Carbon-sulphur analyses

Bulk chemical composition was determined by X-Ray Fluorescence (XRF) and carbon-sulphur analyses to (i) define the best sample preparation methodology for Po analysis by alpha spectrometry and (ii) estimate the matrix attenuation effect of 46.5 keV gamma photon emissions from Pb by gamma spectrometry using theoretical elemental mass attenuation coefficients from the literature [4],... 

The total mass attenuation coefficients, p / p, and degree of attenuation. A, for the reference material (hematite) and the in-house RMs are presented in Table 4. They were calculated using equations 3 and 2, respectively, and the bulk chemical composition information from XRF and carbon-sulphur analysis. The total attenuation coefficients ranged from 1.01 to 1.85 and their associated degrees of attenuation from 0.65 to 0.78. 

The authors are grateful to colleagues at Tata Steel, Mr Simon Johnston, Mr Richard Earl and Mr Pete Smith for collecting the stack emission samples used in this study and providing expert advice in XRF and carbon-sulphur analysis. This work has benefitted from collaboration with the regulatory authorities who have confirmed that best practicable means were used to measure and control sinter plant stack emissions. 

Tests giving a realistic approach to the study of leaching behaviour of the residues are described. Results of analysis (carbon, sulphur, major- and trace-elements) are discussed. Morphology, particle size distribution and enrichment effects on single particles are dealt with. A method for the comparison of the results of different leaching tests is presented. 

Halogen, sulphur, nitrogen content Ash content Analysis of ash Organic content by BOD, COD, PV or total carbon methods completed... 

The ratios of subscripts in the formula can be determined if the elemental composition of an organism growing under particular conditions is known. A unique cell formula can then be established by relating elemental composition to one gram-atom of carbon, ie 9 = 1, then a, p, and 8 are set so that the formula is consistent with known relative elemental weight content of the cells. The formula can be extended to include other macro-elements, such as phosphate and sulphur, if elemental analysis shows these elements to be a significant proportion of cell material. 

Elemental analysis of the oils was carried out as follows carbon and hydrogen by micro combustion using a Perkin-Elmer 240 Elemental Analyzer sulphur by X-ray fluorescence using a Telsec Lab X-100 apparatus nitrogen by chemiluminescence using a Dohrmann DN-10 apparatus. 

The EDX spectrum (Fig. 11.8) shows the main surface scale impurity peaks of silica, aluminium, sodium, chloride and iron. If this EDX is compared to that of a new, clean membrane surface (Fig. 11.9), the clean surface shows sulphur, carbon and oxygen, which is typical of a porous polysulphone support. It was concluded that the scale is amorphous, composed of aluminosilicate and silicate. These compounds are normally found in trace amounts in brine solutions. Analysis showed that the surface could be cleaned with hydrochloric acid and analysis of the dissolved scale was similar to the EDX spectrum analysis. Review of the plant operation determined that the precipitation was the result of high pH in combination with high silica concentrations in the brine. 

This technique has found very limited applications in soil and sediment analysis and is particularly useful when routine automated analyses at the mg L 1 level of large numbers of samples is required. The technique has been applied to the determination of total phosphorus, total organic carbon and total nitrogen in soils, total organic carbon in non-saline sediments and total sulphur in saline sediments. 

It is seen by examination of Table 1.11(b) that a wide variety of techniques have been employed including spectrophotometry (four determinants), combustion and wet digestion methods and inductively coupled plasma atomic emission spectrometry (three determinants each), atomic absorption spectrometry, potentiometric methods, molecular absorption spectrometry and gas chromatography (two determinants each), and flow-injection analysis and neutron activation analysis (one determinant each). Between them these techniques are capable of determining boron, halogens, total and particulate carbon, nitrogen, phosphorus, sulphur, silicon, selenium, arsenic antimony and bismuth in soils. 

The analysis of close contacts at divalent sulphur and selenium centres reveals a picture very similar to that observed for halogen atoms. Close contacts again fall into two classes (Ramasubbu et al., 1986 Sakurai et al., 1963 Rosenfield et al., 1977), depending on whether the second centre involved is an electrophile E (a metal cation or an electrophilic hydrogen, or carbon halogen atom), or a nucleophilic anion Nu. Similar preferences are observed for S-S contacts (Ramasubbu et al., 1986). 

In order to characterise the components further, mass spectral analysis was carried out. When head space volatiles from undigested cow slurry were analysed on a non-polar column the results (Figure 5) demonstrated the presence of several sulphur containing compounds—methanethiol, carbon disulphide, dimethyl sulphide, 2-propanethiol,... 

The analysis of the water gas so far given enumerates the chief constituents, but in reality there are traces of other products, such as carbon bisulphide, carbonyl sulphide, and thiophene, derived from the sulphur in the uel, which, minute in quantity, may nevertheless in the certain chemical processes produce appreciable and un-iesirable results from the iron contained in the fuel, ninute amounts of iron carbonyl are formed, which in nost processes in which water gas is used is a matter jf no importance, but if the gas is to be used for ighting with incandescent mantles, its removal is de-.irable. 

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