Coal fly ash consists mainly of unburned carbon and minerals. It also contains phosphorus with a concentration much higher than that acceptable for the metallurgical coke or boiler fuel. By flotation process, a large portion of the inorganic materials can be separated. However, further treatment is necessary before the fly ash carbon can be reused as a fuel or metallurgical coke. In our study, chlorination method was attempted using phosgene as a chlorinating agent. Our thermodynamic simulation shows that, by using phosgene, the minerals can be converted completely already at the temperature 200degreesC. However, the experimental results showed that the reactivity of minerals with phosgene depends strongly on the reaction temperature; the reactivity is high in the first 10 min. Within 10 min, 80% of the minerals can be extracted from the fly ash at 1050degreesC. Chlorination is also effective in removing phosphorus from fly ash. At 1000degreesC, the content of phosphorus can be reduced from 2100 to 24 ppm in 10 min. (C) 2003 Elsevier Science B.V. All rights reserved.