Active Standard ASTM D6716 | Developed by Subcommittee: D31.02
Book of Standards Volume: 15.04
Historical (view previous versions of standard)
Significance and Use
5.1 This test method is useful in determining the approximate amount of nonvolatile inorganic material in wet blue. This may be in the form of salts or oxides of the elements. In a mixed-chrome tannage, the approximate percentage of other elements in the wet blue may be determined by subtracting the chromic oxide that may be conveniently determined on the ash. (See Test Method D6714.)
5.2 The specified temperature of 600°C is high enough to produce a reproducible result but it does not completely dehydrate such oxides as aluminum oxide (Al2O3) and chromic oxide (Cr2O3). Likewise, such salts as sulfates and phosphates may be incompletely dehydrated, and if alkalis and chromium are present simultaneously, oxidation to chromate may occur. Therefore, caution is advised in drawing conclusions based on quantitative relations of the elements.
1.3 Total ash in wet blue may be reported upon a number of different bases (for example, fat-free, moisture-free, as received, excluding chromium, and so forth). Before proceeding with any tests, it is very important to determine upon which basis that the total ash is to be reported and to identify all other test methods that will be required to be executed in order to achieve the determined reporting method.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
D3495 Test Method for Hexane Extraction of Leather
D6658 Test Method for Volatile Matter (Moisture) of Wet Blue by Oven Drying
D6659 Practice for Sampling and Preparation of Wet Blue for Physical and Chemical Tests
D6714 Test Method for Chromic Oxide in Ashed Wet Blue (Perchloric Acid Oxidation)
ICS Number Code 17.060 (Measurement of volume, mass, density, viscosity)