Conventional methods for precious metals gravimetric concentration involve equipment such as shaking tables, centrifuging concentrators, jigs, trommels, or a combination of those. A less commonly used technique is elu...Conventional methods for precious metals gravimetric concentration involve equipment such as shaking tables, centrifuging concentrators, jigs, trommels, or a combination of those. A less commonly used technique is elutriation, which represents an efficient, safe and low-cost method of separation. The goal of the present investigation was to make a comparative study of gold concentration by elutriation from different precious metal bearing ores: an oxide ore, a mineral consisting of a sulfide matrix, a mineral in which the precious metals are free and disseminated and a slimy and clayey black sand material. The best recoveries of precious metals by elutriation were attained for the free disseminated ore and for the black sands, obtaining gold recoveries of 70% and 96% respectively, with appreciable ratios of concentration as well.展开更多
[Objectives]This study aimed to analyze the dyeing status and dyeing components of counterfeit cinnabar(elutriation),in order to provide technical basis for cinnabar(elutriation)supervision.[Methods]The scarlet 808 in...[Objectives]This study aimed to analyze the dyeing status and dyeing components of counterfeit cinnabar(elutriation),in order to provide technical basis for cinnabar(elutriation)supervision.[Methods]The scarlet 808 in cinnabar(elutriation)was identified qualitatively using thin-layer chromatography(TLC)and high-performance liquid chromatography(HPLC),and the positive samples were confirmed by high-performance liquid chromatography-mass spectrometry(HPLC-MS).The conditions were as follows:column,Agilent Eclipse Plus C 18;mobile phase,acetonitrile-0.1%formic acid(85∶15);detection wavelength,520 nm;ion source,electrospray ion source;scanning mode,positive ion scanning;scanning range,100-700 m/z;cone voltage,3.5 kv;drying gas temperature,350℃;drying gas flow rate,12 L/min.[Results]The thin-layer chromatography spots were clear and separated well.Among the 13 batches of samples,12 batches were positive for scarlet 808.[Conclusions]The counterfeit cinnabar(elutriation)currently circulating in the market has dyeing problem,with scarlet 808 as the dye.The TLC,HPLC and HPLC-MS methods established in this article can quickly screen and confirm the scarlet 808 in cinnabar(elutriation).展开更多
Natural radionuclides are powerful tools for understanding the sources and fate of suspended particulate matter(SPM).Particulate matter with different particle sizes behaves differently with respect to adsorption and ...Natural radionuclides are powerful tools for understanding the sources and fate of suspended particulate matter(SPM).Particulate matter with different particle sizes behaves differently with respect to adsorption and desorption.We analyzed the activi-ties and distribution characteristics of multiple natural radionuclides(238U,226Ra,40K,228Ra,7Be and 210Pbex)on size-fractionated SPM at the Lijin Hydrographic Station(Huanghe or Yellow River)every month over a one-year period.Results showed that medium silt(16–32µm)was the main component.As expected,the activity of each radionuclide decreased with an increase of particle size.We examined the sources of SPM with different particle sizes using activity ratios of 226Ra/238U,228Ra/226Ra,40K/238U and 7Be/210Pbex,and concluded that SPM with different particle sizes originated from different sources.Our results indicate that fine SPM(<32µm)was mainly from the erosion of soil along the lower reaches of the Yellow River,while coarse SPM(>32µm)was mainly derived from resuspension of riverbed sediment.During high runoff periods,the concentration of SPM increased significantly,and the pro-portion of fine particles originating upstream increased.Naturally occurring radioactive isotopes,especially on size-fractionated par-ticles,are therefore seen as useful tracers to understand the sources and behaviors of riverine particles transported from land to sea.展开更多
文摘Conventional methods for precious metals gravimetric concentration involve equipment such as shaking tables, centrifuging concentrators, jigs, trommels, or a combination of those. A less commonly used technique is elutriation, which represents an efficient, safe and low-cost method of separation. The goal of the present investigation was to make a comparative study of gold concentration by elutriation from different precious metal bearing ores: an oxide ore, a mineral consisting of a sulfide matrix, a mineral in which the precious metals are free and disseminated and a slimy and clayey black sand material. The best recoveries of precious metals by elutriation were attained for the free disseminated ore and for the black sands, obtaining gold recoveries of 70% and 96% respectively, with appreciable ratios of concentration as well.
文摘[Objectives]This study aimed to analyze the dyeing status and dyeing components of counterfeit cinnabar(elutriation),in order to provide technical basis for cinnabar(elutriation)supervision.[Methods]The scarlet 808 in cinnabar(elutriation)was identified qualitatively using thin-layer chromatography(TLC)and high-performance liquid chromatography(HPLC),and the positive samples were confirmed by high-performance liquid chromatography-mass spectrometry(HPLC-MS).The conditions were as follows:column,Agilent Eclipse Plus C 18;mobile phase,acetonitrile-0.1%formic acid(85∶15);detection wavelength,520 nm;ion source,electrospray ion source;scanning mode,positive ion scanning;scanning range,100-700 m/z;cone voltage,3.5 kv;drying gas temperature,350℃;drying gas flow rate,12 L/min.[Results]The thin-layer chromatography spots were clear and separated well.Among the 13 batches of samples,12 batches were positive for scarlet 808.[Conclusions]The counterfeit cinnabar(elutriation)currently circulating in the market has dyeing problem,with scarlet 808 as the dye.The TLC,HPLC and HPLC-MS methods established in this article can quickly screen and confirm the scarlet 808 in cinnabar(elutriation).
基金financially supported by the National Natural Science Foundation of China(Nos.U22A20580,42130410,and U1906210)the Fundamental Research Funds for the Central Universities(No.201962003).
文摘Natural radionuclides are powerful tools for understanding the sources and fate of suspended particulate matter(SPM).Particulate matter with different particle sizes behaves differently with respect to adsorption and desorption.We analyzed the activi-ties and distribution characteristics of multiple natural radionuclides(238U,226Ra,40K,228Ra,7Be and 210Pbex)on size-fractionated SPM at the Lijin Hydrographic Station(Huanghe or Yellow River)every month over a one-year period.Results showed that medium silt(16–32µm)was the main component.As expected,the activity of each radionuclide decreased with an increase of particle size.We examined the sources of SPM with different particle sizes using activity ratios of 226Ra/238U,228Ra/226Ra,40K/238U and 7Be/210Pbex,and concluded that SPM with different particle sizes originated from different sources.Our results indicate that fine SPM(<32µm)was mainly from the erosion of soil along the lower reaches of the Yellow River,while coarse SPM(>32µm)was mainly derived from resuspension of riverbed sediment.During high runoff periods,the concentration of SPM increased significantly,and the pro-portion of fine particles originating upstream increased.Naturally occurring radioactive isotopes,especially on size-fractionated par-ticles,are therefore seen as useful tracers to understand the sources and behaviors of riverine particles transported from land to sea.
