Major and minor elements

Edmond, J. M., Measures, C., McDuff, R. E. et al. (1979). Ridge crest hydrothermal activity and the balance of the major and minor elements in the... 

Edmond, J., Measures, C., McDuff, E. et al. (1979) Ridge crest hydrothermal activity and the balances of major and minor elements in the ocean The Galapagos data. Earth Planet. Sci. Lett., 46, 1-18. Elderfield, H. and Schultz, A. (1996) Midocean ridge hydrothermal fluxes and the chemical composition of the ocean. Annu. Rev. Earth Planet Sci. Lett., 24, 191-224. 

Short-term precision (major and minor elements) <1 % RSD... 

Dyrssen D, Wedborg M (1980) Major and minor elements, chemical speciation in estuarine waters. In Olausson E, Cato I (eds) Chemistry and biogeochemistry of estuaries. Wiley, New York, pp 71-119... 

Chromite major and minor element composition was determined by microprobe. The IPGE contents of chromite were determined at UQAC by a LA-ICPMS (Thermo X7 ICP-MS coupled to a New Wave Research 213 nm UV laser, 80 pm spot diameter, 10 Hz pulse rate, 0.3 mJ/pulse power). In addition to the IPGE other elements were monitored to control the nature of ablated material and the presence of included phases. 

Although fly ash is largely non-crystalline glass, the major and minor elements in fly ash (O, Si, Al, Fe, Ca, Mg, and S) foim several different phases that have been characterized by XRD in many research projects (Diamond 1984 McCarthy 1988 Bergeson etal. 1988 Thedchanamoorthy McCarthy 1989 Ainsworth et al. 1993). The phases of major elemental constituents that have been commonly identified in fly ash include quartz mullite, Al6Si20 3 tricalcium aluminate, Ca3Al206... 

As already mentioned, normalized apparent release rates of major and minor elements present in HT materials converge toward similar values on longer terms of corrosion (ca. 0.2-0.25 g/m2 x day see Fig. 11). This is confirmed on Fig. 13, where the influence of the differences in AGhydr on the release rates vanishes for 10-day leaching (quasi-flat slope). This result indicates that the corrosion of HT materials is very different during the initial stage of dissolution, but... 

A second method of determining major and minor element abundances in meteorites is X-ray fluorescence analysis. In this method, a sample of meteorite is ground into a fine powder and irradiated by a monochromatic X-ray beam. The atoms in the sample absorb some of the X-rays, causing electrons to be ejected. The ejection of an electron causes other electrons to drop to lower energy levels to fill the vacancy, and characteristic X-rays are emitted. The X-ray energies are unique to each element and permit the chemical composition to be determined. X-ray fluorescence was used to determine the compositions of meteorites in the late 1950s and 1960s. If done correctly the compositions have the same accuracy as wet chemical analyses, but some of the measurements in the literature have problems with alkali elements. 

The Mars Pathfinder rover carried an Alpha Proton X-ray Spectrometer (APXS), and the two Mars Exploration Rovers (MER - Spirit and Opportunity) carried Alpha Particle X-ray Spectrometers (also called APXS, but in this case more precise versions of the Pathfinder instrument, though without the ability to monitor protons for light element analyses). These instruments contained radioactive curium sources (Fig. 13.16) whose decay produced a-particles, which irradiated target rocks and soils. The resulting characteristic X-rays provided measurements of major and minor element abundances. The MER rovers also carried Mossbauer spectrometers, which yielded information on iron oxidation state. 

In Figure 6.1, two parts of the mass spectrum of the glass sample NIST SRM 613 measured by rf GDMS are illustrated.4 In the mass spectrum of the glass sample, the orientation for a qualitative analysis focuses on the ions from matrix, major and minor elements (Si+, Al+, Na+, Rb+, Sr+ or Pb+) and the plasma gas species, such as 40Ar16O+, 40Ar2+ or 40Ar12C+. The plasma gas ions... 

Preliminary Investigation of Major and Minor Elements in Whole Coal and Coal Ash... 

The use of x-ray fluorescence was originally intended to obtain information about the major element matrix of coal ashes that were to be analyzed for trace elements by optical emission spectroscopy. Both low-temperature (<150°C) and high-temperature (450°C) coal ashes, prepared as described by Ruch et al. (I), were analyzed, and the method of Rose et al. (2) was adapted to determine the major and minor elements (Si, Ti, Al, Fe, Mg, Ca, K, and V). The instrumental parameters used for these elements are given in Table I. 

Because of these encouraging results and previous work on brown coals by Sweatman et al. (4) and Kiss (5), which indicated that major and minor elements could be determined in whole coal, a series of 25 coals was prepared for x-ray fluorescence analysis. For each coal, a low-temperature ash, a high-temperature ash, and the whole coal itself... 

ASTM D-3682. Standard Test Method for Major and Minor Elements in Combustion Residues from Coal Utilization Processes. 

Major and minor elements in coal, having concentrations easily detectable by most modem analytical techniques, can be determined by a number of acceptable procedures. Various approaches, combining a. number of specific procedures, are frequently referenced in the literature. For example, the presently accepted procedure (ASTM D-2795) determines silicon, aluminum, iron, titanium, and phosphorus colorimetrically, calcium and magnesium chelatometrically, and sodium and potassium by flame photometry. This standard test method was withdrawn in 2001 but is still used in some laboratories. 

There is also a standard test method for determination of major and minor elements in coal ash by inductively coupled plasma (ICP)-atomic emission spectrometry (ASTM D-6349). In the test method, the sample to be analyzed is ashed under standard conditions and ignited to constant weight. The ash is fused with a fluxing agent followed by dissolution of the melt in dilute acid solution. Alternatively, the ash is digested in a mixture of hydrofluoric, nitric, and hydrochloric acids. The solution is analyzed by (ICP)-atomic emission spectrometry for the elements. The basis of the method is the measurement of atomic emissions. Aqueous solutions of the samples are nebulized, and a portion of the aerosol that is produced is transported to the plasma torch, where excitation and emission occurs. Characteristic line emission spectra are produced by a radio-frequency inductively coupled plasma. A grating monochromator system is used to separate the emission lines, and the intensities of the lines are monitored by photomultiplier tube or photodiode array detection. The photocurrents from the detector... 

Several types of interference effects may contribute to inaccuracies in the determination of major and minor elements. The interferences can be classified as spectral, physical, and chemical. Spectral interferences involve an overlap of a spectral line from another element, unresolved overlap of molecular band spectra, background contribution from continuous or recombination phenomena, and background contribution from stray light from the line emission of high-concentration elements. The second effect may require selection of an alternative wavelength. The third and fourth effects can usually be compensated by a background correction adjacent to the analyte line. 

Coal contains several elements whose individual concentrations are generally less than 0.01%. These elements are commonly and collectively referred to as trace elements. These elements occur primarily as part of the mineral matter in coal. Hence, there is another standard test method for determination of major and minor elements in coal ash by ICP-atomic emission spectrometry, inductively coupled plasma mass spectrometry, and graphite furnace atomic absorption spectrometry (ASTM D-6357). The test methods pertain to the determination of antimony, arsenic, beryllium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, vanadium, and zinc (as well as other trace elements) in coal ash. 

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