In coal mines, main occupational hazard is coal-mine dust, which can cause health problem including coal workers’ pneumoconiosis and lung cancer. Some heat shock proteins (Hsps) have been reported as an acute respons...In coal mines, main occupational hazard is coal-mine dust, which can cause health problem including coal workers’ pneumoconiosis and lung cancer. Some heat shock proteins (Hsps) have been reported as an acute response to a wide variety of stressful stimuli. Whether Hsps protect against chronic environmental coal-mine dust over years is unknown. It is also interesting to know that whether the expression of Hsp27 and Hsp70 proteins as a marker for exposure is associated risk of lung cancer among coal miners. We investigated the association between levels of Hsp27 and Hsp70 expression in lymphocytes and plasma and levels of coal-mine dust exposure in workplace or risk of lung cancer in 42 cancer-free non-coal miners, 99 cancer-free coal miners and 51 coal miners with lung cancer in Taiyuan city in China. The results showed that plasma Hsp27 levels were increased in coal miners compared to non-coal miners (P<0.01). Except high cumulative coal-mine dust exposure (OR=13.62, 95%CI=6.05—30.69) and amount of smoking higher than 24 pack-year (OR=2.72, 95% CI=1.37—5.42), the elevated levels of plasma Hsp70 (OR=13.00, 95% CI=5.14—32.91) and plasma Hsp27 (OR=2.97, 95% CI=1.40—6.32) and decreased expression of Hsp70 in lymphocytes (OR=2.36, 95% CI=1.05—5.31) were associated with increased risk of lung cancer. These findings suggest that plasma Hsp27 may be a potential marker for coal-mine dust exposure. And the expression of Hsp27 and Hsp70 levels in plasma and lymphocytes may be used as biomarkers for lung cancer induced by occupational coal-mine dust exposure.展开更多
It took that the weight minimum and drive efficiency maximal were as double optimizing target,the optimization model had built the drilling string,and the optimization solution was used of the ant colony algorithm to ...It took that the weight minimum and drive efficiency maximal were as double optimizing target,the optimization model had built the drilling string,and the optimization solution was used of the ant colony algorithm to find in progress.Adopted a two-layer search of the continuous space ant colony algorithm with overlapping or variation global ant search operation strategy and conjugated gradient partial ant search operation strat- egy.The experiment indicates that the spiral drill weight reduces 16.77% and transports the efficiency enhance 7.05% through the optimization design,the ant colony algorithm application on the spiral drill optimized design has provided the basis for the system re- search screw coal mine machine.展开更多
In order to effectively decrease the safety accidents caused by coal miners’human errors,this paper probes into the causality between human errors and life events,coping,psychological stress,psychological function,ph...In order to effectively decrease the safety accidents caused by coal miners’human errors,this paper probes into the causality between human errors and life events,coping,psychological stress,psychological function,physiological function based on life events’vital influence on human errors,establishing causation mechanism model of coal miners’human errors in the perspective of life events by the researching method of structural equation.The research findings show that life events have significantly positive influence on human errors,with a influential effect value of 0.7945 and a influential effect path of‘‘life events—psychological stress—psychological function—physiological function—human errors’’and‘‘life events—psychological stress—physiological function—human errors’’.展开更多
We aimed to investigate the short-term correlation between blood lead levels and oxidative stress generation in coal miners. The study involved 94 male coal miners from the Velenje Coal mine, arranged into four groups...We aimed to investigate the short-term correlation between blood lead levels and oxidative stress generation in coal miners. The study involved 94 male coal miners from the Velenje Coal mine, arranged into four groups: three groups according to the number of consecutive working days, and a fourth control group. Miners who worked for three consecutive days had higher blood levels of lead and 8-isoprostane than the control group(P 〈 0.001). Correlation between lead and 8-isoprostane was of medium strength(r = 0.512, P 〈 0.001). Short-term lead environmental exposure can potentially harmful and should be considered when formulating improvements in working processes.展开更多
The main objective of this work is to relate the coalescence of inherent minerals and the fragmentation of extraneous minerals to the slagging propensities of South African pulverised feed coals during combustion.By i...The main objective of this work is to relate the coalescence of inherent minerals and the fragmentation of extraneous minerals to the slagging propensities of South African pulverised feed coals during combustion.By incorporating the behaviour of inherent mineral matter or extraneous mineral matter in these coals under combustion conditions into ash-deposition prediction methods,the heterogeneous nature of the ash properties,which were disregarded in previous conventional ash deposition predictions,is considered in the study.The mode of occurrence of mineral matter in feed coals plays a crucial role in the formation