Synergistic CO_(2) mineralization using coal fly ash and red mud as a composite system

CO_(2) mineralization plays a critical role in the storage and utilization of CO_(2).Coal fly ash(CFA)and red mud(RM)are widely utilized as CO_(2) mineralizers.However,the inert calcium species in CFA limit its carbonation capacity,meanwhile the substantial Ca^(2+)releasing of RM is hindered by a covering layer of calcium carbonate.In this study,CO_(2) mineralization in a composite system of CFA and RM was investigated to enhance the carbonation capacity.Multiple analyzers were employed to characterize the raw materials and resulting mineralization products.The results demonstrated that a synergistic effect existed in the composite system of CFA and RM,resulting in improving CO_(2) mineralization rate and efficiency.The produced calcium carbonate was ectopically attached the surface of CFA in the composite system,thus slowing down its coverage on the surface of RM.This phenomenon facilitated further releasing Ca^(2+)from the internal RM,thereby enhancing CO_(2) mineralization efficiency.Meanwhile,the inclusion of RM significantly improved the alkalinity of the composite system,which not only promoted the dissolution of Ca^(2+)of the inert CaSO_(4)(H_(2)O)_(2) in CFA,but also accelerated CO_(2) mineralization rate.The investigation would be beneficial to CO_(2) mineralization using industrial solid wastes.

CWM-CM模型在采空区遗煤自燃风险评价中的应用

为更科学分析遗煤自燃危险性状态,建立基于组合赋权法-正态云模型(CWM-CM模型)进行采空区遗煤自燃风险评价。首先,选取了8个典型性影响因素,构建采空区遗煤自燃风险评价体系;其次,利用G1-云模型、改进CRITIC-云模型和CWM-CM模型,计算指标综合权重,并通过计算综合确定度,以最大隶属度为判别准则,综合评估风险等级;最后,应用该模型对山西省某煤矿3个采空区遗煤自燃风险实例分析,并与物元可拓和未确知测度模型评估结果比较。结果显示:3个采空区遗煤自燃风险均为易燃等级,3种模型评估结果完全一致,验证了该模型在采空区遗煤自燃风险评价方面具有可行性和适用性,可为遗煤自燃风险评估提供新思路。

基于ISM-MICMAC的煤矿工人违章行为影响因素研究

为探究煤矿工人违章行为影响因素及其相互作用关系,建立了违章行为影响因素指标体系,并采用解释结构模型(ISM)和交叉影响矩阵相乘法(MICMAC),深入剖析了影响因素之间的逻辑关系,构建了影响因素的多级递接结构模型及驱动力-依赖度象限分类图。结果表明:煤矿工人违章行为影响因素可划分为4级3阶的多级递接结构;安全知识技能、安全意识水平、安全行为习惯、自保互保意识属于依赖簇,具有强依赖性,是影响违章行为的重要因素;安全生产投入、安全管理制度、矿领导安全理念、管理者安全意识、企业安全氛围属于独立簇,具有强驱动力,是影响违章行为的关键因素。

Bioleaching of vanadium from barren stone coal and its effect on the transition of vanadium speciation and mineral phase

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.

Influence of coal blending on mineral transformation at high temperatures

Transformation of mineral matter is important for coal utilization at high temperatures.This is especially true for blended coal.XRD and FTIR were employed together to study the transformation of mineral matter at high temperature in blended coals.It was found that the concentration of catalytic minerals, namely iron oxides, increases with an increasing ratio of Shenfu coal, which could improve coal gasification.The transformation characteristics of the minerals in blended coals are not exactly predictable from the blend ratio.This was proved by comparing the iron oxide content to the blending ratio.The results from FTIR are comparable with those from XRD.FTIR is an effective method for examining variation in mineral matter.

Expression of Hsp27 and Hsp70 in Lymphocytes and Plasma in Healthy Workers and Coal Miners with Lung Cancer

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.

Composition and mode of occurrence of minerals in Late Permian coals from Zhenxiong County,northeastern Yunnan,China

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.

Transformation of minerals at the boundary of magma-coal contact zone:case study from Wolonghu Coal Mine, Huaibei Coalfield, China

