This study demonstrated using yttrium(Y)as an indicator to estimate the total rare earth element and Y contents(REY)in coal-associated samples and to facilitate selection of samples with high REY assays in a fast and ...This study demonstrated using yttrium(Y)as an indicator to estimate the total rare earth element and Y contents(REY)in coal-associated samples and to facilitate selection of samples with high REY assays in a fast and inexpensive manner.More than 10 anthracite-associated samples were collected from each of three Pennsylvanian sites(sites B,J and C)based on Thorium gamma ray logging suggesting high REY content.Several samples from each site were analyzed by ICP-MS to determine the rare earth distribution patterns and to establish the site-specific linear equations of Y and REY.The Y contents of the remaining samples were measured by a portable X-ray fluorescence analyzer,and the REY values were estimated based on the site-specific linear equation developed earlier.R-squared values above 0.70 were obtained for all the estimation equations from all three sites on both a whole sample basis and an ash basis.Previously,ash content has been widely used as an indicator of high REY content.This may not be applicable for a specific site.Site B in this study is an example where ash contents could not be statistically correlated with REY,so using Y for estimation is more applicable.The demonstrated sample screening process is suitable for samples from sites that share more similar distribution patterns(either MREY or LREY or HREY)as well as for samples from sites that share multiple distribution patterns(LREY/MREY/HREY)depending on the desirable accuracy.The demonstrated process lowers the analytical cost from$70 to 80 dollars per sample to$10-15 per sample while significantly reducing the processing time and acid consumption for ICP digestion.This is particularly true when a relatively large sample size is involved,for example,100 samples from one site analyzed by ICP-MS/OES.展开更多
In China,the connection between coal utilization and environmental pollution has been increasingly evident due to the rapid growth in energy consumption.Clean coal technology(CCT)is one of the effective methods to add...In China,the connection between coal utilization and environmental pollution has been increasingly evident due to the rapid growth in energy consumption.Clean coal technology(CCT)is one of the effective methods to address coal-associated pollution.However,CCT needs the practical and theoretical support of clean coal geology(CCG).In this paper,a new definition of CCG is proposed,based on the definitions of coal,coal geology,and CCT,combined with the development of national CCG.CCG is the discipline comprehensively researching the genesis,nature,distribution,cleaning potential,clean utilization and environmental effects of resources(coal,coal bed methane,and other coal-associated resources)that can be cleaned by CCT.The research content of CCG is discussed from different aspects,such as cleaning potential evaluation,geological guarantee for coal mining,ash yields and sulfur contents,trace elements,pollution caused by coal,and mine reclamation.The progress of CCG in China is also briefly divided into four stages and delineated.Finally,scientific problems in CCG are summarized and an outlook for CCG is given.展开更多
LHD's are expensive vehicles; therefore, it is important to accurately define the financial consequences associated with the investment of purchasing the mining equipment. This study concentrates on longterm incre...LHD's are expensive vehicles; therefore, it is important to accurately define the financial consequences associated with the investment of purchasing the mining equipment. This study concentrates on longterm incremental and sensitivity analysis to determine whether it is feasible to incorporate current battery technology into these machines. When revenue was taken into account, decreasing the amount of haulage in battery operated equipment by 5% or 200 kg per h amounts to a $4.0 × 10~4 loss of profit per year. On average it was found that using battery operated equipment generated $9.5 × 10~4 more in income annually, reducing the payback period from seven to two years to pay back the additional $1.0 × 10~5 investment of buying battery powered equipment over cheaper diesel equipment. Due to the estimated 5% increase in capital, it was observed that electric vehicles must possess a lifetime that is a minimum of one year longer than that of diesel equipment.展开更多
Coal-derived natural graphite(CDNG)has multiple industrial applications.Here,ten metamorphic coals from anthracite to CDNG were obtained from Lutang and Xinhua in the Hunan Province and Panshi in the Jilin Province.Bu...Coal-derived natural graphite(CDNG)has multiple industrial applications.Here,ten metamorphic coals from anthracite to CDNG were obtained from Lutang and Xinhua in the Hunan Province and Panshi in the Jilin Province.Bulk characterization(proximate and ultimate analyses,X-Ray powder diffraction(XRD),and powder Raman spectroscopy),along with optical microscopy,scanning electron microscope(SEM)and micro-Raman spectroscopy were utilized to examine the transitions from anthracite to semi-graphite to CDNG.The XRD and Raman spectroscopy data indicate that from anthracite to highly ordered graphite the average crystal diameter(La)and height(Lc)increased from 6.1 and 4.6 nm to 34.8 and 27.5 nm,respectively.The crystalline parameters of the CDNG samples from Panshi and Lutang varied slightly when closer to the intrusive body.Optical microscopy and SEM indicated that in the anthracite samples there were thermoplastic vitrinite,devolatilized vitrinite,and some“normal”macerals.In the meta-anthracite,pyrolytic carbon,mosaic structure,and crystalline tar were present.In the CDNG there were flake graphite,crystalline aggregates,and matrix graphite.The crystalline aggregates show the highest structural ordering degree as determined from Raman spectral parameters(full-width at half maxima(G-FWHM)~20 cm^(−1),D1/(D1+D2+G)area ratio(R2)value<0.5).The flake graphite is less ordered with G-FWHM~28 cm^(−1) and 0.5<R2<1,but a larger grain size(up to 50μm).The mosaic structures were likely the precursors of the matrix graphite through in situ solid-state transformation.The pyrolytic carbon and crystalline tars are the transient phase of gas-state and liquid-state transformations.This study is beneficial to realize the rational utilization of CDNG.展开更多
基金the Department of Energy[Grant Number DE-FE-0030146]。
文摘This study demonstrated using yttrium(Y)as an indicator to estimate the total rare earth element and Y contents(REY)in coal-associated samples and to facilitate selection of samples with high REY assays in a fast and inexpensive manner.More than 10 anthracite-associated samples were collected from each of three Pennsylvanian sites(sites B,J and C)based on Thorium gamma ray logging suggesting high REY content.Several samples from each site were analyzed by ICP-MS to determine the rare earth distribution patterns and to establish the site-specific linear equations of Y and REY.The Y contents of the remaining samples were measured by a portable X-ray fluorescence analyzer,and the REY values were estimated based on the site-specific linear equation developed earlier.R-squared values above 0.70 were obtained for all the estimation equations from all three sites on both a whole sample basis and an ash basis.Previously,ash content has been widely used as an indicator of high REY content.This may not be applicable for a specific site.Site B in this study is an example where ash contents could not be statistically correlated with REY,so using Y for estimation is more applicable.The demonstrated sample screening process is suitable for samples from sites that share more similar distribution patterns(either MREY or LREY or HREY)as well as for samples from sites that share multiple distribution patterns(LREY/MREY/HREY)depending on the desirable accuracy.The demonstrated process lowers the analytical cost from$70 to 80 dollars per sample to$10-15 per sample while significantly reducing the processing time and acid consumption for ICP digestion.This is particularly true when a relatively large sample size is involved,for example,100 samples from one site analyzed by ICP-MS/OES.