of high-temperature mineral phases under combustion conditions.The float and sink fractions of the three different coals evaluated in this distinctive alternative approach provide different chemical and mineralogical properties of the derived ashes when subjected to elevated temperatures under oxidising conditions.Formation of significant concentrations of high-temperature minerals(such as mullite and cristobalite)is mainly due to the transformation reactions of extraneous kaolinite and quartz which are not associated with the extraneous fluxing minerals at elevated temperatures.However,the formation of anorthite at elevated temperatures can be attributed to the interaction of either inherent or extraneous fluxing minerals(namely calcite,dolomite,pyrite,and siderite)that are associated with either inherent or extraneous kaolinite in the coal samples under the oxidising condition.Furthermore,the anorthite,mullite,and calcium/magnesium/iron/aluminosilicate and silica glasses in ashes are formed either via crystallisation during the cooling of the hightemperature molten solution or via the solid state reactions.These high-temperature minerals and their glasses present in ashes can therefore be used as the indicators of the slagging propensity of coals.The implementation of results from this unique case study,will be of great significance to other industrial combustion processes to minimise or control ash deposition,slagging,and equipment erosion problems by either blending the density-separated fractions of coals or coals from different mines based on the chemical and mineralogical properties to prepare suitable feed coals.Furthermore,this unique alternative approach can be followed to further evaluate other feed coals in the global power stations during combustion.展开更多
Minerals in the Late Permian coals from the Niuchang-Yigu mining area,Zhenxiong County,northeastern Yunnan,China,were investigated using optical microscopy and low temperature ashing plus X-ray diffraction(LTA?XRD).Th...Minerals in the Late Permian coals from the Niuchang-Yigu mining area,Zhenxiong County,northeastern Yunnan,China,were investigated using optical microscopy and low temperature ashing plus X-ray diffraction(LTA?XRD).The results showed that minerals in the coal LTAs are mainly quartz,kaolinite,chamosite,mixed-layer illite/smectite(I/S),pyrite,and calcite,with trace amounts of marcasite,dolomite,and bassanite.The authigenic quartz generally occurs in collodetrinite or as a filling in cleats or cell cavities.This silica was mainly derived from aqueous solutions produced by the weathering of basaltic rocks in the Kangdian Upland and from hydrothermal fluids.The presence of b-quartz paramorph grains in collodetrinite probably indicates that these grains were detrital and came from a volcanic ash.Clay minerals are generally embedded in collodetrinite and occur as cell-fillings.Pyrite occurs as framboidal,anhedral,and euhedral grains and a cell-filling.The coals are high in pyrite and the high pyrite content probably results from seawater invading during the stage of peat accumulation.Calcite generally occurs as vein-fillings,indicating an epigenetic origin.展开更多
This study determined the optimal conditions required to obtain maximum vanadium extraction and examined the transition of mineral phases and vanadium speciation during the bioleaching process. Parameters including th...This study determined the optimal conditions required to obtain maximum vanadium extraction and examined the transition of mineral phases and vanadium speciation during the bioleaching process. Parameters including the initial p H value, initial Fe^(2+) concentration, solid load, and inoculum quantity were examined. The results revealed that 48.92 wt% of the vanadium was extracted through bioleaching under optimal conditions. Comparatively, the chemical leaching yield(H_2SO_4, pH 2.0) showed a slower and milder increase in vanadium yield. The vanadium bioleaching yield was 35.11 wt% greater than the chemical leaching yield. The Community Bureau of Reference(BCR) sequential extraction results revealed that 88.62 wt% of vanadium existed in the residual fraction. The bacteria substantially changed the distribution of the vanadium speciation during the leaching process, and the residual fraction decreased to 48.44 wt%. The X-ray diffraction(XRD) and Fourier transform infrared(FTIR) results provided evidence that the crystal lattice structure of muscovite was destroyed by the bacteria.展开更多
In Brazil, intense coal exploitation activities have led to environmental deterioration, including soil mortification, water contamination, loss of ecosystem, and atmospheric contamination. In addition,considerable qu...In Brazil, intense coal exploitation activities have led to environmental deterioration, including soil mortification, water contamination, loss of ecosystem, and atmospheric contamination. In addition,considerable quantities of sulfur-rich residues are left behind in the mining area; these residues pose grave environmental issues as they undergo sulfide oxidation reactions. When sulfur oxides come in contact with water, extreme acid leachate is produced with great proportions of sulfate, and hazardous elements(HEs), which are identified as coal drainage(CMD). CMD is an environmental pollution challenge, particularly in countries with historic or active coal mines. To prevent CMD formation or its migration, the source must be controlled; however, this