Destruction of Chlorofluorocarbons in a Cement Kiln

Abstract

One of the thermal oxidation technologies recommended by the United Nations Environment Programme (UNEP) is destruction of chlorofluorocarbons (CFCs) in a cement kiln. The destruction of CFC12, CFC11 and CFC113 was studied in a cement kiln plant in actual commercial operation. CFCs were completely destroyed in the kiln under normal operating conditions. Hydrogen fluoride and hydrogen chloride generated by CFC decomposition were absorbed by cement materials. No formation of toxic ha-logenated organic compounds, such as polychlorinated dibenzo-p-dioxins or dibenzofurans (PCDDs/PCDFs), was observed in the CFC incineration.     

Characterization of metal concentration,heavy metal elution,and desalination behavior of municipal solid waste incineration bottom and grate sifting deposition ash based on particle size

Resource and environmental safety protocols of incineration residues were evaluated by analyzing the metal concentration, heavy metal elution, desalination behavior, and chlorine removal ratio owing to particle size differences between bottom ash (BA) and grate sifting deposition ash (GA). In the total content test, Cl, Zn, and Cr in the incinerator BA exceeded the cement acceptance standard (Cl: 1000 mg/kg; Zn: 1700 mg/kg, and Cr: 170 mg/kg) at almost all of the particle sizes, while Au, Ag, Pd, and Zn had high contents in the GA. When using BA as a construction material, heavy metal elution values and contents are restricted as per the product quality standards based on the Japanese soil pollution control law. Lead within the BA and GA exceeded the standard values for most particle sizes. We predicted that there would be a limit on the elution of K by only washing with water. The removal ratio of total chlorine by particle size was approximately 20–70%, where the effect of the particle size on the removal ratio was small, suggesting that the elution of chlorine was complete in approximately 6 hours. These results contribute to information on the recycling of BA and GA.