Hard coal classification

Ha.rd Coa.1, The amount of coal in international commerce since ca 1945 necessitated an international system of coal classification and in 1956 the Coal Committee of the European Economic Community agreed on a system designated the International Classification of Hard Coal by Type (3). Volatile matter and gross calorific value on a moist, ash-free basis are among the parameters considered. Table 4 shows the various classes of the international system and gives the corresponding national names used for these coals. 

International Classification of Hard Coals by Type, United Nations PubHcation No. 1956 II, E.4 E/ECE/247 E/ECE/Coal/100,1956. 

Hard and soft acid and base (HSAB) principle, 16 780 Hard blacks, 21 775 Hard-burned quicklime, 15 28 Hard coals, 6 703 classification, 6 712 Hard copper alloys, 7 723t relief annealed, 7 723t Hard copy systems, 9 513-514 Hard core repulsion, 23 93 Hard-elastic olefin fibers, 11 242 Hardenability, of steel, 23 283—284 Hardened MF resins, analysis of,... 

Classilicalion of coals in Europe and other parts of the world differs somewhat from the American system. European classifications include ( ) the International Classification of Hard Coals by Type and (2) the International Classification of Brown Coals. These systems were developed by a Classification Working Party established in 1949 by the Coal Committee of die Economic Commission for Europe. The term "hard coal" is defined as a coal with a clorific value of more than 10.260 Blu per pound (5705 Calories/kg) on the moist, ash-free basis. The term "brown coal" refers to a coal containing less than 10.260 Blu per pound (5705 Calories/kg). In European terminology, ihe term "type" is equivalent to rank in American coal classification terminology and the term class approximates ihe ASTM rank. Space docs not permit a full comparison or the various systems. Reference to various ASTM publications is suggested. 

TABLE 1.9 International Classification of Hard Coal Using Calorific Value... 

The ASA-ASTM system established four classes or ranks of coal anthracite, bituminous, sub-bituminous, and lignite, based on fixed-carbon content and heating value measured in British thermal units per pound (BTU lb ). Anthracite, a hard black coal that burns with little flame and smoke, has the highest fixed-carbon content, 86-98% and a heating value of (9.2-10.7) 10 J kg (Speight 2006, see Tables 2.51 and 2.55). This classification was already used 100 years ago (Robertson 1919) and Seyler (1900) used the C/H ratio for the coal classification, from lignite ( 10) to anthracite (>26). Based on raw coal, the chemical composition varies widely (in %) ... 

This classification is not perfect, unlike the other classifications for example the calcareous fly ash is not distinguished regarding the differences of anhydrite content (SO3). As it results from the analysis presented in Table 7.3, the fly ash from Belchatow could be even used in the production of CEM n/B-V cement, after CaO transformation into the calcium hydroxide, while the fly ash from Konin only in a limited range, because of the SO3 content. The transition of CaO to Ca(OH)2 is necessary, because in the PN-EN 197-1 standard the reactive CaO content in fly ash is restricted to 10%. The aforementioned classification rates Polish fly ash from the hard coal combustion to the siliceous ash and that from the brown coal combustion in Turoszow coal-field— to the aluminous ones respectively. 

Brown coals, like the hard coals, are also defined in terms of their calorific value (see the previous text) and were also recognized as potential fuels. The International System for the classification of brown coals is based on two inherent characteristics which indicate the value of brown coals as fuels (1) the total moisture (ash-free basis) and (2) the yield of tar (daf basis). Thus, the six classes of brown coal based on the ash-free, equilibrium moisture content are divided into groups according to the yield of tar on a dry, ash-free basis (Table 2.14). This system indicates... 

In the ASTM system for the classification of coals by rank and in the International System for the classification of hard coals (Chapter 2), high-volatile coals are classified according to their calorific value on a moist basis. In this instance, the calorific value is quoted for the coal containing its natural bed moisture. 

International Organization for Standardization, Central Secretariat, 1 rue de Varembe, BP 56, CH- 1211 Geneve 20 Cellular materials definitions of terms and classification Hard coal Size analysis... 

Other Classifications of Coal by Rank. There are other classifications of coal by rank (or type) which are currently in limited use on the European continent. These are the International Classification of Hard Coals by Type, and the International Classification of Brown Coals. Other criteria for the classification of coal by rank have been proposed by various authorities. 

The types of coal, in increasing order of alteration, are lignite (brown coal), subbituminous, bituminous, and anthracite. It is believed that coal starts off as a material that is closely akin to peat, which is metamorphosed (due to thermal and pressure effects) to lignite. With the further passing of time, lignite increases in maturity to subbituminous coal. As this process of burial and alteration continues, more chemical and physical changes occur and the coal is classified as bituminous. At this point, the coal is dark and hard. Anthracite is the last of the classifications, and this terminology is used when the coal has reached ultimate maturation. 

Laser-microprobc mass spectrometry has an unusually high sensitivity (down to 10 g), is applicable to both inorganic and organic (including biological) samples, has a spatial resolution of about I pm, and produces data at a rapid rate. Some typical applications of laser-microprobe mass spectrometry include determination of Na/K concentration ratios in frog nerve fiber, determination of the calcium distribution in retinas, classification of asbestos and coal mine dusts, determination of fluorine distributions in dental hard tissue, analysis of amino acids, and study of polymer surfaces. ... 

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