彬长矿区4号煤层煤质特征及洁净等级划分

为实现彬长矿区优质煤炭资源的清洁高效利用,在对彬长矿区以往勘查钻孔的煤质化验资料统计分析的基础上,系统分析了该矿区主采煤层4号煤的煤岩、煤质特征,论述了硫分、灰分、挥发分、发热量和有害微量元素的分布规律,依据最新煤炭资源潜力评价提出的煤炭洁净等级6级划分方案,选用灰分、硫分、有害元素(F、Cl、As及Pb)6个评价指标对矿区内4号煤层的煤炭资源洁净等级进行了初步划分。彬长矿区4号煤层以低硫、低中灰、中高挥发分、特高热值不黏煤为主,局部含小范围的弱黏煤,彬长矿区4号煤层原煤洁净等级为Ⅲ级,属较好洁净煤;浮煤洁净等级为Ⅱ级,属好洁净煤。整个矿区内4号煤层原煤洁净等级以Ⅲ级较好洁净煤为主,分布区占矿区面积的73.03%,仅在矿区西部洪家镇—巨家镇一带和中东部出现小范围的Ⅳ级中等洁净煤分布区,面积占比为26.97%。     

Exploring the possibilities of using Brazilian subbituminous coals for blast furnace pulverized fuel injection

The current study investigates the combustion and blast furnace injection performance of three Brazilian subbituminous coals (Mina do Recreio) and their beneficiation products using laboratory scale combustion tests. The coals have relative high ash yields (up to 40 wt%) that were reduced stepwise to levels as low as 12 wt%, dry basis. The reduction of ash yields is paralleled by a significant decrease in sulphur and inertinite contents.The combustion tests were performed in a drop tube reactor operating at 1300 °C using two different atmospheres (2.5 and 5% O₂). The chars exhibited preferentially rounded shapes with thick walls and abundant secondary porosity for the 2.5% O₂ chars, whereas the 5% O₂ chars showed very thin walls as a consequence of extensive burnout. The intrinsic reactivities of both set of chars were similar. The differences in conversion between the two working atmospheres were 24-37% and roughly tend to increase with increasing mineral matter content. Conversions as high as 76-81% were reached operating under 5% O₂ indicating that the coals are easy to burn. The small differences in burnout among the coals and their beneficiation products cannot be clearly attributed neither to mineral matter or inertinite content. A rough inverse relationship was found between the intrinsic reactivity of the chars and the inertinite content of the parent coal indicating that the char material derived from inertinite was intrinsically less reactive than that derived from vitrinite. These differences were no longer relevant at high temperature.Blast furnace injection performance was studied through thermobalance experiments using CO₂ atmosphere and 1050 °C temperature. It is apparent that the beneficiation process has no effect on the reactivity of the coals from Recreio Mine. The only exception is the low ash coal-2-LabB (11.5 wt%), for which a higher reactivity is indicated. The reactivity tests show also that the coals have adequate properties to be used together with imported coal blends in pulverized coal injection in the blast furnace (PCI).     

宁东煤田中部2号煤煤相特征

采用煤岩学方法,对宁东煤田中部2号煤煤相特征进行了分析,研究结果表明2号煤层属于淡水陆相沉积,其成煤植物以草本植物为主,煤相类型以低位泥炭沼泽相为主、潮湿森林沼泽相为辅。通过煤相分析,为宁东煤田中部2号煤成煤环境的研究提供了佐证。     

Coal microlithotype response to froth flotation in selected Western Kentucky coals

Seven coals representing four western Kentucky coal seams and the coal rank range from high volatile C to high volatile A bituminous were selected for bench-scale froth flotation processing. Each coal was represented by two splits of the run-of-mine coal: a 12.7 mm × 0 fraction (crushed to 28 mesh × 0) and a 28 mesh × 0 fraction. The original 28 mesh × 0 split was found to be higher in the inertinite macerals fusinite and semifusinite than the coarser fraction. The separation of the inertinite macerals, expressed as the microlithotype inertite, from the vitrinite-rich vitrite and clarite microlithotypes proved to be markedly rank dependent. In the higher rank coals vitrite and clarite were concentrated in the clean coal while inertite was concentrated in the clean product in the high volatile C coals. Whereas in gravity-based coal cleaning only the finest pyrite usually remains in the clean coal, in this study no consistent trend in pyrite-size or pyrite-quantity partitioning was noted.     

