Immobilizatiaon of heavy metals in municipal solid waste incineration fly ash with red mud-coal gangue
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ORIGINAL ARTICLE
Immobilizatiaon of heavy metals in municipal solid waste incineration fly ash with red mud‑coal gangue Xian Zhou1,2 · Ting Zhang3 · Sha Wan4 · Bo Hu1,2 · Jun Tong1,2 · Hui Sun1,2 · Yuchi Chen4 · Jinfeng Zhang5 · Haobo Hou4 Received: 25 April 2019 / Accepted: 10 July 2020 © Springer Japan KK, part of Springer Nature 2020
Abstract In this research, Bayer red mud (RM) and coal gangue (CG) bend with a ratio of 8:2 was prepared as a geopolymer precursor (RG) through mechanochemistry-alkali activation. It was used for municipal solid waste incineration (MSWI) fly ash solidification/stabilization (S/S). TCLP test, sequential extraction test, long-term immersion test and compressive strength test were used to evaluate the effectiveness and stability of the geopolymer S/S regent. Meanwhile, XRD, SEM–EDS and FTIR were applied for characterization of the geopolymer S/S solid samples. The results showed that more than 99.6% of the heavy metals in geopolymer S/S solid could be immobilized when the RG content exceeded 60%. The S/S effectiveness decreased in the order of Pb > Zn > Cr > Cd. Total content of heavy metals controlled the TCLP leaching behavior, while the availability and diffusivity of heavy metals controlled the long-term leaching behavior. According to XRD results, the MSWI FA can participate in the hydration process to generate Ca-based and Al/Si-based products, thus has double effects to the geopolymerization. In consequence, most heavy metals in the geopolymeric S/S solid were successfully immobilized in the hydration phases and geopolymer structure, transformed from the available fractions into the stable fractions, and the long-term security of heavy metals in RM–CG–MSWI FA ternary system geopolymer was safe. Keywords Geopolymer · Red mud · Municipal solid waste incineration fly ash · Heavy metal · Solidification/stabilization
Introduction
* Xian Zhou [email protected] * Ting Zhang [email protected] 1
Changjiang River Scientific Research Institute, Wuhan 430010, People’s Republic of China
2
Key Laboratory of Geotechnical Mechanics and Engineering of the Ministry of Water Resources, Changjiang River Scientific Research Institute, Wuhan 430010, People’s Republic of China
3
School of Environment and Energy Engineering, Anhui Jianzhu University, Hefei 230601, People’s Republic of China
4
School of Resource and Environmental Science, Wuhan University, Wuhan 430079, People’s Republic of China
5
Hubei Provincial Water Resources and Hydropower Planning Survey and Design Institute, Wuhan 430072, People’s Republic of China
Incineration technology is widely used in municipal solid waste (MSW) management, which can relieve urban land resource shortages. In the grand plan of the 12th Five-year Period (2011–2015), the MSW incineration capacity was increased from 32,485 kiloton to 85,070 kiloton, accounting for 31% of the total MSW treatment capacity in mainland China, and this figure is expected to exceed 50% by the end of the 2020 [1]. Incineration has already become the
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