Quality Improvement of Incineration Residues—Wet physical separation of MSWI Bottom Ash

摘要

Because of the risk of underground water and surface water contamination as a result of the leaching of salts and heavy metals from bottom ash, the different grade utilization of bottom ash is limited. This paper introduces a wet physical separation technology which could effectively remove the heavy metal and salts from larger than 2 mm bottom ash fraction at high grade and recovery. The highly effective removal of these metals improves the engineering and environmental properties of the resulting granular product. Compared to the chemical treatments of bottom ash, the wet physical separation technology has more advantages such as higher recovery efficiency and lower cost of treatment. To evaluate the environmental quality of output products, the granular products with different size were checked by leaching test. Results show that after treatment the fraction larger than 2 mm well satisfy the American environmental standard of landfill. The 0-2mm fraction needs further improvements. In order to enhance the grade of bottom ash products and recovery of metals, research is ongoing to investigate the relationship between the components of MSW, combustion condition and composition of bottom ash. A set of new processesof pre-treating MSW and optimize the combustion conditions is expected to be achieved.