云南胶磷矿选矿脱铬试验研究

对云南胶磷矿进行了铬元素分析,结果表明铬在胶磷矿中是一种痕量元素.多种选矿工艺试验研究结果表明,铬元素没有赋存于胶磷矿的主要脉石矿物白云石和硅质矿物中,无法利用选矿的方式有效脱除.从磷精矿粒度分布来看,粗粒级中铬质量分数较低,而细粒级中铬质量分数较高,利用该分布规律可以对磷精矿进行分级利用.     

Distribution of water-soluble chlorine in coals using stains and acetate peels

A technique has been developed to show the distribution of readily leachable chlorine in high chlorine coals using silver nitrate as a stain. Acetate peels may be taken of the precipitated silver chloride for closer investigation of the relations between the water-soluble chlorine and the coal lithotypes. High chlorine coals from Yorkshire Main Colliery (Barnsley Seam) and Thoresby Colliery (Top Hard Seam), showed that the durain fraction of coal will rapidly yield at least some of its water-soluble chlorine. However, vitrinite is the major host of water-soluble chlorine and the predominant component of bright coal. Bright coal shows no water-soluble chlorine component. This apparent discrepancy is explained by the size and distribution of pores and the permeability of different coal macerals. The water-soluble chlorine component is believed to be a NaCl solution held within coal pores. Pores found within the dull coal are much larger than those found in bright coal especially where the former has a high detrital mineral matter component. Bedding planes within durain bands which are coated by fossil remains or thin fusain layers are seen to be the major contributory fractions of the dull coal.     

Quantitative X-ray powder diffraction analysis of clay minerals in Australian coals using Rietveld methods

The mineralogy of clay-rich mineral matter isolated from a range of Australian bituminous coals has been evaluated in quantitative terms from X-ray powder diffraction (XRD) patterns using a Rietveld-based data processing technique. The chemical composition of coal ash derived from this mineral matter has been calculated and compared to the directly determined composition of the ash prepared from the same coal samples. Although there are some minor differences due in part to uncertainty regarding the actual composition of several minerals, the compositions indicated by the two methods show a relatively high correlation, suggesting that the Rietveld technique provides mineralogical analyses that are consistent with independently determined chemical data. Comparison of the normalised clay mineral percentages from the Rietveld analysis to quantitative interpretations based on a peak intensities in glycolated and heat-treated oriented aggregates of the respective clay fractions also shows a high correlation, confirming mutual consistency of the two different mineralogical analysis methods. Such quantitative mineralogical data are significant to a range of coal exploration, mining and utilization activities, including seam correlation, material handling and ash and slag formation in combustion processes.     

Correlation relations between mineralogical components in ash from Kaa-Khem coals

Regression analysis was used to study correlation relations between the mineral components of coals. Regularities in the variability of the concentrations of individual ash-forming elements with changing ash contents of coals and changing seam depth were found. The X-ray diffraction characteristics of coal ashes and the qualitative composition of their mineralogical components are presented.     

Perspectives of environmental efficiency improvement of coal preparation processes. Part 3

The prospects for developing coal-preparation processes based on the best available technologies, with minimal environmental impact, are considered. Against a background of changing coal resources, preparation flowsheets must be designed so as to minimize circulating slime flows and produce pure circulatory water and solid phase with the conditional water content. By beneficiation of the middlings of gravity beneficiation and the overburden rock, the yield of concentrate may be increased and the losses of the coal’s combustible mass may be reduced. More intense dewatering of the flotational concentrate may eliminate the need for thermal drying, a resource-draining process with considerable environmental impact. Another goal is the extraction of coal particles from stored slimes and tailings beneficiation and their inclusion in commercial concentrate. Beneficiation tailings would ideally be stored in discarded mineshafts. At the same time, it is expedient to utilize the inorganic component of the tailings in the production of construction materials, as well as rare, trace, and noble metals.     

