due to their impact on bubble size and froth stabilization. This study aimed to investigate the influence of surfactants on the performance of apatite flotation in column. Three different categories of surfactants were examined: anionic, amphoteric, and nonionic, specifically Lupromin, Genagen, and Triton X-100, respectively. The critical coalescence concentration (CCC) and surface tension of each surfactant were determined. The impact of these surfactants on reducing bubble size was quantified, and their subsequent effects on apatite flotation in a column were assessed. The most favorable flotation response for Genagen was achieved at CCC and pH 11, resulting in the highest apatite recovery and the smallest bubble size. For Triton X-100, the best condition was attained at ¼ CCC and pH 11. However, overall, Lupromin was the surfactant that yielded the best flotation results (at ¼ CCC and pH 11). The superior performance of this anionic surfactant was corroborated by chemical adsorption results, as demonstrated by FTIR analyses. [ABSTRACT FROM AUTHOR]

The main mechanism of flotation is bubble-particle interaction, which is strongly dependent on the particle size and the bubble size distribution (BSD). It is known that air bubbles are responsible for collecting and delivering hydrophobic particles from the pulp to the foam zone. Controlling the size and distribution of bubbles generated is essential to promote greater bubble-particle interaction. The aim of this study was to investigate the influence of bubble size on the flotation performance of apatite of a low-grade phosphate ore for different particle sizes: fine (d32 = 13.95 µm), intermediate (d32 = 50.86 µm), and coarse (d32 = 108.96 µm). Through the results, it was possible to identify the best bubble size range for each particle size studied. The fine particles showed a better flotation performance when medium-sized bubbles (800–1,000 µm) were used, while the coarse particles had an improved performance when large bubbles (d32 > 1,000 µm) were used. However, the best flotation result was obtained with intermediate particles, which accepted a large range of bubble size distribution under different operating conditions since the collision and attachment mechanisms are favored in this particle size range. [ABSTRACT FROM AUTHOR]

In this research, the effect of bubble size distribution on the performance of column flotation of fine particles of apatite was investigated. The Brazilian apatite ore sample used in this study was low grade (18.38% P 2 O 5 content) with a Sauter mean diameter of 13.95 μm. Bubbles were measured in a system consisting of a high-speed digital camera and software for image analysis. In addition, probes were used for shooting bubbles. The effect of the presence of mineral particles on the bubble size distribution was also investigated comparing the bubble size in air-water and air-water-ore systems. The presence of ore particles adhered to the bubble surface, prevented bubble coalescence, consequently reducing the bubble size, compared to the air-water system. The flotation tests were performed for different bubble size distributions: small bubbles (d 32 < 300 μm), medium-sized bubbles (300 < d 32 < 1000 μm) and large bubbles (d 32 > 1000 μm). The best bubble size range for flotation of fines particles of apatite was identified and the images from probes helped us to correlate the performance results (P 2 O 5 content and recovery) with the flotation mechanisms. The highest P 2 O 5 content was obtained when the flotation of fine apatite was performed with small bubbles (d 32 < 300 μm), however, the P 2 O 5 recovery was very low (40%) at this condition. The highest P 2 O 5 recovery was obtained in flotation using larger bubbles (d 32 > 1000 μm) but with low P 2 O 5 content. The best flotation performance, simultaneously considering both responses (P 2 O 5 content and recovery), was obtained with medium-sized bubbles. Unlabelled Image • The effect of bubble size distribution on flotation performance of fine particles was studied. • The effect of the presence of apatite particles on bubble size was investigated. • Highest P 2 O 5 content was obtained when the flotation was performed with small bubbles. • Highest P 2 O 5 recovery was obtained when the flotation was performed with larger bubbles. • The size range that led to the best performance for both responses was 800 to 1000 μm. [ABSTRACT FROM AUTHOR]

The flotation performance is associated with the probability of bubble–particle collision and the aggregate stability. Currently, one of the major challenges of the mining industry is the flotation of fine particles and the generation of medium-sized bubbles (100–1000 μm) can be a good alternative to increase the recovery of these particles. Therefore, new strategies to determine and control bubble sizes, to achieve the desired diameters are very important. This study aimed to characterize and control the bubble size distribution and to consider its relation with the flotation performance. Two different methods (offline and online) were used to measure the bubble size distribution. The results showed that the addition of surfactant was a good alternative to generate bubbles with high percentages of medium-sized bubbles (80–90%) and high air hold-up values (10–12%), simultaneously. Kinetic test showed a direct relation between the bubble size distribution and the P 2 O 5 content. [ABSTRACT FROM AUTHOR]