may not be feasible at many locations. In such scenarios, the mine water should be collected, treated, and discharged. In this study, data from 2005 to2010 was gathered on the geochemistry of 11 CMD discharges from ten different mines. There are several concerns and questions on the formation of nanominerals in mine acid drainage and on their reactions and interfaces. The detailed mineralogical and geochemical data presented in this paper were derived from previous studies on the coal mine areas in Brazil. Oxyhydroxides, sulfates, and nanoparticles in these areas possibly go through structural transformations depending on their size and formation conditions. The geochemistry of Fe-precipitates(such as jarosite, goethite, and hematite) existent in the CMD-generating coal areas and those that could be considered as a potential source of hazardous elements(HEs)(e.g., Cr) were also studied because these precipitates are relatively stable in extremely low pH conditions. To simplify and improve poorly ordered iron, strontium, and aluminum phase characterization, field emission scanning electron microscopy(FE-SEM), high-resolution transmission electron microscopy(HR-TEM), micro-Raman spectroscopy, and X-ray diffraction(XRD) and sequential extraction(SE) studies were executed on a set CMD samples from the Brazilian mines. This study aimed to investigate the role of both nanomineral and amorphous phase distribution throughout the reactive coal cleaning rejects profile and HEs removal from the water mine to provide holistic insights on the ecological risks posed by HEs, nanominerals, amorphous phases, and to assess sediments in complex environments such as estuaries.展开更多
In order to study the physical and chemical reaction after CO2 injected into coal beds at different condition.The physical and chemistry reaction among CO2,H2O and coal was studied,and the influence on permeability an...In order to study the physical and chemical reaction after CO2 injected into coal beds at different condition.The physical and chemistry reaction among CO2,H2O and coal was studied,and the influence on permeability and porosity of coal beds was carried out.The experimental method was used,so did the basic theory of mineralogy,coal petrology,geochemistry,analytical geochemistry and physical chemistry.In this experiment,the changes of mineral and permeability of coal and water quality were observed through CO2 solution reacting with different coal samples.The differences could be found out by comparing the properties and microcrystalline structure before and after the reaction.There are three results were carried out:First,the content of carbonate in coal beds decreases because of the dissolution reaction between carbonate minerals and CO2 solution,and precipitation is formed by reaction of chlorite and orthoclase.Second,the result that permeability and porosity of coal beds are improved after the reaction is proposed.Third,the initial permeability of different coal samples plays a great role on the reaction,and the improvement of permeability is not obvious in the samples which have too low or too high permeability,and the improvement is good in medium permeability(0.2–3 mD).展开更多
A high volatile bituminous coal was subjected to a series of organic acid treatment in steps using citric acid (1 hr and 2 hr) and buffered EDTA with acetic acid (1 to 3 hr) at room temperature. Leaching was performed...A high volatile bituminous coal was subjected to a series of organic acid treatment in steps using citric acid (1 hr and 2 hr) and buffered EDTA with acetic acid (1 to 3 hr) at room temperature. Leaching was performed with acetic acid (2N) also for 1 hr. Citric acid procedure reduced the mineral matter below 1.94%. Calcites and aluminates are completely removed along with substantial quantity of silicates by citric acid leaching. The change in absorption of organic functional groups and mineral matter in coal samples were studied using Fourier transform infrared spectroscopy (FTIR). Analysis indicated that oxygen containing species were decreased in the coal structure during acetic acid and citric acid (40%) procedure and buffered EDTA 3 hours leaching. As the period of leaching with buffered EDTA increased from 1 hr to 3 hr, organic functional groups and mineral functional groups decreased its intensity. The results indicated that the described acid treatment procedures with citric acid have measurable effects on the coal structure.展开更多
The effects of the constituents of mineral matter in brown coals from different deposits of Kansk-Achinsk, Lenaand from Yallourn Basins on the structural parameters and steam gasification reactivities of respective co...The effects of the constituents of mineral matter in brown coals from different deposits of Kansk-Achinsk, Lenaand from Yallourn Basins on the structural parameters and steam gasification reactivities of respective coal chars at moderate temperature and at low and high pressure were studied in this paper. The data on how the preliminary decationization with diluted hydrochloric, acetic and sulphuric acids affect char gasification reactivities are presented. The importance of surface area and crystallinity of chars and the presence of naturally occurring metals on gasification reactivity is considered. Quantitative correlations between the calcium contents and the extents of gasification are revealed. The gasification results obtained in a flow reactor with steam stream and in an autoclave reactor at high pressure of gaseous products are compared. The catalytic effect of dispersed calcium oxide-carbonate particles produced from the naturally occurring calcium containing carboxylates was shown to be a key factor for char gasification reactivity, the effect in the flow reactor being much larger as compared to that in the autoclave reactor. This was mainly related to different forms of catalytically active calcium species and to the composition of the gaseous reaction mixture.展开更多
