ASTM D6658-01(2006)

The result obtained by this test is normally considered to be the moisture content of the wet blue sample. This result is used to correct all other chemical tests to a moisture-free basis.

Materials that are volatile under these conditions, other than water, may be present in the wet blue, although their amount in any normal wet blue would be expected to be a very small percentage of the total volatile matter.

Under the conditions of this test, certain materials in wet blue, such as protein fiber and chromium tanning salts, may retain moisture. Other materials, such as natural animal fats, may be oxidized. Both of these effects produce negative errors in the moisture determination.

The amount of volatile matter (moisture) released by a given sample varies with (a) method and time of sample preparation, (b) weight of sample taken, (c) temperature and time of the oven drying, (d) type of oven (gravity versus mechanical convection) used.

Because of the above unknown errors, the result of this test is a purely arbitrary value for the moisture content of the sample. It is, therefore, essential that the method be followed exactly in order to obtain reproducible results among laboratories. This is particularly true if other chemical analytical tests being performed on the same sample are reported on the moisture-free basis.

1.1 This test method covers the determination of volatile matter (moisture) in all types of wet blue.

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.