1、Designation: D 6018 96 (Reapproved 2006)Standard Test Method forDetermining the Presence of Lead Salts in Leather1This standard is issued under the fixed designation D 6018; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method covers qualitati
3、vely determining thepresence of lead salts in leather.1.2 The values stated in SI units are to be regarded as thestandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-
4、priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 Federal Standard:Federal Test Standard No. 311, Method 6551 Lead Salts,Presence of23. Significance and Use3.1 This test method may indicate the presence of lead salts
5、in leather. Lead salts may be found in pigments used in leathermanufacture.4. Apparatus4.1 Muffle Furnace.4.2 Porcelain Crucible.5. Reagents5.1 Nitric Acid, 1:1 dilution (equal volumes of nitric acidand distilled water).5.2 Hydrochloric Acid, specific gravity 1.19.5.3 Ammonium Acetate,3N, (231 g of
6、ammonium acetatedissolved in distilled water to make 1 L).5.4 Potassium Chromate, 5 % solution (50 g potassiumchromate dissolved in distilled water to make 1 L).6. Procedure6.1 Place about5gofthespecimen in a tared porcelaincrucible. Place the specimen in a cold muffle furnace orpre-carbonized over
7、a burner prior to placing in a hot furnace.Gradually raise the temperature of the furnace to 600 6 25Cand maintain at this temperature for 60 min. Remove thecrucible and contents, cool in a desiccator, and weigh. Replacein the furnace at 600 6 25C for 30 min and repeat theweighing procedure until a
8、constant weight is obtained (60.01g). If it is difficult to obtain a constant weight, leach the residuewith hot distilled water and filter through an ashless filterpaper. Place the filter paper in the crucible and ash. Add thefiltrate to the crucible and evaporate. Then put the crucibleback in the m
9、uffle furnace and heat, cool, and weigh as aboveuntil a constant weight (60.01 g) has been obtained.6.2 After the crucible containing the ash has cooled, add 5mL of nitric acid (1:1) and carefully evaporate the mixture todryness. Then add 1 mL of concentrated hydrochloric acid andevaporate to drynes
10、s. Then add 5 mL of distilled water andevaporate to dryness. Add 10 mL of hot distilled water, filter,and wash the residue twice with 5 mL portions of hot 3Nammonium acetate collecting all the washings. Heat the filtrateslightly and add a few drops of concentrated hydrochloric acidfollowed by a few
11、drops of 5 % potassium chromate. Theformation of a yellow precipitate of lead chromate indicates thepresence of lead.7. Report7.1 Report the presence or absence of lead.8. Precision and Bias8.1 This test method is adopted from Federal Test StandardNo. 311, Method 6551 where it has long been in use a
12、nd wasapproved for publication before the inclusion of precision andbias statements was mandated. The user is cautioned to verifyby the use of reference materials, if available, that the precisionand bias (or reproducibility) of this test method is adequate forthe contemplated use.9. Keywords9.1 lea
13、d; lead chromate; lead salts; leather1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.06 on Chemical Analysis. Thistest method was developed from Federal Test Method Standard No. 311,Method 6551 in cooperation with the U.S. Army Natick Research Development or through the ASTM website(www.astm.org).D 6018 96 (2006)2