As the mercury emitted from coal combustion can lead to serious environmental issues, researchers pay more attention to the content, distribution and occurrence of mercury in coal. In this paper, the content, distribu...As the mercury emitted from coal combustion can lead to serious environmental issues, researchers pay more attention to the content, distribution and occurrence of mercury in coal. In this paper, the content, distribution, and occurrence of mercury in the Permian tectonically deformed coals from Peigou Mine, Xinmi coalfield, Henan Province were investigated. A total of 18 bench samples were taken from No.2-1 coals seam in Peigou Mine, including 15 coal bench samples, two roofs and one floor. The mercury concentration, mineral composition, and main inorganic element content of 18 samples were determined by DMA-80 direct mercury analyzer, XRD, and XRF respectively. The results show that the mercury content ranges from 0.047 ppm to 0.643 ppm, with an average of 0.244 ppm. Though the coal seam has turned into typical tectonically deformed coal by the strong tectonic destruction and plastic deformation, the vertical distribution of mercury has remarkable heterogeneity in coal seam section. By the analysis of correlation between mercury and the main inorganic elements and the mineral composition in coal, we infer that majority of mercury mainly relates to pyrite or kaolinite.展开更多
In order to avoid environmental pollution from Coal gangue (CG) and copper tailings (CT), the utilization as cement clinker calcinations was experimentally investigated. Low-calcium limestone was also selected as ...In order to avoid environmental pollution from Coal gangue (CG) and copper tailings (CT), the utilization as cement clinker calcinations was experimentally investigated. Low-calcium limestone was also selected as another raw material. The clinker component and microstructure were analyzed by XRD and SEM. The experimental results showed that qualified cement clinker could be generated by substituting CG and CT compound for clay. While mixed with high-calcium limestone and low-calcium limestone, the calcinations temperature were 50 ℃ or 100 ℃ lower than that of clay. CT and CG contain oxygen-rich minerals and potential of geological rock energy. The energy of CG performs functions and drops down sintering temperature. The calcination time was shortened and the clinker sintering coal consumption reduced while substituting CG and CT for clay, and also served the reutilization of low-calcium limestone, CG and CT.展开更多
Vanadium - bearing stone coal is a new resource of vanadium. V in stone coal mainly exists in three oxidation states: 7.84% V(III), 72.08% V(IV) and 20.08% V(V). The change and distribution of valency during oxidizing...Vanadium - bearing stone coal is a new resource of vanadium. V in stone coal mainly exists in three oxidation states: 7.84% V(III), 72.08% V(IV) and 20.08% V(V). The change and distribution of valency during oxidizing roasting shows that organic matter in the coal determines the valency at low temperatures. At about 450°C, V(III) is completely oxidized to V(IV); above 500°C, temperature is the most important factor for the oxidation of V. At 700-1000°C, 92% of V in the coal has been oxidized to V(V). At higher temperature, no more oxidation of V takes place, equilibrium being established. The role of NaCl in the recovery of V2O5 from the coal is discussed. The best conditions for roasting are an oxidation-chlorination atmosphere, temperature 800°C for 30 minutes, ore:NaCl = 100:10, ηroast reaching 90%.展开更多
Coal is one of the main sources of energy in many parts of the world and has one of the largest reserves/production ratios amongst all the non-renewable energy sources. Gasification of coal is one among the advanced t...Coal is one of the main sources of energy in many parts of the world and has one of the largest reserves/production ratios amongst all the non-renewable energy sources. Gasification of coal is one among the advanced technologies that has potential to be used in a carbon constrained economy. However, gasification availability at several commercial demonstrations had run into problems associated with fouling of syngas coolers due to unpredictable flyash formation and unburnt carbon losses. Computer models of gasifiers are emerging as a powerful tool to predict gasifier performance and reliability, without expensive testing. Most computer models used to simulate gasifiers tend to model coal as a homogenous entity based on bulk properties. However, coal is a heterogeneous material and comminution during feedstock preparation produces particle classes with different physical and chemical properties. It is crucial to characterize the heterogeneity of the feedstocks used by entrained flow gasifiers. To this end, a low ash US bituminous coal that could be used as a gasifier feedstock was segregated into density and size fractions to represent the major mineral matter