The properties and thickness of the bubbles in the froth control the flotation process. There is no work showing how to measure bubble film composition and thickness by a straightforward manner. In this work, a novel ...The properties and thickness of the bubbles in the froth control the flotation process. There is no work showing how to measure bubble film composition and thickness by a straightforward manner. In this work, a novel approach, a custom-designed bubble cell associated with layer interferometry(in the UV-vis region) and FT-IR spectroscopy was used to investigate the effect of solid particle type(hydrophilic vs hydrophobic), concentration and bubble diameter on stability of a bubble blown in air. Stability was quantified by measuring bubble lifetime and hydrated film thickness. Kerosene with silicone oil as a foaming agent was used to evaluate the impact of bubble diameter(test series I). Frother solutions(MIBC, Dowfroth 250, Hexanol and F-150) were used for the solid type concentration experiments(test series II). In the first series of experiments, it was determined that as the diameter of a bubble increased from 10 to 25 mm, so did the hydrated film thickness from 350 to 1000 nm. In the second series, as the silica concentration increased(0 to 10%), an increase in bubble lifetime and hydrated film thickness was resulted(130%-250%). An impact of solid hydrophobicity was found but to a lesser degree than expected. It is possible that the small particle size(<0.1 m) of silica was responsible for this behavior. The findings are used to interpret the effect of solids in flotation froth.展开更多
Incipient plasmonic bubble formation is observed around gold nanopillars with different inter-nanopillar separations. The experimental measurements and theoretical analysis show that the nanobubble formation is due to...Incipient plasmonic bubble formation is observed around gold nanopillars with different inter-nanopillar separations. The experimental measurements and theoretical analysis show that the nanobubble formation is due to the enhanced plasmonic resonance rather than from the laser heating. Inter-nanopillar distribution may lead to threshold fluence variations. The lifetime of plasmonic bubbles can reach several minutes. Furthermore, both the radius and the growth rate of the plasmonic nanobubble increase as the inter-nanopillar distribution decreases.Smaller-spacing distributed arrays produced larger bubbles. The maximum growth rate of the bubbles can be reached at about 883.5 × 10^-6m∕s on 1 μm nanopillars, but it is only 56.9 × 10^-6m∕s on 4 μm nanopillars.展开更多
基金Project(2013BAB14B05)supported by National Key Technology Research and Development Program of the Ministry of Science and Technology of China
文摘The properties and thickness of the bubbles in the froth control the flotation process. There is no work showing how to measure bubble film composition and thickness by a straightforward manner. In this work, a novel approach, a custom-designed bubble cell associated with layer interferometry(in the UV-vis region) and FT-IR spectroscopy was used to investigate the effect of solid particle type(hydrophilic vs hydrophobic), concentration and bubble diameter on stability of a bubble blown in air. Stability was quantified by measuring bubble lifetime and hydrated film thickness. Kerosene with silicone oil as a foaming agent was used to evaluate the impact of bubble diameter(test series I). Frother solutions(MIBC, Dowfroth 250, Hexanol and F-150) were used for the solid type concentration experiments(test series II). In the first series of experiments, it was determined that as the diameter of a bubble increased from 10 to 25 mm, so did the hydrated film thickness from 350 to 1000 nm. In the second series, as the silica concentration increased(0 to 10%), an increase in bubble lifetime and hydrated film thickness was resulted(130%-250%). An impact of solid hydrophobicity was found but to a lesser degree than expected. It is possible that the small particle size(<0.1 m) of silica was responsible for this behavior. The findings are used to interpret the effect of solids in flotation froth.
基金supported by the Fundamental Research Funds for the Central Universities (No. 2014QNA39)the Outstanding Young and Middle-Aged University Teachers and Presidents Training Abroad Project of Jiangsu Provincethe Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Incipient plasmonic bubble formation is observed around gold nanopillars with different inter-nanopillar separations. The experimental measurements and theoretical analysis show that the nanobubble formation is due to the enhanced plasmonic resonance rather than from the laser heating. Inter-nanopillar distribution may lead to threshold fluence variations. The lifetime of plasmonic bubbles can reach several minutes. Furthermore, both the radius and the growth rate of the plasmonic nanobubble increase as the inter-nanopillar distribution decreases.Smaller-spacing distributed arrays produced larger bubbles. The maximum growth rate of the bubbles can be reached at about 883.5 × 10^-6m∕s on 1 μm nanopillars, but it is only 56.9 × 10^-6m∕s on 4 μm nanopillars.
