Process for the production of perlite filter aids

摘要

Expanded perlite is ground on a roll mill and the ground material is screened. As compared with perlite filter aids according to the state of the art, which has been ground in beater mills or impact mills, the resulting product has a substantially lower wet density, a lower bulk density, a more uniform particle size, a greater pore volume and a considerably smaller proportion of floating particles, the result being higher throughputs and longer lives with sharp clarification. A modified cyclone which acts as a classifier and can advantageously be used for the process, is also disclosed. IMAGE