FREMGANGSMAATE VED REGENERERING AV EN SULFITTAVLUT, SAMT ANORDNING FOR UTOEVELSE AV FREMGANGSMAATEN

In the process, the cooking liquor is burnt, the magnesium oxide and sulphur dioxide contained in the resulting combustion gases are extracted for the manufacture of magnesium monosulphite (MgSO3) and magnesium bisulphite (Mg(HSO3)2), a part of the MgSO3 is thermally cleaved and the resulting products are recovered. In order to free the hot process gas practically completely from fine MgO dust without significant cooling and thereby be sure of avoiding encrustation of parts of the plant during the subsequent cooling of the process gas, the hot process gas containing S02, MgO and H2O arising from the cleaving of the magnesium monosulphite is subjected to filtration by means of a random non-woven (5, 18) to separate the MgO dust and the non-woven is cleaned as necessary. The filter apparatus consists of a heat-resistant housing (1) and a filter element which can be inserted in the housing (1) in the stream of process gas to be filtered, the filter element being fitted with a random non-woven of high temperature-resistant, sintered metallic material, in particular made of stainless chromium-nickel steel or chromium-nickel-molybdenum steel, or with a ceramic non-woven, with cleaning devices being provided within the apparatus.