Large areas of muddy sediments on the coastal shelves of China provide important samples for studying climate and ecological changes. Analysis of a large number of such samples, which is essential for systematic study...Large areas of muddy sediments on the coastal shelves of China provide important samples for studying climate and ecological changes. Analysis of a large number of such samples, which is essential for systematic study on environmental information recorded in mud areas because of complicated sedimentary environment and variable sedimentary rate, requires a fast and economical method. In this study, we investigated the potential of X-ray fluorescence core scanner (XRFS), a fast analytical instrument for measuring the elemental concentrations of muddy sediments, and observed a significant correlation between the element concentrations of muddy sediments determined by regular X-ray fluorescence spectrometer (XRF) and XRFS, respectively. The correlations are mainly determined by excitation energy of elements, but also influenced by solubility of element ions. Furthermore, we found a striking link between A1 concentrations and marine-originated organic carbon (MOC), a proxy of marine primary productivity. This indicates that MOC is partly controlled by sedimentary characteristics. Therefore, XRFS method has a good potential in fast analysis of a large number of muddy sediment samples, and it can also be used to calibrate MOC in ecological study of coastal seas.展开更多
Mg ion-exchanged samples were prepared with acid-washed Shengli lignite.The chemical composition of the ash of the raw sample was determined by X-ray fluorescence.The equilibrium adsorption water contents of samples w...Mg ion-exchanged samples were prepared with acid-washed Shengli lignite.The chemical composition of the ash of the raw sample was determined by X-ray fluorescence.The equilibrium adsorption water contents of samples were determined in a range of relative humidity.The ion-exchange process was characterized by FT-IR,ash content,and p H value.A possible mechanism is proposed for equilibrium adsorption water of ion-exchanged samples at different humidities.The extent of ion-exchange reaction between Mg2+and lignite is controlled by the concentration of Mg2+in Mg SO4solution.The effect of Mg2+on equilibrium adsorption water content varies with relative humidity and content of Mg2+.The factor that controls equilibrium adsorption water content at low relative humidity is water interactions with sorption sites,which are Mg2+–carboxyl group complex.At middle relative humidity capillary force between Mg2+–water clusters Mg+(H2O)nand capillary is more important.At high relative humidity,free water–free water interactions are more significant.展开更多
Determination of chemical elements assay plays an important role in mineral processing operations.This factor is used to control process accuracy,recovery calculation and plant profitability.The new assaying methods i...Determination of chemical elements assay plays an important role in mineral processing operations.This factor is used to control process accuracy,recovery calculation and plant profitability.The new assaying methods including chemical methods,X-ray fluorescence and atomic absorption spectrometry are advanced and accurate.However,in some applications,such as on-line assaying process,high accuracy is required.In this paper,an algorithm based on Kalman Filter is presented to predict on-line XRF errors.This research has been carried out on the basis of based the industrial real data collection for evaluating the performance of the presented algorithm.The measurements and analysis for this study were conducted at the Sarcheshmeh Copper Concentrator Plant located in Iran.The quality of the obtained results was very satisfied;so that the RMS errors of prediction obtained for Cu and Mo grade assaying errors in rougher feed were less than 0.039 and 0.002 and in final flotation concentration less than 0.58 and 0.074,respectively.The results indicate that the mentioned method is quite accurate to reduce the on-line XRF errors measurement.展开更多
Plutonic and volcanic rocks were analyzed by INAA (Instrumental Neutron Activation Analysis) ana XRF (X-ray flurescence) in their major components for its classification. The samples proceed from the sites/regions...Plutonic and volcanic rocks were analyzed by INAA (Instrumental Neutron Activation Analysis) ana XRF (X-ray flurescence) in their major components for its classification. The samples proceed from the sites/regions corresponding to the Precambrian to Paleozoic/Postpaleozoic magmatism in the eastern and western Paraguay. The analysed elements were Si, A1, Na and K and thus the SiO2, AI/O3, Na2O and K2O content determined. The activation were performed in an annular 25Ci Am-Be neutron source with total flux of 5×10^7n.s^-1. The reactions used were (1) ^28Si (n, p) ^27A1, (2) ^27A1 (n, p) ^27Mg; (3) ^23Na (n, γ) ^24Na, the fourth element of interest, potassium, was analysed by XRF. The procedure overall uncertainties were checked as per the analysis of three compositae samples of SiO2: + A12O3 + NaHCO3 + K2CO3 prepared as standards in convenient proportions. The determination of these parameters according to the last recommendations of the IUGS (International Union of Geosciences), permits the classification of the rocks in the categories acid, intermediate, basic and ultrabasie, as well as the identification of the rock family and in certain cases, the norm and their magmatic provenance.展开更多