粉煤灰的形成和特性及其应用前景

阐明了粉煤灰各类颗粒组分的形成机理及其显微结构、化学与物相组成、微量元素分布等特征,并对其利用潜力及环境危害进行了系统评价,展望了粉煤灰资源化利用的发展前景．     

煤岩显微组分分离富集物热化学反应特性

依据煤中不同类型有机质性质差异对其进行分离，进而分质利用是实现煤炭清洁高效利用的有效手段。论文利用重选法将一种低变质烟煤分质得到镜质组较原煤48.25%增加至76.02%的富镜样，惰质组较原煤43.96%增加至63.98%的富惰样，以及矿物质含量高于61.99%的富矿样。利用热重-质谱分析仪，考察了分离富集物的热解反应特性及气体逸出规律，及其燃烧和气化反应特性。结果表明，分离所得富镜样热解反应失重量及热解过程中逸出的小分子挥发分的量及组成与富惰样和富矿样均有明显差异，表明分质实现了煤中不同类型官能团的分离富集。而由分离所得富镜样、富惰样和原煤热解失重峰温基本一致则表明分质所得煤的主体官能团结构仍较为接近，但含量有明显差距。富镜、富惰与原煤的燃烧曲线整体趋势较为类似，燃烧活性差别不大。以气化反应峰值温度高低判断，富镜样气化反应活性最低，富惰样与原煤气化反应活性较为接近，富矿样气化反应活性最高。将原煤在对应热反应时的理论反应曲线与实验曲线进行对比，发现煤分质过程及煤中镜质组、惰质组和矿物质的分离与否对热解过程挥发分的逸出影响较小，但导致了其燃烧和气化反应活性有所降低。     

Studies of lagoon ash from Sarawak to assess the impact on the environment

Coal utilization, mainly in thermal power plants, has increased significantly from 4.2 to 13 million tonnes within 2000 to 2005, which resulted in the production of approximately 2 million tonnes of coal ash in Malaysia. Of this only a small percentage is used as a cement ingredient, in concrete industry, as a fill material, etc. and with the rest of the amount being disposed in ash ponds or lagoons. If the lagoons are not properly designed with a landfill liner or if there is spillage from the ash pond, the toxic heavy metal present in coal ash can result in the contamination of the subsurface soil and the ground water. The concentration of heavy metals or trace elements in coal residues depends on the composition of a particular parent coal and the bulk utilization of lagoon ash for various purposes requires a complete characterization of the ash. Hence, this paper analyzes the coal ash for its trace element content and characterizes mainly physical, chemical, mineralogical, morphological and thermal properties of the lagoon ash from a local coal based thermal power plant from Sarawak, Malaysia. The results also indicated that, the concentration of some trace elements is quite high from the environmental perspective in this particular lagoon ash.     

Hydrogen/deuterium transfer in coal liquefaction

Reactions have been made with deuterium-labelled solvent (d₄- and d₁₂-tetralin) and both Powhatan bituminous (Pittsburgh Seam) coal and model compounds under coal liquefaction conditions to study hydrogen transfer mechanisms. Powhatan coal liquefies quickly. Hydrogen transfer from the solvent to the reaction products continues throughout the heating period (up to 60 min). Significant hydrogen/deuterium exchange occurs and this strongly affects the distribution of deuterium in the products and also affects the extent of conversion as measured by the amount of THF-insoluble material. Increased deuteration of the solvent leads to decreased conversion. This exchange is enhanced by heavy aromatic species and by the presence of mineral matter and unconverted coal solids.     

大同侏罗纪10-11#煤中微量元素分布赋存特征

讨论了大同 1 0 - 1 1 #煤中 36种微量元素的含量分布 ,通过浮沉试验及煤岩组分定量统计 ,运用 Salori方法 ,计算了 1 4种有害微量元素在大同煤不同煤岩组分中的分布 ,进而分析了其赋存状态及其在煤炭洗选过程中的脱除潜力 .结果表明 ,大同煤中大部分微量元素含量较低 ,但As,Hg,Cr,Sb等元素的有机组分含量偏高 ;大部分微量元素主要分布于矿物中 ,而 B,Be,Cd,Co,Ni和 Sb等有害元素含量偏高 ;同时 ,相对而言 ,As,B,Ba,Cd,Co,Cr,Mn和 Ni等元素在镜质组中含量较高 ,而 Be,Li,Pb和 Sb等元素在丝质组中含量较高 .浮沉试验表明 ,微量元素在煤炭洗选过程中的迁移、脱除行为主要受其赋存特征影响     

The amenability of some Witbank bituminous ultra fine coals to binderless briquetting

Five ultra fine bituminous coals from the Witbank coalfield were studied. Selected chemical and physical properties, coal petrographic characteristics and mineralogical compositions of the coals were measured. The coals were compacted, using a briquetting press, at various feed moisture contents. The formed briquettes were then tested for compressive strength and water resistance and the values correlated with the coal characteristics and the briquetting conditions. The coals were found to be amenable to conventional binderless briquetting. The bonding in the briquettes was found to be due mainly due to the impurities in the coals, particularly kaolinite. This may add a new perspective to the fundamentals of the binderless briquetting of bituminous coals.     

