High intensity conditioning(HIC)was used as a model to study the fundamental of fine sulphide particle flotation.The effect of impeller design,mechanical energy input,and agitation speed on aggregate size of fine spha...High intensity conditioning(HIC)was used as a model to study the fundamental of fine sulphide particle flotation.The effect of impeller design,mechanical energy input,and agitation speed on aggregate size of fine sphalerite was tested.The aggregate size of fine sphalerite was measured with the Malvern Hydro 2000 Mastersizer.The results show that the size of aggregates of sphalerite particles ground for 3 min can be enlarged significantly with the activator and collector addition in HIC using the high energy impeller.The improved particle aggregation by using the high energy impeller is not directly related to a higher energy input into the system.With the same energy input into HIC,the aggregate size obtained with the high energy impeller is much coarser than that obtained with the low energy impeller.With the new impeller in HIC,the sphalerite aggregate size decreases with increasing agitation speed from 700 to 2 500 r/min.However,the recovery does not decrease until the agitation speed reaches 2 500 r/min.展开更多
The column leaching experiment of ore granular media was carried out with the home-made multi-functional experimental apparatus and the pore structure of ore granular media was scanned by the X-ray computed tomography...The column leaching experiment of ore granular media was carried out with the home-made multi-functional experimental apparatus and the pore structure of ore granular media was scanned by the X-ray computed tomography machine before and after leaching.The porosities of each section before and after leaching were calculated based on CT images processing,and the permeability of each zone before and after leaching were also calculated with Carman-Kozeny equation.The permeability evolvement law was disclosed.The results indicate that before leaching the permeability of the ore granular media in different height has not much difference and the value ranges from 5.70×10-4mm 2to 1.11×10 -3mm 2,where the lowest one locates in the bottom zone.After leaching the permeability distributes inhomogeneously along the height of the column and the value ranges from 3.44×10 -4 mm 2 to 2.25×10 -2 mm 2 ,where the lowest one is in the same place.Except for the bottom zone,the permeability of other zones increases after leaching,especially the top zone.Through comparison of the permeability at bottom zone before and after leaching,the whole permeability after leaching decreases by 39.65%that coincides with the measured experimental data.展开更多
Inundation of the Three Gorges Reservoir has created a 30-m water-level fluctuation zone with seasonal hydrological alternations of submergence and exposure, which may greatly affect soil properties and bank stability...Inundation of the Three Gorges Reservoir has created a 30-m water-level fluctuation zone with seasonal hydrological alternations of submergence and exposure, which may greatly affect soil properties and bank stability. The aim of this study was to investigate the response of soil pore structure to seasonal water-level fluctuation in the reservoir, and particularly, the hydrological change of wetting and drying cycles. Soil pore structure was visualized with industrial X-ray computed tomography and digital image analysis techniques. The results showed that soil total porosity(? 100 ?m), total pore number, total throat number, and mean throat surface area increased significantly under wetting and drying cycles. Soil porosity, pore number and throat numberwithin each size class increased in the course of wetting and drying cycles. The coordination number, degree of anisotropy and fractal dimension were indicating an increase. In contrast, the mean shape factor, pore-throat ratio, and Euler-Poincaré number decreased due to wetting and drying cycles. These illustrated that the wetting and drying cycles made soil pore structure become more porous, continuous, heterogeneous and complex. It can thus be deduced that the water-level fluctuation would modify soil porosity, pore size distribution, and pore morphology in the Three Gorges Reservoir, which may have profound implications for soil processes, soil functions, and bank stability.展开更多
Based on the analysis of high-speed video images, the detachment behavior of dust cake from the ceramic candle filter surface during pulse cleaning process is investigated. The influences of the dust cake loading,the ...Based on the analysis of high-speed video images, the detachment behavior of dust cake from the ceramic candle filter surface during pulse cleaning process is investigated. The influences of the dust cake loading,the reservoir pressure, and the filtration velocity on the cleaning effectiveness are analyzed. Experimental results show that there exists an optimum dust cake thickness for pulse-cleaning process. For thin dust cake, the patchy cleaning exists and the cleaning efficiency is low; if the dust cake is too thick, the pressure drop across the dust cake becomes higher and a higher reservoir pressure may be needed. At the same time there also exists an optimum reservoir pressure for a given filtration condition.展开更多
基金Project(50674103)supported by the National Natural Science Foundation of ChinaProject(2005CB6237601)supported by the NationalBasic Research Program of China
文摘High intensity conditioning(HIC)was used as a model to study the fundamental of fine sulphide particle flotation.The effect of impeller design,mechanical energy input,and agitation speed on aggregate size of fine sphalerite was tested.The aggregate size of fine sphalerite was measured with the Malvern Hydro 2000 Mastersizer.The results show that the size of aggregates of sphalerite particles ground for 3 min can be enlarged significantly with the activator and collector addition in HIC using the high energy impeller.The improved particle aggregation by using the high energy impeller is not directly related to a higher energy input into the system.With the same energy input into HIC,the aggregate size obtained with the high energy impeller is much coarser than that obtained with the low energy impeller.With the new impeller in HIC,the sphalerite aggregate size decreases with increasing agitation speed from 700 to 2 500 r/min.However,the recovery does not decrease until the agitation speed reaches 2 500 r/min.