Pickling sludge generated during the neutralization of pickling wastewater with calcium hydroxide in stainless steel pickling process was characterized using X-ray fluorescence spectrometry, X-ray diffractometry, scan...Pickling sludge generated during the neutralization of pickling wastewater with calcium hydroxide in stainless steel pickling process was characterized using X-ray fluorescence spectrometry, X-ray diffractometry, scanning electron microscopy, thermogravimetry and differential scanning calorimetry, etc. The major compositions of pickling sludge are CaF2, CaSO4, Me(OH), (M: Fe, Cr, Ni), and the content of CaF2 is high in the sludge. The melting point of pickling sludge is about 1350℃ and the viscosity is about 0.14 Pa.s at 1450 ℃, which are comparatively lower than those of normal refining slag. After heat treatment, the contents of sulfur and fluorine in the pickling sludge were reduced, confirming the thermal decomposition of sulfate in the sludge. Fluorine in the sludge is reduced by the gaseous SiF4 and A1F3 generated through the reactions of CaF2 with SiO2 and Al2O3. The preliminary results from the reduction test indicate that the sulfur content in the steel is not affected by the presence of sulfur in the sludge. The recovery of nickel is about 40%, and the chromium content changes marginally due to the protective atmosphere under the reduction condition of chromic oxide. The pickling sludge is a potential auxiliary material for the production of stainless steel.展开更多
The recovery of nickel from molybdenum leach residue by the process of segregation roasting-sulfuric acid leaching-solvent extraction was investigated. The residue was characterized by microscopic investigations, usin...The recovery of nickel from molybdenum leach residue by the process of segregation roasting-sulfuric acid leaching-solvent extraction was investigated. The residue was characterized by microscopic investigations, using X-ray fluorescence spectrometry (XRF) and X-ray diffractometry (XRD) techniques and the residue after segregation roasting was characterized by chemical phase analysis method. A series of experiments were conducted to examine the mass ratio of activated carbon (AC) to the residue, segregation roasting time and temperature, sulfuric acid concentration, liquid-to-solid ratio, leaching time, leaching temperature, addition amount of 30% H2O2, stirring speed (a constant) on the leaching efficiency of nickel. A maximum nickel leaching efficiency of 90.5% is achieved with the mass ratio of AC to the residue of 1:2.5, segregation roasting time of 2 h, segregation roasting temperature of 850 ℃, sulfuric acid concentration of 4.5 mol/L, liquid-to-solid ratio of 6:1, leaching time of 5 h, leaching temperature of 80 ℃, addition of 30% H202 of 0.6 mL for 1 g dry residue. Under these optimized conditions, the average leaching efficiency of nickel is 89.3%. The nickel extraction efficiency in the examined conditions is about 99.6%, and the nickel stripping efficiency in the examined conditions is about 99.2%.展开更多
The influence of mischmetal addition on physicochcmical properties of PtSnNa/ZSM-5 catalyst was studied by means of XRF, H2 chemisorption, XRD, TPR, NH3-TPD and TPO techniques. The results showed that the presence of ...The influence of mischmetal addition on physicochcmical properties of PtSnNa/ZSM-5 catalyst was studied by means of XRF, H2 chemisorption, XRD, TPR, NH3-TPD and TPO techniques. The results showed that the presence of mischmetal had an obvious impact on the catalytic performance of the PtSnNa/ZSM-5 catalyst. A suitable content of mischmetal not only could enhance the interactions between Pt species and the support, but also inhibit the formation of coke during the reaction, thus improving the catalytic activity and stability. In our experiments, when the content of mischmetal was 3m%, the catalyst exhibited best catalytic performance. However, the continuous addition of mischmetal could promote the reduction of Sn species to metallic tin, which was disadvantageous to the reaction.展开更多
PtSnNa/AlSBA-15 catalysts with different amounts of Sn were prepared for propane dehydrogenation.The catalysts were characterized by XRF,BET,H2 chemisorption,NH3-TPD,H2-TPR,and TPO techniques.Test results indicated th...PtSnNa/AlSBA-15 catalysts with different amounts of Sn were prepared for propane dehydrogenation.The catalysts were characterized by XRF,BET,H2 chemisorption,NH3-TPD,H2-TPR,and TPO techniques.Test results indicated that the presence of tin not only modified the acid function and the interfacial character between metal and support,but also reduced the coke deposition effectively.Among these catalysts investigated thereby,the PtSn(0.7%)Na/AlSBA-15 catalyst had the best catalytic performance in terms of propane conversion and stability.With the continuous addition of Sn,more amounts of Sn0 species appeared,which was unfavorable to the reaction.The PtSn(0.7%)Na/AlSBA-15 catalyst was parametrically characterized in order to obtain necessary information to integrate the process operating conditions.A weight hourly space velocity of 3 h-1,a reaction temperature of 610 ℃ and a H2/C3H8 molar ratio of 0.25 were found to be optimum conditions for achieving a higher dehydrogenation activity of the catalyst.展开更多