distributions in the coal. Float and sink method and sieving were employed to partition the ground coal. The organic and inorganic content of all density fractions was characterized for particle size distribution, heating value, ultimate analysis, proximate analysis, mineral matter composition, ash composition, and petrographic components, while size fractions were characterized for heating value, ash composition, ultimate and proximate analysis. The proximate, ultimate and high heating value analysis showed that variation in these values is limited across the range of size fractions, while the heterogeneity is significant over the range of density fractions. With respect to inorganics, the mineral matter in the heavy density fractions contribute significantly to the ash yield in the coal while contributing very little to its heating value. The ash yield across the size fractions exhibits a bimodal distribution. The heterogeneity is also significant with respect to the base-to-acid ratio across the size and density fractions. The results indicate that the variations in organic and inorganic content over a range of density and size classes are significant, even in the low ash, vitrinite rich coal sample characterized here. Incorporating this information appropriately into particle population models used in gasifier simulations will significantly enhance their accuracy of performance predictions.展开更多
文摘In coal mines, main occupational hazard is coal-mine dust, which can cause health problem including coal workers’ pneumoconiosis and lung cancer. Some heat shock proteins (Hsps) have been reported as an acute response to a wide variety of stressful stimuli. Whether Hsps protect against chronic environmental coal-mine dust over years is unknown. It is also interesting to know that whether the expression of Hsp27 and Hsp70 proteins as a marker for exposure is associated risk of lung cancer among coal miners. We investigated the association between levels of Hsp27 and Hsp70 expression in lymphocytes and plasma and levels of coal-mine dust exposure in workplace or risk of lung cancer in 42 cancer-free non-coal miners, 99 cancer-free coal miners and 51 coal miners with lung cancer in Taiyuan city in China. The results showed that plasma Hsp27 levels were increased in coal miners compared to non-coal miners (P<0.01). Except high cumulative coal-mine dust exposure (OR=13.62, 95%CI=6.05—30.69) and amount of smoking higher than 24 pack-year (OR=2.72, 95% CI=1.37—5.42), the elevated levels of plasma Hsp70 (OR=13.00, 95% CI=5.14—32.91) and plasma Hsp27 (OR=2.97, 95% CI=1.40—6.32) and decreased expression of Hsp70 in lymphocytes (OR=2.36, 95% CI=1.05—5.31) were associated with increased risk of lung cancer. These findings suggest that plasma Hsp27 may be a potential marker for coal-mine dust exposure. And the expression of Hsp27 and Hsp70 levels in plasma and lymphocytes may be used as biomarkers for lung cancer induced by occupational coal-mine dust exposure.
基金the Liaoning Technical University Outstanding Youth Science Foundation(jx09-10)
文摘It took that the weight minimum and drive efficiency maximal were as double optimizing target,the optimization model had built the drilling string,and the optimization solution was used of the ant colony algorithm to find in progress.Adopted a two-layer search of the continuous space ant colony algorithm with overlapping or variation global ant search operation strategy and conjugated gradient partial ant search operation strat- egy.The experiment indicates that the spiral drill weight reduces 16.77% and transports the efficiency enhance 7.05% through the optimization design,the ant colony algorithm application on the spiral drill optimized design has provided the basis for the system re- search screw coal mine machine.
基金supported by the National Natural Science Foundation of China (No. 71271206)
文摘In order to effectively decrease the safety accidents caused by coal miners’human errors,this paper probes into the causality between human errors and life events,coping,psychological stress,psychological function,physiological function based on life events’vital influence on human errors,establishing causation mechanism model of coal miners’human errors in the perspective of life events by the researching method of structural equation.The research findings show that life events have significantly positive influence on human errors,with a influential effect value of 0.7945 and a influential effect path of‘‘life events—psychological stress—psychological function—physiological function—human errors’’and‘‘life events—psychological stress—physiological function—human errors’’.
文摘We aimed to investigate the short-term correlation between blood lead levels and oxidative stress generation in coal miners. The study involved 94 male coal miners from the Velenje Coal mine, arranged into four groups: three groups according to the number of consecutive working days, and a fourth control group. Miners who worked for three consecutive days had higher blood levels of lead and 8-isoprostane than the control group(P 〈 0.001). Correlation between lead and 8-isoprostane was of medium strength(r = 0.512, P 〈 0.001). Short-term lead environmental exposure can potentially harmful and should be considered when formulating improvements in working processes.
基金the NRF and DSI(Coal Research Chair Grant Nos.86880,UID85643,and UID85632)Sasol,South Africa for their assistance in funding this project.
