ISSN:0090-8312    

DOI:10.1080/00908319008960202

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Platinum group element (PGE) concentrations in seven Cretaceous and Tertiary coal deposits in Canada were determined using plasma mass spectrometry, neutron activation analysis, and direct current plasma spectroscopy. PGE concentrations are generally below detection limits; however, elevated values were determined in Quintette (100 to 1,700ppbplatinum and up to 180 ppb rhodium) and Blakeburn, Tulameen, samples (up to 10,000 ppb platinum). In the Quintette and Bullmoose deposits Pt increases up-section with decreasing ash, and in faulted Blakeburn coal, highest Pt and Pd values are associated with lowest ash. In the Number 2 seam, Quinsam deposit, Pd decreases upward with increasing ash. Platinum and Pd in these deposits appear to be organically associated. In the Number 1 seam, Quinsam, Pd, and ash decrease up-section, indicating a possible detrital source. Where organically associated, the PGE were likely introduced from circulating groundwaters, with elevated concentrations related to enhanced groundwater flow through faults (Blakeburn mine) or more permeable coarse-grained strata directly overlying coal seams (Quintette deposit). Coal rank does not appear to affect PGE concentrations significantly.

ISSN:0090-8312    

DOI:10.1080/00908319008960203

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Sydney Coalfield of Nova Scotia is one of the largest coal basins in eastern Canada and to date has produced 342 million tons of bituminous coal. Production for 1988 was 2.9 million metric tons. Eleven of 22 coal seams of the coalfield were investigated for uranium content and variation, using delayed neutron activation methods for accuracy and precision. At this level of sampling, no systematic variation was detected between uranium concentration and age of coals, but the data indicate that the younger, thick seams (>35 cm) are on average somewhat richer than their older counterparts; the thick seams on average have one-tenth the uranium concentration of the thin seams; lateral uranium variation in a seam is large; seams show distinct trends described by relative enrichmentldepletion patterns in top/bottom coal; and no secondary (epigenetic) uranium enrichment is evident. The best available mean estimate for the entire coalfield is 0.51 ± 0.99 ppm U, an estimate whose variance requires better circumscription. Sydney Coalfield is uranium-poor in comparison with some other coalfields of the same age, and depleted relative to the crustal abundance of 2.7 ppm U. Uranium variation is related to the depositional conditions, controlled by monsoonal changes (within-seam variation) and tectonic instability (between-seam variation) that prevailed during the life of the Sydney Basin. The syngenetic variation was probably modified as a result of coalification, a process that probably was also responsible for uranium-poor coals in Sydney. Uranium release into the environment from coal-fired power plants or from open-air coal storage is mentioned as potential pollution.

ISSN:0090-8312    

DOI:10.1080/00908319008960204

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Intact samples of coal have been analyzed by SIMS (secondary ion mass spectrometry) ion imaging and ion probe techniques for determination of the distribution of trace elements in pyrite and marcasite and in the associated clay minerals. Ion mapping of site-specific concentrations of trace elements is important as we consider ike environmental consequences of not only the combustion of coal, but also the disposal of coat-washing plant refuse and the placement of mine spoils during reclamation. Iron sulfides and clays are both involved in the oxidalion-nydralion reactions that result In the formation of acid waters and the release of trace elements into the ecosystem.

ISSN:0090-8312    

DOI:10.1080/00908319008960205

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

A suite of 24 tonsteins from the East Kootenay Coalfields is studied for mineralogical and elemental composition, origin, and the degree of physical and chemical alteration, using x-ray diffraction (XRD), x-ray fluorescence (XRF), instrumental neutron activation analysis (INAA), and inductively coupled plasma (ICP). Concentration of elements greater than the Clarke value is often limited to the litho-philes, i.e., Al. B, Ba, Cr. Co, Cs, Cu, Fe, K, Rb, Mg, Si, Sr, Th, and U, and some chalcophiles, i.e.. As, Sb, Se, and Mo. However, some lithophiles, such as Br, Ca, and CI, are depleted in these samples. The elements Al, Ca, Co, Hf, K, Mg, Na, Th, Se, U, andREEs (rare earth elements) are sensitive indicators of origin and degree of alteration of these tonsteins. Statistical analyses allow indirect observation of the stages of leaching that have affected the tonsteins.

