Investigation of properties change in the reacted molten salts after molten chlorides cyclic thermal treatment of toxic MSWI fly ash

Xu, Sihua; Hu, Hongyun; Guo, Guangzhao; Gong, Lifang; Liu, Huimin; Yao, Hong

doi:10.1016/j.jhazmat.2021.126536

Cited by 19 publications

(3 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This indicates that the proportion of NaOH to Na 2 CO 3 , within the tested range, does not affect the hydrogen production capacity during the continuous pyrolysis. On the other hand, molten salt can react with both algae and ash compounds during pyrolysis, which will in turn change its physicochemical properties and affects the algae conversion. , However, the maximum ash accumulation after five cycle reactions of algae will not exceed 0.6 wt % of the molten salt, the effect of ash on the hydrogen production capacity is negligible . Previous studies have reported that ash occupies 20 wt % of the molten salt did not affect the reaction behavior based on the test results from a pilot scale molten salt coal gasifier during continuous operation…”

Section: Resultsmentioning

confidence: 99%

Algae Pyrolysis in Molten NaOH–Na₂CO₃ for Hydrogen Production

Zeng

Zhong

et al. 2023

Environ. Sci. Technol.

View full text Add to dashboard Cite

Biomass pyrolysis within the alkaline molten salt is attractive due to its ability to achieve high hydrogen yield under relatively mild conditions. However, poor contact between biomass, especially the biomass pellet, and hydroxide during the slow heating process, as well as low reaction temperatures, become key factors limiting the hydrogen production. To address these challenges, fast pyrolysis of the algae pellet in molten NaOH–Na2CO3 was conducted at 550, 650, and 750 °C. Algae were chosen as feedstock for their high photosynthetic efficiency and growth rate, and the concept of coupling molten salt with concentrated solar energy was proposed to address the issue of high energy consumption at high temperatures. At 750 °C, the pollutant gases containing Cl and S were completely removed, and the HCN removal rate reached 44.92%. During the continuous pyrolysis process, after a slight increase, the hydrogen yield remained stable at 71.48 mmol/g-algae and constituted 86.10% of the gas products, and a minimum theoretical hydrogen production efficiency of algae can reach 84.86%. Most importantly, the evolution of physicochemical properties of molten NaOH–Na2CO3 was revealed for the first time. Combined with the conversion characteristics of feedstock and gas products, this study provides practical guidance for large-scale application of molten salt including feedstock, operation parameters, and post-treatment process.

show abstract

Section: Resultsmentioning

confidence: 99%

Algae Pyrolysis in Molten NaOH–Na₂CO₃ for Hydrogen Production

Zeng

Zhong

et al. 2023

Environ. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…Although the reduction–thermal separation process for carbon is inexpensive and poses little safety risk, a significant quantity of remnants of carbon remains in the cleaned fly ash. , Xie et al added molten salt (NaCl–CaCl 2 ) to municipal waste incineration fly ash at 800 °C for experiments and found that more than 70% of Zn, Pb, Cu, and Cd were dissolved in molten salt and separated in the residue with a volatilization of <5%. Although calcination thermal separation uses less energy and separates heavy metals from the fly ash matrix at lower temperatures, molten salt thermal separation still results in the generation of residual molten salts. − Currently, these thermal separation technologies remain at the stage of experimentation or proof-of-concept programs and are not yet widely used.…”

Section: Treatment and Disposal Of Heavy Metals In Fly Ashmentioning

confidence: 99%

Advances and Outlook of Heavy Metal Treatment Technology from Municipal Solid Waste Incineration Fly Ash: A Review

Xiao,

Huang,

Cheng

et al. 2023

Energy Fuels

View full text Add to dashboard Cite

With the global industrialization process and socioeconomic development, the amount of municipal solid waste (MSW) generated is growing significantly. With the growth trend of municipal solid waste, incineration is widely used for waste treatment but produces a large amount of municipal solid waste incineration fly ash, which contains heavy metals that can seriously harm human health and the ecological environment. In this Review, the current situation of MSWI fly ash disposal is reviewed, and the technologies for harmless disposal and resource utilization of heavy metals in MSWI fly ash are summarized, including solidification stabilization, leaching extraction, heat treatment, combination methods, etc. We meticulously summarized the recent progress of various incineration fly ash disposal technologies, analyzed the difficulties and solutions in formulating various feasible technical strategies, and compared their potential in the safe, environmentally friendly, and economical utilization of MSW fly ash resources. Furthermore, we also provide an outlook on the potential challenges and prospects of future progress in the harmless disposal and resource recycling of fly ash.

