Heavy Metal Leaching Behavior of Glasses Containing EAF Dust

Alkali-activated materials (AAMs) not only have the potential to replace cement applications in architecture and civil engineering, but also have an excellent effect on the stabilization solidification of hazardous industrial wastes. This study used two types of municipal solid waste incineration fly ash (MSWI-FA)—grate firing fly ash (GFFA) and fluidized bed fly ash (FBFA)—as AAMs brick raw materials. It is discovered from this study that AAMs bricks with different weight ratios of GFFA and FBFA can both meet the required standard of GB21144-2007 (Solid concrete brick). From the results obtained from the four leaching tests, the equilibrium pH of the leachate varies, resulting in significant differences in the leaching of heavy metals in Raw GFFA, Raw FBFA, and AAMs bricks with GFFA and FBFA. The AAMs brick with the addition of GFFA and FBFA has an alkali activation system to encapsulate heavy metals. By comparing the results obtained from the CEN/TS 14429 leaching behavior test and the four batch leaching tests, it was found that the most influential factors for the heavy metal leaching concentration are whether the heavy metal has been solidified/stabilized in the samples. GFFA and FBFA tend to have consistent characteristics after being activated by alkali to form AAMs bricks. This can be confirmed by the acid neutralization ability concentrated on a specific pH range. The results obtained from CEN/TS14429 verified that the AAMs bricks with the addition of GFFA and FBFA have excellent environmental compatibility and that it provides a comprehensive evaluation on the environmental compatibility of the test materials and products. This demonstrated that the MSWI-FA is suitable for used as alkali-activated materials and its products have the potential to be commercially used in the future.

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Heavy Metal Leaching Behavior of Glasses Containing EAF Dust

Materials Science Forum ◽

10.4028/www.scientific.net/msf.486-487.382 ◽

2005 ◽

Vol 486-487 ◽

pp. 382-386 ◽

Cited By ~ 2

Author(s):

Hee Tai Eun ◽

Seung Gu Kang ◽

Yoo Taek Kim ◽

Gi Kang Lee ◽

Jung Hwan Kim

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Silicate Glass ◽

Structural Changes ◽

Chemical Durability ◽

Metal Leaching ◽

Lead Silicate ◽

Heavy Metal Leaching ◽

Eaf Dust ◽

Ft Ir

Stabilizing characteristics of heavy metals in the silicate glass (SD) and lead silicate glass(PD) containing Electric Arc Furnace(EAF) dust was studied by the toxic characterization leaching procedure(TCLP) test. Dependence of the amount of EAF dust upon structural changes of SD and PD glasses and TCLP results was also investigated by FT-IR spectroscopy. In the TCLP test, the concentration of heavy metals leached from a glass increased with the amount of EAF dust added. The SD series specimens showed heavy metal leaching lower than the PD series specimens, but the Pb leaching from the PD series specimens was the highest owing to the high Pb content in the PD glass composition. The value R(oxygen/network former ion ratio) was used to compare the leaching characteristics of glasses, and the SD had a higer R than PD series specimens to show a better chemical durability. Adding the EAF dust to the SD mother glass decreased the Si-O-Si symmetry and increased the non-bridging oxygen, which weakened the structure and decreased the chemical durability of glasses. It is concluded that SD is more effective in stabilizing the heavy metals of EAF dust than PD series glass.

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Corrosion of Silicate Glasses and Glass-Ceramics Containing EAF Dust in Acidic Solution

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.124-126.1585 ◽

2007 ◽

Vol 124-126 ◽

pp. 1585-1588 ◽

Cited By ~ 2

Author(s):

Hwan Sik Kim ◽

Yoo Taek Kim ◽

Gi Gang Lee ◽

Jung Hwan Kim ◽

Seung Gu Kang

Keyword(s):

Heavy Metal ◽

Glass Ceramic ◽

Acidic Solution ◽

Glass Ceramics ◽

Glass Network ◽

Metal Leaching ◽

Leaching Test ◽

Spinel Crystal ◽

Heavy Metal Leaching ◽

Eaf Dust

The corrosion behavior of glass and glass-ceramics fabricated with silicate glass frit mixed with 50~70 wt% EAF dust in the acidic solution was analyzed by both heavy metal leaching test and microstructural observation. The crystallization temperature, Tc of glassy specimens was around 850 measured by DTA and the heat treatment temperature to crystallize a glassy specimen was selected as 950 / 1 hr. The spinel crystal peaks were found in XRD analysis for the glass containing dust > 60 wt%. For the glass-ceramics, however, the spinel peaks in a specimen containing dust > 50 wt% was found with weak willemite peaks. The glass and glass-ceramic specimens showed the first stage of corroding reaction according to Clark models in acidic solution. The glass-ceramic specimens showed much lower a heavy metal leaching concentration than that of glass specimens in the corrosion test in acidic solution of pH=2.95. Especially, the glass-ceramics containing dust 60 wt% showed a heavy metal leaching concentration of 66 % Pb, 60 % Zn and 98 % Fe lower than that of glass specimens due to crystal phases formed, thermodynamically more stable than a glass network structure. From the leaching test that more Zn ion leached out than Fe ion, the spinel crystal phase [ZnFe2O4] showed better corrosion resistant in the acidic solution than the willemite [Zn2SiO4].

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