ISSN:0090-8312    

DOI:10.1080/00908319008960206

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The concentrations of 20 elements in two suites of coal samples from India were determined by RABBIT neutron activation analysis (NAA) and x-ray fluorescence spectroscopy (XRF). Sulphur was determined by Leco and ash was determined in the lab at approximately 550°C. One group of samples was collected from feed coals at 11 power plants representing approximately 15% of all the coal burned in India: Korba, Madhya Pradesh (6 plants); Talcher, Orissa (1); Neyveli, Tamil Nadu (2); and Delhi (2). Effective coal concentration (ECC) is defined here as the total amount of a given element mobilized yearly due to coal utilization. For the above plants the ECC are (metric tons/year): ash (7.896 × 106), Al (1.031 × 106), Ba (3,768), Ca (1.03 × 105), Cl (2,229), Co (72), Cr (580), Dy (148), l (108), ln (1), Mg (4.02 × 105), Mn (1.921), Na (6,834), Ni (317), Rb (325, only 10 plants included), S (2.06 × 105), Si(2.017 × 106), Sr(l,325), Ti(77,340), V(1,128), andZn (642). A second set of channel samples was collected from India's largest lignite mine in Neyveli, Tamil Nadu. Depth versus concentration plots, correlation with ash, and correlation with each other are used to describe the vertical distribution of the elements. Of those elements exhibiting high correlation with ash (figures in parentheses are correlation with ash), only Si (0.94) is concentrated at both the top and bottom margins of the seam. Chromium (0.94), V (0.89), Al (0.83), Ti (0.82), Mg (0.82). Mn (0.80), Ba (0.76), and In (0.63) are more concentrated at the bottom of the seam relative to the top. Indium is also enriched in one of the middle samples. Iodine (−0.95), Cl ( − 0.84), and S ( − 0.50) show significant negative correlation with ash and are concentrated in the middle of the seam relative to the margins. Iodine and Cl elements do not correlate well with ash and exhibit only weak trends going from top to bottom. Sodium and Sr resemble Ca, as shown in Figure 4(a). They are lower in the top of the seam and generally increase in concentration with depth. The opposite is true for Zr and Ni, whose profiles are similar to that of Co in Figure 4(b). The general trends with sharp fluctuations may represent changes in water chemistry and/or Eh and pH during peat accumulation. This may have resulted in precipitation of finely disseminated mineral grains periodically as the peat accumulated. The facts that the chalcophile elements Co, Ni, and Zn along with S are enriched in the upper half of the profile and the lithophile elements Na, Sr, and Ca are more prominent at the bottom also suggests a change in depositional environment over time.

ISSN:0090-8312    

DOI:10.1080/00908319008960207

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Thermal alteration of both organic and inorganic components of a coal seam from Telkwa, British Columbia, is examined, using reflected light microscopy, x-ray diffraction (XRD), and neutron activation analysis (INAA). The alteration resulted from intrusion of an alkali basaltic dike.

ISSN:0090-8312    

DOI:10.1080/00908319008960208

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The elemental and mineralogical variation in a self-burning coal seam from Coalspur, Alberta, is determined using instrumental neutron activation analysis (INAA) and x-ray diffraction (XRD). The elemental variation in the coal seam is related to temperatures in the various alteration zones, i.e., oxidation, combustion, or carbonization and nature of elements. Mobilization of elements is greatest for As, Br, Cl, Mo, N, S, and Sb. Some of these elements are released to the atmosphere, as evident by the presence of orthorombic sulfur crystals on the surface or in vents at the top of the burning seam or saturation of oxidation char by volatile matter (tar). V/he-wellite (Ca C2O4, H2O) is the only Ca-bearing mineral found in the cooler area of the coal seam. Decomposition of this mineral, coupled with the presence of SO2formed by reaction of organic sulfur with O2in combustion, resulted information of a relatively high gypsum content in the combustion zone.

ISSN:0090-8312    

DOI:10.1080/00908319008960209

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The authors used the techniques of non destructive neutron activation analysis to determine trace metal and rare earth content of black precipitation events occurring in the Cairngorm Mountains in remote areas of Scotland. Thirty-one elements were determined in the particulate matter of snowpack cores that were sliced into sections. An additional analysis was performed for a black acidic snow event. Based on these results and on wind trajectories, increased loadings of many of the heavy metals and rare earth elements appeared to have originated from central Europe. Enrichment factor calculations showed anthropogenic emissions for indium, arsenic, zinc, and selenium.

ISSN:0090-8312    

DOI:10.1080/00908319008960210

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Although all forms of life are of critical importance biogeochemicalfy, bacteria are especially significant. This uniqueness arises not only from the great diversity of environments populated by bacteria, but also because they perform many biogeochemical transformations that are carried out poorly or not at all by higher organisms. In addition, bacteria exhibit a profound ability to bind substantial quantities of metallic ions. This retention of metals is facilitated by electrostatic interactions with anionic carboxyl or phosphoryl groups in the structural polymers of the cells. The macromolecular constituents in cell walls and external sheaths of bacteria are particularly reactive, so metals tend to concentrate at the cell surface. These cellular structures also tenaciously bind metallic ions during diagenesis and serve as distinct nucleation sites for the formation of authigenic minerals. Evidence of micro-fossils in ancient sedimentary rocks suggests further that bacteria contributed to analogous processes in the past.

ISSN:0090-8312    

DOI:10.1080/00908319008960211

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor