Correlation between the content of volatile matter and mineral matter in hard coals

If coal is heated to 900 °C, in the absence of air the organic coal substance and the associated mineral matter are decomposed. The analytically determined volatile-matter yield includes the volatile decomposition products of both the coal substance and the minerals. The correlation between mineral matter and ash and the volatile-matter yield is derived, and its accuracy shown by evaluation of test results. Methods are proposed for calculating a value for the volatile matter dmmf for coals of a particular mine. Various formulae for calculating the volatile matter of coals to dmmf basis are critically considered. Finally, a generally applicable equation for calculating dmmf volatile matter is derived which can be used for classification.     

Influence of volatile matter and deposited carbon on coke yield from coals

The relations between coke yields and the volatile matter content of 30 individual and 30 blended coals were investigated. Coke yields and deposited carbon related to volatile matter content can be expressed in the following equations: CY (%) = 97.89?0.86 VMch+VMc; and DC (%)= ?2.24+0.16 VMch; where: CY=real coke yield; VMch = volatile matter content of charging coal; VMc=volatile matter content of coke, and in the case of <2%; DC = deposited carbon. The test results show excellent correlation with practice.     

油页岩中矿物质对挥发分不凝气释放过程的影响

对桦甸油页岩（OS-R）采用HCl/HF/HNO3处理,分别得到去碳酸盐样品（OS-C）、去碳酸盐及硅酸盐样品（OS-F）以及有机质样品（OS-N）,用XRD鉴别其矿物组成,然后通过TG-FTIR-MS研究有机质脱挥发分机理及不同矿物质对挥发分不凝气释放过程的影响。结果表明：黄铁矿的存在使挥发分不凝气体释放的初始温度明显降低,反应更易进行,且使生成的不凝气产量更高,尤其是对不凝气中H2O生成促进作用更显著;硅铝酸盐的存在使不凝气体产量明显减少,提高了不凝气释放的初始温度,减少了不凝气释放的过程时间。然而碳酸盐的存在能增加不凝气产量,使CO2脱出的初始温度更低。     

Effect of inorganic matter removal from coals and chars on their surface areas

Removal of inorganic matter from coals by acid treatment brings about random and, in some cases, significant changes in surface areas measured by adsorption of N₂ and CO₂. Changes in surface areas of chars are generally more pronounced than those found in coals. However, the surface area changes in chars are markedly dependent upon whether the acid treatment is given to the coal precursor prior to charring or to the char produced from the raw coal. Changes in surface areas of raw coals and chars produced therefrom have been attributed to: (i) ‘physical’ removal of inorganic matter from the aperture-cavity system, (ii) bonding of HCl to basic nitrogen present in pyridine-like structures, and (iii) adsorption of acid. Results suggest that the removal of inorganic matter from coals prior to charring affects the carbonization process and, hence, the surface area of the resultant char.     

碳酸盐抑制剂CY的试验研究

碳酸盐矿物的有效抑制剂CY用于王集磷矿选矿,获得了与用C_(711)时的精矿品位相近,收率提高2％的指标。CY与CCLS捕收剂配合使用浮选原苏联卡拉套磷块岩矿石,回收率有一定提高。该药剂来源广,易加工,价格低,便于包装和运输,使用方便。经过计算,有较好的经济效益。     

Mineral matter identification in some Pakistani coals

Extractions of some of the inorganic elements from Pakistani coal samples were made with ammonium acetate, HCl, HNO₃, and acid mixture. The various extracts and the residues were analyzed for the inorganic elements like Cu, Zn, Mn, Fe, Ca, Mg, K and Na. Even though ammonium acetate and acids extracted a considerable amount of inorganic elements, complete demineralization was not achieved. These elements are present both in the form of ion exchangeable cations (extractable with ammonium acetate) and as part of discrete-mineral particles (extractable with acids).     

