ASTM D6656-16

5.1 The procedure described is specific for chromium in Wet Blue. Vanadium is the only common interfering element and is rarely present in quantity. The precision and accuracy of the methods are usually, at least, as good as the sampling of Wet Blue itself.

5.2 The chromium content of Wet Blue is related to the degree of tannage obtained, and hence may be a matter for specification in the purchase of Wet Blue. The procedure described provides adequate accuracy for this purpose.

1.1 This test method covers the determination of chromic oxide in Wet Blue that has been partly or completely tanned with chromium compounds. In general, the samples will contain chromium content between 1 % and 5 % when calculated as chromic oxide expressed upon a dry basis otherwise referred to as moisture-free basis (mfb).

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 This test method does not apply to Wet White.

1.4 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. See Section 9 for specific safety hazards.