Residual mineral matter

Identification of Minerals in Coal. Once the low-temperature mineral matter residue has been obtained by radiofrequency ashing, the minerals can be identified, and their concentrations can be determined by a variety of instrumental techniques. The best developed, most inclusive, and probably most reliable method used thus far in distinguishing minerals in coal is x-ray diffraction analysis. It has been used extensively by Gluskoter (15), Wolfe (17), O Gorman and Walker (2), and Rao and Gluskoter (1) and has been somewhat successful in quantifying mineral analyses. 

Ash is the inorganic residue that remains after the coal has been burned under specified conditions, and it is composed largely of compounds of sihcon, aluminum, iron, and calcium, and minor amounts of compounds of magnesium, sodium, potassium, phosphorous, sulfur, and titanium. Ash may vaiy considerably from the original mineral matter, which is largely kaolinite, iUite, montmoriUonite, quartz, pyrites, and gypsum. 

Atmospheric particulate emissions can be reduced by choosing cleaner fuels. Natural gas used as fuel emits negligible amounts of particulate matter. Oil-based processes also emit significantly fewer particulates than coal-fired combustion processes. Low-ash fossil fuels contain less noncombustible, ash-forming mineral matter and thus generate lower levels of particulate emissions. Lighter distillate oil-based combustion results in lower levels of particulate emissions than heavier residual oils. However, the choice of fuel is usually influenced by economic as well as environmental considerations. 

Walker, P. L. Spackman, W. Given, P. H. Davis, A. Jenkins, R. G. Painter, P. C. "Characterization of Mineral Matter in Coals and Coal Liquefaction Residues", Annual Rept. AF-832 from Pennsylvania State University to Electric Power Research Institute, 1978. 

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... 

Ash is the noncombustible residue remaining after complete coal combustion. Generally, the mass of ash is slightly less than that of mineral matter before burning. Sulfur is an undesirable constituent in coal, because the sulfur oxides formed when it bums contribute to air pollution and cause combustion system corrosion. 

A source of fly ash particulates is the mineral matter in the biomass feedstock. As material is gasified, the inorganic matter from the feedstock may be either retained in the gasifier bed or entrained in the product gas and swept out from the reactor. The mineral concentrations in clean wood are typically 1 to 2%, and herbaceous crops may contain up to 10% or more. Crop residues such as straw or rice hulls typically contain 15 to 20% inorganic material. Mineral matter... 

Mineral impurities may be detested by incinerating a portion of the sample in a platinum capsule. Pure quinin leaves no residue. Or a portion of the suspected quinin may bo treated with alcohol at a gantlc heat. Quinin dissolves, whilst any mineral matter which may be present, as well os gum, starch, stearin, will romain untouched. If a portion is burned upon platinum foil, sugar and margario acid may be detected by their peculiar smoke and small... 

The elemental analyses of the products from the extraction of Bruceton coal are shown in Table III. The mineral matter was separated from the extract quite efficiently as shown by the ash content of the extracts and the insoluble residue. The elemental composition of all fractions was quite similar to that of the original coal. Only the hydrogen content varied to some extent, increasing with increased solubility. The elemental analysis of the products from the extraction of Ireland Mine coal was incomplete. 

ASH. (1) In analytical chemistry the residue remaining after complete combustion of a material. It consists of mineral matter (silica, alumina, iron oxide, etc.), the amount often being a specification requirement. (2) The end product of large-scale coal combustion as in power plants now said to be the sixth most plentiful mineral in the U.S. It consists principally of fly ash, bottom ash, and boiler ash. Some of its values are recoverable, and there are a number of industrial uses of fly ash, e.g., in cement products and road rill. 

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... 

In more exact determinations it is necessary to subtract from the weight of the insoluble matter that of the mineral matter (sand, etc.), to obtain that of the pure cellular substance. For this purpose the filtration should take place through a dried and tared paper, the weighed insoluble matter being afterwards incinerated and the weight of ash subtracted from that of the total insoluble residue. 

In absence oj mineral matter. The residue obtained on steam distilling the varnish (see p. 314) is collected on a moistened filter and when all the water has run through, the oily residue is poured on to a dry double filter and filtered in an oven at 50-60° into a dry vessel. The filtrate is tested as follows ... 

Mineral and other Inert Substances.—The residue from the preceding determination, i.e., the part insoluble in the solvents of the rubber (or the part insoluble in acetone where the nitrosite method is used), may contain the mineral substances, the carbon and various inert organic substances (starch and other carbohydrates, vegetable textile fibres, etc.). Some of these, such as the fibres, may be recognised by the eye or under the microscope the starch may be removed with boiling water and recognised by means of iodine and the mineral matter may be identified by qualitative reactions. 

Analysis of ebonite is more difficult than that of ordinary vulcanised rubber, as it is less readily attacked by solvents the sample for analysis should be finely powdered. The determinations of moisture, ash, sulphur, etc., are made as in manufactured rubber the extraction with acetone should be prolonged, sometimes to 1-2 days, to be complete. The residue insoluble in acetone is extracted first with epichlorhydrin for 3 hours to remove resins insoluble, or almost so, in acetone (copal, mastic, amber) and then with pyridine as indicated for manufactured rubber next comes the treatment with alcoholic potash to dissolve any brown factis present. The residue from this last treatment comprises the pure rubber, the sulphur combined therewith and the mineral matter in one part of it the ash and the sulphur of the ash are determined, and in another the total sulphur, the sulphur united with the rubber being obtained by difference the pure rubber is then calculated by difference. 

The aqueous solution thus obtained is filtered and 200 c.c. (corresponding with 4 grams of the leather) evaporated on a water-bath and the residue dried at ioo° this represents total soluble matter or loss on washing. The dried residue is then incinerated, the ash representing the soluble mineral matter or soluble ash (which may be examined qualitatively) the difference gives the soluble organic matter. 

Ash.—The dry residue from the determination of the water is incinerated and the ash weighed. If this exceeds 1%, adulteration with mineral matter is probable, this being confirmed by qualitative analysis of the ash. Such analysis is useful in any case to detect the presence of heavy metals (especially iron), which may be introduced during the manufacturing processes and are harmful in the dyeing. The ash of alizarin consists normally of sodium or calcium salts. 

The various forms of moisture in coal are described according to the manner in which they are measured by some prescribed standard method. These forms are (1) inherent moisture, (2) surface or free moisture, (3) total moisture, (4) air-dry loss moisture, (5) residual moisture, (6) as-received moisture, (7) decomposition moisture, and (8) water of hydration of mineral matter. 

---