Process for thermically recovering old sands obtained in casting plants and for treating the dusts obtained during circulation of the sand

摘要

A process for thermically recovering old sand obtained in casting plants and for treating dust containing combustible organic components and incombustible inorganic components is disclosed. Dust obtained by mechanical preparation of the old sand is separated from the sand. The sand is used to form a fluid bed in a fluid-bed kiln having a post-combustion space and an outlet for releasing combustion gases. Dust containing combustible organic components and incombustible inorganic components is introduced into the fluid bed, the combustion of the organic components being used to maintain reaction temperature in the fluid bed. The heat of the fluid bed and the post-combustion space deactivates inorganic components of the dust, which are transported by released combustion gases to effectively separate the inorganic components of the dust from the thermically recovered old sand. These deactivated inorganic components of the dust can be separated from the released combustion gases for easy disposal.