Treatment of effluent gases from refuse incineration - by absorption into calcium carbonate, esp. chalk

摘要

In a process for purifying effluent gases from refuse incineration units, calcium carbonate, esp. chalk in suspension or dry form is used in a suitable absorption unit such as tube leads or filter beds. The chalk absorbs only the HCl and HF present in the effluent gas and does not absorb the CO2. This leads to economies since only the stoichiometric amt. of chalk is needed to absorb the HF and HCl, whereas more than the stoichiometric amt. of caustic alkali or hydrated lime is needed, and the latter are in addn. more expensive than chalk. The chalk also gives rise to insoluble Ca salts as a result of the absorption, which can easily be disposed of, while caustic alkalis give water soluble salts which are difficult to dispose of.