The Chemical Analysis of Argonne Premium Coal Samples

Edited by Curtis A. Palmer
U.S. Geological Survey Bulletin 2144

THE CHEMICAL ANALYSIS OF ARGONNE PREMIUM COAL SAMPLES

By Curtis A. Palmer

ABSTRACT

Methods used to determine the concentrations of 67 elements in 8 Argonne Premium Coal samples are summarized in this bulletin. Seventeen different procedures involving 11 different techniques were used. Sample identification, sample protocol, and sample descriptions are presented.

INTRODUCTION

This bulletin contains papers discussing the U.S. Geological Survey's chemical analyses of eight Argonne Premium Coal samples. The papers present analytical results obtained from all the methods used in the analyses and give a comparison of the results for elements where more than one technique was used. This paper describes the samples, explains the numbering protocol used throughout this bulletin, and lists the elements whose concentrations were determined by each technique used.

A detailed description of the samples, the reasons for their collection, and other background information have been reported by Vorres (1990, 1993). Table 1 contains the sample identification for the eight Argonne Premium Coal samples used in this study, with the seam, location, rank, and ash yield for each. The samples come from seven different States and range in rank from lignite to low volatile bituminous. The sample identification protocol is similar to that used by Vorres (1990). It consists of a two- to four-letter identifier that represents either the State or the seam from which the sample was obtained, followed by one or more spaces, the letters 'PC' for Premium Coal, and a dash followed by sample numbers 1 through 8. In the papers that follow, splits are identified by the addition of a dash and another number after the sample number. For example, split 2 of Premium Coal sample 1 is identified as UF PC-1-2, with UF designating the Upper Freeport coal seam from which Premium Coal sample 1 was obtained.

Seventeen different procedures involving 11 different techniques were used to determine concentrations of 67 different elements. Ten of these procedures required coal ash, and the other seven used the whole coal. Table 2 shows the elements, listed by atomic number, whose concentrations were determined by each procedure. Procedures include two direct-current arc atomic emission spectrography (DCAES) procedures, one on the ash and one on the whole coal; four X-ray fluorescence spectrometry (XRF) procedures, including both wavelength- and energy-dispersive procedures for the analysis of both the whole coal and the ash; and four atomic absorption spectrometry (AAS) procedures, including came and graphite furnace AAS on the ash, cold-vapor atomic absorption spectrometry (CVAAS) procedures for mercury on the whole coal, and a hydride-generation AAS (HGAAS) procedure for selenium. Other techniques include instrumental neutron activation analysis (INAA) and combustion/gas chromatographic analyses for carbon, hydrogen, and nitrogen (CHN), which were determined on the whole coal only. Five inductively coupled argon plasma procedures were made on the ash only. Three of these procedures used an acid digest: the two inductively coupled argon plasma-atomic emission spectrometry (ICAP-AES) procedures (one in Reston and one in Denver) and the inductively coupled argon plasma-mass spectrometry (ICAP-MS) on the acid digest prepared in Denver. Two additional procedures used a sinter digest: the ICAP-AES and the ICAP-MS procedures in Denver. Ash yield (see paper by Doughten, this volume) and moisture content (see paper by Krasnow and Finkelman, this volume) are also reported. A detailed description of each of these procedures is given in the following papers.

In addition to the concentrations of 38 elements determined by DCAES on the ash, lower limits of detection were reported for another 24 elements, making a total of 62 elements reported by DCAES in the paper by Skeen, Libby, and Crandell. Of the 67 different elements with reported concentrations, 51 were determined by more than one technique. Results obtained by different techniques are compared by Palmer and Klizas in this volume.

This bulletin is a greatly expanded version of a preliminary report edited by Palmer and Walthall (1991) that contained information on 58 elements, 33 of which had been determined by more than one technique. All of the preliminary data were collected at the analytical facilities of the U.S. Geological Survey (USGS) in Reston, Va., and represented the procedures used to analyze coal through 1990. In 1990, work was begun to develop a procedure to determine trace-element concentrations by only high-precision techniques. The determination of several of the elements by DCAES was replaced by ICAP-MS, a technique available within the USGS only in laboratories in Denver, Colo. Because the dissolution procedures for ICAP-MS and ICAP-AES are the same, all routine ICAP-AES determinations on coal were moved to the Denver facilities. These two techniques were appropriate for most of the elements previously determined by the Reston high-precision techniques: INAA, XRF, and AAS. Those techniques, therefore, have been dropped for routine analysis, although INAA is still used for many samples when determinations on the whole coal are necessary or when sample size is critical. One element determined by INAA and not determined with the new procedures was selenium. A hydride-generation AAS method was developed in Denver to determine selenium. A new procedure to determine mercury by CVAAS was also added. CHN information is routinely obtained by ultimate and proximate analysis of coal by an outside laboratory, although CHN is still determined in USGS laboratories on some research samples.

The following chapters include papers modified from the open-file report by Palmer and Walthall (1991), as well as new papers describing the new Denver techniques. Results in each paper are reported in the manner in which results are normally reported by the laboratory performing the analysis. In all the papers except the last, results from methods used to analyze ash are reported on an ash basis, whereas results from methods used to analyze whole coal are reported on a whole-coal basis. Similarly, concentrations of major rock-forming elements are reported on an oxide basis or an element basis depending on the standard practice of the laboratory performing the analysis. The units parts per million (ppm) and micrograms per gram (mg/g) are equivalent as are weight percent and percent (%); all results in this report are on a weight basis.

The comparison chapter by Palmer (1991) in the open-file report has been completely rewritten by Palmer and Klizas as the last paper in this report to include all the new techniques and a statistical analysis of results for all 51 elements that were determined by more than one procedure. All results in the last paper are converted to an element basis and a whole-coal basis and are expressed in weight percent and parts per million. Although only eight samples are included in this bulletin, comparison of the data for old and new techniques is useful in determining the accuracy of the data in the National Coal Resource Data System (NCRDS), which contains data for over 13,000 coal and rock samples, 7,400 of which are available on CD-ROM (Bragg and others, 1994). [Currently available as OF 97-134]

REFERENCES

Bragg, L.J., Oman, J.K., Tewalt, S.J., Oman, C.L., Rega, N.H., Washington, P.M., and Finkelman, R.B., 1994, U.S. Geological Survey coal quality (COALQUAL) data base--Version 1.3: U.S. Geological Survey Open-File Report 94-205 (CD-ROM). Currently available as OF 97-134]

Palmer, C.A., 1991, Compilation of multi-element analysis of eight Argonne Premium Coal samples for 33 elements, in Palmer, C.A., and Walthall, F.G., eds., The chemical analysis of Argonne Premium Coal samples: U.S. Geological Survey Open-File Report 91-638, chap. 1, p. 84-112.

Palmer, C.A., and Walthall, F.G., eds., 1991, The chemical analysis of Argonne Premium Coal samples. U.S. Geological Survey Open-File Report 91-638, 112 p.

Vorres, K.S., 1990, The Argonne Premium Coal Sample Program: Energy and Fuels, v. 4, no. 5, p. 420-426.

------1993, Users handbook for the Argonne Premium Coal Sample Program: Argonne National Laboratories Report ANL/PCSP-93/1, 200 p.

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