PURPOSE: To avoid a formation of highly condensed aromatic hydrocarbons and dioxines by eliminating dust using ceramic filter element with a specified porosity which is made of SiO2, Al2O3 and/or ZrO2 and an inorganic binder.

CONSTITUTION: The dust is eliminated by utilizing ceramic filter elements 13a and 13b, with a porosity of 50-90%, which composes 15-50 wt.% SiO2, 30-70 wt.% Al2O3 and/or ZrO2 and 1-10 wt.% and inorganic binder (for example: alkali silicate salt), used in a dedusting filter 10 behind a combustion furnace 1. This filter element has thickness of 10-30 mm, pressure drop of 500-1,000 mm bar, and composes of a felt which fibers are compacted with the inorganic binder. As a result, the formation of aromatic hydrocarbons and dioxines is avoided in the combustion device and the formation is securely prevented during cooling of an exhaust gas; and these substances is not detected in the dust.