Mesozoic and Cenozoic magma activity in the Wolong Lake mining area of Huaibei is frequent,and the degree of magma intrusion into coal seams remarkable.On the one hand,magma intrusion affects the utilization of coal resources;on the other hand,the macro and trace elements in coal are redistributed to form new mineral types.This study uses the Wolong Lake magma intrusion coal seam as a research object.The mineral paragenesis for igneous rock,coke,and thermally-altered coal in an igneous intrusion zone is studied using SEM,XRD,and Raman spectroscopy.During igneous intrusion,the temperature and pressure of igneous rock metamorphose ambient low-rank coal to high-rank coal and coke.The response mechanism of minerals and trace elements to magmatic intrusion is discussed.The results are:①SEM analysis shows that ankerite and pyrite are formed from magma intrusion.Both minerals are strongly developed in the magma-coal contact zone,and less well developed in thermally-altered coal.②XRD analysis shows that igneous intrusion strongly influences the types and content of minerals in coke and thermally-altered coal.In addition to the increase amounts of ankerite and pyrite,chlorite,serpentine,and muscovite,and other secondary minerals,are generated following igneous intrusion.③Raman analysis suggests that thermally-altered coal possesses the characteristics of both pyrite and coke.Coke from the magma-coal boundary zone possesses the typical characteristics of pyrite.Igneous rock contains a mineral similar to pyrite,confirmed by both having similar Raman peaks.The scattering intensity of Ag indicates that the formation pressure of pyrite increases from thermally-altered coal via the boundary between the coke zone and the igneous rock.

Effect of chemical conditioning on the triboelectrification of coal and mineral particles

Chemical conditioning was used to modify the triboelectrification of coal and mineral particles.The chemicals tested included starch,lignin,kerosene,ethanol,acetic acid,salicylic acid,sodium oleate,Sodium Hexametaphosphate(SH),sodium silicate, Sodium Dodecylbenzenesulfonate(SDBS),Sodium Bicarbonate(SB) and ammonia.A high-speed,dry mixing method was employed.The charge-to-mass ratio of the coal and mineral samples,both untreated and treated,was tested using a Faraday cup. Dielectric constants were determined by measuring capacitance.It is found that the selectivity of the additives toward coal or minerals is not consistent.Salicylic acid is the optimal additive to enhance the triboelectrification performance of coal samples.Starch, lignin and sodium oleate are suitable for removal of pyrite.SH,sodium silicate,SDBS,SB and ammonia are suitable additives for the removal of ash-forming minerals.

Demineralization mechanism and influence of parameters on high ash Indian coal by chemical leaching of acid and alkali solution

The current research was investigated the mechanism of coal demineralization and the effect of leaching parameters on high ash coal and study the characterization of pre and post-treated coal. The two high ash Indian coal selected from Mahanadi Coalfield Limited, Odisha, pulverized to 375, 230 and 180 gm particle size were undergone simultaneous acid and alkali treatment at a different concentration, temperature and time. The percent demineralization was increased with decrease the size of the particle and rises with leaching parameters. The investigation suggested 180 μm particle size offers efficient demineralization for both coals at 30% NaOH and 30% H2SO4 concentration. The alkali leaching leads to obtaining the demineralization 46% and 42% whereas acid treatment resulted in 34% and 32% of the original coal samples. The extent of demineralization was improved the calorific value of coal. Besides, the degree of demineralization was proved from the FTIR, XRF and FESEM-EDX analysis results. FTIR analysis result showed that the peak intensity of mineral band decreased by the leaching effect and the degree of demineralization was significantly obtained to large extent by the X-ray Fluorescence spectrometer; which elucidates major minerals removed from coal by the leaching effect of acid and alkali solution.

Optimization design of drilling string by screw coal miner based on ant colony algorithm

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.

Geochemistry and Mineralogy of Paleocene Coal from the Padhrar and Darra Adam Khel Coalfields of Pakistan

Pakistan is rich in coal resources,which amount to around 186 billion tons.The Paleocene Padhrar and Darra Adam Khel coalfields are located in the Central Salt Range Punjab Province and the Khyber Pakhtunkhwa Province,Pakistan,respectively.Padhrar coal has not been studied in detail and the Darra Adam Khel coalfields are newlydiscovered,so no research has been done,due to security considerations.In this study,an attempt has been made to study the geochemical and mineralogical characteristics of the Padhrar and Darra Adam Khel coals,in order to learn about the coal quality,element enrichment mechanism,sedimentary medium conditions and potentially valuable elements for coal utilization.The Padhrar and Darra Adam Khel coals are low to medium ash,low moisture content,high in volatiles and high total sulfur coal.The vitrinite reflectance in Darra Adam Khel coal is higher than in Padhrar coal,indicating either a greater burial depth or the effects of Himalayan tectonism.The vitrinite content is dominant in the Padhrar and Darra Adam Khel coals,followed by inertinite and liptinite,the major minerals including quartz,clay minerals,calcite and pyrite.The trace elements Ni,As,Be Zn,Ge,Mo,Ta,W,Co and Nb,Sn,Hf,Ta,Pb,Th,Cd,In,Be,V,Cr,Zr,Ag,Li,W and Co are concentrated in some of the Padhrar and Darra Adam Khel coal samples,respectively.The Padhrar coal shows positive Ce,Eu and Gd anomalies,with most of the Darra Adam Khel coal showing negative Ce,Eu and positive Gd anomalies with high LREE.The Al2O3/TiO2 values indicate that the sediment source of the Padhrar and Darra Adam Khel coals is mostly related to intermediate igneous rocks.The Sr/Ba,SiO2+Al2O3,Fe2O3+CaO+MgO/SiO2+Al2O3 and high sulfur content in the Padhrar and Darra Adam Khel coals indicate epithermal and marine water influence with a tidal flat,coal-forming environment and a deltaic coal-forming environment,respectively.