基金This paper was jointly supported by the National Key Basic Research Program of China(2014CB238905)the National Natural Science foundation of China(41572146)+2 种基金the National Coal Resource Potential Evaluation Project(1212011121043)the Survey Project of Special and Scarce Coal Resources(1212011085511)the Public Welfare Project of the Ministry of Land and Resources(201211003)。
文摘In China,the connection between coal utilization and environmental pollution has been increasingly evident due to the rapid growth in energy consumption.Clean coal technology(CCT)is one of the effective methods to address coal-associated pollution.However,CCT needs the practical and theoretical support of clean coal geology(CCG).In this paper,a new definition of CCG is proposed,based on the definitions of coal,coal geology,and CCT,combined with the development of national CCG.CCG is the discipline comprehensively researching the genesis,nature,distribution,cleaning potential,clean utilization and environmental effects of resources(coal,coal bed methane,and other coal-associated resources)that can be cleaned by CCT.The research content of CCG is discussed from different aspects,such as cleaning potential evaluation,geological guarantee for coal mining,ash yields and sulfur contents,trace elements,pollution caused by coal,and mine reclamation.The progress of CCG in China is also briefly divided into four stages and delineated.Finally,scientific problems in CCG are summarized and an outlook for CCG is given.
文摘LHD's are expensive vehicles; therefore, it is important to accurately define the financial consequences associated with the investment of purchasing the mining equipment. This study concentrates on longterm incremental and sensitivity analysis to determine whether it is feasible to incorporate current battery technology into these machines. When revenue was taken into account, decreasing the amount of haulage in battery operated equipment by 5% or 200 kg per h amounts to a $4.0 × 10~4 loss of profit per year. On average it was found that using battery operated equipment generated $9.5 × 10~4 more in income annually, reducing the payback period from seven to two years to pay back the additional $1.0 × 10~5 investment of buying battery powered equipment over cheaper diesel equipment. Due to the estimated 5% increase in capital, it was observed that electric vehicles must possess a lifetime that is a minimum of one year longer than that of diesel equipment.
基金This work is supported by the National Natural Science Foundation of China(Grant Nos.41672150 and 42002187)the Scholarship from the China Scholarship Council(No.201906430017).
文摘Coal-derived natural graphite(CDNG)has multiple industrial applications.Here,ten metamorphic coals from anthracite to CDNG were obtained from Lutang and Xinhua in the Hunan Province and Panshi in the Jilin Province.Bulk characterization(proximate and ultimate analyses,X-Ray powder diffraction(XRD),and powder Raman spectroscopy),along with optical microscopy,scanning electron microscope(SEM)and micro-Raman spectroscopy were utilized to examine the transitions from anthracite to semi-graphite to CDNG.The XRD and Raman spectroscopy data indicate that from anthracite to highly ordered graphite the average crystal diameter(La)and height(Lc)increased from 6.1 and 4.6 nm to 34.8 and 27.5 nm,respectively.The crystalline parameters of the CDNG samples from Panshi and Lutang varied slightly when closer to the intrusive body.Optical microscopy and SEM indicated that in the anthracite samples there were thermoplastic vitrinite,devolatilized vitrinite,and some“normal”macerals.In the meta-anthracite,pyrolytic carbon,mosaic structure,and crystalline tar were present.In the CDNG there were flake graphite,crystalline aggregates,and matrix graphite.The crystalline aggregates show the highest structural ordering degree as determined from Raman spectral parameters(full-width at half maxima(G-FWHM)~20 cm^(−1),D1/(D1+D2+G)area ratio(R2)value<0.5).The flake graphite is less ordered with G-FWHM~28 cm^(−1) and 0.5<R2<1,but a larger grain size(up to 50μm).The mosaic structures were likely the precursors of the matrix graphite through in situ solid-state transformation.The pyrolytic carbon and crystalline tars are the transient phase of gas-state and liquid-state transformations.This study is beneficial to realize the rational utilization of CDNG.
