The rheological, mechanical and heavy metal leaching properties of cemented paste backfill under the influence of anionic polyacrylamide

Water treatment sludge from algal blooms were analyzed and compared with general water treatment sludge as the pyrolysis temperature was varied from 300 °C to 900° C. Elemental analysis showed that the water treatment sludge in the eutrophication region has ~12% carbon content, higher than that (8.75%) of general water treatment sludge. X-ray diffraction (XRD) analysis of both types of sludge showed that amorphous silica changed to quartz and weak crystalline structures like kaolinite or montmorillonite were decomposed and changed into stronger crystalline forms like albite. Fourier transform infrared spectroscopy (FT-IR) peaks of humic/fulvic acid that indicated the affinity to combine with heavy metals disappeared above 700 °C. Toxicity characteristic leaching procedure (TCLP), conducted to determine the heavy metal leaching amount of pyrolyzed water treatment sludge, showed the lowest value of 5.7 mg/kg at 500 °C when the humic acid was not decomposed. At 500 °C, the heavy metal leaching ratio to the heavy metal content of high organic content water treatment sludge and low organic content water treatment sludge were 1.87% and 3.19%, respectively, and the water treatment sludge of higher organic content was more stable. In other words, pyrolysis of water treatment sludge with high organic content at 500 °C increases the inorganic matter crystallinity and heavy metal leaching stability.

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Heavy Metal Leaching from Contaminated Soils during the Percolation of EDTA: Observations and Modeling

Chelating Agents for Land Decontamination Technologies ◽

10.1061/9780784412183.ch07 ◽

2012 ◽

pp. 171-197

Author(s):

Monika A. M. Kedziorek ◽

Fabrice Compère ◽

Alain Dupuy ◽

Alain C. M. Bourg

Keyword(s):

Heavy Metal ◽

Contaminated Soils ◽

Metal Leaching ◽

Heavy Metal Leaching

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The heavy metal leaching property and cementitious material preparation by treating municipal solid waste incineration fly ash through the molten salt process

Waste Management & Research ◽

10.1177/0734242x19883921 ◽

2019 ◽

Vol 38 (1) ◽

pp. 27-34

Author(s):

Peng Zhao ◽

Minghai Jing ◽

Lei Feng ◽

Bai Min

Keyword(s):

Heavy Metal ◽

Fly Ash ◽

Molten Salt ◽

Waste Incineration ◽

Cementitious Material ◽

Metal Leaching ◽

Municipal Solid Waste Incineration ◽

Heavy Metal Leaching ◽

Material Preparation ◽

Molten Salt Process

This research investigated the heavy metal leaching property and cementitious material preparation by treating municipal solid waste incineration fly ash through the molten salt process. The results indicated that the heavy metal thermal evaporation of fly ash in the molten salt was related to molten salt composition, heat treatment temperature and atmosphere. After treatment with sodium chloride molten salts (contains 10–50 wt% calcium chloride) from 900°C to 1000°C for 2 h, the leaching concentrations of lead, cadmium, copper, zinc and other heavy metals in fly ash were decreased more than 90% and they could fully meet with the landfill standard. Moreover, after molten salt treatment, the weight fraction of fly ash was reduced by 50 wt% than the original one, and the fly ash has been changed as a kind of cementitious material, which has excellent cementitious property. The X-ray diffraction result indicated that the main crystal mineral composition of cementitious materials obtained was alite, belite, alinite and calcium sulphate.

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