11. Recovery of phosphorus and metals from the ash of sewage sludge, municipal solid waste, or wood biomass : a review and proposals for further useSara Tominc, Vilma Ducman, Wolfgang Wisniewski, Terttu Luukkonen, Kirkelund Gunvor M., Ottosen Lisbeth M., 2023, izvirni znanstveni članek Povzetek: This review provides an overview of methods to extract valuable resources from the ash fractions of sewage sludge, municipal solid waste, and wood biomass combustion. The resources addressed here include critical raw materials, such as phosphorus, base and precious metals, and rare earth elements for which it is increasingly important to tap into secondary sources in addition to the mining of primary raw materials. The extraction technologies prioritized in this review are based on recycled acids or excess renewable energy to achieve an optimum environmental profile for the extracted resources and provide benefits in the form of local industrial symbioses. The extraction methods cover all scarce and valuable chemical elements contained in the ashes above certain concentration limits. Another important part of this review is defining potential applications for the mineral residues remaining after extraction. Therefore, the aim of this review is to combine the knowledge of resource extraction technology from ashes with possible applications of mineral residues in construction and related sectors to fully close material cycle loops.
Ključne besede: critical raw materials, extraction, sewage sludge ash, municipal solid waste incineration ash, wood biomass ash
Objavljeno v DiRROS: 03.11.2023; Ogledov: 359; Prenosov: 131
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12. Textile industry as a major source of microplastics in the environmentBranka Mušič, 2023, pregledni znanstveni članek Povzetek: This review brings together data on the impact of (micro)plastics, on the environment. Critically evaluates studies on the use of various techniques for recycling textile plastic, which is a major polluter of the environment. In this review, let’s focus a bit more on industrial waste in the textile industry since it would be easiest possible to capture and recycle it again. We also discuss LCA studies, bottlenecks, and future perspectives, for a lower impact on the environment. The main challenges which make further recycling progress difficult are discussed, such as the lamination of textile fibers with metal, new textile fibers that appear as a result of rapid development, the difference in the density of textile fibers, low recycling efficiency, etc. Finally, the possible uses of more environmentally friendly polymers are shown, which can be an alternative to the current synthetic polymers. The results of the literature review showed that for the development of a sustainable textile industry, which would mitigate the impact of microplastics on the environment, from a long-term perspective, the integration of more intensive, complex decisions into the business models of manufacturing companies is necessary. The environmental consequences will be even more intense due to the massive releases of textile microfibers into the environment and excessive accumulation, therefore, in order to achieve the specific goals of sustainable development, a reduction in the production of microplastics is first required, which is only possible with a global partnership of all countries to achieve a specific goal on a global level.
Ključne besede: textile plastics, microplastics, environment, industrial textile waste, LCA, synthetic polymers alternative, recycling techniques
Objavljeno v DiRROS: 05.09.2023; Ogledov: 283; Prenosov: 158
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13. Life cycle assessment of prefabricated geopolymeric façade cladding panels made from large fractions of recycled construction and demolition wasteDavor Kvočka, Anja Lešek, Friderik Knez, Vilma Ducman, Matteo Panizza, Constantinos Tsoutis, Adriana Bernardi, 2020, izvirni znanstveni članek Povzetek: The construction and demolition sector is one of the biggest consumers of natural resources in the world and consequently, one of the biggest waste producers worldwide. The proper management of construction and demolition waste (CDW) can provide major benefits for the construction and recycling industry. However, the recycling rate of CDW is relatively low, as there is still a lack of confidence in the quality of recycled CDW materials. Therefore, new research projects are looking for innovative solutions within recycling of CDW in order to overcome uncertainties currently associated with the use of construction products made from recycled or re-used CDW. In this paper, a “cradle-to-cradle” life cycle assessment (LCA) study has been conducted to investigate the environmental performance of the prefabricated geopolymeric façade cladding panels made from large fractions of CDW. The LCA results indicate that the majority of the environmental burden arises within the manufacturing stage; however, the environmental burden can be reduced with simple optimisation of the manufacturing process. Furthermore, the environmental impact of the prefabricated geopolymeric façade cladding panels is generally lower than the environmental burden associated with the façade cladding panels made from virgin materials.
Ključne besede: construction and demolition waste, alkali activated materials, geopolymers, LCA
Objavljeno v DiRROS: 24.08.2023; Ogledov: 249; Prenosov: 128
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14. Up-scaling and performance assessment of façade panels produced from construction and demolition waste using alkali activation technologyAna Frankovič, Vilma Ducman, Sabina Dolenec, Matteo Panizza, Sergio Tamburini, Marco Natali, Katherine-Maria Pappas, Constantinos Tsoutis, Adriana Bernardi, 2020, izvirni znanstveni članek Povzetek: Novel prefabricated insulating façade panels were developed from construction and demolition waste (CDW) aggregates under the framework of the European H2020 project InnoWEE. These non-structural components, aimed at improving the thermal efficiency of existing buildings, consist of an insulating plate covered by a facing layer made of CDW aggregates bound with metakaolin, furnace slag and class F fly ash activated by a potassium silicate solution. The paper presents the design and assessment of the binder and panels for exterior use, taking into account mechanical performance, behaviour in the presence of water and durability issues. Testing was carried out on both laboratory prototypes and panels from the pilot industrial production.
