Limestone bedded

Pulverized coal combustion systems are most commonly used in power plants. In pulverized coal combustion, temperatures typically reach around 1480 °C at atmospheric pressure. In the past couple of decades, fluidized bed combustion (FBC) technologies have been commercialized. These combustors often use limestone bed materials to capture sulfur gases. They operate at about 880 °C and usually at atmospheric pressure (Smoot and Smith, 1985), 38. 

The distribution of the emitted PAH between the four traps, the cyclones, the condenser, the Teflon filter and the XAD-2 resin, with sand and limestone beds, is shown in Table 3. In spite that the 16 PAH listed by USEPA were comprised in this study, only Fluorene, Pyrene, Acenaphthene, Benzo(a)Anthracene and Coronene could be quantified. Three other PAH, Benzo(a)Pyrene, Chrysene and Anthracene, were detected but were emitted below quantification limits. The remaining studied PAH were not detected. 

Geodes hollow, globular bodies varying in size, 2 to >20 cm, characteristic of certain limestone beds but rarely in shales. 

Major faults of the Illinois Basin area are shown in Fig. 10. The southern portion of the basin is intensely faulted northeast-trending faults in southeast Illinois and northwest Kentucky are associated with the lllinois-Kentucky Huorspar district. A number of these faults in Mississippian limestone beds are mineralized with the ore minerals fluorite (CaF2), sphalerite, and galena, and with gangue minerals such as calcite and pyrite... 

Apart from recurrent thin dolomitic limestone beds in The Narrows sequence, carbonates are present in all deposits in only trace or accessory amounts. Siderite occurs in all deposits, and is persistent through the sequence at Byfield and Condor, except for the carbonaceous units where its incidence is variable. At Condor, a second, possibly calcian siderite, occurs but only with an identical distribution through the sequence to the buddingtonite. Other evaporites, gypsum, halite and jarosite occur only in trace amount in the deposits. 

The number of fossil meteorites discovered in ordinary limestone beds in Swedish quarries imply that the meteorite flux on Earth -480 Ma ago was lOOx higher than the contemporary flux. Chromite grains (highly resistent to weathering) from fossil L chondrites have CRE ages of 0.1-1.2 Ma. This implies that these L chondrites arrived on Earth within 100-200 ka after the major collisional breakup that produced contemporary L chondrite falls. 

One sample of purple shale of the Watts Needle Formation has a Rb-Sr model date of 720 Ma assuming an initial Sr/ Sr ratio of 0.715. Limestone beds in... 

In the type area near Mt. Mackellar the Mackellar Formation contains several white and nonfossiliferous limestone beds up to 30 cm thick which extend for several meters. Brown-weathering gray limestone beds also occur in the lower part of the formation in the Queen Elizabeth Range. Elsewhere, limestone beds are not common in the Mackellar Eormation. The strontium in the lenticular limestone beds is enriched in radiogenic Sr (Eaure and Barrett 1973) which indicates that they were deposited by aqueous solutions of non-marine origin. 

Lime manufacturing is one of the oldest processes known to man, having been carried out since prehistoric times. The remains of fossils, according to geologists, formed the limestone bed thousands of... 

As calcium carbonate generated by marine animals of various kinds, principally as shells or exoskeletons that are deposited on seabeds—this appears to be the method of formation of the very extensive oolitic limestone beds and... 

I stratigraphic zone of discontinuous crystalline limestone beds ... 

Although the carbonates are not very soluble in water, they are bases thus, they dissolve readily in acidic solutions. As mildly acidic groundwater seeps through limestone beds, insoluble CaCOs is converted to soluble Ca(HC03)2-... 

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