The occurrence of trace elements in coal

The standard comparison of relationships of trace element concentrations in coal is based on a comparison of mean values of elemental concentrations. This method is extended by including some functions of covariances among trace element concentrations. In the proposed method, the comparison is based on: the pattern of the mass spectrum of mean values of concentrations; the spectrum of the covariance matrix; the eigenvectors of the covariance matrix; and the order of eigenvectors. The method has been applied to the coal of the Istrian coal basin and the same genesis of the elements calcium, sulphur, iron, titanium and vanadium throughout the considered coal seam has been established.     

The effect of froth stability on the beneficiation of low-rank coal by flotation

The nature and type of minerals associated with a low-rank (NCB 902) coal were determined by scanning electron microscopy and dispersive X-ray analysis.

The mineralogical examination showed the presence of fluorapatite and other minerals which would be troublesome on combustion. It also showed that the minerals would, to a large extent, be liberated by fine grinding.

The effect of kerosine and a branched chain aliphatic alcohol (2-ethyl-hexan-1-ol) on the beneficiation of finely ground samples of this coal under conditions of agglomeration flotation were studied.

A relationship between beneficiation and froth stability was noted and results are reported for the beneficiation of individual wet-screened fractions for selected runs.

A mechanism for beneficiation is proposed which is consistent with the experimental observations.     

陕北低阶烟煤显微组分结构特征及分子结构模型

为了更好地利用我国丰富的低阶煤资源,以变质程度较低的陕北低阶烟煤镜质组、惰质组富集物作为研究对象,采用常规的煤质分析、傅立叶变换红外光谱、高分辨固体13C核磁共振、X射线衍射等分析表征手段,对样品结构进行全面分析,得到了陕北低阶烟煤显微组分分子结构特征及结构参数,建立了镜质组和惰质组的部分分子结构模型。结果表明,陕北低阶烟煤镜质组和惰质组氧含量均较高,硫含量很低,所选镜质组的芳碳率为0.634,平均缩合环数约为2.98个;惰质组的芳碳率为0.734,平均缩合环数约为3.15个;相对于镜质组,惰质组的缩合程度更高,芳核尺寸更大,排列也更加规则有序。今后低阶烟煤加工转化工艺的研究应从分子层面揭示其不同显微组分结构特征的差异性,为低阶烟煤清洁高效利用新工艺的开发奠定基础。     

神东矿区侏罗纪2-2#煤煤质特征研究

根据煤岩学、煤化学与扫描电镜分析结果 ,研究了神东矿区 2 -2 # 煤的煤岩特征及主要性质 ,探讨了神东煤变质程度、显微组成 (包括矿物组成 )对其性质的影响 ,认为高含量的丝质组影响了其液化性能 ,而煤中相对含量较高的次生方解石影响了其煤灰熔融性 ,动力配煤和煤岩分选技术是进一步改善神东煤利用性能的两种有用技术     

基于显微组分化学键特征的宁夏庆华煤热解特性及动力学分析

通过X射线光电子能谱和傅里叶红外光谱表征宁夏宁东庆华煤不同显微组分的官能团种类、表面结构元素价态分布及化学键赋存特征。采用热重-质谱联用考察庆华煤镜质组和惰质组在不同热解温度下的失重行为和关键气体组分变化。进一步基于Coats-Redfern模型从化学键断裂特征和反应动力学角度探讨煤镜质组和惰质组的热解行为差异。结果表明,庆华煤显微组分的热解失重峰与相应化学键断裂信息能够很好地吻合。不同显微组分的热重曲线变化趋同,但相同热解温度下镜质组的失重率始终高于惰质组。快速热解阶段镜质组较惰质组表现出更大的失重率和最大失重速率。其主要原因在于镜质组的脂肪族官能团相对含量更高,快速热解阶段会发生更多的C_al—C_al断裂。不同热解温度下庆华煤显微组分三个主要热解阶段的活化能和频率因子大小次序为：快速热解阶段>快速缩合阶段>缓慢热解阶段。在快速热解阶段,镜质组和惰质组的平均活化能均约为75 kJ/mol,但镜质组的频率因子更高。