Characteristics Analysis of Chlorine Bypass Dust and Water- washed Residue

The main components of chlorine bypass dust are calcium, alkali, and chlorine. Chlorine components must be removed from chlorine bypass dust to enable its recycling as a cement raw material. Cement companies usually employ water-washing treatment to recover KCl from chlorine bypass dust. In this study, the chemical composition, mineral properties, and microstructure of the chlorine bypass dust and washed residues obtained from a 35,000 ton/year chlorine-bypass-dust-washing facility were analyzed to determine the feasibility of recycling the dust and its washed residues. The chlorine content of the dust decreased from 23.9% to 1.4% after washing, thus confirming the possibility of using the washed residues as a cement raw material. The CaO component increased from 22.4% to 49.8% whereas the K2O component decreased from 25.2% to 5.45%. The average particle diameter of the water-washed residues was 22.72 μm, which was significantly higher than that of the chlorine bypass dust before washing (12.13 μm). This result was attributed to the dissolution of chlorine compound particles measuring less than 1 μm in the chlorine bypass dust during washing.