Behaviour of inorganic matter during heating of Bulgarian coals: 2. Subbituminous and bituminous coals

Bulgarian subbituminous (Pernik, Bobov Dol) and bituminous (Balkan) coals were gradually heated under air from 100 °C to their fluid ash-fusion temperatures (1400–1600 °C) via 100 °C intervals and the behaviour of their inorganic matter (IM) was studied. The original minerals and newly formed inorganic phases in the oxidation and combustion products (OCPs) of these coals were identified and the behaviour of 33 minerals and phases was described. The coals studied reveal high detrital abundance and low authigenic mineralization with sulphide–sulphate, carbonate or mixed sulphide–sulphate and carbonate tendencies. The IM of coals is composed mainly of quartz, kaolinite, illite + muscovite, feldspars, pyrite, and calcite, while the other minerals identified have subordinate occurrence. The IM of OCPs includes various pre-existing minerals and newly formed phases. The latter phases are glass, quartz–cristobalite–tridymite, mullite, amorphous clay material, hematite–magnetite, anhydrite, and others originating from the heating of these coals or storage of their OCPs. The physico-chemical processes and temperatures that result in the formation of new phases in OCPs are described. The relationships between the ash-fusion behaviour and chemical and mineral composition of the coals are also discussed. A systematization of the physico-chemical transformations and some comparative characterizations, as well as prediction of certain technological and environmental problems related to the behaviour of IM during heating of Bulgarian lignites, subbituminous and bituminous coals are also described and summarized.     

Occurrence,abundance and origin of minerals in coals and coal ashes

The mineralogy of coal and coal ash samples from a wide variety of deposits worldwide has been studied by X-ray diffractometry, light microscopy, SEM, TEM, and DTA-TGA methods. The common major minerals identified in the crystalline matter of coals are quartz, kaolinite, illite, calcite, pyrite, plagioclase, K-feldspar and gypsum, and occasionally dolomite, ankerite, siderite, Fe oxyhydroxides and sulphates. A number of minor and especially accessory minerals are also present. The modes of occurrence and some genetic peculiarities of the minerals found are described and summarized. Minerals and phases of probable detrital origin include mainly silicates, volcanic glass, oxyhydroxides and phosphates. Authigenic minerals of syngenetic origin may be sulphides, clay minerals, carbonates and rarely sulphates and phosphates. Epigenetic minerals, formed by the infiltration of low-temperature hydrothermal solutions, may include sulphides, carbonates, sulphates, clay minerals, quartz, chlorides, and probably alkaline-earth hydroxides and zeolites. The alteration products of detrital and authigenic minerals may be Fe and Al oxyhydroxides, sulphates, kaolinite, illite, chlorite, muscovite, zeolites and calcite. The behaviour of these minerals and phases during low- and high-temperature ashing is also discussed.     

Effect of blending on liquefaction of coals

After solvent extraction of Taiheiyo, Miike and Balmer coals using wash oil under nitrogen atmosphere at 370 °C for 30 min, the extraction yield is always within the additivity law. Further studies used Yallourn, Soyakoishi, Taiheiyo, Horonai, Miike, Shin Yubari, Balmer coals and their blends which were hydrogenated in tetralin, wash oil or creosote oil, with or without catalyst, at 400–450 °C under 10 or 3 MPa of initial hydrogen pressure. When hydrogen is available, the additivity law exists for blended coals, but when the hydrogen supply is deficient, the experimental conversion of blended coals is always lower than calculated conversions. This may be due to the faster consumption of the hydrogen by more reactive coals and thus the less reactive coals were unable to react with hydrogen.     

Effect of the mineral components of brown coals on the properties of organic matter in the interaction with solvents

The cation-exchange forms of a considerable portion of metals that occur in brown coals from various deposits were identified. Based on swelling data, the interaction of the organic matter of coals with solvents was studied depending on the concentrations of mineral components. It was found that natural brown coals exhibit a densely crosslinked supramolecular structure with the predominance of molecular-size pores. In the course of decationization, the organic matter underwent partial depolymerization; the rate of diffusion and the accessibility of fragments to solvents with relatively bulky molecules dramatically increased.     

