The ball-pan hardness test method has been widely used for determining degradation resistance of granulated activated carbons. Model SSA-39 set consists of a special 8in (204mm) diameter brass ball-pan and 15 each steel balls of 1/2in (12.7mm) and 3/8in (9.5mm) diameter. The ball-pan has a special 8mm thick hardened brass bottom plate dished out at 1,092mm inner radius to give a 3.2mm thickness at its center. The bottom plate is mounted in a standard full-height sieve frame with extended rim for stacking. Ball-Pan extended rim will need an additional regular pan to nest properly with the sieve stack in the Ro-Tap shaker.
In use, a 100ml sized sample is placed in the ballpan with the 30 steel balls and run for 30 minutes in a Model SS-30 Ro-Tap Sieve Shaker. The heavy ball-pan is loosely stacked (free to rotate) with five regular 8in sieves, sieve pan, and cover. “Hardness” of the activated carbon sample is determined by degradation resistance as measured by sieving the ground sample. The SS-30 Ro-Tap, sieves, sieve pan, and cover are all available from Gilson.