Coal balls are limestone concretions encountered in coal seams which represent peat (sensu Cohen Spackman I 977, I 980) that was permineralized by calcium and magnesium carbonates, before appreciable compaction or alteration took place, giving an exceptionally preserved fossil plant assemblage (Stopes Watson I908; Mamay Yochelson I962; Sch...
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[1] Coal balls are in coal seams across North America and Eurasia. North American coal balls are in more places than in Europe. The oldest coal balls were found in Germany and former Czechoslovakia . In 1962, Sergius Mamay and Ellis Yochelson found signs of marine animal remains in North American coal balls. [2]
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fossil See all related content → coal ball, a lump of petrified plant matter, frequently spheroid, found in coal seams of the Upper Carboniferous Period (from 325,000,000 to 280,000,000 years ago). Coal balls are important sources of fossil information relating to the forests preceding the Coal Age.
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1. Introduction. At present, coal is still the main raw material for power generation [1], [2], [3].In 2015, 750 million tons of coal were used to generate electricity [4] 1 ton of coal combustion produced ton of CO 2 and ton of fly ash [5].Coalfired power plants contributed to more than 30% of the world's carbon emissions [6].At the same time, the longterm accumulation of fly ash ...
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[6] There are two theories the autochthonous ( in situ) theory and the allochthonous (drift) theory that attempt to explain the formation of coal balls, although the subject is mostly speculation. [7]
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Typically, ball/tube mills have dominated cement milling; however, some application of vertical spindle (roller) mills has occurred in recent years. ... The chemical composition of coal ash varies considerably from deposit to deposit as well as within the same deposit. Ash contents of bituminous coals usually lie in the range of 5% to 20% but ...
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Study on separation of lowrank coal macerals in enhanced gravity field. This paper presents an original method for the micronization of coal particles in a hydrojet mill, which allows effective ...
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The geological setting of Holocene coal balls of the Hitchcox limey peat soil, from Eight Mile Swamp of South Australia (Figs. 15) lends some support for all previous theories of coal ball formation: (1) intrusion of marine influenced water and carbonate cements into coastal peat swamps (Stopes and Watson, 1909; Evans and Amos, 1961; DeMaris et...
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To begin with, the chemical composition of coal is analyzed by proximate and ultimate analyses (ASTM, 1993 ). Proximate analysis determines by using set procedures regarding moisture, volatile matter, fixed carbon, and ash content ( Figure ). Proximate analysis is reported by percent on asreceived, moisturefree, and moist and ashfree ...
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Coal balls (exceptionally preserved calcareous permineralized peat), widely described from tropical Carboniferous Euramerian coal seams, have yielded diverse data on the biology, ontogeny and ecology of swamp plants and ecosystems. Probably over 75% of ...
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the depth of the coal beds, the composition of the rocks surrounding the coal beds, the amount of time the rock and water react, and the origin of the water entering the coal beds. Traceelement concentrations in CBM water are commonly low (<1 mg/L) as are volatile organic compounds (Gas Research Institute, 1995; Rice, 2000). In
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To achieve the required size, large pieces of coal were ground in a ball mill. The mill included a ceramic drum (porcelain) with a volume of 3 L, grinding balls made of the same material. ... In this regard, with this composition of ash, combustion of brown coal and its mixtures is possible without the introduction of an additional sulfur ...
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Pore structure of coal fly ash. The results of the total intrusion volume, average pore diameter and specific surface area of fly ash samples, shown in Fig. 2, presented the great changes of those parameters with the ballmill total intrusion volume and average pore diameter decreased sharply as the milling time was increased and exhibited small peak when the ball mill time is around ...
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Highlights The earliest cement in coal balls from the Kalo Fm. is marine, highMg calcite. Early diagenetic pyrite and highMg calcite indicate a marine origin for coal balls. Coal balls with meteoric and marine calcite formed in hydrologically dynamic mires. Burial diagenesis has altered most coalball calcite to lowMg, ferroan calcite. Diagenetically altered coalball cements may not retain ...
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A ball mill consists of a hollow cylindrical shell rotating about its axis. The axis of the shell may be either horizontal or at a small angle to the horizontal. It is partially filled with balls. The grinding media are the balls, which may be made of steel ( chrome steel ), stainless steel, ceramic, or rubber.
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The elemental composition of organic matter in coal continues to change during latestage coalification (Figure 7). In H/C versus O/C van Krevelen plots, bituminous coals and anthracites show a somewhat smaller drop in O/C and a sharper drop in H/C values compared to brown coals and lignites ( Tissot and Welte, 1984 ).
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A coal ball is a type of concretion, varying in shape from an imperfect sphere to a flatlying, irregular slab. ... This reveals information about the crystallographic structure, chemical composition, and physical properties of the examined material. The scattered intensity of the Xray pattern is observed and analysed, with the measurements ...
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Throughout the world, coal is responsible for generating approximately 38% of power. Coal ash, a waste product, generated from the combustion of coal, consists of fly ash, bottom ash, boiler slag, and flue gas desulfurization material. Fly ash, which is the main component of coal ash, is composed of spherical particulate matter with diameters that range from μm to >100 μm. Fly ash is ...
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Pulverized coal injection (PCI) is a process which involves injecting large volumes of fine coal particles into the raceway of the blast furnace (BF). Pulverized coal is an important auxiliary fuel used in the BF ironmaking. PCI provides auxiliary fuel for partial coke replacement and has proven both economically and environmentally favourable.
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Lignite coal, or brown coal, is a very soft coal that contains up to 70% water by weight. Emits more pollution than other coals ... [<% of a rock's composition] of zinc, copper, boron, lead, arsenic, cadmium, chromium, selenium) CCTR Indiana Center for Coal Technology Research 8
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Geology Coal is composed of macerals, minerals and water. [18] Fossils and amber may be found [where?][by whom?] in coal. Formation Example chemical structure of coal The conversion of dead vegetation into coal is called coalification. At various times in the geologic past, the Earth had dense forests [19] in lowlying wetland areas.
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