The thesis had a deep research about the fiberglass filter paper's influence on the PM2.5 assaying. It has chosen XRF to make a quantitative analysis. Based on multiple regression theory it regard fiberglass filter p...The thesis had a deep research about the fiberglass filter paper's influence on the PM2.5 assaying. It has chosen XRF to make a quantitative analysis. Based on multiple regression theory it regard fiberglass filter paper's quality, element content and the quality of the loaded sample as independent variable, while the element's quality that the sample has collected as dependent variable. Furthermore, it has established four multiple quadric response surface models which concerning Ca by using of Mathematica and Matlab: Y = 0.8649-2.094x1-2.08x2 -1.375x3-10.58x1x2+8.53x1x3+1.549x2x3-3.443x1^2+6.555x2^2+6. 547x3^2; Y = 0.8649-2.094x1-2.08x2-1.375x3; Y = 0.8649 -2.094x2-2.08x2-1.375x3-3.443x1^2+6.525x2^2+6.547x3^2 ; Y =0.8649-2.094x1-2.08x2-1.375x3-10.58x1x2+8.53x1x3+1.549x2x3. After comparison it has finally found the best model. In combining with the sample it present a multiple data fitting analysis method which could adjust the fiberglass filter paper model accordingly.展开更多
Content of macro- and microelements in plant and soil was studied after biochar, compost, digestate, lignite, and lignohumate application. Pot experiments were carried out in Phytotron CLF Plant Master (Wertingen, Ge...Content of macro- and microelements in plant and soil was studied after biochar, compost, digestate, lignite, and lignohumate application. Pot experiments were carried out in Phytotron CLF Plant Master (Wertingen, Germany). As tested plant lettuce (Lactucasativa) was used. Elemental composition was determined by AAS and XRF spectroscopy. Macronutrients content (Ca, Mg, K, and P) was determined by Mehlich III. Total content of carbon and nitrogen were determined by LECO TruSpec CN analyser. Results showed that different exogenous organic amendments statistically significantly influenced macro and micronutrients content in soil and plant. Satisfactory C/N ratio for soil microorganisms was measured only after compost and digestate application. As concerns hazardous elements, no legislation limits were overstepped after application of the tested organic amendments. Bioavailability and their uptake by plants followed the order: Cd 〉 Mn 〉 Zn 〉 Fe.展开更多
We studied the geochemical characteristics of illite clay rocks and their importance from the 5hihezi Formation of Late Permian in the Hanxing mining area by means of ICP-M5 and sequential X-ray fluorescence spectrome...We studied the geochemical characteristics of illite clay rocks and their importance from the 5hihezi Formation of Late Permian in the Hanxing mining area by means of ICP-M5 and sequential X-ray fluorescence spectrometry. The results show that the amount of SiO2 is between 53.37% and 61.58% (by weight) and that of Al2O3 22.40% and 31.31% (by weight). The ratio of SiO2/Al2O3 lies between 1.71 and 2.75. The amount of K2O ranges from 1.11% to 2.56% (by weight). The amounts of Fe and Ti are higher than the theoretical values in illite clay rock would indicate. The amounts of some trace elements, such as Ga, As, Ba, Cu, Th and U are higher than their Clark values, while that of another 23 trace elements are found to be dose to their Clark values. The amounts of REE range from 22.59 to 570.54 μg/g, with an average of 163.23μg/g. The ratios of LREE/HREE range from 5.41 to 21.82, with an average of 8.87. These characteristics show that LREE are much richer in content than HREE. The REE distribution patterns of our samples were characterized by clearly negative Ce and Eu anomalies. We analyzed the sedimentary environment of the Hanxing mining area in Late Permian by the characteristic element ratio method. The ratios of Mn/Fe range from 0 to 0.0168, which are lower than those in a marine sedimentary environment. The ratios of Sr/Ba (0.20-0.41) are less than 1. These are all indications that the sediments of the Hanxing mining area in Late Permian form largely a continental sedimentary environment. The sedimentary water is freshwater, a conclusion reached on the basis of the ratios of Th/U (2.66-6.62) and of Ca/(Ca + Fe) (0.01-0.059); the average ratio of Fe2+/Fe3+ is 4.8. The sedimentary water condition is weakly acidic and weakly oxidative-weakly reductive, a conclusion reached on the basis of ratios of Fe2+/Fe3+ (4.8) and of Ceanom (-0.08).展开更多
