Safe disposal and recyclability of MSWI fly ash via mold-pressing and alkali-activation technology: Promotion of metakaolin and mechanism

Wei，Xuankun1,2; Shao，Ningning3; Yan，Feng2; Wang，Pengju2; Xie，Feng2; Zhang，Zuotai2

2022-04-01

10.1016/j.jece.2022.107166

Journal of Environmental Chemical Engineering   影响因子和分区

2213-2929

2213-3437

The long-term, efficient and low-cost immobilization of the heavy metals contained in municipal solid waste incineration (MSWI) fly ash, is an important path to realize its harmless and resource treatment. The disposal of MSWI fly ash into geopolymers through alkali activation technology (AAT) can effectively simultaneously immobilize heavy metals and reuse MSWI fly ash. However, how to reduce the dosage of alkaline activator (AA) and improve the compressive strength of treated materials has always been a difficulty in the field. In this study, metakaolin (MK) was added (0 −20 wt%) as an aluminosilicate source to explore its effects on the compressive strength and heavy metal immobilization efficiency of the geopolymers; additionally, mold-pressing method was used to investigate its feasibility of reducing the consumption of AA. The results revealed that, in the case of the 20 wt% MK samples, the compressive strength of the geopolymers can significantly increase to 30.31 MPa, meanwhile, the AA requirement is only 25 wt% of the MSWI fly ash and MK, and the leaching toxicities of various heavy metals were below the limit established by the Chinese standard (GB 16889–2008). The content of free CaO in the optimal samples was observed to decrease to < 1 wt%. In addition, the results revealed that an increase in mold pressure tended to coincide with an increase in the proportion of gel pores (up to 6.98%), which increased geopolymer compressive strength. The main products yielded by the mold-pressed MSWI fly ash geopolymer are sodium-aluminosilicate-hydrate (N-A-S-H) gels.

Geopolymer Heavy metal Metakaolin Mold-pressing MSWI fly ash

SCI ; EI

英语

其他

National Key R&D Program of China[2018YFC1902904] ; National Natural Science Foundation of China[22008104,51772141,52008265] ; Shenzhen Science and Technology Innovation Committee["JCYJ20200109141642225","JCYJ20200109141437586","JCYJ2020010 9141227141","SZIITWDZC2021B01"] ; Basic and Applied Basic Research Foundation of Guangdong Province[2021A1515010148]

Engineering

Engineering, Environmental ; Engineering, Chemical

WOS:000803774500004

ELSEVIER SCI LTD

20220411491070

Aluminosilicates ; Chemical activation ; Compressive strength ; Fly ash ; Geopolymers ; Heavy metals ; Inorganic polymers ; Municipal solid waste ; Sodium compounds ; Waste disposal ; Waste incineration ; Waste treatment

Masonry Materials:414 ; Municipal and Industrial Wastes; Waste Treatment and Disposal:452 ; Industrial Wastes Treatment and Disposal:452.4 ; Metallurgy and Metallography:531 ; Chemical Reactions:802.2 ; Chemical Products Generally:804 ; Inorganic Polymers:815.1.2

2-s2.0-85122976592

Scopus

1.College of Engineering,Peking University,Beijing,100871,China
2.School of Environmental Science and Engineering,Southern University of Science and Technology (SUSTech),Shenzhen,518055,China
3.of Technology for Marine Civil Engineering,Shenzhen Institute of Information Technology,Shenzhen,518172,China

Wei，Xuankun,Shao，Ningning,Yan，Feng,et al. Safe disposal and recyclability of MSWI fly ash via mold-pressing and alkali-activation technology: Promotion of metakaolin and mechanism[J]. Journal of Environmental Chemical Engineering,2022,10(2).

Wei，Xuankun,Shao，Ningning,Yan，Feng,Wang，Pengju,Xie，Feng,&Zhang，Zuotai.(2022).Safe disposal and recyclability of MSWI fly ash via mold-pressing and alkali-activation technology: Promotion of metakaolin and mechanism.Journal of Environmental Chemical Engineering,10(2).

Wei，Xuankun,et al."Safe disposal and recyclability of MSWI fly ash via mold-pressing and alkali-activation technology: Promotion of metakaolin and mechanism".Journal of Environmental Chemical Engineering 10.2(2022).