Waste Management and Recycling

摘要

Dowa Clean Technical Service (DCT) processes solid and liquid waste by incineration, chemical neutralization, and solidification and recovers nonferrous metals. The waste is incinerated at the three steps of combustion by the five steps of exhausted gas. The feature of the exhausted gas processing of DCT is that the combustion gas is rapidly cooled down from the temperature of 850 deg C to 80 deg C, which is a very effective method to prevent the generation of dioxin. The dioxin concentration of the exhausted gas falls below 0.1ng-TEQ/Nm~3in the end. Wastes containing fluorocarbon is also treated at DCT. Fluorocarbon is decomposed in the rotary kiln at the rate of 30kg/h. Decomposition rate of fluorocarbon is 99.9999 percent or more. Fluorocarbon even in the heat insulator of the refrigerator can be decomposed at DCT.Electronic circuit board containing low metal concentrated materials had not been recycled in Japan before DCT began recovering the metal resources in cooperation with Kosaka Smelter. At present, DCT recovered more than 200tons per year of copper.In addition, DCT has developed the recycling system of car shredder dust. The recycling system is developed by the calcium chloride manufacturing technology from the combustion gas for car shredder dust. The metal resources are physically selected from the combustion residue. The 55 percent copper concentration can be recovered at the recovery rate of 75 percent.The waste management technology of DCT is based on the nonferrous smelting technology. The quantity of recovery of nonferrous metals is increasing.