Frozen soils or those with permafrost cover large areas of the earth's surface and support unique vegetative ecosystems. Plants growing in such harsh conditions have adapted to small niches, which allow them to su...Frozen soils or those with permafrost cover large areas of the earth's surface and support unique vegetative ecosystems. Plants growing in such harsh conditions have adapted to small niches, which allow them to survive. In northern Alaska, USA, both moist acidic and non-acidic tundra occur, yet determination of frozen soil p Hs currently requires thawing of the soil so that electrometric pH methods can be utilized. Contrariwise, a portable X-ray fluorescence(PXRF) spectrometer was used in this study to assess elemental abundances and relate those characteristics to soil pH through predictive multiple linear regressions. Two operational modes, Soil Mode and Geochem Mode, were utilized to scan frozen soils in-situ and under laboratory conditions, respectively, after soil samples were dried and ground. Results showed that lab scanning produced optimal results with adjusted coefficient of determination(R^2) of 0.88 and 0.33 and root mean squared errors(RMSEs) of 0.87 and 0.34 between elemental data and lab-determined pH for Soil Mode and Geochem Mode, respectively. Even though the presence of ice attenuated fluoresced radiation under field conditions, adjusted R^2 and RMSEs between the datasets still provided reasonable model generalization(e.g., 0.73 and 0.49 for field Geochem Mode). Principal component analysis qualitatively separated multiple sampling sites based on elemental data provided by PXRF, reflecting differences in the chemical composition of the soils studied. Summarily, PXRF can be used for in-situ determination of soil pH in arctic environments without the need for sample modification and thawing. Furthermore, use of PXRF for determination of soil pH may provide higher sample throughput than traditional eletrometric-based methods, while generating elemental data useful for the prediction of multiple soil parameters.展开更多
Field portable X-ray fluorescence (PXRF) spectrometry has become an increasingly popular technique for in-situ elemental characterization of soils. The technique is fast, portable, and accurate, requiring minimal sa...Field portable X-ray fluorescence (PXRF) spectrometry has become an increasingly popular technique for in-situ elemental characterization of soils. The technique is fast, portable, and accurate, requiring minimal sample preparation and no consumables. However, soil moisture 〉 20% has been known to cause fluorescence denudation and error in elemental reporting and few studies have evaluated the presence of soil moisture in solid form as ice. Gelisols (USDA Soil Taxonomy), permafrost-affected soils, cover a large amount of the land surface in the northern and southern hemispheres. Thus, the applicability of PXRF in those areas requires further investigation. PXRF was used to scan the elemental composition (Ba, Ca, Cr, Fe, K, Mn, Pb, Rb, Sr, Ti, Zn, and Zr) of 13 pedons in central and northern Alaska, USA. Four types of scans were completed: 1) in-situ frozen soil, 2) re-frozen soil in the laboratory, 3) melted soil/water mixture in the laboratory, and 4) moisture-corrected soil. All were then compared to oven dry soil scans. Results showed that the majority of PXRF readings from in-situ, re-frozen, and melted samples were significantly underestimated, compared to the readings on oven dry samples, owing to the interference expected by moisture. However, when the moisture contents were divided into 〉 40% and 〈 40〈 groups, the PXRF readings under different scanning conditions performed better in the group with 〈 40% moisture contents. Most elements of the scans on the melted samples with 〈 40% moisture contents acceptably compared to those of the dry samples, with R2 values ranging from 0.446 (Mn) to 0.930 (St). However, underestimation of the melted samples was still quite apparent. Moisture-corrected sample PXRF readings provided the best correlation to those of the dry, ground samples as indicated by higher R2 values, lower root mean square errors (RMSEs), and slopes closer to 1 in linear regression equations. However, the in-situ (frozen) sample scans did not differ appreciably from the melted sample scans in their correlations to dry sample scans in terms of R2 values (0.81 vs. 0.88), RMSEs (1.06 vs. 0.85), and slopes (0.88 vs. 0.92). Notably, all of those relationships improved for the group with moisture contents 〈 40%.展开更多
Surface sediment samples collected off the Huanghe (Yellow) River mouth during the period 2007-2009 were analyzed for major and trace element concentrations. Concentrations of 16 elements were measured using X-ray f...Surface sediment samples collected off the Huanghe (Yellow) River mouth during the period 2007-2009 were analyzed for major and trace element concentrations. Concentrations of 16 elements were measured using X-ray fluorescence spectrometry. Results demonstrate that sediment grain size is the dominant factor controlling the spatial variations of elemental concentrations. Correlation and cluster analyses allowed classification of the study area into four geochemical regions: Regions Ⅰ and Ⅲare characterized by high concentrations ofAl2O3, Fe2O3, MgO, Na2O, K2O, Cr, Cu, Mn, Ni, Pb, V, and Zn, and contain fine-grained sediments with mean grain size (Mz)〈22 μm; and; Regions Ⅱ and Ⅳcontain mostly coarse-grained sediments, and are characterized by high concentrations of SiO2, Na2O, and Zr. The sediment entering the sea from the Huanghe River and its tributaries is enriched in Ca. Thus, the Ca/Al ratio was used as an indicator of the proportion of sediments in the study area that originated from the Huanghe River. Ca/Al ratios decrease from Regions Ⅰ and Ⅱ(located in the nearshore zone of the Huanghe River delta) to Regions Ⅲand Ⅳ(distributed in the offshore zone of the northern Huanghe River delta, southern and southeastern Laizhou Bay area).展开更多
