Bituminous coals minerals

Crable JV, Keenan RG, Wolowicz FR, et al. 1967. The mineral content of bituminous coal miners lungs. Am Ind Hyg Assoc J 28 8-12. 

Estimated Amounts of Silicate Species in Bituminous Coal Mineral Matter... 

Silicate Minerals in Coal. The silicate minerals, kaolinite and potassium aluminosilicate species together with quartz constitute the bulk of mineral matter in most coals. The approximate amounts of different silicate species of the bituminous coal mineral matter can be estimated from ash analysis. 

Lee, T., C. Anderson, and J. Kraus. 1993. Acute traumatic injuries in underground bituminous coal miners. American Journal of Industrial Medicine 23(3) 407-415. 

Coal Hquefaction iavolves raising the atomic hydrogen-to-carbon ratio from approximately 0.8/1.0 for a typical bituminous coal, to 2/1 for Hquid transportation fuels or 4/1 for methane (4). In this process, molecular weight reduction and removal of mineral matter and heteroatoms such as sulfur, oxygen, and nitrogen may need to be effected. 

In addition to carbon, all coals contains many noncombustible mineral impurities. The residue from these minerals after coal has been burned is called ash. Average ash content of the entire thickness of a coal seam typically ranges from 2 to 3 percent, even for very pure bituminous coals, and 10 percent or... 

In contrast to sporinite, resinite from a Utah high volatile A bituminous coal reacted rapidly and more completely than the corresponding vitrinite. Table V shows the conversion levels achieved for a concentrate containing 75% resinite (mineral-free basis) reacted under relatively mild conditions. The results are curious. A fairly respectable level of conversion is achieved in 15 minutes at 350°C (under which conditions the associated vitrinite would presumably show little conversion), but longer times and a temperature of 370° have little further effect even raising the temperature to 400° does not show a major increase in conversion. 

Table I shows that most of the South African bituminous coal contain high quantities of mineral matter which is often intimately associated with the organic matter of the coal. About half of the resources yield between 30 and 35 per cent ash.

A notable feature of the Western Canadian coals is their low sulphur content (usually <0.5%) which tends, however, to be partly offset by higher mineral matter contents than are associated with the Eastern coals. As well, bituminous coals in the mountain belts are typically deficient in vitrinite, which often represents less than 50% of the coal "substance" and only occasionally reaches 70-75%, but this is compensated by the fact that their micrinites and semifusinites tend to be "reactive" constituents when the coals are carbonized. Notwithstanding their low fluidity (rarely >1000 dd/min), Western mvb coals therefore make excellent metallurgical cokes when carbonized in suitably proportioned blends. 

One of the more important considerations in determining the end use of synthetic graphite is its contamination with metallic components Metals such as iron, vanadium, and especially in nuclear applications, boron are deleterious to the performance of graphite Table 3 presented the extraction yields of NMP-soluble material for three bituminous coals. For these coals, mineral matter and insoluble coal residue were separated from the extract by simple filtration through 1-2 pm filter paper fable 13 lists the high-temperature ash content in the dry coal, and in their corresponding NMP-insoluble and NMP-soluble products. The reduced ash content of the extract is typically between 0.1 to 0.3 wt% using traditional filtration techniques for the small-scaled extraction experiments... 

Two bituminous coals of moderate ash content were chosen for this paper to illustrate this method of determining coal-mineral association. The first sample was an Upper Freeport coal with 1.3% moisture, 9.88% ash, and 1.56% total sulfur. The second sample was an Indiana No. 3 coal having 10.5% moisture, 7.35% ash, and 4.26% total sulfur. Both coals had been precleaned at a coarse particle size, ground to minus 325 mesh (44 ym), and then separate samples were cleaned by float-sink and by froth flotation techniques, as described elsewhere [5]. Analyses of the feed coals are included in Table I. 

Much of the quartz in the fly ash originates from the coal as silt- and sand-sized particles, and it remains in the ash because it survives thermal transformation during the combustion process (Helmuth 1987). Small amounts of volatilized Si may also oxidize to form very fine crystals of quartz within the fly ash glass (Diamond 1984 Hubbard et al. 1984). Although bituminous coal ash may contain more than 50 wt% analytical Si02, only 5-10 wt% of it is present in the form of quartz (McCarthy et al. 1990). Some Si is present in the mineral mullite, but the majority of it is in the amorphous glass phase. 

The molar ratio of Al Si in clay minerals is variable, kaolinite (0.85), mica-illite (0.61), and smectitic clays (0.35) (McCarthy et al. 1987). Bituminous coal tends to have higher concentrations of kaolinite, while lignite and subbituminous coals contain mica-illite or smectitic clays. McCarthy et al. (1987) predicted that the higher the Al Si ratio of the clay minerals the... 

Coke (Coke in Fr or ftal Cok or coque in Span Koks in Ger or Rus). Coke is the solid residue which remains when certain types of bituminous coals are heated in retorts or special ovens (such as "behive type) to high temps out of contact with air until practically all of the volatile constituents are removed. Coke consists principally of C and of small amts of S, H, N, O mineral matter present in the original coal. It is a hard, cellular form, porous substance, ranging in color from silvery gray to dull black. Its true density 1.85 -1.90, is higher than that of coal, but its bulk d is lower because of porosity... 

Bituminous coal is a dense coal, usually black, sometimes dark brown, often with well-defined bands of bright and dull material, used primarily as fuel in steam-electric power generation, with substantial quantities also used for heat and power applications in manufacturing and to make coke. The moisture content of bituminous coal is usually less than 20% by weight. The heat content of bituminous coal ranges from 21 to 30 million Btu/ton on a moist, mineral-matter-free basis. 

The total moisture in coal is the determination of the moisture (in all forms except water of crystallization of the mineral matter) that resides within the coal matrix. In fact, moisture (or water) is the most elusive constituent of coal to be measured in the laboratory. The moisture in coal ranges from 2 to 15% by weight in bituminous coal to nearly 45% by weight in lignite. 

Inherent or equilibrium moisture is used for calculating moist, mineral-matter-free calorific values for the rank classification of high-volatile bituminous coals. It is also used for estimating free or surface moisture, since total moisture is equal to the sum of the inherent moisture and the free moisture and is considered the inherent moisture of the coal as it occurs in the unexposed seam, where the relative humidity is probably near 100%. However, due to physical limitations, equilibrium moisture determinations are made at 96 to 97% relative humidity and used as inherent moisture values. 

Three methods for determining mineral carbon dioxide in coal were investigated using bituminous coal. The titrimetric method is claimed to be superior to either of the then-used British standard gravimetric or manometric methods (BS 1016). The procedure involves the decomposition of carbonate minerals with hydrochloric acid and absorption of the evolved carbon dioxide in a mixture of benzylamine, ethanol, and dioxan. This mixture forms a stable salt of benzylcar-bamic acid, which is then titrated with sodium methoxide. The method was said to be suitable for all concentrations of carbon dioxide. It is especially accurate for low concentrations, and it is much more rapid than other methods tested. 

---