Bulk chemical analysis

Building Services Piping, 29 480 Built-up edge, cutting tool failure mode, 4 659-660 Bukeite, 5 785t Bulk casting, PMMA, 10 200 Bulk chemical analysis, of solid waste, 25 866... 

Recently, MCM-9 (ref. 9) has been shown to be a mixture of Si-VPI-5 and SAPO-11 (refs. 10-12). However, it is not clear what the framework silicon concentrations are in either Si-VPI-5 (ref. 5) or MCM-9 (ref. 12). If one assumes the maximum levels of substitution from bulk chemical analysis, the silicon concentrations are low. Low element substitution was shown to be true for Co-VPI-5 (cobalt containing VPI-5) (ref. 5) as well. 

Most likely, the chemical system remains closed, as far as the other components in the silicate phases are concerned, as diagenesis or low grade metamorphism becomes more evident. Although there may be transfer of calcium, it seems, from bulk chemical analysis, that there is no systematic increase in potassium nor decrease in sodium content of argillaceous sediments. The transfer of Na and K is between the two size fractions—clay and coarse fraction—or between phyllosilicates and tectosilicates. Albitization of argillaceous rocks should be a common phenomenon where mixed layered phases are predominant in clay assemblages and especially evident in the illite-chlorite zone. 

Bulk chemical analysis of the solids. The three rock types were chemically analyzed by neutron activation (NAA) and x-ray fluorescence (XRF). The resulting data (not included in this report) were used for depth-of-leaching calculations given below. With the measurement of volatile components in the basalt and shale, the total measured abundances in all three samples was close to 100 percent. 

Despite its bad reputation as an analytical tool, XRF is potentially a traceable method according to the CCQM definition and could be a primary method although it was not selected as such, and won t be for a long time. In fact, it is the only microanalytical method which can at present be considered as a candidate for accurate microscopic elemental analysis. Proof of this statement follows from Monte Carlo calculations in which experimental XRF spectra can be accurately modelled starting from first principles [23], This is not an easy approach but with computing power now available it is feasible, though not worth the effort for bulk chemical analysis where other alternatives are available. 

Large particles of Si Al=40 exhibited more A1 near the particle surface than in the particle center. These results indicate that the overall Si-to-Al ratio from bulk chemical analysis should not be taken as the analysis at each point in the particle. 

Particles of ZSM-5 with different Si Al ratio may have different chemical profiles across the particle. Small (0.3ym) particles of low Si Al may either be composed of 30nm crystals stacked together or be a single crystal with more aluminum in the center. Large 2pm particles of higher Si Al exhibit a chemical profile showing more aluminum near the particle surface than in the interior. Therefore, the overall Si Al ratio from bulk chemical analysis should not be taken as the analysis at each point in each particle. 

The nickel concentration on this particle is extremely low with traces of the nickel impurity at the external surface. This low nickel concentration means that the particle in Figure 2 was in the refinery unit only a short time, otherwise more nickel would be present for the average particle (by bulk chemical analysis) contains 900ppm Ni and 4700 ppm V. The particle in this image contains a disproportionate amount of vanadium relative to nickel. If the nickel on the external skin of the catalyst accumulates by nickel porphyrin cracking at the first surface contacted, then vanadium must arrive not only by cracking vanadyl porphyrins but also by some other means like transfer from older catalyst particles in the FCC unit. The high vanadium concentration relative to nickel on new catalyst particles provides evidence that vanadium has interparticle mobility as well as intraparticle mobility. 

The methods that have proved effective for quantitative determination of phases in clinkers are based on light microscopy (Section 4.2.1), X-ray diffraction (Section 4.3.2) and calculation from the bulk chemical analysis. The last two of these are applicable also to cements. SEM with image analysis (Section 4.3.1) shows promise, but other methods that have been investigated, such as IR spectroscopy, appear to have little potential. Sections 4.4.2 to 4.4.5 describe a method of calculation from the bulk analysis and Section 4.4.6 compares the results of the various methods. 

For a calculation of the quantitative phase composition of a clinker from the bulk chemical analysis to give correct results, the following conditions are necessary and sufficient ... 

Table 4.3 Distribution of oxide components among phases in a typical Portland cement clinker, calculated from the bulk chemical analysis... 

The local environments of T-atoms in SAPO materials were examined using solid-state NMR, a bulk probe, and XPS, a surface sensitive probe. T-a-tom 2 p binding energies in XPS were found to vary in a predictable fashion with changes in NMR chemical shifts. The comparison demonstrates that XPS is sensitive to variations in the second coordination sphere for T-atoms in SAPO molecular sieves. XPS was also found to give a reasonable, quantitative measure of superficial (surface) T-atom fractions thus providing information about elemental homogeneity by comparison to bulk chemical analysis. 

