Reference Material Coal Research Articles

Elemental composition of fly ash: a comparative study using nuclear and related analytical techniques / Skład pierwiastkowy popiołów lotnych: studium przypadku z wykorzystaniem metod nuklearnych i analitycznych

Abstract Epithermal neutron activation analysis along with ICP-OES, LA ICP-MS, and XRF were used to determine the elemental composition of coal fly ash from the Malta coal power station in the Mpumalanga province of South Africa. A total of 54 major, trace and rare earth elements were obtained by the four analytical techniques. The results were compared and the discrepancies discussed to show the merits and drawbacks of each of the techniques. It was shown that the elemental content of this particular coal fly ash are of the same order as the NIST standard reference material Coal Fly Ash 1633b.

Extraction of trace elements in coal for determination by inductively coupled plasma-optical emission spectrometry using N,N-dimethylformamide and ultrasound

Coal usage continues to increase due to global energy demands. Increasing environmental monitoring and concern means that better methods of trace element determination are always required. This study investigated the use of N,N-dimethylformamide (DMF), Triton X-100, HNO3 and ultrasound to extract trace elements (Cr, Mn, Pb, Sr and V) from coal prior to analysis using ICP-OES and ICP-MS. It was found that the proportion extracted was lowest for V (17%) and highest for Pb (100%). Partial dissolution of the coal particles used in the slurries was demonstrated using scanning electron microscopy studies. Trace element determination of two reference material coal samples demonstrated that this method of extraction is effective. Trace elements in three bituminous coals from different seams being mined in South Africa were determined.

Utilization of oxygen flask combustion method for the determination of mercury and sulfur in coal

By use of oxygen flask combustion (OFC), a rapid and convenient determination method for mercury (Hg) and sulfur (S) in coal was developed. For the determination of Hg in coal, the OFC method with a KMnO 4 solution as an absorbent was carried out, and the resulting solution was analyzed by cold vapor atomic fluorescence spectrometry (CVAFS). For six certified reference material coals, the Hg concentrations obtained by this method were in good accordance with the certified or reference values. In addition, nine brands of Japanese standard coals (SS coals) were analyzed by the present method, and the data were compared to those from the authentic microwave-acid digestion (MW-AD) method. For the determination of total S in coal, the OFC method with H 2O 2 solution as an absorbent followed by ICP-AES or precipitation titration was successfully applied.

Determination of major, minor, and trace elements in coal slurries by direct current plasma-atomic emission spectrometry

The application of slurry atomization direct current plasma-atomic emission spectrometry (DCP-AES) to major, minor, and trace element determination in coals has been investigated. Attention was paid to the preparation of the coal slurries. Using the bottle and bead technique the optimal grinding time was 4 h and 0.1% Aerosol OT was the preferred choice of surfactant. Two certified reference material coals were analyzed by DCP-AES using aqueous standards for calibration. Good agreement between the results and certified values were obtained for 11 elements, illustrating the effectiveness of the slurry technique for the rapid determination of major, minor, and trace elements in whole powdered coal with existing instrumentation and aqueous calibration.

Direct determination of beryllium in coal slurries using graphite furnace atomic absorption spectrometry with automatic injection

A Perkin-Elmer autosampler (AS-40) was modified by incorporating magnetic stirring of the samples for the analysis of slurries. Platform atomisation and matrix modification were used for the determination of beryllium in three South African Reference Material coals SARMs 18, 19 and 20. The good precision and accuracy of the procedure are illustrated by the results obtained for the SARM samples.

Direct atomic spectrometric analysis by slurry atomisation. Part 7. Analysis of coal using inductively coupled plasma mass spectrometry

The application of slurry atomisation-inductively coupled plasma mass spectrometry (ICP-MS) to major, minor and trace element determination in coals has been investigated. Eight certified reference material (CRM) coals have been ground by the bottle and bead method and analysed using both rapid scan semi-quantitative analysis, employing a single rhodium internal standard, and full quantitative analysis using simple aqueous standards for calibration. The semi-quantitative mode, which determines the concentration using the mass-response curve for 68 elements against the single internal standard, produced values which were within a factor of two of the certified reference value, in most instances. The full quantitative determination gave excellent agreement with the certified reference material coals for a large number of elemental constituents. The results from the determination of 16 elements of interest are discussed including the effects of polyatomic interferents and isotope sensitivity. Low recoveries were observed for aluminium and the factors which influence its response are discussed with respect to internal standards. When coal slurries of up to 1%m/V were analysed no effect from cone blockage was observed.

Direct atomic spectrometric analysis by slurry atomisation. Part 4. Determination of selenium in coal by electrothermal atomisation atomic absorption spectrometry

The determination of selenium in whole powdered coal without sample dissolution is described. The sample was introduced into a graphite furnace as a slurry for analysis by atomic absorption spectrometry. The coal was slurried in nickel nitrate (matrix modifier), nitric acid and ethanol (wetting agent). The effects of the type of background correction (continuum source or Smith-Hieftje), the furnace programme, the various matrix modifiers and air ashing, particularly on a spectral interference from iron, were investigated. Method calibration was achieved using aqueous standards and sample destruction was carried out in situ in the furnace. The preferred method used Smith-Hieftje background correction, the 196.0-nm resonance line and in situ air ashing. Selenium was successfully determined in four certified reference material coals with a typical relative standard deviation of 5% at the 1 µg g–1 level. The limit of detection (2σ) of the method is 0.05 µg g–1.

Direct atomic spectrometric analysis by slurry atomisation. Part 2. Elimination of interferences in the determination of arsenic in whole coal by electrothermal atomisation atomic absorption spectrometry

The analysis of whole powdered coal without sample dissolution has been investigated. Techniques have been established for the determination of arsenic by slurry injection into an electrothermal atomiser for atomic absorption spectrometry. The effects of the furnace programme, type of background correction, form of atomisation and slurry matrix have been investigated. Calibration was achieved using aqueous standards with sample distruction performed in situ in the furnace.The coal was slurried in nickel nitrate (matrix modifier), magnesium nitrate (ashing aid), nitric acid and ethanol (wetting agent). The use of conventional continuum-source and Smith-Hieftje background correction systems was compared for correction of a broadened aluminium line interference at the most sensitive As line (193.7 nm). Only the latter was effective, because the interfering line is within the monochromator band pass. A carefully designed heating programme to separate temporarily the arsenic and aluminium absorption peaks was also advantageous. The less sensitive 197.2-nm line yielded comparable results with either form of background correction.Complete recoveries of arsenic were achieved when the particle size was reduced to 30 µm. Samples could be injected from either constantly agitated slurries or thixotropically stabilised suspensions. A number of certified reference material coals were analysed (NBS SRM 1632a and 1635 and BCR No. 40). Excellent agreement was obtained between the results from the preferred slurry method and certificate value.

Determination of Elemental Composition of NBS SRM Coals Via Automated Neutron Activation Analysis

An automated multidetector system for instrumental thermal neutron activation of geological and environmental materials was used for the measurement of up to 34 elements in six National Bureau of Standards Standard Reference Material coal samples. Good agreement was achieved with NBS certified and literature consensus values.