METHOD FOR TREATMENT OF DUST RECOVERED FROM OFFGASSES IN METALLURGICAL PROCESSES

摘要

ABSTRACTMethod of treating dust precipitated from waste gases frommetalurgical processes, especially dust precipitated fromwaste gases in connection with production of steel, in orderto transfer the dust to a form in which it can be depositedwithout danger of environmental pollution and from which thevaluable components of the dust can be revovered.According to the method the dust is treated in the followingsteps:a) continuous or approximately continuous supply of dusttogether with reducing agent and possible fluxes to agastight covered electrothermic smelting furnace.b) smelting and selective reduction together with vola-tilization of volatile metals in the smelting furnace.c) continuous or intermittent tapping of an inert slagphase and possibly a liquid metal phase from thesmelting furnace.d) continuous removal from the smelting furnace of a gasphase containing chiefly CO-gas, metal fumes, sulphur,chlorides and fluorides together with entrainedunreacted dust.e) possible selective condensation of one or more metalsfrom the metal fumes in the waste gas from the smeltingfurnacef) controlled afterburning of oxydizable components in thewaste gasg) removal of dust from the waste gash) final purification and neutralization of the waste gas.