ISSN 1002-1027  CN 11-2952/G2

Acta scientiarum naturalium Universitatis Pekinensis

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A Study on Chloride Extraction and Sintering Stabilization of MSWI Fly Ash

LI Xiaodong1,2LIU Yangsheng2,3   

  1. 1 The Key Laboratory for Environmental and Urban Sciences,Peking University Shenzhen Graduate School, Shenzhen, 518055; 2 Department of Environmental Engineering, Peking University, and the Key Laboratory of Water and Sediment Scienc
  • Received:2006-08-21 Online:2007-11-20 Published:2007-11-20

Abstract: This study investigates the effects of water-washing process(such as water to ash weight ratio, contact time, temperature, and number of extraction steps)of fly ash on the removal of the soluble chloride salts, and the effect of sintering on heavy metal stabilization. The results indicate that more than 93% of Cl is found to be leached at L/S=4. The ratio of liquid to solid is thought to be mostly responsible for the extraction of chlorine, and the extractible amount of chlorine have a good linear relationship with logarithm of L/S. Simultaneously, the reduction of chloride salt and the formation of relatively low-melting point calcium-containing aluminosilicates are identified by X-ray diffraction (XRD) techniques. Compared with the original fly ash, the washed fly ash has a lower leaching concentrations of heavy metals (Pb、Cd、Ni) after sintering. The heavy metal leaching toxicity of the washed fly ash can evidently meet demand of the regulation after sintering at 800℃. The technology combining the water-washing process with sintering has a good promising for the incinerator fly ash to reduce the leaching toxicity of heavy metals.