文摘The main objective of this work is to relate the coalescence of inherent minerals and the fragmentation of extraneous minerals to the slagging propensities of South African pulverised feed coals during combustion.By incorporating the behaviour of inherent mineral matter or extraneous mineral matter in these coals under combustion conditions into ash-deposition prediction methods,the heterogeneous nature of the ash properties,which were disregarded in previous conventional ash deposition predictions,is considered in the study.The mode of occurrence of mineral matter in feed coals plays a crucial role in the formation of high-temperature mineral phases under combustion conditions.The float and sink fractions of the three different coals evaluated in this distinctive alternative approach provide different chemical and mineralogical properties of the derived ashes when subjected to elevated temperatures under oxidising conditions.Formation of significant concentrations of high-temperature minerals(such as mullite and cristobalite)is mainly due to the transformation reactions of extraneous kaolinite and quartz which are not associated with the extraneous fluxing minerals at elevated temperatures.However,the formation of anorthite at elevated temperatures can be attributed to the interaction of either inherent or extraneous fluxing minerals(namely calcite,dolomite,pyrite,and siderite)that are associated with either inherent or extraneous kaolinite in the coal samples under the oxidising condition.Furthermore,the anorthite,mullite,and calcium/magnesium/iron/aluminosilicate and silica glasses in ashes are formed either via crystallisation during the cooling of the hightemperature molten solution or via the solid state reactions.These high-temperature minerals and their glasses present in ashes can therefore be used as the indicators of the slagging propensity of coals.The implementation of results from this unique case study,will be of great significance to other industrial combustion processes to minimise or control ash deposition,slagging,and equipment erosion problems by either blending the density-separated fractions of coals or coals from different mines based on the chemical and mineralogical properties to prepare suitable feed coals.Furthermore,this unique alternative approach can be followed to further evaluate other feed coals in the global power stations during combustion.
基金This research was supported by the National Key Basic Research and Development Program(No.2014CB238902)National Natural Science Foundation of China(Nos.41272182 and 40930420)the Program for Changjiang Scholars and Innovative Research Team in University.
文摘Minerals in the Late Permian coals from the Niuchang-Yigu mining area,Zhenxiong County,northeastern Yunnan,China,were investigated using optical microscopy and low temperature ashing plus X-ray diffraction(LTA?XRD).The results showed that minerals in the coal LTAs are mainly quartz,kaolinite,chamosite,mixed-layer illite/smectite(I/S),pyrite,and calcite,with trace amounts of marcasite,dolomite,and bassanite.The authigenic quartz generally occurs in collodetrinite or as a filling in cleats or cell cavities.This silica was mainly derived from aqueous solutions produced by the weathering of basaltic rocks in the Kangdian Upland and from hydrothermal fluids.The presence of b-quartz paramorph grains in collodetrinite probably indicates that these grains were detrital and came from a volcanic ash.Clay minerals are generally embedded in collodetrinite and occur as cell-fillings.Pyrite occurs as framboidal,anhedral,and euhedral grains and a cell-filling.The coals are high in pyrite and the high pyrite content probably results from seawater invading during the stage of peat accumulation.Calcite generally occurs as vein-fillings,indicating an epigenetic origin.
基金financially supported by the Major Science and Technology Program for Water Pollution Control and Treatment of China (No. 2015ZX07205003)
文摘This study determined the optimal conditions required to obtain maximum vanadium extraction and examined the transition of mineral phases and vanadium speciation during the bioleaching process. Parameters including the initial p H value, initial Fe^(2+) concentration, solid load, and inoculum quantity were examined. The results revealed that 48.92 wt% of the vanadium was extracted through bioleaching under optimal conditions. Comparatively, the chemical leaching yield(H_2SO_4, pH 2.0) showed a slower and milder increase in vanadium yield. The vanadium bioleaching yield was 35.11 wt% greater than the chemical leaching yield. The Community Bureau of Reference(BCR) sequential extraction results revealed that 88.62 wt% of vanadium existed in the residual fraction. The bacteria substantially changed the distribution of the vanadium speciation during the leaching process, and the residual fraction decreased to 48.44 wt%. The X-ray diffraction(XRD) and Fourier transform infrared(FTIR) results provided evidence that the crystal lattice structure of muscovite was destroyed by the bacteria.
