| 1. |
- Ebert, Benjamin A. R., et al.
(author)
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Screening of untreated municipal solid waste incineration fly ash for use in cement-based materials: chemical and physical properties
- 2020
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In: SN Applied Sciences. - : Springer Science and Business Media LLC. - 2523-3971 .- 2523-3963. ; 2:5
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Journal article (peer-reviewed)abstract
- The environmental impact during concrete manufacturing can be reduced by using less cement or using types of cement with high amounts of secondary cementitious materials (SCMs) and fillers. Fly ash from municipal solid waste incineration (MSWI) is an unused material, which could potentially be used as an SCM or filler. The applicability of MSWI fly ash samples in cement-based materials was investigated through an indirect determination based on the chemical composition, toxic metal content and particle size distribution of the samples. Furthermore, how the samples compared to each other and how representative the samples were for MSWI fly ash, in general, were investigated by multivariate modelling. MSWI fly ash samples were obtained from Denmark, Sweden and Greenland. Comparing the chemical composition of the MSWI fly ash samples with the chemical requirements for coal fly ash to be used in concrete, specified in EN 450-1 2012, indicated a low potential as SCMs. Additionally, the MSWI fly ash contained and leached more toxic metals than the allowed limits. The particle size distributions were larger than cement and indicated limited potential as filler. A principal component analysis showed that the obtained samples were chemically different materials compared to each other and would have different effects if used in cement-based materials. Additionally, the samples from Denmark were unrepresentative of MSWI fly ash, while the Greenlandic and Swedish samples were comparable to previously studied MSWI fly ash samples.
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| 2. |
- Gogolev, Ivan, 1984, et al.
(author)
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Investigation of biomass alkali release in a dual circulating fluidized bed chemical looping combustion system
- 2021
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In: Fuel. - : Elsevier BV. - 0016-2361. ; 297
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Journal article (peer-reviewed)abstract
- Chemical looping combustion (CLC) of biomass is a promising technology for power generation with integrated carbon capture. In CLC, alkali content of biomass poses potential issues of bed agglomeration, as well as heat exchanger fouling and corrosion. The fate of biomass alkalis was investigated in a dual-interconnected circulating fluidized bed CLC system. Experiments were conducted in oxygen carrier aided combustion (OCAC) and CLC modes. Ilmenite and braunite oxygen carriers and three biomass fuels (wood pellets, wood char, straw pellets) were tested. Flue gas alkali emissions in the air reactor (AR) and fuel reactor (FR) were measured with a surface ionization detector (SID). Results showed that CLC operation yields gas-phase alkali emissions that are up to 15 times higher than in comparable OCAC operation. Results analysis concluded that increased alkali emissions in CLC arise from the steam atmosphere in the FR, whereby steam accelerates the decomposition of alkali compounds in the biomass. Retention of alkalis in the condensed phase was found to be >97% for ilmenite and >92% for braunite CLC operation. Up to 60?80% of the retention was attributed to fuel ash formation. The residual retention was attributed to absorption of alkalis by the oxygen carriers. Absorption likely occurred mainly through formation of alkali manganates and silicates in braunite, and formation of alkali silicates, aluminosilicates, manganates, and titanates in ilmenite. Gas-phase alkali emissions in the AR, although less than in the FR, were found to occur due to combustion of unconverted fuel carried over from the FR to the AR.
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| 3. |
- Liu, Hu, et al.
(author)
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Comprehensive treatments of tungsten slags in China: A critical review
- 2020
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In: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 270
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Research review (peer-reviewed)abstract
- As a critical and strategic metal, tungsten is widely used in the fields of machinery, mining and military industry. With most of the tungsten resources reserves in the world, China is the largest producer and exporter of tungsten. This has resulted in the generation of a huge amount of tungsten slag (slag) stored in China. This slag always contains not only valuable elements, such as tungsten (W), scandium (Sc), tin (Sn), niobium (Nb) and tantalum (Ta), but also toxic elements, such as arsenic (As), lead (Pb), chromium (Cr) and mercury (Hg). Due to a lack of developed technologies, most of these slags cannot be treated safely, which results in a waste of resources and serious environmental and ecological risks. In this review we briefly describe the distribution and proportion of tungsten deposits in China, the tungsten extraction process and the properties of tungsten slag. We also mainly discuss the comprehensive treatments for the valuable and toxic slag, including the amounts of valuable metal elements that can be recovered and the stabilization of toxic elements. These aspects are summarized in a comparison of their advantages and disadvantages. In particular, we focus on the efforts to analyze the relationship between the existing processes and attempts to establish a comprehensive technology to treat tungsten slag and also suggest areas for future research.
