Ash elemental analysis

Combining the fusion technique with ICPES measurements gives a rapid and accurate method for the ash elemental analysis. The total analysis time needed is 20-25 minutes per sample. However, although the fusion procedure is excellent for the determination of all major elements, it is not suitable for the determination of trace elements, because the final solution (1 L) is too dilute for detection of trace elements. If the solution volume is kept small, extremely high concentrations of lithium and boron in the solution give an undesirable high background spectrum for trace element measurements. Hence, it is necessary to resort to a separate procedure where both trace and major elements can be simultaneously determined. 

Sample No. Heating Condition Residual Organic Matter (% of Initial Sample) Ash (%) Elemental Analysis (on Ash-Free Basis) Atomic H/C Ratio ESR Properties Solubility in NaOH Evolved n-Alkanes (htglS Initial Sample)... 

Traditional analyses of fuels include proximate, ultimate, and ash elemental analysis along with calorific value and, increasingly, trace metal concentrations. These values are presented below however fuel characterization increasingly needs to focus attention on additional measures of fuel structure, fuel volatility, and fates of certain elen nts such as fuel nitrogen. 

Table 4-7. Ash Elemental Analysis of Typical Wood Fuels...

A development in the 1960s was that of on-line elemental analysis of slurries using x-ray fluorescence. These have become the industry standard. Both in-stream probes and centralized analyzers are available. The latter is used in large-scale operations. The success of the analyzer depends on how representative the sample is and how accurate the caUbration standards are. Neutron activation analyzers are also available (45,51). These are especially suitable for light element analysis. On-stream analyzers are used extensively in base metal flotation plants as well as in coal plants for ash analysis. Although elemental analysis provides important data, it does not provide information on mineral composition which is most cmcial for all separation processes. Devices that can give mineral composition are under development. 

The combination of oxidi2ing effect, acidic strength, and high solubiHty of salts makes perchloric acid a valuable analytical reagent. It is often employed in studies where the absence of complex ions must be ensured. The value of wet ashing techniques, in which perchloric acid is used to destroy organics prior to elemental analysis for the determination of trace metals in organics, has been well estabHshed (see Trace and residue analysis). 

In frames of the present work the problems of elemental analysis of human bio-substrates (blood semm, hair and bones) are diseussed. Sample pretreatment proeedures using ash and mineral aeids digestion were developed. The main sourees of systematie errors were studied and their elimination ways were suggested. 

Raw foods were freeze-dried and analyzed for carbon isotopes using mass spectrometry. Cooked foods were prepared following historic recipes, then were freeze-dried prior to analysis. For the trace element analysis, foods (both raw and cooked) were wet ashed using nitric acid in Teflon lined pressure vessels and digested in a CEM Microwave oven. Analysis of Sr, Zn, Fe, Ca and Mg was performed using Atomic Absorption Spectrometry in the Department of Geology, University of Calgary. 

The thermal cracking of a light ffaction of mixed plastics waste was carried out in a fluidised bed reactor and the fractions obtained were analysed by elemental analysis, gas chromatography and ashing. The main components of the waste were PE and PP with a small amount of PS and the bed was fluidised by pyrolysis gas, nitrogen or preheated steam. Experiments conducted at different temperatures and residence times were compared by calculating the crack severity for each experiment. The results obtained revealed that the amounts of ethene and propene obtained by pyrolysis with steam were comparable with those obtained using a commercial steam cracker. 

Dry ashing procedures for elemental and ash content analysis fall into the following categories ... 

Applications A limited number of papers refer to the use of AAS in relation to polymer/additive deformulation. Elemental analysis of polymers and rubbers by AAS may be carried out after dissolution in an organic solvent (Table 8.21), after oxidative wet digestion (Table 8.12), after dry ashing (Table 8.22) or directly in the solid state (Table 8.23). 

Haslam et al. [32] reported the determination of Al in polyolefins by AAS. Typical AAS tests on rubber compounds involve several steps. The sample is combusted, and the resulting ash is dissolved in distilled de-ionised water. The solution is then used for AAS [126]. AAS or EDS can also be used for element analysis of filler particles. In order to determine the uniformity of tin compounds in polychloroprene after milling and pressing, Hornsby et al. [127] have ashed various pieces from one composition. After fusion of the residue with sodium peroxide and dissolution in HC1, the Sn content was determined by means of AAS. Typical industrial AAS measurements concern the determination of Ca in Ca stearate, Zn in Zn stearate, Ca- and Zn stearate in PE, Ca and Ti in PE film or Al and V in rubbers. 

Bettinelli, M., Baroni, U., Pastorelli, N. and Bizzarri, G. (1992). ICP-AES, GFAAS, XRF and NAA coal fly-ash analysis - comparison of different analytical techniques. In Elemental Analysis of Coal and Its By-Products, ed. Vourvopoulos, G., World Scientific, Kentucky, pp. 372-394. 

Infrared data in the 1575-400 cm region (1218 points/spec-trum) from LTAs from 50 coals (large data set) were used as input data to both PLS and PCR routines. This is the same spe- tral region used in the classical least-squares analysis of the small data set. Calibrations were developed for the eight ASTM ash fusion temperatures and the four major ash elements as oxides (determined by ICP-AES). The program uses PLSl models, in which only one variable at a time is modeled. Cross-validation was used to select the optimum number of factors in the model. In this technique, a subset of the data (in this case five spectra) is omitted from the calibration, but predictions are made for it. The sum-of-squares residuals are computed from those samples left out. A new subset is then omitted, the first set is included in the new calibration, and additional residual errors are tallied. This process is repeated until predictions have been made and the errors summed for all 50 samples (in this case, 10 calibrations are made). This entire set of... 

Si02 and AI2O3 are within the ASTM limits for those elements. Note that all these errors are better than the value of 4.8 resulting from the mineralogical analysis. (However, the mineral analysis was not optimized to predict ash elementals.)... 

Trace element analysis of coal and extract ashes... 

Trace element analysis was carried out on the ash by fusing with lithium metaborate, followed by dissolution in 10 % hydrochloric acid. The resulting solution was analysed using atomic emission and absorption spectrometry (AA). The method has been described previously (9). 

Coal is a rich source of carbon and has been a valuable source of fuel for centuries. It is classified by both coal type and coal rank. Coal type is determined by the nature of the original biomass that led to the formation of the coal. Coal rank signifies the degree of maturation or chemical change in coal and usually determines coal quality. The calorific value, moisture content, elemental analysis, volatile matter, ash, and fixed carbon content are important qualities of coal. 

The chemical composition of carbon blacks (see Section 4.2), as determined by common elemental analysis methods, is of little significance for predicting their properties. Special characteristic properties are, therefore, determined for the characterization and quality control of carbon blacks. Traces of heavy metals are determined spectroscopically in the ash. Copper and manganese ions, etc., are of special interest to the rubber industry because of their interference with the aging process of rubber goods. 

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