基金supported by the National Basic Research Program of China(2010CB428902)National Natural Science Foundation of China(40876088)
文摘Large areas of muddy sediments on the coastal shelves of China provide important samples for studying climate and ecological changes. Analysis of a large number of such samples, which is essential for systematic study on environmental information recorded in mud areas because of complicated sedimentary environment and variable sedimentary rate, requires a fast and economical method. In this study, we investigated the potential of X-ray fluorescence core scanner (XRFS), a fast analytical instrument for measuring the elemental concentrations of muddy sediments, and observed a significant correlation between the element concentrations of muddy sediments determined by regular X-ray fluorescence spectrometer (XRF) and XRFS, respectively. The correlations are mainly determined by excitation energy of elements, but also influenced by solubility of element ions. Furthermore, we found a striking link between A1 concentrations and marine-originated organic carbon (MOC), a proxy of marine primary productivity. This indicates that MOC is partly controlled by sedimentary characteristics. Therefore, XRFS method has a good potential in fast analysis of a large number of muddy sediment samples, and it can also be used to calibrate MOC in ecological study of coastal seas.
基金Supported by the National Basic Research Program of China(2012CB214900)the National Natural Science Foundation of China(51274197)+1 种基金the 111 Project(B12030)the Fundamental Research Funds for the Central Universities(2014XT05)
文摘Mg ion-exchanged samples were prepared with acid-washed Shengli lignite.The chemical composition of the ash of the raw sample was determined by X-ray fluorescence.The equilibrium adsorption water contents of samples were determined in a range of relative humidity.The ion-exchange process was characterized by FT-IR,ash content,and p H value.A possible mechanism is proposed for equilibrium adsorption water of ion-exchanged samples at different humidities.The extent of ion-exchange reaction between Mg2+and lignite is controlled by the concentration of Mg2+in Mg SO4solution.The effect of Mg2+on equilibrium adsorption water content varies with relative humidity and content of Mg2+.The factor that controls equilibrium adsorption water content at low relative humidity is water interactions with sorption sites,which are Mg2+–carboxyl group complex.At middle relative humidity capillary force between Mg2+–water clusters Mg+(H2O)nand capillary is more important.At high relative humidity,free water–free water interactions are more significant.
基金the support of the Department of Research and Development of Sarcheshmeh Copper Plants for this research
文摘Determination of chemical elements assay plays an important role in mineral processing operations.This factor is used to control process accuracy,recovery calculation and plant profitability.The new assaying methods including chemical methods,X-ray fluorescence and atomic absorption spectrometry are advanced and accurate.However,in some applications,such as on-line assaying process,high accuracy is required.In this paper,an algorithm based on Kalman Filter is presented to predict on-line XRF errors.This research has been carried out on the basis of based the industrial real data collection for evaluating the performance of the presented algorithm.The measurements and analysis for this study were conducted at the Sarcheshmeh Copper Concentrator Plant located in Iran.The quality of the obtained results was very satisfied;so that the RMS errors of prediction obtained for Cu and Mo grade assaying errors in rougher feed were less than 0.039 and 0.002 and in final flotation concentration less than 0.58 and 0.074,respectively.The results indicate that the mentioned method is quite accurate to reduce the on-line XRF errors measurement.
文摘Plutonic and volcanic rocks were analyzed by INAA (Instrumental Neutron Activation Analysis) ana XRF (X-ray flurescence) in their major components for its classification. The samples proceed from the sites/regions corresponding to the Precambrian to Paleozoic/Postpaleozoic magmatism in the eastern and western Paraguay. The analysed elements were Si, A1, Na and K and thus the SiO2, AI/O3, Na2O and K2O content determined. The activation were performed in an annular 25Ci Am-Be neutron source with total flux of 5×10^7n.s^-1. The reactions used were (1) ^28Si (n, p) ^27A1, (2) ^27A1 (n, p) ^27Mg; (3) ^23Na (n, γ) ^24Na, the fourth element of interest, potassium, was analysed by XRF. The procedure overall uncertainties were checked as per the analysis of three compositae samples of SiO2: + A12O3 + NaHCO3 + K2CO3 prepared as standards in convenient proportions. The determination of these parameters according to the last recommendations of the IUGS (International Union of Geosciences), permits the classification of the rocks in the categories acid, intermediate, basic and ultrabasie, as well as the identification of the rock family and in certain cases, the norm and their magmatic provenance.
