ASTM D444-88 (2020) pdf free.Standard Test Methods for Chemical Analysis of Zinc Yellow Pigment (Zinc ChromateYellow.)
For this determination take about 20 g of Type lpigment or about 5 g of Type ll pigment as defined inSpecification D478. Weigh the specimen into a 1-L beaker. Add75 mL of HCl (sp gr 1.19).Boil the solution under a hood untilthe rapid evolution of chlorine has subsided. Add 5 mL ofmethyl alcohol and boil to a volume of about 35 mL (Note 9).Add 25 mL of HCl and continue boiling.Add 5 mL of methy1alcohol and again boil to a volume of about 35 mL.If the volume is reduced below 35 mL, a precipitate may formthat will not dissolve upon dilution. It is imperative, however, that all thechromium be reduced.
Dilute the solution to 400 mL with water. If thesolution is not clear at this point, filter it. Heat to boiling andadd 50 mL of glacial acetic acid.Add 10 mL of BaCl5 solution(100 g/L) dropwise, while stirring. Boil for 30 min and allowto stand overnight (Note 10). Filter through a tared Goochcrucible and wash with hot water.
The values stated in Sl units are to be considered thestandard.The values given in parentheses are for informationonly.
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-priate safety，health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards，Guides and Recommendations issued by the World Trade Organization ‘TechnicalBarriers to Trade (TBT) Committee.
This test method has been developed to standardize thechemical analysis of zinc chromate yellow pigment and toprovide alternate methods of analysis for chromium and zinc.4. Preparation of Sample
Mix the laboratory sample thoroughly. Take a sufficientquantity for the chemical analyses and pass it through ai80-um (No.80) sieve, grinding in a mortar if necessary.ASTM D444 pdf download.