show abstract

“…However, MSWI y ash is also an acknowledged hazardous waste formulated in Directory of National Hazardous Wasted (Version 2021) , causing harm to environment, human body, and the ecosystem due to the enriched in soluble chloride (Čarnogurská et al 2015; Xu et al 2022), some leaching of heavy metals, such as Cd, Pb, Cr, and Zn (Alorro et al 2009; Kirk et al 2002;Mangialardi 2001; Mangialardi et al 1999), and persistent toxic organic compounds, such as PAH, and PCDD/Fs (Min et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Effects and mechanism of the conditions of sintering on heavy metal leaching characteristic in municipal solid waste incineration fly ash

Zhou

et al. 2022

Environ Sci Pollut Res

View full text Add to dashboard Cite

Municipal solid waste incineration (MSWI) y ash treated with toxicity metals holds enormous potential for constructure use to economize on resources and protect environment. To reach the goal, this study investigated the effects of sintering conditions on leaching characteristic of heavy metals for MSWI y ash, especially Cr, Cr 6+ , Ag, and Ba, with orthogonal and Box-Benhnken design experiment, which considered grain size (D 50 =30, 45, and 60μm), uxing agent (CaO=0, 2.5, and 5%), setting temperature (1000, 1050, and 1100℃), and setting time (120, 180, and 240min). The mechanism of immobilization for heavy metals was also discussed through the analyses of morphological characterizations, mineral phases, chemical composition and leaching values of metals. The results indicated that changing grain size and adding uxing agent of CaO has positive in uence on reducing the leaching of heavy metals compared with direct sintering. The leaching values of As, Pb, Cd, Cu, Ni, Zn, Mn, Hg, Be, Se and uoride are not detected after sintering. Ideal sintered condition with desirability of 1.00 was predicted and optimized by Box-Benhnken response method in grain size of D 50 =30μm, uxing agent of CaO=5%, setting temperature=1050℃, and setting time=180min, which immobilized Cr, Cr 6+ , Ag, and Ba lower than the limitation of standards. Actual experiment was consistent with numerical optimization. Furthermore, the model of leaching characteristic for heavy metals in MSWI y ash was established to better explain the mechanism during sintering.

show abstract

Investigation of properties change in the reacted molten salts after molten chlorides cyclic thermal treatment of toxic MSWI fly ash

Cited by 19 publications

References 26 publications

Algae Pyrolysis in Molten NaOH–Na₂CO₃ for Hydrogen Production

Algae Pyrolysis in Molten NaOH–Na₂CO₃ for Hydrogen Production

Advances and Outlook of Heavy Metal Treatment Technology from Municipal Solid Waste Incineration Fly Ash: A Review

Effects and mechanism of the conditions of sintering on heavy metal leaching characteristic in municipal solid waste incineration fly ash

Contact Info

Product

Resources

About

Investigation of properties change in the reacted molten salts after molten chlorides cyclic thermal treatment of toxic MSWI fly ash

Cited by 19 publications

References 26 publications

Algae Pyrolysis in Molten NaOH–Na2CO3 for Hydrogen Production

Algae Pyrolysis in Molten NaOH–Na2CO3 for Hydrogen Production

Advances and Outlook of Heavy Metal Treatment Technology from Municipal Solid Waste Incineration Fly Ash: A Review

Effects and mechanism of the conditions of sintering on heavy metal leaching characteristic in municipal solid waste incineration fly ash

Contact Info

Product

Resources

About

Algae Pyrolysis in Molten NaOH–Na₂CO₃ for Hydrogen Production

Algae Pyrolysis in Molten NaOH–Na₂CO₃ for Hydrogen Production