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Supplement to A.S.T. M. Methods of Chemical Analyses of Metals.—This method is a revision of an"T supersedes the former Tentative Method of Quantitative Spectro-chemical Analysis of High Grade Pig Lead for Copper, Bismuth, Silver, and Nickel (E 25 - 35 T) which latter method appears on pages 238 to 242 of the Society's publication "A.S.T. M. Methods of Chemical Analyses of Metals (1936)." Since this method replaces the former Tentative Method E 25 - 35 T, this copy should be substituted in the compilation of Methods of Chemical Analyses of Metals.
TENTATIVE METHOD OF TEST i 0
QUANTITATIVE SPECTROCHEMICAL ANALYSIS OF HIGH
GRADE PIG LEAD1
A.S.T. M. Designation: E 25-37 T
This is a Tentative Standard and under the Regulations of the Society is subject to annual revision. Suggestions for revision should be addressed to the Headquarters of the Society, 260 S. Broad St., Philadelphia, Pa.
Issued, 1935; Revised, 1937.2
1. This method3 may be applied to any high grade of lead, provided the impurities to be determined are not present in. quantities over 0.1 per cent. An arc spectrum is used, employing graphite electrodes, one of which is treated with a solution of the sample to be analyzed. Quantitative estimations are made by the comparison of the spectrum of the sample with the spectra of standard samples of known composition.
Preparation of Sample Solution
2. A 20-g. portion of turnings, or filings, from a representative sample of the pig lead to be analyzed shall be weighed and then dissolved in a solution of 20 ml. of nitric acid and 80 ml. of distilled water. The solution shall be gently warmed until a perfectly clear solution results. After the sample has gone completely into solution, sufficient distilled water shall be added to bring the volume to exactly 100 ml. at room temperature, and the solution transferred to a small glass-stoppered bottle. Each 0.1 ml. of this solution will contain 0.02 g. of sampi. . This procedure shall be repeated, thus making available duplicate sample solutions.
3. (a) Fifty milligrams of filings of the lead sample shall be introduced into a recessed graphite electrode (Note 1). This electrode shall be made the lowe.r and positive member of a pair uf electrodes, between which an
' Cnder the standardization procedure of the v.'-'. . , this rr.ethcd is under the jurisdiction of the A.S.T. M. Committee l-2 or. Spect-orrriphic Analvsis.
2 Revision accepted by Committee E-10 on Standards. August 26, 1937. M- 1 The procedure is based upon the technique of spectrograph^ analysis as described by C. C. Nitchie, Quantitative Analysis with the Spectrograph," Induttrial and Engintfrint Chtmutry, Analytical Edition, Vol. 1, p. 1 (1929).
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