基金Project(2010JM7010)supported by the Natural Science Foundation of Shaanxi Province,ChinaProject supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education,ChinaProject supported by the Technology Foundation for Selected Overseas Chinese Scholars,Department of Human Resources and Social Security of Shaanxi Province,China
文摘Pickling sludge generated during the neutralization of pickling wastewater with calcium hydroxide in stainless steel pickling process was characterized using X-ray fluorescence spectrometry, X-ray diffractometry, scanning electron microscopy, thermogravimetry and differential scanning calorimetry, etc. The major compositions of pickling sludge are CaF2, CaSO4, Me(OH), (M: Fe, Cr, Ni), and the content of CaF2 is high in the sludge. The melting point of pickling sludge is about 1350℃ and the viscosity is about 0.14 Pa.s at 1450 ℃, which are comparatively lower than those of normal refining slag. After heat treatment, the contents of sulfur and fluorine in the pickling sludge were reduced, confirming the thermal decomposition of sulfate in the sludge. Fluorine in the sludge is reduced by the gaseous SiF4 and A1F3 generated through the reactions of CaF2 with SiO2 and Al2O3. The preliminary results from the reduction test indicate that the sulfur content in the steel is not affected by the presence of sulfur in the sludge. The recovery of nickel is about 40%, and the chromium content changes marginally due to the protective atmosphere under the reduction condition of chromic oxide. The pickling sludge is a potential auxiliary material for the production of stainless steel.
基金Project(2007CB613604)supported by the National Basic Research Program of China
文摘The recovery of nickel from molybdenum leach residue by the process of segregation roasting-sulfuric acid leaching-solvent extraction was investigated. The residue was characterized by microscopic investigations, using X-ray fluorescence spectrometry (XRF) and X-ray diffractometry (XRD) techniques and the residue after segregation roasting was characterized by chemical phase analysis method. A series of experiments were conducted to examine the mass ratio of activated carbon (AC) to the residue, segregation roasting time and temperature, sulfuric acid concentration, liquid-to-solid ratio, leaching time, leaching temperature, addition amount of 30% H2O2, stirring speed (a constant) on the leaching efficiency of nickel. A maximum nickel leaching efficiency of 90.5% is achieved with the mass ratio of AC to the residue of 1:2.5, segregation roasting time of 2 h, segregation roasting temperature of 850 ℃, sulfuric acid concentration of 4.5 mol/L, liquid-to-solid ratio of 6:1, leaching time of 5 h, leaching temperature of 80 ℃, addition of 30% H202 of 0.6 mL for 1 g dry residue. Under these optimized conditions, the average leaching efficiency of nickel is 89.3%. The nickel extraction efficiency in the examined conditions is about 99.6%, and the nickel stripping efficiency in the examined conditions is about 99.2%.
基金the Specialized Research Fund for the Doctoral Program of Higher Education of China (No.20100092120047)the Production and Research Prospective Joint Research Project (No.BY2009153)the National Nature Science Foundation of China (No.50873026) for financial supports
文摘The influence of mischmetal addition on physicochcmical properties of PtSnNa/ZSM-5 catalyst was studied by means of XRF, H2 chemisorption, XRD, TPR, NH3-TPD and TPO techniques. The results showed that the presence of mischmetal had an obvious impact on the catalytic performance of the PtSnNa/ZSM-5 catalyst. A suitable content of mischmetal not only could enhance the interactions between Pt species and the support, but also inhibit the formation of coke during the reaction, thus improving the catalytic activity and stability. In our experiments, when the content of mischmetal was 3m%, the catalyst exhibited best catalytic performance. However, the continuous addition of mischmetal could promote the reduction of Sn species to metallic tin, which was disadvantageous to the reaction.
基金the Production and Research Prospective Joint Research Project(BY2009153)the Science and Technology Support Program(BE2008129) of Jiangsu Province of Chinathe National Nature Science Foundation of China(50873026) for financial supports
文摘PtSnNa/AlSBA-15 catalysts with different amounts of Sn were prepared for propane dehydrogenation.The catalysts were characterized by XRF,BET,H2 chemisorption,NH3-TPD,H2-TPR,and TPO techniques.Test results indicated that the presence of tin not only modified the acid function and the interfacial character between metal and support,but also reduced the coke deposition effectively.Among these catalysts investigated thereby,the PtSn(0.7%)Na/AlSBA-15 catalyst had the best catalytic performance in terms of propane conversion and stability.With the continuous addition of Sn,more amounts of Sn0 species appeared,which was unfavorable to the reaction.The PtSn(0.7%)Na/AlSBA-15 catalyst was parametrically characterized in order to obtain necessary information to integrate the process operating conditions.A weight hourly space velocity of 3 h-1,a reaction temperature of 610 ℃ and a H2/C3H8 molar ratio of 0.25 were found to be optimum conditions for achieving a higher dehydrogenation activity of the catalyst.
