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
In Fukushima NPP-1, large amounts of HALW （high-activity-level water） accumulated in the reactor, turbine building and the trench in the facility is treated by circulating injection cooling system. The development o...In Fukushima NPP-1, large amounts of HALW （high-activity-level water） accumulated in the reactor, turbine building and the trench in the facility is treated by circulating injection cooling system. The development of highly functional adsorbents and stable solidification method contributes to the advancement of the decontamination system and environmental remediation. The present study deals with： （1） preparation of insoluble ferrocyanide loaded zeolites; （2） selective uptake of Cs~ in seawater; and （3） estimation of Cs immobilization ratio and stable solidification. Various kinds of Cs-selective composites loaded with insoluble ferrocyanides （CoFC, NiFC） into the zeolites （zeolite A （A51, A-51J）, zeolite X （LSX）, chabazite （modified chabazite） and natural mordenite （SA-5）） matrices have been prepared to use successive impregnation/precipitation methods by Tohoku University. As for Cs~ adsorption, these composites had relatively large uptake （%） over 95%, distribution coefficients （Kd） above 103 cm3/g and excellent adsorption kinetics even in seawater. The immobilization ratio （%） of Cs for the CoFC saturated with Cs＋was estimated at different calcination temperatures up to 1,200 ℃ in advance. The immobilization ratio was less than 0.1% above 1,000℃, indicating that the adsorbed Cs~ ions are completely volatilized and insoluble ferrocyanides had no immobilization ability for Cs. In contrast, the insoluble ferrocyanide-loaded zeolites had excellent Cs immobilization ability; in the case of insoluble ferrocyanide-loaded natural zeolites （NiFC-SA-5, CoFC-modified chabazite）, the immobilization ratio was above 99% and 96% even after calcination at 1,000 ℃ and 1,100 ℃, respectively, indicating that nearly all Cs ions are immobilized in the sintered solid form. On the other hand, the immobilization ratio for the insoluble ferrocyanide-loaded A and X zeolites （NiFC-A （A51, A51J）, NiFC-X） tended to decrease with calcining temperature; for example, the immobilization ratio for NiFC-X at 1,000 ℃and 1,100 ℃ was estimated to be 74.9% and 55.4%, respectively, and many spots concentrating Cs were observed on the surface. The difference in immobilization behavior between natural zeolites and synthetic ones is probably due to the phase transformation and surface morphology at higher temperature above 1,000 ℃. The stable solidification of insoluble ferrocyanides was thus accomplished by using the excellent Cs immobilization abilities of zeolite matrices （Cs trapping and self-sintering abilities）.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.
文摘In Fukushima NPP-1, large amounts of HALW （high-activity-level water） accumulated in the reactor, turbine building and the trench in the facility is treated by circulating injection cooling system. The development of highly functional adsorbents and stable solidification method contributes to the advancement of the decontamination system and environmental remediation. The present study deals with： （1） preparation of insoluble ferrocyanide loaded zeolites; （2） selective uptake of Cs~ in seawater; and （3） estimation of Cs immobilization ratio and stable solidification. Various kinds of Cs-selective composites loaded with insoluble ferrocyanides （CoFC, NiFC） into the zeolites （zeolite A （A51, A-51J）, zeolite X （LSX）, chabazite （modified chabazite） and natural mordenite （SA-5）） matrices have been prepared to use successive impregnation/precipitation methods by Tohoku University. As for Cs~ adsorption, these composites had relatively large uptake （%） over 95%, distribution coefficients （Kd） above 103 cm3/g and excellent adsorption kinetics even in seawater. The immobilization ratio （%） of Cs for the CoFC saturated with Cs＋was estimated at different calcination temperatures up to 1,200 ℃ in advance. The immobilization ratio was less than 0.1% above 1,000℃, indicating that the adsorbed Cs~ ions are completely volatilized and insoluble ferrocyanides had no immobilization ability for Cs. In contrast, the insoluble ferrocyanide-loaded zeolites had excellent Cs immobilization ability; in the case of insoluble ferrocyanide-loaded natural zeolites （NiFC-SA-5, CoFC-modified chabazite）, the immobilization ratio was above 99% and 96% even after calcination at 1,000 ℃ and 1,100 ℃, respectively, indicating that nearly all Cs ions are immobilized in the sintered solid form. On the other hand, the immobilization ratio for the insoluble ferrocyanide-loaded A and X zeolites （NiFC-A （A51, A51J）, NiFC-X） tended to decrease with calcining temperature; for example, the immobilization ratio for NiFC-X at 1,000 ℃and 1,100 ℃ was estimated to be 74.9% and 55.4%, respectively, and many spots concentrating Cs were observed on the surface. The difference in immobilization behavior between natural zeolites and synthetic ones is probably due to the phase transformation and surface morphology at higher temperature above 1,000 ℃. The stable solidification of insoluble ferrocyanides was thus accomplished by using the excellent Cs immobilization abilities of zeolite matrices （Cs trapping and self-sintering abilities）.