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| 4. |
- Lombardo, Gabriele, 1990, et al.
(author)
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Comparison of the effects of incineration, vacuum pyrolysis and dynamic pyrolysis on the composition of NMC-lithium battery cathode-material production scraps and separation of the current collector
- 2021
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In: Resources, Conservation and Recycling. - : Elsevier BV. - 0921-3449 .- 1879-0658. ; 164
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Journal article (peer-reviewed)abstract
- The rising demand for lithium batteries is challenging battery producers to increase their production. This is causing an accumulation of production scrap which must be treated to allow re-utilization of cathode material in production. Several industrial lithium battery recycling processes use thermal pre-treatment in an oxidative or inert atmosphere, or in a vacuum, to separate the battery components and remove organic material. However, a comparison of the effects of incineration, dynamic pyrolysis (under a constant flow of inert gas), and pyrolysis under vacuum on the microstructure and composition of scrap cathode material has not been explored. Scrap cathodes, with active material based on Li(NixMnyCoz)Oj, were subjected to incineration, dynamic pyrolysis, and pyrolysis under vacuum at 450˚, 550˚, and 650°C for 30, 60, 90, and 150 min to determine the best approach to cathode material recovery. While the incineration did not cause any chemical transformation of cathode material, under pyrolysis conditions the organic components in the cathodes triggered carbothermic reduction of the active material, yielding Co3O4, NiO, Mn3O4, and Li2CO3 as products. In the gas by-products, formed from the decomposition of the organic material, CO, CO2, and HF were determined. The decomposition especially of the binder in polyvinylidene fluoride (PVDF) facilitated the separation of the active material from the current collector by mechanical treatment. By subsequent ball milling, the best technique to recover cathode material is the incineration at a temperature higher than 550˚ C and below 650˚ C for at least 90 min, with >95% of recovered active material.
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| 5. |
- Lombardo, Gabriele, 1990, et al.
(author)
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Determination of Hydrofluoric Acid Formation During Fire Accidents of Lithium-Ion Batteries with a Direct Cooling System Based on the Refrigeration Liquids
- 2023
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In: Fire technology. - : Springer. - 0015-2684 .- 1572-8099. ; 59:5, s. 2375-2388
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Journal article (peer-reviewed)abstract
- To avoid overheating of the batteries, which could lead to a fire, Lithium-ion batteries are provided with a thermal management system using refrigeration liquids. Since some of the commercial dielectric liquids used as refrigeration liquids contain halogens, their presence will contribute to a formation of hazardous emissions such as hydrofluoric acid during a potential fire. In this study, a simulation of a high temperature accident has been performed for lithium-ion batteries cooled with the direct immersion cooling systems using single-phase dielectric liquids to define their contribution to HF formation. Four commercial refrigeration liquids based on perfluoropolyethers, hydrofluoroether and polyalphaolefin were investigated in this work. By simulation of a fire, it was observed that the refrigeration liquids delayed the smoke formation by a factor of 2 to 2.5 in comparison to the case when the battery was burned without the cooling liquid. By analysis of the fluoride concentration in the washing system, it was determined that without the refrigeration liquid approximately 46.8 mmol/l of [F] was captured after the fire. When refrigeration liquids based on two perfluoropolyethers and hydrofluoroether were applied, the fluoride concentration in the washing system was 259 mmol/l, 173 mmol/l and 145 mmol/l, respectively. This work also proposed the reaction mechanisms of the refrigeration liquid ' s decomposition during a fire. It was concluded that the refrigeration liquid based on polyalphaolefin does not contribute to the additional formation of hydrofluoric acid due to the chemical stability and low content of fluoride and can be considered as a more sustainable alternative for a direct cooling system for Lithium-ion batteries.
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| 6. |
- Lombardo, Gabriele, 1990, et al.