文摘The thesis had a deep research about the fiberglass filter paper's influence on the PM2.5 assaying. It has chosen XRF to make a quantitative analysis. Based on multiple regression theory it regard fiberglass filter paper's quality, element content and the quality of the loaded sample as independent variable, while the element's quality that the sample has collected as dependent variable. Furthermore, it has established four multiple quadric response surface models which concerning Ca by using of Mathematica and Matlab: Y = 0.8649-2.094x1-2.08x2 -1.375x3-10.58x1x2+8.53x1x3+1.549x2x3-3.443x1^2+6.555x2^2+6. 547x3^2; Y = 0.8649-2.094x1-2.08x2-1.375x3; Y = 0.8649 -2.094x2-2.08x2-1.375x3-3.443x1^2+6.525x2^2+6.547x3^2 ; Y =0.8649-2.094x1-2.08x2-1.375x3-10.58x1x2+8.53x1x3+1.549x2x3. After comparison it has finally found the best model. In combining with the sample it present a multiple data fitting analysis method which could adjust the fiberglass filter paper model accordingly.
文摘Content of macro- and microelements in plant and soil was studied after biochar, compost, digestate, lignite, and lignohumate application. Pot experiments were carried out in Phytotron CLF Plant Master (Wertingen, Germany). As tested plant lettuce (Lactucasativa) was used. Elemental composition was determined by AAS and XRF spectroscopy. Macronutrients content (Ca, Mg, K, and P) was determined by Mehlich III. Total content of carbon and nitrogen were determined by LECO TruSpec CN analyser. Results showed that different exogenous organic amendments statistically significantly influenced macro and micronutrients content in soil and plant. Satisfactory C/N ratio for soil microorganisms was measured only after compost and digestate application. As concerns hazardous elements, no legislation limits were overstepped after application of the tested organic amendments. Bioavailability and their uptake by plants followed the order: Cd 〉 Mn 〉 Zn 〉 Fe.
基金supported by the National Nature Science Foundation of China (Nos. 41072031 and 40172119)the Natural Science Foundation of Hebei Province,China (No.D2009000833)
文摘We studied the geochemical characteristics of illite clay rocks and their importance from the 5hihezi Formation of Late Permian in the Hanxing mining area by means of ICP-M5 and sequential X-ray fluorescence spectrometry. The results show that the amount of SiO2 is between 53.37% and 61.58% (by weight) and that of Al2O3 22.40% and 31.31% (by weight). The ratio of SiO2/Al2O3 lies between 1.71 and 2.75. The amount of K2O ranges from 1.11% to 2.56% (by weight). The amounts of Fe and Ti are higher than the theoretical values in illite clay rock would indicate. The amounts of some trace elements, such as Ga, As, Ba, Cu, Th and U are higher than their Clark values, while that of another 23 trace elements are found to be dose to their Clark values. The amounts of REE range from 22.59 to 570.54 μg/g, with an average of 163.23μg/g. The ratios of LREE/HREE range from 5.41 to 21.82, with an average of 8.87. These characteristics show that LREE are much richer in content than HREE. The REE distribution patterns of our samples were characterized by clearly negative Ce and Eu anomalies. We analyzed the sedimentary environment of the Hanxing mining area in Late Permian by the characteristic element ratio method. The ratios of Mn/Fe range from 0 to 0.0168, which are lower than those in a marine sedimentary environment. The ratios of Sr/Ba (0.20-0.41) are less than 1. These are all indications that the sediments of the Hanxing mining area in Late Permian form largely a continental sedimentary environment. The sedimentary water is freshwater, a conclusion reached on the basis of the ratios of Th/U (2.66-6.62) and of Ca/(Ca + Fe) (0.01-0.059); the average ratio of Fe2+/Fe3+ is 4.8. The sedimentary water condition is weakly acidic and weakly oxidative-weakly reductive, a conclusion reached on the basis of ratios of Fe2+/Fe3+ (4.8) and of Ceanom (-0.08).
