Leaching behavior of heavy metals with hydrochloric acid from
fly ash generated in municipal waste incineration plants
fly ash generated in municipal waste incineration plants
(1. Department of Nonferrous Metallurgy, University of Science and Technology Beijing, Beijing 100083, China;
2. Department of Applied Chemistry, Saga University, Honjo 1, Saga 840-8502, Japan)
2. Department of Applied Chemistry, Saga University, Honjo 1, Saga 840-8502, Japan)
Abstract: The extraction behavior of heavy metals from municipal waste incineration (MWI) fly ash was investigated systematically. The extraction process includes two steps, namely, fly ash was firstly washed with water, and then subjected to hydrochloric acid leaching. The main parameters for water washing process were tested, and under the optimal conditions, about 86% Na, 70% K and 12% Ca were removed from fly ash, respectively. Hydrochloric acid was used for the extraction of valuable elements from the water-washed fly ash, and the optimal extraction was achieved for each heavy metal as follows: 86% for Pb, 98% for Zn, 82% for Fe, 96% for Cd, 62% for Cu, 80% for Al, respectively. And the main compositions of the finally obtained solid residue are Ca2PbO4, CaSi2O5, Pb5SiO7, Ca3Al2Si3O12 and SiO2.
Key words: municipal waste incineration; fly ash; heavy metals; leaching; hydrochloric acid