Pneumatic selection of fly ash: selection methods - influence of the operating parameters

This work concerns the use of a pneumatic classifier in the valorization of fly ash. This classifier is characterized by a rotor positioned vertically . Firstly, a study in laboratory was carried out. Three parameters were ret ained: the rotation speed of the rotor, the air flow and the ash feeding ra te. The main parameter is the rotation speed of the rotor. There is a relat ion between the cut diameter and the speed rotation: d(50) = K/V with V as the speed and K as a factor in function of the process. The increase of the air flow and the ash feeding rate favours the extraction of the fine parti cles. After that, we realized a study of the industrial feasibility of the selection. We observe the same relation as those obtained during the labora tory study. We have found a set of operating parameters so as to obtain fou r granulometric fractions (<10, <30, <50 and <80 mu m). (C) 1999 Elsevier S cience S.A. All rights reserved.