Effect of alkali metal carbonate additives on the rate of oxidation of the organic matter of anthracite

The results of thermogravimetric experiments showed that the temperature of a maximum weight loss rate of anthracite with 5% K₂CO₃ on combustion was lower by ～90°C than that for a sample with no additive. The effect of the additive was explained by the thermionic emission of electrons from potassium metal, which was formed in a redox reaction: a portion of electrons bombarded the anthracite surface to secondary electron emission—the emission of electrons by the organic matter of anthracite and the acceleration of its degradation and combustion.     

单种煤煤岩参数对焦炭质量的影响规律

通过研究各单种煤的镜质组平均最大反射率R0max及分析单种煤40kg小焦炉试验所得焦炭气孔结构,得到焦炭气孔结构参数的回归方程及其影响规律,可用于指导配煤炼焦。     

分析水对无烟煤挥发分测定产生的影响

根据GB／T212-2008《煤的工业分析方法》中的规定,在测定挥发分时,通过实验对比,无烟煤中水分随着煤的变质程度加深而呈规律性变化。从泥炭、褐煤、烟煤到年轻无烟煤水分逐渐减少,从年轻无烟煤到老年无烟煤的水分又逐渐增加。由于煤中水分过高和煤的氧化增重,导致挥发分测定值产生负值,影响挥发分的测定结果。     

Mineral matter and elemental concentrations in selected western canadian coals

Major and trace element analyses were performed on coals from various locations in western Canada, and on low-temperature (150 °C) and high-temperature (1000 °C) coal ash produced from these coals. Elemental analyses were carried out by X-ray fluorescence spectroscopy and intense neutron activation analyses. Based on their trace elements, the coals in this study fall into two groups: 1. low-rank coals (lignite-subbituminous) of late Cretaceous and Tertiary age; and 2. high-rank coal (bituminous-semianthracite) of Jurassic-Cretaceous age. The elemental analyses of the coals and coal ash indicate that the local conditions had considerable influence on the concentrations of certain trace elements.Antimony and selenium in coals are the only elements which are enriched relative to concentrations in the earth's crust; arsenic is concentrated in lignite to subbituminous coal, but is depleted in bituminous-anthracite coals; as expected the ash of these coals showed many more instances of enrichment.     

Modification of the organic matter of brown coals with nitrous oxide

The results of the treatment of brown coals from the Kansk-Achinsk Basin in an atmosphere of nitrous oxide are given. It was established that the main products of nitrous oxide interaction with the organic matter of brown coal are soluble low-molecular-weight products (ketones and aromatic acids) and oxodiazoline structures in a coal matrix. The thermal-oxidative degradation of terminal oxygen-containing groups, which accompanied this process, facilitated the formation of strong crosslinks and the strengthening of a supramolecular structure.     

挥发性物质降到最低的环保型滑板

通过选择最佳的原材料和烧成温度研发出长寿命、环保型滑板,使其在使用过程中挥发出的有毒物质降至最低.     

Removal of mineral matter from bituminous coals by aqueous chemical leaching

Most of the ash-forming minerals in bituminous coals are insoluble in water or acids, but a high proportion (more than 90%) can be extracted with aqueous sodium hydroxide solutions at 200–300°C under pressure. The major minerals extracted —silica and kaolin — are converted into sodium alumino-silicates (sodalites) which form a separate insoluble phase in contact with water or alkali, but which are readily soluble in aqueous acids. Minor mineral components are also partly removed. The spent leachants can be regenerated for recycling; the extracted minerals form a solid by-product. The chemical extraction steps may be coordinated with conventional coal-cleaning procedures which use physical separation techniques. Experiments with three Australian coals from the Liddell and Lithgow seams (NSW) and the Theodore seam (Queensland), and a vitrinite concentrate from Liddell, gave beneficiated products with ash yields of 0.25–0.75%. Demineralized coal may have applications as a low-ash fuel or carbonaceous raw material.