文摘In Brazil, intense coal exploitation activities have led to environmental deterioration, including soil mortification, water contamination, loss of ecosystem, and atmospheric contamination. In addition,considerable quantities of sulfur-rich residues are left behind in the mining area; these residues pose grave environmental issues as they undergo sulfide oxidation reactions. When sulfur oxides come in contact with water, extreme acid leachate is produced with great proportions of sulfate, and hazardous elements(HEs), which are identified as coal drainage(CMD). CMD is an environmental pollution challenge, particularly in countries with historic or active coal mines. To prevent CMD formation or its migration, the source must be controlled; however, this may not be feasible at many locations. In such scenarios, the mine water should be collected, treated, and discharged. In this study, data from 2005 to2010 was gathered on the geochemistry of 11 CMD discharges from ten different mines. There are several concerns and questions on the formation of nanominerals in mine acid drainage and on their reactions and interfaces. The detailed mineralogical and geochemical data presented in this paper were derived from previous studies on the coal mine areas in Brazil. Oxyhydroxides, sulfates, and nanoparticles in these areas possibly go through structural transformations depending on their size and formation conditions. The geochemistry of Fe-precipitates(such as jarosite, goethite, and hematite) existent in the CMD-generating coal areas and those that could be considered as a potential source of hazardous elements(HEs)(e.g., Cr) were also studied because these precipitates are relatively stable in extremely low pH conditions. To simplify and improve poorly ordered iron, strontium, and aluminum phase characterization, field emission scanning electron microscopy(FE-SEM), high-resolution transmission electron microscopy(HR-TEM), micro-Raman spectroscopy, and X-ray diffraction(XRD) and sequential extraction(SE) studies were executed on a set CMD samples from the Brazilian mines. This study aimed to investigate the role of both nanomineral and amorphous phase distribution throughout the reactive coal cleaning rejects profile and HEs removal from the water mine to provide holistic insights on the ecological risks posed by HEs, nanominerals, amorphous phases, and to assess sediments in complex environments such as estuaries.
基金supported by the China National Major Scientifc and Technological Special Project for ‘‘Physical and Chemical Reaction between CO2 and Coal and Rock after Infuse CO2 into Deep Coal Bed’’ during the Twelfth Five-Year Plan Period(No.2011ZX05042-03)
文摘In order to study the physical and chemical reaction after CO2 injected into coal beds at different condition.The physical and chemistry reaction among CO2,H2O and coal was studied,and the influence on permeability and porosity of coal beds was carried out.The experimental method was used,so did the basic theory of mineralogy,coal petrology,geochemistry,analytical geochemistry and physical chemistry.In this experiment,the changes of mineral and permeability of coal and water quality were observed through CO2 solution reacting with different coal samples.The differences could be found out by comparing the properties and microcrystalline structure before and after the reaction.There are three results were carried out:First,the content of carbonate in coal beds decreases because of the dissolution reaction between carbonate minerals and CO2 solution,and precipitation is formed by reaction of chlorite and orthoclase.Second,the result that permeability and porosity of coal beds are improved after the reaction is proposed.Third,the initial permeability of different coal samples plays a great role on the reaction,and the improvement of permeability is not obvious in the samples which have too low or too high permeability,and the improvement is good in medium permeability(0.2–3 mD).
文摘A high volatile bituminous coal was subjected to a series of organic acid treatment in steps using citric acid (1 hr and 2 hr) and buffered EDTA with acetic acid (1 to 3 hr) at room temperature. Leaching was performed with acetic acid (2N) also for 1 hr. Citric acid procedure reduced the mineral matter below 1.94%. Calcites and aluminates are completely removed along with substantial quantity of silicates by citric acid leaching. The change in absorption of organic functional groups and mineral matter in coal samples were studied using Fourier transform infrared spectroscopy (FTIR). Analysis indicated that oxygen containing species were decreased in the coal structure during acetic acid and citric acid (40%) procedure and buffered EDTA 3 hours leaching. As the period of leaching with buffered EDTA increased from 1 hr to 3 hr, organic functional groups and mineral functional groups decreased its intensity. The results indicated that the described acid treatment procedures with citric acid have measurable effects on the coal structure.
文摘The effects of the constituents of mineral matter in brown coals from different deposits of Kansk-Achinsk, Lenaand from Yallourn Basins on the structural parameters and steam gasification reactivities of respective coal chars at moderate temperature and at low and high pressure were studied in this paper. The data on how the preliminary decationization with diluted hydrochloric, acetic and sulphuric acids affect char gasification reactivities are presented. The importance of surface area and crystallinity of chars and the presence of naturally occurring metals on gasification reactivity is considered. Quantitative correlations between the calcium contents and the extents of gasification are revealed. The gasification results obtained in a flow reactor with steam stream and in an autoclave reactor at high pressure of gaseous products are compared. The catalytic effect of dispersed calcium oxide-carbonate particles produced from the naturally occurring calcium containing carboxylates was shown to be a key factor for char gasification reactivity, the effect in the flow reactor being much larger as compared to that in the autoclave reactor. This was mainly related to different forms of catalytically active calcium species and to the composition of the gaseous reaction mixture.