(author)
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Incineration of EV Lithium-ion batteries as a pretreatment for recycling – Determination of the potential formation of hazardous by-products and effects on metal compounds
- 2020
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In: Journal of Hazardous Materials. - : Elsevier BV. - 1873-3336 .- 0304-3894. ; 393
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Journal article (peer-reviewed)abstract
- In several industrial Lithium-ion batteries recycling processes, a thermal treatment with oxidative atmosphere is used to separate the battery components and to remove the organic components. This method is often combined with hydrometallurgical processes with the aim to increase the metal recovery rate or to improve the efficiency of the existing processes. Despite such efforts, the effects of a thermal treatment in an oxidative atmosphere on the microstructure and composition on cathode and anode materials has not been explored. In this manuscript, spent batteries which cathode active material has the composition Li(NixMnyCoz)Oz, i.e. NMC-LiBs, were subjected to thermal treatment at 400˚, 500˚, 600˚, and 700 °C for 30, 60, and 90 min. The microstructure and the composition were studied using XRD and ICP-OES. Thermodynamic calculations were performed to forecast the trend of the carbothermic reduction of active materials. It was observed the formation of gas and organic oil by-products from the decomposition of the polypropylene separator and the polyvinylidene fluoride binder. The identification of the composition of these by-products has great importance since they have a corrosive and toxic behavior. It was observed the fluorine behavior during the thermal treatment and its presence in the oil by-products.
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| 7. |
- Rissler, Jenny, et al.
(author)
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Identification and Quantification of Chemical Forms of Cu and Zn in MSWI Ashes Using XANES
- 2020
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In: Energy & Fuels. - : American Chemical Society. - 0887-0624 .- 1520-5029. ; 34:11, s. 14505-14514
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Journal article (peer-reviewed)abstract
- Incineration is in many countries a common treatment method for municipal solid waste, and utilization of the ash residues has attracted significant interest. The bottom ash is best suited as a secondary construction material, whereas the fly ash is being investigated as a secondary raw material for recovery of, for example, Zn, Cu, and salts. For both types of application, knowledge about the chemical speciation of Zn and Cu in the ashes is valuable. The present work focuses on identifying and quantifying the chemical species of Zn and Cu in 12 samples of fly ash and bottom ash from three waste-to-energy plants using X-ray absorption near edge structure (XANES). The XANES spectra of the ash samples showed similar distinctive features, and both in the bottom and fly ash samples, the same chemical forms were identified but in various ratios. Cu and Zn occurred in several chemical forms, with typically 5-7 forms present in the same sample. For Cu, the XANES spectra of the fly ash samples were nearly identical, indicating very similar chemical speciation (same chemical forms and similar ratios). Cu was found to exist in various oxide, hydroxide, chloride, silicate, and metallic forms. The most commonly occurring Zn compounds were the aluminate, ferrite, silicate, and oxide along with chloride, basic carbonate (hydrozincite), and occasionally metallic forms, probably alloyed with Cu in brass. Cu occurred in different oxidation states from zero to +II, with a higher prevalence of the lower oxidation states in bottom ash than in fly ash. Zn occurred mainly in oxidation state +II in all ashes analyzed. Finally, we showed that during outdoor storage of bottom ash, levels of Cu and Zn hydroxycarbonates were increased compared to fresh bottom ash. This carbonate formation aims to make Cu and Zn less leachable.
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| 8. |
- Smol, Marzena, et al.
(author)
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Strategies for sustainable and circular management of phosphorus in the baltic sea region: The holistic approach of the inPhos project
- 2020
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In: Sustainability. - : MDPI AG. - 2071-1050. ; 12:6
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Journal article (peer-reviewed)abstract
- Despite the significant reduction of phosphorus (P) discharge in the Baltic Sea in the last decades, obtained through the implementation of some approaches within the Helsinki Convention, eutrophication is still considered the biggest problem for the Baltic Sea environment. Consequently, the reduction of P load is an urgent need to solve, but the complexity of both the environmental and legislative context of the area makes this process difficult (more than in the past). Eutrophication is an intricate issue requiring a proper framework of governance that is not easy to determine in the Baltic Sea Region where the needs of several different countries converge. To identify the most suitable strategy to reduce the eutrophication in the Baltic Sea, the InPhos project (no. 17022, 2018-2019, funded by the European Institute of Innovation & Technology (EIT) Raw Materials) adopted a holistic approach considering technical, political, economic, environmental and social aspects of P management. With the aims to raise awareness about the P challenge, foster the dialogue among all the stakeholders, and find solutions already developed in other countries (such as Germany and Switzerland) to be transferred in the Baltic Sea Region, the InPhos project consortium applied the methodology proposed in this paper, consisting of three main phases: (i) analysis of the available technologies to remove P from waste streams that contribute to eutrophication; (ii) analysis of the main streams involving P in Baltic Sea countries to highlight the potential of more sustainable and circular P management; (iii) study of the current context (e.g., already-existing initiatives and issues). This approach allowed us to identify four categories of recommendations and practical actions proposed to improve P management in the Baltic Sea region. During the project, the consortium mainly addressed social aspects. Following steps beyond the project will be more quantitative to determine the techno-economic feasibility of circular P management in selected demo cases in the region.