文摘Frozen soils or those with permafrost cover large areas of the earth's surface and support unique vegetative ecosystems. Plants growing in such harsh conditions have adapted to small niches, which allow them to survive. In northern Alaska, USA, both moist acidic and non-acidic tundra occur, yet determination of frozen soil p Hs currently requires thawing of the soil so that electrometric pH methods can be utilized. Contrariwise, a portable X-ray fluorescence(PXRF) spectrometer was used in this study to assess elemental abundances and relate those characteristics to soil pH through predictive multiple linear regressions. Two operational modes, Soil Mode and Geochem Mode, were utilized to scan frozen soils in-situ and under laboratory conditions, respectively, after soil samples were dried and ground. Results showed that lab scanning produced optimal results with adjusted coefficient of determination(R^2) of 0.88 and 0.33 and root mean squared errors(RMSEs) of 0.87 and 0.34 between elemental data and lab-determined pH for Soil Mode and Geochem Mode, respectively. Even though the presence of ice attenuated fluoresced radiation under field conditions, adjusted R^2 and RMSEs between the datasets still provided reasonable model generalization(e.g., 0.73 and 0.49 for field Geochem Mode). Principal component analysis qualitatively separated multiple sampling sites based on elemental data provided by PXRF, reflecting differences in the chemical composition of the soils studied. Summarily, PXRF can be used for in-situ determination of soil pH in arctic environments without the need for sample modification and thawing. Furthermore, use of PXRF for determination of soil pH may provide higher sample throughput than traditional eletrometric-based methods, while generating elemental data useful for the prediction of multiple soil parameters.
文摘Field portable X-ray fluorescence (PXRF) spectrometry has become an increasingly popular technique for in-situ elemental characterization of soils. The technique is fast, portable, and accurate, requiring minimal sample preparation and no consumables. However, soil moisture 〉 20% has been known to cause fluorescence denudation and error in elemental reporting and few studies have evaluated the presence of soil moisture in solid form as ice. Gelisols (USDA Soil Taxonomy), permafrost-affected soils, cover a large amount of the land surface in the northern and southern hemispheres. Thus, the applicability of PXRF in those areas requires further investigation. PXRF was used to scan the elemental composition (Ba, Ca, Cr, Fe, K, Mn, Pb, Rb, Sr, Ti, Zn, and Zr) of 13 pedons in central and northern Alaska, USA. Four types of scans were completed: 1) in-situ frozen soil, 2) re-frozen soil in the laboratory, 3) melted soil/water mixture in the laboratory, and 4) moisture-corrected soil. All were then compared to oven dry soil scans. Results showed that the majority of PXRF readings from in-situ, re-frozen, and melted samples were significantly underestimated, compared to the readings on oven dry samples, owing to the interference expected by moisture. However, when the moisture contents were divided into 〉 40% and 〈 40〈 groups, the PXRF readings under different scanning conditions performed better in the group with 〈 40% moisture contents. Most elements of the scans on the melted samples with 〈 40% moisture contents acceptably compared to those of the dry samples, with R2 values ranging from 0.446 (Mn) to 0.930 (St). However, underestimation of the melted samples was still quite apparent. Moisture-corrected sample PXRF readings provided the best correlation to those of the dry, ground samples as indicated by higher R2 values, lower root mean square errors (RMSEs), and slopes closer to 1 in linear regression equations. However, the in-situ (frozen) sample scans did not differ appreciably from the melted sample scans in their correlations to dry sample scans in terms of R2 values (0.81 vs. 0.88), RMSEs (1.06 vs. 0.85), and slopes (0.88 vs. 0.92). Notably, all of those relationships improved for the group with moisture contents 〈 40%.
基金Supported by the National Natural Science Foundation for Young Scientists of China (No.40806026)the National Special Research Fund for the Non-Profit Sector (No.200805063,201205001)+1 种基金the 908 Project of the State Oceanic Administration, China (No.908-02-02-05)the Basic Scientific Research Operations of the First Institute of Oceanography, State Oceanic Administration (Nos.GY02-2008T28,GY02-2009G22)
文摘Surface sediment samples collected off the Huanghe (Yellow) River mouth during the period 2007-2009 were analyzed for major and trace element concentrations. Concentrations of 16 elements were measured using X-ray fluorescence spectrometry. Results demonstrate that sediment grain size is the dominant factor controlling the spatial variations of elemental concentrations. Correlation and cluster analyses allowed classification of the study area into four geochemical regions: Regions Ⅰ and Ⅲare characterized by high concentrations ofAl2O3, Fe2O3, MgO, Na2O, K2O, Cr, Cu, Mn, Ni, Pb, V, and Zn, and contain fine-grained sediments with mean grain size (Mz)〈22 μm; and; Regions Ⅱ and Ⅳcontain mostly coarse-grained sediments, and are characterized by high concentrations of SiO2, Na2O, and Zr. The sediment entering the sea from the Huanghe River and its tributaries is enriched in Ca. Thus, the Ca/Al ratio was used as an indicator of the proportion of sediments in the study area that originated from the Huanghe River. Ca/Al ratios decrease from Regions Ⅰ and Ⅱ(located in the nearshore zone of the Huanghe River delta) to Regions Ⅲand Ⅳ(distributed in the offshore zone of the northern Huanghe River delta, southern and southeastern Laizhou Bay area).