Mechanical properties of activated carbon
One of the primary mechanical properties of activated carbon is its mechanical strength. It can be defined as the resistance to abrasion or attrition during use.
A variety of tests are available for evaluating the mechanical strength of granular activated carbon. These tests determine the change in particle size distribution or the amount of fines produced. Different mechanical strength test methods measures different aspects of strengths and thus cannot be mathematically related to one another. The most common test method is Hardness number followed by abrasion number.
Mechanical strength: Hardness and abrasion number
- The Hardness number (DSTM 20) measures the external integrity against outer wear and breakage of small points of activated carbon. It is expressed as a percentage loss on a particular sieve after shaking granules under certain conditions.
- The abrasion number (AWWA B604) measures the structural strength of granular activated carbon. It is a measure of the particle's ability to resist shear forces caused by particles rubbing together or particles rubbing against another surface such as a column wall or supporting screen. It is measured by shaking granules with steel balls in a container under certain conditions and is expressed as a percentage reduction in Mean Particle Diameter (mpd).