Ključne besede: construction and demolition waste, alkali activated materials, geopolymers, properties, up-scalimg
Objavljeno v DiRROS: 21.08.2023; Ogledov: 266; Prenosov: 144
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15. Optimization and mechanical-physical characterization of geopolymers with construction and demolition waste (CDW) aggregates for construction productsMatteo Panizza, Marco Natali, Enrico Garbin, Vilma Ducman, Sergio Tamburini, 2020, izvirni znanstveni članek Povzetek: The paper presents the mechanical and physical characterization of a metakaolin-slag-fly ash-potassium silicate geopolymer mortar embedding inorganic recycled aggregates from Construction and Demolition Waste (CDW). The binder was holistically optimized to comply with the pilot plant requirements for producing architectural panels of satisfactory quality, among them: reduced viscosity, minimum open time of 1 h, use of commercial reagents, sufficient strength and limited shrinkage. Size and aspect ratio of small scale cylindrical specimens were investigated in compression, comparing the performance of tested geopolymers to available provisions for natural rocks, cement concrete and mortars. Empirical correlations between compressive and splitting tensile strength were calibrated through the results of about 130 geopolymer mixtures produced in former and current activities. Lastly, the suitability of reusing geopolymers at their end-of-life as recycled aggregates in a new geopolymer production was preliminarily assessed to explore the feasibility of a closed-loop process.
Ključne besede: construction and demolition waste, alkali activated materials, geopolymers, properties
Objavljeno v DiRROS: 17.08.2023; Ogledov: 277; Prenosov: 154
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16. Mechanical, microstructural and mineralogical evaluation of alkali-activated waste glass and stone woolMajda Pavlin, Barbara Horvat, Ana Frankovič, Vilma Ducman, 2021, izvirni znanstveni članek Povzetek: Mineral waste wool represents a significant part of construction and demolition waste (CDW) not yet being successfully re-utilized. In the present study, waste stone wool (SW) and glass wool (GW) in the form received, without removing the binder, were evaluated for their potential use in alkali activation technology. It was confirmed that both can be used in the preparation of alkali-activated materials (AAMs), whether cured at room temperature or at an elevated temperature in order to speed up the reaction. The results show that it is possible to obtain a compressive strength of over 50 MPa using SW or GW as a precursor. A strength of 53 MPa was obtained in AAM based on GW after curing for 3 days at 40 °C, while a similar compressive strength (58 MPa) was achieved after curing the GW mixture for 56 days at room temperature. In general, the mechanical properties of samples based on GW are better than those based on SW. The evolution of mechanical properties and recognition of influential parameters were determined by various microstructural analyses, including XRD, SEM, MIP, and FTIR. The type of activator (solely NaOH or a combination of NaOH and sodium silicate), and the SiO2/Na2O and liquid to solid (L/S) ratios were found to be the significant parameters. A lower SiO2/Na2O ratio and low L/S ratio significantly improve the mechanical strength of AAMs made from both types of mineral wool.
Ključne besede: alkali activation, waste mineral wool, mechanical strength
Objavljeno v DiRROS: 31.07.2023; Ogledov: 248; Prenosov: 235
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17. Influence of microwaves in the early stage of alkali activation on the mechanical strength of alkali-activated materialsBarbara Horvat, Majda Pavlin, Vilma Ducman, 2023, izvirni znanstveni članek Povzetek: This study focuses on the influence of microwave irradiation dosimetry on alkali-activated slurry in its early stages. The impact on the chemistry and mineralogy along with the mechanical properties were evaluated by changing the power of microwaves and their duration of exposure. This influenced the dissolution of amorphous content, diffusion, and self-assembly into an aluminosilicate network. The precursors used in this study were metakaolin, a non-waste material commonly used in geopolymerisation technology, and local fly ash and ladle furnace slag as secondary materials. Furthermore, they were chemically and mineralogically analysed, and their mixtures with NaOH and Na-water glass provided the optimal ratio of the amount of elements obtained using the pre-calculation approach. However, the potential extra addition of water was experimentally determined to allow complete wetting of the material and solid workability during moulding. Using Fourier-transform infrared spectroscopy, the influence of water was further investigated in alkali-activated slag and fly ash irradiated with microwaves, which resulted in the highest values of mechanical strength in the dosimetry-mapping part of the analysis. In addition to the time dependence of the expected mechanical strength on the ageing of the alkali- activated material, the synthesised material exhibited a significant dependence on the dose of microwave irra- diation, which was different for every precursor as well as every mixture with different chemistries.
