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Validation of an alkali reaction, borate fusion, X-ray fluorescence method for silicon metal

Published online by Cambridge University Press:  01 March 2012

John R. Sieber
Affiliation:
National Institute of Standards, Gaithersburg, Maryland 20899
Elizabeth A. Mackey
Affiliation:
National Institute of Standards, Gaithersburg, Maryland 20899
Anthony F. Marlow
Affiliation:
National Institute of Standards, Gaithersburg, Maryland 20899
Rick Paul
Affiliation:
National Institute of Standards, Gaithersburg, Maryland 20899
Ryan Martin
Affiliation:
Globe Metallurgical Inc., Beverly, Ohio 45715

Abstract

The value assignment of candidate Standard Reference Material (SRM®) 57b Silicon Metal provided an opportunity to develop an alkali reaction procedure as a precursor to borate fusion for the preparation of test specimens from the metal powder for X-ray fluorescence spectrometry (XRF). Suggested for this purpose by Blanchette in a 2002 Advances in X-ray Analysis article [45, 415–420 (2002)], the alkali reaction uses LiOH∙H2O to convert Si to Li2SiO3. Lithium silicate is fused with lithium borate flux without damage to platinum ware. Once specimens are fused and cast as beads, calibration standards are prepared to closely match the compositions of the specimens, allowing a linear calibration for each analyte. The XRF method yields results that are directly traceable to the mole through NIST SRM spectrometric solutions. The method was validated in two ways. First, the reaction was used on older SRMs for Si metal: SRM 57 and SRM 57a. Second, XRF results for candidate SRM 57b were compared to results obtained using prompt gamma-ray activation analysis (PGAA) and inductively coupled plasma optical emission spectrometry (ICPOES). Bias tests show the XRF results are accurate for the elements Al, S, Ca, Ti, Cr, Mn, Ni, Cu, and Zr. Levels of S, Ca, Cr, and Cu in candidate SRM 57b are near the limits of quantification of the borate fusion method. Iron results may be subject to a low bias. Phosphorus is not quantitatively retained during the alkali reaction and borate fusion. These elements, plus B, which cannot be determined after borate fusion, are listed in manufacturing specifications for Si metal.

Type
X-Ray Fluorescence
Copyright
Copyright © Cambridge University Press 2007

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References

ASTM International (2000). ASTM A 922–93 (Reapproved 2000), Standard Specification for Silicon Metal, Historical Standard (ASTM International, West Conshohocken, PA).Google Scholar
Becker, D., Christensen, R., Currie, L., Diamondstone, B., Eberhardt, K., Gills, T., Hertz, H., Klouda, G., Moody, J., Parris, R., Schaffer, R., Steel, E., Taylor, J., Watters, R., and Zeisler, R. (1992). Use of Standard Reference Materials for Decisions on Performance of Analytical Chemical Methods and Laboratories, NIST Spec. Pub. 829. (U.S. Government Printing Office, Washington, DC).Google Scholar
Blanchette, J. (2002). “A quick and reliable fusion method for silicon and ferrosilicon,” Adv. X-Ray Anal.AXRAAA 45, 415420.Google Scholar
Claisse, F. (1957). “Accurate X-ray fluorescence analysis without internal standard,” Norelco Rep.NORRA5 4, 95.Google Scholar
Claisse, F. and Blanchette, J. S. (2004). Physics and Chemistry of Borate Fusion (Fernand Claisse, Québec City).Google Scholar
Currie, L. A. (1997). “Detection: International update, and some emerging di-lemmas [sic] involving calibration, the blank, and multiple detection decisions,” Chemom. Intell. Lab. Syst.CILSEN 37, 151181.CrossRefGoogle Scholar
Elkem ASA (2002). “Product data sheet: Silicon 99 Refined,” Rev. Sept. 2002. Elkem ASA, Oslo, Norway.Google Scholar
Government of Western Australia. (2005). Silicon Products Investment Opportunity Report (Department of Industry and Resources, Government of Western Australia, Perth), 〈http://www.doir.wa.gov.au/documents/investment/siliconJan06.pdf〉.Google Scholar
ISO (1993). Guide to the Expression of Uncertainty in Measurement (International Organization for Standardization, Geneva).Google Scholar
ISO (2006). ISO Guide 35:2006, Reference Materials—General and Statistical Principles for Certification (International Organization for Standardization, Geneva).Google Scholar
Lindstrom, R. M. (1998). “Reference material certification by prompt-gamma activation analysis,” Fresenius' J. Anal. Chem.FJACES 360, 322324.CrossRefGoogle Scholar
May, W. E., Parris, R. M., Beck II, C. M., Fassett, J. D., Greenberg, R. R., Guenther, F. R., Kramer, G. W., Wise, S. A., Gills, T. E., Colbert, J. C., Gettings, R. J., and MacDonald, B. S. (2000). Definitions of Terms and Modes Used at NIST for Value-Assignment of Reference Materials for Chemical Measurements, NIST Spec. Pub. 260-136. (U. S. Government Printing Office, Washington, DC), p. 16.Google Scholar
Mineral Information Institute (2006). “Silicon or Silica” (Mineral Information Institute, Golden, CO), 〈http://www.mii.org/Minerals/photosil.html〉.Google Scholar
NIST (2006a). Certificate of Analysis, Standard Reference Material 57, Refined Silicon (National Institute of Standards and Technology, Gaithersburg, MD), 〈http://ts.nist.gov/MeasurementServices/ReferenceMaterials/ARCHIVED/CERTIFICATES/57pdf〉.Google Scholar
NIST (2006b). Certificate of Analysis, Standard Reference Material 57a, Silicon Metal (National Institute of Standards and Technology, Gaithersburg, MD), 〈https://srmors.nist.gov/certificates/view_cert2gif.cfm?certificate=57A〉.Google Scholar
Paul, R. L. (2000). “Measurement of Phosphorus in Metals by RNAA,” J. Radioanal. Nucl. Chem.JRNCDM 245, 1115.CrossRefGoogle Scholar
Paul, R. L., Simons, D. S., Guthrie, W. F., and Lu, J. (2003). “Radiochemical Neutron Activation Analysis for Certification of Ion-Implanted Phosphorus in Silicon,” Anal. Chem.ANCHAM 75, 40284033.CrossRefGoogle ScholarPubMed
Schoonover, R. M. and Jones, F. E. (1981). “Air-Buoyancy Correction in High-Accuracy Weighing on Analytical Balances,” Anal. Chem.ANCHAM 53, 900902.CrossRefGoogle Scholar
Sieber, J. (2002). “Matrix-independent XRF methods for certification of standard reference materials,” Adv. X-Ray Anal.AXRAAA 45, 493504.Google Scholar
Sieber, J., Broton, D., Fales, C., Leigh, S., MacDonald, B., Marlow, A., Nettles, S., and Yen, J. (2002). “Standard reference materials for cements.” Cem. Concr. Res.CCNRAI 32, 18991906.CrossRefGoogle Scholar
Sieber, J. R., Yu, L. L., Marlow, A. F., and Butler, T. A. (2005). “Uncertainty and traceability in alloy analysis by borate fusion and XRF,” X-Ray Spectrom.XRSPAX 34, 153159.CrossRefGoogle Scholar
Taylor, B. N. and Kuyatt, C. E. (1994). Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurement Results, NIST Technical Note 1297 (U. S. Government Printing Office, Washington, DC).Google Scholar