Dust Formation by Attrition of Granular Activated Carbons

摘要

A dust attrition factor, DA, for a granular charcoal is evaluated by a new technique based on the vibration of a specified volume of particles. It is defined as the weight of abraded material carried by an air flow through the wire-mesh bottom of the sample container and retained on a weighted glass paper filter. The relevant factors in modeling were based on observations of plant operations that transmit vibrations of plant-scale equipment to the charcoal containers. The results for a number of commercial charcoals are given. There is a rapid initial drop in DA during the first three 10-minute intervals on the vibrator. This is followed by a slow and steady decrease which is compatible with a slow wear mechanism leading to rounded edges and beveled corners among the interacting particles. It is possible to align the different charcoals in a sequence of diminishing DA that varies fivefold. The first testing of a sample releases the excess dust accumulated in previous handling of the charcoal, but subsequent vibration in 10-minute intervals retains the observed alignment among the various charcoals. A test procedure based on the results of the study will be prepared and submitted to the D-28 Committee of ASTM for round-robin testing.