X-Ray Powder Diffraction Study of NBS Fly Ash Standard Reference Materials

1988 ◽  
Vol 3 (3) ◽  
pp. 156-161 ◽  
Author(s):  
Gregory J. McCarthy ◽  
Diane M. Johansen

AbstractThe fly ash Standard Reference Materials (SRMs) issued by the U.S. National Bureau of Standards have been studied by X-ray powder diffraction (XRD). Based on observations of large diffuse scattering maxima in their X-ray diffractograms, it was evident that all of the ashes had a high glass content. SRM 1633a and 2689, derived from the combustion of bituminous coal, contained different amounts of quartz, mullite, hematite and ferrite spinel (magnetite). SRM 2891, derived from subbituminous coal had quite a different chemical composition and a more complex crystalline phase assemblage, that included these four phases plus anhydrite, tricalcium aluminate, lime, periclase and minor phases. SRM 2690, also derived from subbituminous coal, had only quartz, mullite and ferrite spinel as detectable phases in its diffractogram. Analytical CaO is an important factor in determining the phase assemblage; SRM 2691 had 25.8 wt%, SRM-2690 had 8.0%, and the ash derived from bituminous coals had only 1.6-3.0%. The changing composition of the glass phases in the SRMs is detected in a shift in the position and shape of the diffuse scattering maximum in the diffractograms. Use of an internal intensity standard permitted quantitative comparisons of the relative amounts of crystalline phases among the four fly ash SRMs.

1987 ◽  
Vol 113 ◽  
Author(s):  
Gregory I. McCarthy

ABSTRACTA brief summary of the use of x-ray powder diffraction for studying the mineralogy of fly ash is presented. Mineralogies of low-, intermediate- and high-calcium fly ashes are discussed and illustrated by results from XRD characterization of U.S. National Bureau of Standards fly ash Standard Reference Materials.


1975 ◽  
Vol 47 (7) ◽  
pp. 1102-1109 ◽  
Author(s):  
J. M. Ondov ◽  
W. H. Zoller ◽  
Ilhan. Olmez ◽  
N. K. Aras ◽  
G. E. Gordon ◽  
...  

1982 ◽  
Vol 26 ◽  
pp. 45-51
Author(s):  
Camden R. Hubbard

Standard Reference Materials (SRMs) from the National Bureau of Standards are samples or artifacts certified for one or more particular parameters. The NBS has produced SRHs since 1905 to aid commerce, to improve measurement technology and to assist in the enforcement of regulations. Today nearly 900 different SRHs are available to serve major segments of industry such as ferrous metals, nonferrous metals, mining, glass, primary chemicals, computer, nuclear power and electronics. In addition to the industrial customers, major SRM users include both federal and state governments, universities and nonprofit research organizations.


1987 ◽  
Vol 2 (4) ◽  
pp. 242-248 ◽  
Author(s):  
W. Wong-Ng ◽  
C. R. Hubbard

AbstractExternal standard and internal standard calibrations are important procedures for achieving high accuracy in X-ray powder diffraction studies. The theoretical basis as well as procedures for obtaining calibration curves are given. Methods and examples of selecting Standard Reference Materials (SRMs) which are produced and issued by the National Bureau of Standards (NBS), and procedures of sample preparation with these standards are also described. Three examples are presented to indicate the value of using SRMs.


1985 ◽  
Vol 65 ◽  
Author(s):  
Howard M. Kanare

Three new fly ash standard reference materials (SRM's) have been produced by CTL under contract with the U.S. National Bureau of Standards (NBS). Each unit of the SRM's consists of approximately ten grams of well-blended fly ash hermetically sealed in a glass vial. Twenty-thousand vials of each SRM were produced. The SRM's will be certified for major and minor chemical elements, loss on ignition, and for the percentage residue on the No. 325 standard sieve. The SRM's are suitable for use in developing new methods of chemical and physical analysis, for checking the performance of instruments and analysts, and for research into the composition and properties of fly ash.


1973 ◽  
Vol 17 ◽  
pp. 1-15
Author(s):  
H. Thomas Yolken

AbstractA review of the procedures and efforts at the National Bureau of Standards (NBS) to provide for meaningful measurements through the use of Standard Reference Materials (SRM's) is presented.The examples of NBS Standardization efforts for x-ray analysis range from basic metrology to applied environmental measurements. These examples include a determination of x-ray wavelength by a method which in part utilizes simultaneous x-ray and optical interferometry measurements of the atomic planes of near perfect silicon. In addition, Standard Reference Materials (SRM's) are being developed and applied to trace element analysis using x-ray fluorescence techniques. These efforts include development of SRM's for trace element analysis of air particulates. In another area, work is proceeding on the development of a silicon powder Standard Reference Material intended for x-ray diffractometer calibration. An effort to develop a suitable x-ray diffraction technique to determine the amount of quartz in mine dust is also underway. NBS efforts to provide SRM's for the calibration of electron microprobes and the validating of correction factor calculations are also described.


1986 ◽  
Vol 1 (4) ◽  
pp. 294-298 ◽  
Author(s):  
A. L. Dragoo

AbstractStandard Reference Materials (SRM) are stable materials which have one or more properties certified by the National Bureau of Standards. A general introduction is given to the types of SRM's and their certification. SRM's for X-ray diffraction are described in detail, including their intended use and their certified and other properties. New SRM's are under consideration as quantitative standards, intensity and line shape standards, and materials properties standards.


2000 ◽  
Vol 15 (3) ◽  
pp. 163-172 ◽  
Author(s):  
Ryan S. Winburn ◽  
Dean G. Grier ◽  
Gregory J. McCarthy ◽  
Renee B. Peterson

Rietveld quantitative X-ray diffraction analysis of the fly ash Standard Reference Materials (SRMs) issued by the National Institute of Standards and Technologies was performed. A rutile (TiO2) internal standard was used to enable quantitation of the glass content, which ranged from 65% to 78% by weight. TheGSASRietveld code was employed. Precision was obtained by performing six replicates of an analysis, and accuracy was estimated using mixtures of fly ash crystalline phases and an amorphous phase. The three low-calcium (ASTM Class F) fly ashes (SRM 1633b, 2689 and 2690) contained four crystalline phases: quartz, mullite, hematite, and magnetite. SRM 1633b also contained a detectable level of gypsum, which is not common for this type of fly ash. The high-calcium (ASTM Class C) fly ash, SRM 2691, had eleven crystalline phases and presented a challenge for the version ofGSASemployed, which permits refinement of only nine crystalline phases. A method of analyzing different groups of nine phases and averaging the results was developed, and tested satisfactorily with an eleven-phase simulated fly ash. The results were compared to reference intensity ratio method semiquantitative analyses reported for most of these SRMs a decade ago.


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