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| 9. |
- Tao, Meng, et al.
(author)
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Major challenges and opportunities in silicon solar module recycling
- 2020
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In: Progress in Photovoltaics: Research and Applications. - : Wiley. - 1099-159X .- 1062-7995. ; 28:10, s. 1077-1088
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Journal article (peer-reviewed)abstract
- This article examines some of the basic questions about silicon module recycling: (1) What can be recovered from silicon modules? (2) What recycling technologies are needed? (3) What are the potential revenues for different recycling scenarios? And (4) what are the major challenges for different recycling scenarios? Three recycling scenarios are considered: module reuse, component extraction, and material extraction. Recycling process sequences for different scenarios are outlined. The discussions conclude that module reuse generates the highest revenue with the fewest processing steps, while material extraction leads to the lowest revenue with the most processing steps. It is suggested that gentle and clean separation of silicon solar cells from the glass pane is a critical technology for silicon module recycling. It is also argued that two low-concentration metals must be recovered from silicon modules: silver as a scarce material and lead as a toxic material. Their recovery requires chemical methods, while bulky materials including glass cullet, aluminum frame, and copper wiring can be recovered with physical methods. The silicon in the cells can be extracted with different qualities: ferro-silicon, metallurgical-grade silicon, or solar-grade silicon, with a higher revenue and more complicated recycling process for purer silicon. Markets outside the solar industry for the recovered silicon should be explored. The biggest challenge for module reuse is to find a large and sustained market for hundreds of gigawatts peak of decommissioned modules a year, and the biggest challenge for component extraction is the many different module and cell structures on the market and cell efficiency variability. For all the three scenarios, the cost of collecting and processing waste modules is a common challenge.
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| 10. |
- Yilmaz, Duygu, 1987, et al.
(author)
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Comparative Study: Impacts of Ca and Mg Salts on Iron Oxygen Carriers in Chemical Looping Combustion of Biomass
- 2021
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In: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 6:25, s. 16649-16660
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Journal article (peer-reviewed)abstract
- Chemical looping combustion (CLC) is one of the most promising methods for carbon capture and storage (CCS). An oxygen carrier, i.e., a mineral that can be oxidized and reduced, is used to convert the fuel in the process. The produced CO2 is inherently separated from the air components that enables easier CCS. The use of biomass-based fuels is desirable since it can lead to negative CO2 emissions. On the other hand, alkali compounds from the biomass may interact with the oxygen carrier causing problems, such as deactivation of the oxygen carrier. The most common oxygen carriers contain iron, since iron-based ores and industrial waste materials are readily available and cost-efficient. Therefore, the interaction between the iron oxygen carriers and the biomass ash-forming compounds needs to be investigated. Since Ca/Mg are abundant in biomass, it is important to clarify how their compounds interact with the oxygen carrier. In this study, the effect of Ca/Mg carbonates, chlorides, nitrates, sulfates, and phosphates along with synthetic biomass-derived ash on iron oxides was investigated. Redox reactions were investigated at 950 degrees C during 5 h under both oxidizing and reducing atmospheres. The results showed that the effect of Ca/Mg salts on the oxygen carrier varied depending on the anion of the salt. Generally, the nitrate- and phosphate-based salts of both Ca and Mg showed the harshest effect regarding agglomeration of the oxygen carriers. It was shown that the Ca/Mg-based compounds interacted differently with iron oxides, which was an unexpected result.
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