Several methods have been employed in the past for determining the resistance of activated carbons to particle size degradation under service conditions, including the ball-pan method, the stirring bar method, and the dust elutriation method. None of these has proved completely satisfactory for all applications, and all have been questioned by ASTM Committee D28 on Activated Carbon as tests for establishing degradation resistance. However, the ball-pan method has been used widely in the past and has a broad history in the activated carbon industry for measuring the property loosely described as “hardness.” In this context the test is useful in establishing a measurable characteristic of a carbon. Conceding the fact that the test does not actually measure in-service resistance to degradation, it can be used to establish the comparability of lots ostensibly of the same grade of carbon.

1.1 This test method covers a procedure for determining the ball-pan hardness number of granular activated carbons. For the purpose of this test, granular activated carbons are those having particles 90 % of which are larger than 80 mesh (180 m) as determined by Test Method D 2862.

1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.3 sibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.