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Fly ash and zinc slag blended geopolymer: Immobilization of hazardous materials and development of paving blocks

IR@NML: CSIR-National Metallurgical Laboratory, Jamshedpur

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Title Fly ash and zinc slag blended geopolymer: Immobilization of hazardous materials and development of paving blocks
 
Creator Nath, S K
 
Subject Waste Management
 
Description The potential for practical application of fly ash, zinc slag and their blends for geopolymer synthesis at ambient temperature have been investigated in this paper. Fly ash is an alumino-silicate byproduct suitable for geopolymer reaction, but its low reactivity at ambient condition is the restriction of its bulk utilization. Above limitation can be overcome by blending with zinc slag (ZS). Additionally, ZS contains heavy and toxic metals (Pb, Zn, Cr, Cd, As), which can be stabilize in Al-Si based geopolymer network structure. Isothermal conduction calorimetry (ICC) is used to monitor the geopolymer reaction with time. Slag rich specimens are characterized with higher rate of reaction with augmented peak. The mineralogy and microstructure of the geopolymers have been examined through X-ray diffraction and scanning electron microscope. The detected chief reaction product is N-(C)-A-S-H and C-(N)-A-S-H1 type hydrated gel. Continual improvement of compressive strength of the geopolymers with increasing slag content is explained with higher degree of reaction, formation of more reaction products and development of compact microstructure. According to toxicity characteristic leaching procedure (TCLP), toxic metals leaching is within permissible limit. Paver blocks using 40−80 wt% ZS has been developed, which meets IS 15,658: 2006 standard and comply with US-EPA specification.
 
Publisher Elsevier
 
Date 2020-04-05
 
Type Article
PeerReviewed
 
Format application/pdf
 
Identifier http://eprints.nmlindia.org/8062/1/ZnS_FA_JHM.pdf
Nath, S K (2020) Fly ash and zinc slag blended geopolymer: Immobilization of hazardous materials and development of paving blocks. Journal of Hazardous Materials, 387 (IF-9.038). p. 121673.
 
Relation https://doi.org/10.1016/j.jhazmat.2019.121673
http://eprints.nmlindia.org/8062/