The mantle comprises 68% by mass of Earth, and an accurate estimate for its composition is the very basis for unraveling the origin and differentiation of our planet. The bulk chemical analysis of xenoliths has been central to understanding the composition of the Earth s mantle, the genesis of basalt and the physical properties in the lithosphere that bear on its stability in the rigid part of the mantle system. 

In industry, many manufacturing or processing lines are controlled by measurement of chemistry alone simply because these values can be readily obtained to a high degree of accuracy and precision. When quantification of crystal form, or phase, is used in plant optimization and control it is often derived from bulk chemical analysis rather than being measured directly. This is achieved by normative calculation where particular elements are assigned to specific phases based on an assumed knowledge of individual phase composition. 

In the face of this complexity there are few analytical techniques which do not apply1 An advanced iC process will utilize traditional bulk chemical analysis, i.e. chromatography, spectroscopy, titrimetry, etc., as well as the array of ion and electron beam techniques for thin film and small spot analysis. 

Time-on-stream aetivity/selectivity and product distribution in the aromatization of C2+ hydrocarbons from natural gas over Ga H-ZSM-5 and H-GaAlMFI zeolites (having same bulk composition) at 600 C have been investigated. The zeolites were characterized for their FW-Si/Al and Si/Ga ratios and non-FW Ga by Si MAS NMR and bulk chemical analysis, for crystal size and morphology by SEM and also for their acidity by the chemisorption of pyridine at 400 C. The H-GaAlMFI zeolite shows higher activity and aromatics selectivity and slower deactivation due to coking in the aromatization of C2+ hydrocarbons from natural gas. 

Bulk Chemical Analysis (wt% SiC>2) HREM Thickness (A) BET Surface Area (m2/g)... 

J. V. Smith In my paper, I pointed out that there were difficulties in the interpretation of a bulk chemical analysis of a zeolite. Turkevich s remark supports my suggestion that the claim of DKO for breaks in the relation between cell dimension and A1 content of synthetic faujasite-type zeolite must be treated cautiously. 

Compared to a bulk chemical analysis, this method has the advantage that it detects the Al atoms indirectly from their effect on the Si atoms in the framework, and thus only detects framework Al atoms and the SUAl ratio for the framework. The ratio from chemical analysis, by contrast, will include both... 

Pfeifer, H.-R., Lavanchy, J.-C., Serneels, V.. 1991. Bulk chemical analysis of geological and industrial materials by X-ray fluorescence, recent developments and application to material rich in iron oxide. J. Trace Microprobe Technol. 9, 127-147. 

In addition small-scale exposures at 870"C were used to study further the role of water vapour with 20 vol.-% and 30 vol.-% water vapour in air in an alumina tube furnace. Phase morphology was studied with scanning electron microscope (SEM). To distinguish between the glassy and crystalline phases some samples were etched in 2-% HF-solution. Phase composition was determined by a quantitative X-ray diffraction (XRD) analysis based on the internal standard, Cap2, method. The chemical composition of the amorphous phase in the binder was determined locally with EDS analysis in SEM. A bulk chemical analysis of the amorphous phases in binder was performed by Induction Coupled Plasma Mass-Spectrometry (ICP-MS). The samples were crushed powders of as-received and 500 h at water vapour bulk exposed (w) materials. The glassy phase was dissolved in HF-HNO3 solution. Open porosity, apparent and bulk densities of each specimen were determined by Archimedes method before and after the tests. 

Bulk chemical analysis X-ray fluorescence spectroscopy Atomic absorption spectroscopy Inductively coupled plasma emission spectroscopy Direct-current plasma emission spectroscopy Arc emission spectroscopy Gravimetry Combustion Kjeldahl Impurities... 

The novel large-pore vanadosilicates AM-13 and AM-14 (Aveiro-Manchester, structure number 13 and 14) containing stoichiometric amounts of vanadium (SiA = 10 and 4, respectively), have been synthesised. Characterisation techniques such as bulk chemical analysis (ICP), powder X-ray diffraction (XRD), scanning (SEM) and transmission (TEM) electron microscopy, and N2, -hexane, benzene, tripropylamine and perfluorbutylamine adsorption measurements were used for the structural studies. The acid-base and redox properties of these materials were assessed by the conversion of isopropanol and ethanol oxidation, respectively. Both materials exhibit high selectivity to acetaldehyde indicating that these two novel vanadosilicates are promising redox catalysts. 

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