Effect of Comminution Methods on Low-Rank Coal Bubble–Particle Attachment/Detachment: Implications for Flotation

Surface roughness has an important influence on the wettability of particles. This paper is an innovative exploration to control the surface wettability of apatite and dolomite from the perspective of roughness in the background of phosphate flotation. Roughness characteristics of apatite and dolomite particles and its effects on wettability were investigated with surface roughness, contact angle measurements, and SEM analysis. The relationship between surface energy and wettability of different roughness surfaces was also discussed. The results indicated that the influence of roughness on apatite and dolomite particles showed the same regularity, and wettability increased with the increasing roughness for hydrophilic surfaces, while the wettability decreased for hydrophobic surfaces. The influence of roughness on wettability can be well explained by Wenzel and Cassie models, and the surface energy of different rough surfaces had a strong correlation with their wettability. When sodium oleate was added after acid treatment, the apatite was hydrophilic, while the dolomite was hydrophobic; the difference in wettability between them became greater as surface roughness increased. Thus, it can be predicted that the selective separation of dolomite and apatite under acid reverse flotation conditions can be strengthened by increasing the mineral surface roughness during comminution.

Section: Effect Of Surface Roughness On Contact Angle Of Apatite and mentioning

confidence: 95%

Insight into the Influence of Surface Roughness on the Wettability of Apatite and Dolomite

Wang

Zhang

2020

“…Several separation methods, such as magnetic aspiration, gravity separation, bio-beneficiation and froth flotation, have been developed to facilitate clean and efficient utilization of low-rank coal. Compared with other separation methods, froth flotation is an effective separation method for fine coal cleaning, which depends upon the differences in the surface properties of coal and gangue minerals [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Enhancing Flotation Performance of Low-Rank Coal Using Environment-Friendly Vegetable Oil

Xu,

Zhou,

Hao

et al. 2023

Self Cite

Flotation is widely used for low-rank coal upgrading, although it is always inefficient due to its rough surface morphology and rich oxygen-containing functional groups. In this study, the environment-friendly vegetable oil 1030# was used to enhance the flotation performance of low-rank coal. The mechanism of 1030# enhancing the flotation of low-rank coal was revealed through surface property analysis of coal particles and bubble–particle adhesion tests. The flotation results showed that the flotation yield of low-rank coal increased with the increase in the collector dosage, and the flotation yield of 1030# as a collector is obviously higher than that of diesel. Scanning electron microscopy (SEM) and chromatography–mass spectrometry (GC-MS) were used to analyze the surface morphology of coal particles and components of the reagent. The SEM results showed that the surface of low-rank coal is loose and contains a large number of pores and cracks, which is not conducive to the spreading of chemicals on the coal surface and the mineralization of bubbles and particles. GC-MS results showed that 1030# mainly contained methyl oleate with more unsaturated double bonds than diesel. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to analyze the surface functional groups of the low-rank coal before and after reagent treatment. The results of FTIR and XPS showed that the coal surface of low-rank coal before reagent treatment contained a large number of oxygen-containing functional groups with poor surface hydrophobicity, while the surface of low-rank coal after reagent treatment had reduced oxygen-containing functional groups and increased hydrophobicity. The contact angle of the low-rank coal surface also showed the same variation trend as the FTIR and XPS results. The adhesion force between the bubble and coal surface in different collector solutions was measured. The maximum adhesion between the bubble and coal surface increased with the increase in the collector, and the maximum adhesion force with 1030# treatment was higher than that of diesel. This indicated that 1030# with a large number of polar components is more easily spread on the surface of low-rank coal, thus improving the hydrophobicity of low-rank coal.

“…In relation to mineral liberation, two aspects must be addressed: (1) the characterization of the raw materials to be processed, and (2) the variation of the liberation characteristics according to the treatment to reduce the particle size. This issue covers both topics: techniques of mineral liberation characterization of ores before treatment [2,3], and the relationships between comminution and mineral liberation, taking into account the energy consumption [4][5][6][7][8].…”

mentioning

confidence: 99%

Editorial for Special Issue “Mineral Liberation”

Alfonso

2021