基金Project(2004CB619205)supported by the National Basic Research Program of ChinaProject(50325415)supported by the National ScienceFund for Distinguished Young Scholars+1 种基金Project(50574099)supported by the National Natural Science Foundation of ChinaProject(06B052)supported by Scientific Research Foundation of Hunan Provincial Education Department,China
文摘The column leaching experiment of ore granular media was carried out with the home-made multi-functional experimental apparatus and the pore structure of ore granular media was scanned by the X-ray computed tomography machine before and after leaching.The porosities of each section before and after leaching were calculated based on CT images processing,and the permeability of each zone before and after leaching were also calculated with Carman-Kozeny equation.The permeability evolvement law was disclosed.The results indicate that before leaching the permeability of the ore granular media in different height has not much difference and the value ranges from 5.70×10-4mm 2to 1.11×10 -3mm 2,where the lowest one locates in the bottom zone.After leaching the permeability distributes inhomogeneously along the height of the column and the value ranges from 3.44×10 -4 mm 2 to 2.25×10 -2 mm 2 ,where the lowest one is in the same place.Except for the bottom zone,the permeability of other zones increases after leaching,especially the top zone.Through comparison of the permeability at bottom zone before and after leaching,the whole permeability after leaching decreases by 39.65%that coincides with the measured experimental data.
基金funded by the National Natural Science Foundation of China(Grant No.41771321,41771320 and 41571278)Sichuan Science and Technology Program(Grant No.2018SZ0132)
文摘Inundation of the Three Gorges Reservoir has created a 30-m water-level fluctuation zone with seasonal hydrological alternations of submergence and exposure, which may greatly affect soil properties and bank stability. The aim of this study was to investigate the response of soil pore structure to seasonal water-level fluctuation in the reservoir, and particularly, the hydrological change of wetting and drying cycles. Soil pore structure was visualized with industrial X-ray computed tomography and digital image analysis techniques. The results showed that soil total porosity(? 100 ?m), total pore number, total throat number, and mean throat surface area increased significantly under wetting and drying cycles. Soil porosity, pore number and throat numberwithin each size class increased in the course of wetting and drying cycles. The coordination number, degree of anisotropy and fractal dimension were indicating an increase. In contrast, the mean shape factor, pore-throat ratio, and Euler-Poincaré number decreased due to wetting and drying cycles. These illustrated that the wetting and drying cycles made soil pore structure become more porous, continuous, heterogeneous and complex. It can thus be deduced that the water-level fluctuation would modify soil porosity, pore size distribution, and pore morphology in the Three Gorges Reservoir, which may have profound implications for soil processes, soil functions, and bank stability.
基金Supported by the National Natural Science Foundation of China (No. 50376042)Doctoral Program Foundation of Institute of Higher Education of China (20040425007).
文摘Based on the analysis of high-speed video images, the detachment behavior of dust cake from the ceramic candle filter surface during pulse cleaning process is investigated. The influences of the dust cake loading,the reservoir pressure, and the filtration velocity on the cleaning effectiveness are analyzed. Experimental results show that there exists an optimum dust cake thickness for pulse-cleaning process. For thin dust cake, the patchy cleaning exists and the cleaning efficiency is low; if the dust cake is too thick, the pressure drop across the dust cake becomes higher and a higher reservoir pressure may be needed. At the same time there also exists an optimum reservoir pressure for a given filtration condition.
