Verfahren zur Regeneration von gebrauchten Bleicherden.

摘要

The present invention relates to a process for the regeneration of spent bleaching earth, comprising an oxidative heat treatment in which the amount of oxygen supplied exceeds the stoichiometrical requirement of complete oxidation of all organics present in the spent bleaching earth, wherein the spent bleaching earth and the oxygen are blown through a stationary fluidized bed of inert granulate material. The stationary fluidized should be as high as to limit the temperature in the freeboard to less than 1000 DEG C. As a matter of fact, it has been found that, if the fluidized bed is not high enough, the oxygen required to burn off the organics content of the spent bleaching earth would blow out the powdered bleaching earth from the bed at the stage of incomplete oxidation of the organics present on the earth, resulting in an uncontrolled temperature rise in the freeboard and local overheating of the bleaching earth.