Lead Exposure and Oxidative Stress in Coal Miners

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.

Causation mechanism of coal miners' human errors in the perspective of life events

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’’.

Transformation of inherent and extraneous minerals in feed coals of commercial power stations and their density-separated fractions

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.

Advances in depressants used for pyrite fotation separation from coal/minerals

Pyrite is separated from other minerals mainly by fotation.However,the hydrophilicity of pyrite is afected by many factors,causing it to easily enter the concentrate and consequently reduce the quality of concentrate.Highly efcient pyrite depressants can be selectively adsorbed on the surface of pyrite to improve its hydrophilicity,thereby increasing the fotation separation efciency.Understanding the fundamental inhibition mechanism of depressants on pyrite is a prerequisite to improve the fotation desulfurization efciency.The inhibition ability and mechanism of diferent types of pyrite depressants are reviewed in this manuscript.In recent years,molecular simulation has increasingly become a powerful tool to study the interaction between reagents and minerals,shedding new light on the adsorption mechanisms of reagents on mineral surfaces at the atomic and electronic levels.The properties of sulfde mineral and fotation reagents as well as the microscopic adsorption mechanistic studies of reagents on mineral surfaces based on quantum chemistry and molecular simulation are also reviewed.

Study on the characteristics of mineral matter in Huainan coals by computer controlled scanning electron microscope (CCSEM)

The mineral features, ash composition, ash fusion temperature of Huainan coals were investigated by CCSEM, X-ray fluorescence (XRF) and JIS (Japan Industrial Standard) ash cone melting method respectively. The mineral matter is characterized by higher aluminosilicate clay minerals contents (more than 60% of the total mineral matter in coal) with quartz, which accounts for the higher ash flow temperatures, frequently higher than1 500℃. The contents of calcite and dolomite in Huainan coals range from 0.16% to about 11.57%. Another important non-silicate mineral matter, pyrite, ranges from 0.73% to 12.25%. Low amount of kaolinite-type clays and high amount of calcite and pyrite in the HN115 and XM coals are beneficial to ash melting. It is suggested that the high content of kaolinite in Huainan coals shows the high ash fusion temperature. CCSEM results also provide the size distribution of the minerals in Huainan coals. Generally, the mineral has bimodal size distribution in 6 Huainan coals.

CLAY MINERAL ASSEMBLAGES AND THEIR IMPLICATIONS IN SHIHEZI FORMATION FROM THE HUAIBEI COAL-BEARING STRATA

Clay mineral assemblages in Shihezi Formation of Huaibei coal-bearing strata are determined by X-ray diffraction and Differential Thermal Analyzer, that is restated to the sediment faces and climatic changes in the source area, and to a lesser extent, alterations during burial diagenesis. In the Upper Shihezi Formation, the clay fraction is dominated by kaolinite in northern part of the coal field, which was formed in alluvial sediment environment. But in the South of Huaibei coal field, the clay mineral assemblage consists of mainly illite that reflects the influence of sea water. The predominately kaolinite and sederite composition of the clay fraction in the lower Shihezi Formation sediments documents less relief and gentle erosion of kaolinite rich soils developing under warm source area. In the lower part of Shihezi Formation, some chlorite is detected, which suggests transformation of illite or kaolinite to chlorite under conditions of burial diagenesis.

煤系中关键金属元素的成矿作用研究进展与展望

煤系中关键金属元素的赋存状态、分布规律、成矿机制以及有效提取和综合利用的研究是近10年来煤地质学等相关领域的研究前沿和热点问题,国内外学者在煤系中关键金属矿床的发现,关键金属元素赋存状态,成矿物质来源、迁移、富集和保存,开发利用潜力评价,精细勘查技术研发,关键元素的分离提取等方面取得了重要研究进展,为煤系关键金属矿产资源的开发利用奠定了坚实的理论和技术基础,同时在揭示与煤系关键金属相关重大地球科学问题方面取得了长足进展。本文结合国内外近些年来的进展,对煤系中关键金属元素(主要是锗、镓、锂、铌、锆等)的成矿作用进行了总结和凝练,指出了存在的问题及其解决方案和思路。