基金financially supported by the National Natural Science Foundation of China (Grant Nos.41172141 41272173+3 种基金 41602175)Program for New Century Excellent Talents in University of Ministry of Education of China (Grant No.NCET 10-133)Program for Innovative Research Team of Henan Polytechnic University (Grant No.T2013–2)the Shanxi Province United Research Funding of Coalbed Methane Project (2016012001)
文摘As the mercury emitted from coal combustion can lead to serious environmental issues, researchers pay more attention to the content, distribution and occurrence of mercury in coal. In this paper, the content, distribution, and occurrence of mercury in the Permian tectonically deformed coals from Peigou Mine, Xinmi coalfield, Henan Province were investigated. A total of 18 bench samples were taken from No.2-1 coals seam in Peigou Mine, including 15 coal bench samples, two roofs and one floor. The mercury concentration, mineral composition, and main inorganic element content of 18 samples were determined by DMA-80 direct mercury analyzer, XRD, and XRF respectively. The results show that the mercury content ranges from 0.047 ppm to 0.643 ppm, with an average of 0.244 ppm. Though the coal seam has turned into typical tectonically deformed coal by the strong tectonic destruction and plastic deformation, the vertical distribution of mercury has remarkable heterogeneity in coal seam section. By the analysis of correlation between mercury and the main inorganic elements and the mineral composition in coal, we infer that majority of mercury mainly relates to pyrite or kaolinite.
基金Funded by the "11th-Five-Year" National Key Technologies R&D Program of China (No.2006BAC21B02)
文摘In order to avoid environmental pollution from Coal gangue (CG) and copper tailings (CT), the utilization as cement clinker calcinations was experimentally investigated. Low-calcium limestone was also selected as another raw material. The clinker component and microstructure were analyzed by XRD and SEM. The experimental results showed that qualified cement clinker could be generated by substituting CG and CT compound for clay. While mixed with high-calcium limestone and low-calcium limestone, the calcinations temperature were 50 ℃ or 100 ℃ lower than that of clay. CT and CG contain oxygen-rich minerals and potential of geological rock energy. The energy of CG performs functions and drops down sintering temperature. The calcination time was shortened and the clinker sintering coal consumption reduced while substituting CG and CT for clay, and also served the reutilization of low-calcium limestone, CG and CT.
文摘Vanadium - bearing stone coal is a new resource of vanadium. V in stone coal mainly exists in three oxidation states: 7.84% V(III), 72.08% V(IV) and 20.08% V(V). The change and distribution of valency during oxidizing roasting shows that organic matter in the coal determines the valency at low temperatures. At about 450°C, V(III) is completely oxidized to V(IV); above 500°C, temperature is the most important factor for the oxidation of V. At 700-1000°C, 92% of V in the coal has been oxidized to V(V). At higher temperature, no more oxidation of V takes place, equilibrium being established. The role of NaCl in the recovery of V2O5 from the coal is discussed. The best conditions for roasting are an oxidation-chlorination atmosphere, temperature 800°C for 30 minutes, ore:NaCl = 100:10, ηroast reaching 90%.
文摘Coal is one of the main sources of energy in many parts of the world and has one of the largest reserves/production ratios amongst all the non-renewable energy sources. Gasification of coal is one among the advanced technologies that has potential to be used in a carbon constrained economy. However, gasification availability at several commercial demonstrations had run into problems associated with fouling of syngas coolers due to unpredictable flyash formation and unburnt carbon losses. Computer models of gasifiers are emerging as a powerful tool to predict gasifier performance and reliability, without expensive testing. Most computer models used to simulate gasifiers tend to model coal as a homogenous entity based on bulk properties. However, coal is a heterogeneous material and comminution during feedstock preparation produces particle classes with different physical and chemical properties. It is crucial to characterize the heterogeneity of the feedstocks used by entrained flow gasifiers. To this end, a low ash US bituminous coal that could be used as a gasifier feedstock was segregated into density and size fractions to represent the major mineral matter distributions in the coal. Float and sink method and sieving were employed to partition the ground coal. The organic and inorganic content of all density fractions was characterized for particle size distribution, heating value, ultimate analysis, proximate analysis, mineral matter composition, ash composition, and petrographic components, while size fractions were characterized for heating value, ash composition, ultimate and proximate analysis. The proximate, ultimate and high heating value analysis showed that variation in these values is limited across the range of size fractions, while the heterogeneity is significant over the range of density fractions. With respect to inorganics, the mineral matter in the heavy density fractions contribute significantly to the ash yield in the coal while contributing very little to its heating value. The ash yield across the size fractions exhibits a bimodal distribution. The heterogeneity is also significant with respect to the base-to-acid ratio across the size and density fractions. The results indicate that the variations in organic and inorganic content over a range of density and size classes are significant, even in the low ash, vitrinite rich coal sample characterized here. Incorporating this information appropriately into particle population models used in gasifier simulations will significantly enhance their accuracy of performance predictions.