Ključne besede: odpadni material, alkalijska aktivacija, obsevanje z mikrovalovi, mehanska trdnost, waste material, alkali activation, microwave irradiation, mechanical strength
Objavljeno v DiRROS: 12.07.2023; Ogledov: 366; Prenosov: 274
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18. Preparation of façade panels based on alkali-activated waste mineral wool, their characterization and durability aspectsMajda Pavlin, Barbara Horvat, Vilma Ducman, 2022, izvirni znanstveni članek Povzetek: Mineral wool is a widely used insulation material and one of the largest components of construction and demolition waste, yet it mainly ends up in landfills. In this work, we explored the potential recycling of waste stone wool in the pilot production of alkali-activated façade panels. The current work shows mechanical properties, SEM-EDS and mercury intrusion porosimetry analyses for three different mix designs used for the preparation of façade panels. They are all composed of waste stone wool and differ in the amount of co-binders (local slag, lime, metakaolin and/or fly ash) selected by the preliminary studies. In this study, co-binders were added to increase early strength and improve the mechanical properties and freeze-thaw resistance. The mechanical properties of each were measured up to 256 days, different durability tests were executed, and, by evaluating the mechanical properties, microstructure and workability of the mortar, the most suitable mix was selected to be used for pilot production. In addition, the leaching test of the selected mixture showed no exceeded toxic trace elements and therefore got classified as non-hazardous waste after its use.
Ključne besede: alkali activation, waste mineral wool, SEM, XRF, XRD, mechanical strength
Objavljeno v DiRROS: 19.06.2023; Ogledov: 318; Prenosov: 141
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19. The preparation and characterization of low-temperature foams based on the alkali activation of waste stone woolMajda Pavlin, Barbara Horvat, Mark Češnovar, Vilma Ducman, 2022, izvirni znanstveni članek Povzetek: Waste mineral wool represents a huge amount of construction and demolition waste that is still not adequately returned into the value chain but needs to be landfilled. In the present study, waste stone wool (SW) was evaluated for the preparation of alkali-activated foams. For this purpose SW was milled and sieved below 63 μm, then the activator (sodium silicate) and different amounts of foaming agent (hydrogen peroxide, H2O2), varying between 1 wt% and 3 wt%, were added to the slurry and cured in moulds at an elevated temperature (70 ◦ C) for three days. In this way, foamed, highly porous materials were obtained whose density and mechanical properties were influenced by the amount of foaming agent used. The densities obtained ranged between 1.4 and 0.5 g/cm3, with corresponding mechanical properties of between 12.6 and 1.5 MPa and total porosities in the range 37.8–78.6%, respectively. In the most porous samples with the total porosity of 78.6%, a thermal conductivity of 0.092 W/(m∙K) was confirmed. The study confirmed the suitability of waste mineral wool (in our case SW) as a precursor for alkali-activated foams with potential use in the construction sector or other industrial applications.
Ključne besede: alkali activation, waste mineral wool, mechanical strength, open access, alkalijska aktivacija, odpadna volna, SEM, XRF, XRD, mehanska trdnost, odprti dostop
Objavljeno v DiRROS: 19.06.2023; Ogledov: 265; Prenosov: 205
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20. Environmental acceptability of geotechnical composites from recycled materials : comparative study of laboratory and field investigationsMarija Đurić, Vesna Zalar Serjun, Ana Mladenovič, Alenka Mauko Pranjić, Radmila Milačič, Janez Ščančar, Janko Urbanc, Nina Mali, Alenka Sešek Pavlin, Janez Turk, Primož Oprčkal, 2023, izvirni znanstveni članek Povzetek: The environmental properties of three geotechnical composites made by recycling wastes were investigated on a laboratory scale and in the field with the use of lysimeters designated for the revitalization of degraded mining sites. Composites were prepared by combining the mine waste with paper-mill sludge and foundry sand (Composite 1), with digestate from municipal waste and paper ash (Composite 2), and with coal ash, foundry slag and waste incineration bottom ash (Composite 3). The results of laboratory leaching tests proved that Composites 1 and 3 are envi- ronmentally acceptable, according to the legislative limits, as the potentially hazardous substances were immobilized, while in Composite 2, the legislative limits were exceeded. In the field lysimeters, the lowest rate of leaching was determined for optimally compacted Composites 1 and 3, while for Composite 2 the leaching of Cu was high. This study proved that optimally installed Composites 1 and 3 are environmentally acceptable for use in construction as an alternative to virgin materials, for the revitalization of degraded mining sites or, along with Composite 2, for closure operations with landfills. In this way, locally available waste streams are valorised and channelized into a beneficial and sustainable recycling practice.
Ključne besede: waste, recycling, lysimeter, potentiali hazardous substances, immobilization, revitalisation, environmental, open access
Objavljeno v DiRROS: 29.05.2023; Ogledov: 323; Prenosov: 246
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