Mineral matter coals

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... 

Alkylation Studies. Several preliminary experiments were completed to compare the extent of alkylation obtained with our coal pretreatment method to that obtained with Sternberg and Liotta alkylation. Results for Wyodak coal are summarized in Table III. Clearly, our procedure provides a very mild alkylation treatment compared with the other two methods and does not appear to be sensitive to differences in alkyl chain length (methyl vs. propyl). The increase in THF solubiliw was also small this result again suggests only a small extent of alkylation and in addition, shows that only minimal ion exchange (for example Ca by H ) occurred in the coal mineral matter. The effect of each pretreatment method on low severity liquefaction reactivity is discussed in the next section. 

Taken together, these data suggest that both alkylation and the presence of chlorine ions contributed to the observed liquefaction reactivity enhancement. Although the data are preliminary, we believe that iron pwite and perhaps other species in the coal mineral matter may be chlorinated to form metal chlorides such as FeCU such species are known to be active coal conversion catalysts (1112). 

The evaluation of coal mineral matter by the ashing technique can be taken further insofar as attempts can then be made to determine the individual metal constituents of the ash. On the occasion when the mineral matter has been separated from the coal successfully, it is then possible to apply any one of several techniques (such as x-ray diffraction, x-ray fluorescence, scanning electron microscopy and electron probe microanalysis) not only to investigate the major metallic elements in coal but also to investigate directly the nature (and amount) of the trace elements in the coal (Jenkins and Walker, 1978 Prather et al., 1979 Raymond and Gooley, 1979 Russell and Rimmer, 1979 Jones et al., 1992). Generally, no single method yields a complete analysis of the mineral matter in coal and it is often necessary to employ a combination of methods. 

BOCKRATH and schroeder Coal Mineral Matter Catalysis... 

In such cases, the alkali enters the vapor phase by vaporization from coal minerals, dolomite (10) or limestone, as in sulfurscrubbing processes, or from air-ingested salt particles (e.g., in marine environments). Hardesty and Pohl ( ) have recently reviewed the major problem areas and data limitations relating to the properties of coal mineral matter and ash. 

It is hoped that this volume will serve as a further stimulus to workers in and outside of the field of coal mineral matter and ash chemistry. We all benefit from the work of others to extend our current knowledge and can help make coal not only an abundant fuel, but also a more convenient and desirable resource as well. 

Reactions and Transformations of Coal Mineral Matter at Elevated Temperatures... 

An approximate amount of potassium alumino-silicates in coal mineral matter can be obtained from the potassium oxide (K2O) content of ash. The amount of non-silicate potassium species is small in most coals and the silicate minerals contain on average 11 per cent K2O by weight (O. Thus the potassium alumino-silicate content of coal mineral matter (K l-SIl) 7 weight per cent is ... 

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. 

Hazard, H. R. "Influence of Coal Mineral Matter on Slagging of Utility Boilers" EPRI CS-1418, Project 736, Final Report, Electric Power Research Institute, Palo Alto, CA 94304, 1980. 

Coal Organic Properties Coal Mineral Matter Properties Combustion Kinetics... 

Two very important points are illustrated in Figures 1-4 Firstly, it appears that as coal fracture takes place in this system, mineral matter particles are ejected from the fractured coal system and most without attached coal. The implication is that the coal-mineral matter interfaces are not chemically bound. If those interfaces were chemically bound, one would observe mineral matter... 

The data presented in Table IV can be used to evaluate the effect of treatment on the concentrations of several elements frequently encountered in coal mineral matter. Optical emission spectoscopy was used to obtain approximate measurements. The first two columns list concentrations found in the ash from untreated and treated samples, respectively, and the third column lists relative concentrations in the solid formed from evaporating the liquid... 

Many chemicals in mineral form affect the oxidation rate to some extent, either accelerating or inhibiting it. Alkalis may have an influence of acceleration while borates and calcium chloride can act as retardants. The oxidation process is also promoted if ankerite is a constituent of the coal mineral matter. In contrast to this, silica and alumina retard the oxidation. 

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