X-Ray Quantitative Analysis of Coal By The Reference Intensity Method

Abstract

Twenty-four coal samples representing the four major rank types were analyzed by the X-ray RIM methodology which includes mass absorption analysis by X-ray transmission and quantitative X-ray powder diffraction. Twenty-three separate mineral species were observed in the samples, many of which could be quantified in the whole coal analysis. Several mineral species at levels of 5 weightpercent or less were observed only in the ashed scans. Some dehydration and reconstitution reactions were observed in the ashing process, including the combination of organically bound alkaline-earth elements and sulfur to form bassanite and magnesium sulfates. Quartz and kaolinite dominated the silicate mineral portion of the mineralogy, whereas calcite and siderite represented the carbonate; pyrite with associated sulfate oxidation products were generally present as well. The X-ray transmission studies were successful in estimating the carbonaceous matter in the whole coal samples and comparison of the chemical oxides derived from the X-ray data with direct analyses from the Penn State data sheets revealed good correlations, although significant departures occurred for some species and a systematic underestimation of aluminum oxide from the X-ray clay peaks was observed. This study suggests that the RIM procedure can be applied to coal mineral and amorphous component analysis on a routine basis.

Evaluation of the detectability and quantification of respirable crystalline silica by X-ray powder diffraction methods

“…These procedures are necessary because of the requirement that hazard labels be applied to any product that contains 0.1 weight percent crystalline silica. The more recent papers include silica analysis in clays (Murray and Merkl, 19__;Carter et al,1987); paint (Kamarzchik, 1980); coal, (Davis et al, 1986); dolostone (Emig and Smith, 1989); and rocks (Pawlowski, 1985). A general review of the theory and methods used for bulk analyses is presented by Snyder and Bish (1989).…”

“…Kupel et al (1968), Leroux and Powers (1969), and Bumsted (1973) developed techniques specifically for respirable quartz which has been improved by Altree- Williams (1977), Kolk (1975), Kohyama (1985). Pollack (1975), Davis and Johnson (1982a), Lippman (1983), and Davis (1986) have expanded the technique to prepare filters from small to bulk samples not collected in a personal sampler. Carsey (1987) has devised a larger chamber system, LISA, to evaluate sampling techniques and samplers.…”

“…Kamarchik (1980) describes the determination of quartz, talc, and clay in paints using the RIR method with TiO 2 as the reference material. Davis et al (1986) have analyzed coal samples using the RIR method coupled with absorption measurements to allow for the fact that not all the phases are determined and the coal component is amorphous. Emig and Smith (1989) have quantified quartz in agricultural dolostone using direct calibration methods because of the minimal interference from the other minerals in the rock.…”

Quantitative X-ray powder diffraction analysis applied to transmission diffraction

“…Our recommended procedure for minimizing preferred orientation is to load the powder by vertical suspension and collection onto glass-fiber filters for Bragg-Brentano scanning (Davis, 1984(Davis, , 1986, but membrane filters must be used for transmission work. Liquid filtration may be used to concentrate the particles ultrasonically stripped from lightly loaded glass-fiber filters, but randomness achieved with this method is not as complete.…”

An improved method for quantitative analysis of sedimentary minerals by X-ray diffraction

“…Quantitative analysis of sedimentary minerals is a difficult problem encountered in several fields such as geology, exploration, and the petroleum, coal, and construction material industries (Davis et al, 1986;Miao, 1988;Guan et ah, 1990). Researchers have tried various methods to solve it.…”