MINTEQ modeling for evaluating the leaching behavior of heavy metalsin MSWI fly ash
ZHANG Yan , JIANG Jianguo , CHEN Maozhe
DOI:
Received December 05, 2007,Revised April 30, 2008, Accepted , Available online
Volume 20,2008,Pages 1398-1402
- Summary
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At present, all kinds of municipal solid waste incineration (MSWI) fly ash stabilization technology has been reported and successfully
applied in many countries. However, leaching procedures are very di erent that the technologies lack uniform standard, and it is even
impossible to predict the long-term stabilization. Geochemical model can explain the environmental stabilization based on chemical
phase and thermodynamic crystal structure, and it is also able to guide the development of environment-friendly stabilization technology
and choosing of chemical agents. Both experiment analysis and geochemical modeling were used to study the correlation between
leaching behavior of MSWI fly ash and variation of pH. Dissolution/precipitation mechanism was applied in the simulation. The result
indicated that the pH-dependent leaching behavior predicted by Visual MINTEQ is well in agreement with the result of pH-dependent
test. pH value of leachate can significantly change the leaching behavior of MSWI fly ash. The leaching behavior of heavy metals for
Pb and Cd is controlled by dissolution/precipitation mechanism, whereas for Zn and Ni, it is e ected by surface adsorption reaction
over a special extent of pH value.
