Recycling potential of recycled carbon fibers used in textile concrete from a technical and environmental point of view
© Lehrstuhl fĂĽr Abfallverwertungstechnik und Abfallwirtschaft der Montanuniversität Leoben (11/2022)
As an important element in construction industry, cement production caused alone 2 % of total greenhouse gas emissions in Germany in 2017 and global average was even with a greater value, 8 % (WWF 2019). Considering the great impact of construction industry on the environment, Fiber reinforcement (carbon or glass) is seen as a meaningful alternative to steel reinforcement in the production of concrete. Due to their low weight, high strength and lifetime, carbon fibers have been increasingly used in construction industry. On the one hand, the use of CF reinforced concrete enables great amount of resource savings compared to conventional concrete, specifically steel reinforced concrete (Böhm et al. 2018). On the other hand, CFs have some disadvantages, such as high cost, energy intensive production process and challenging end-of-life (EOL) handling (Zhang et al. 2020).

On the road to 2050: The path to achieving a circular economy for mobility and renewable energy
© Lehrstuhl fĂĽr Abfallverwertungstechnik und Abfallwirtschaft der Montanuniversität Leoben (11/2022)
Climate change is one of the biggest crises humanity is facing at this time (Zwane E. M. 2019). Two of the largest emitters of greenhouse gas (GHG) emissions are the mobility (14% of global GHG emissions in 2018) and energy (34%) sector (Lamb et al. 2021), which require a major shift towards renewable energy and alternative fuel systems to succesfully contribute to GHG emission goals (O’Neill et al. 2018). However, this transition comes with its own set of challenges, in particular an increased resource intensity, its dependence on critical minerals and metals, as well as sustainability challenges in the technologies’ supply chains (Mancini & Nuss 2020, Wang et al. 2020). These challenges highlight the need for more sustainable resource management from mining, to consumption, to reuse and recycling, and progress towards a clean and circular economy (Smol et al. 2020).

Metrology for the Recycling of Technology Critical Elements to Support Europe’s Circular Economy
© Lehrstuhl fĂĽr Abfallverwertungstechnik und Abfallwirtschaft der Montanuniversität Leoben (11/2022)
Technology critical elements (TCEs) are vastly used throughout societal consumer products; including phones, computers, and renewable energy products, such as solar panels and wind turbines. These elements are deemed critical due to their economic importance and supply risk. However, dwindling supplies of TCEs threaten to disrupt such technology production worldwide, which is especially concerning given a recent drive for more renewable energy sources as part of the European Green Deal. Thus, there is a drive for the European Union (EU) to strive for a circular economy approach that reduces dependence on imports of such raw materials. To provide a more secure supply of TCEs, the EU promotes more efficient recycling through the Waste Framework Directive (2018/851/EU).

Experimental Methods to Assess the Thermal Stability of Reactive Chemical Waste stored in Large Waste Tanks
© Lehrstuhl fĂĽr Abfallverwertungstechnik und Abfallwirtschaft der Montanuniversität Leoben (11/2022)
The storage of a reactive chemical waste in large storage tanks can lead to a thermal explosion, as was the case recently in July 2021 at Currenta in Leverkusen-BĂĽrrig (Germany) (Currenta 2022). In addition to considerable property damage, 7 people were killed and 31 injured. Therefore, the thermal risk for the storage of reactive waste must be assessed in advance and appropriate risk-minimizing measures must be taken.

Analysis of different polypropylene waste bales – evaluation of the source material for polypropylene recycling
© Lehrstuhl fĂĽr Abfallverwertungstechnik und Abfallwirtschaft der Montanuniversität Leoben (11/2022)
In 2020 Polypropylene (PP) accounted for almost 20% of the plastic consumption in Europe, making it the second most used plastic (Plastics Europe 2021). Due to the high volume of PP used as packaging material (Plastics Europe 2021), large amounts of PP waste are generated every year. Therefore, mechanical recycling of PP waste is a crucial step towards a circular economy. Although there are already some well-established recycling techniques, the lower quality of recyclates compared to virgin materials still poses an obstacle for their use in more demanding applications. Improvements of every step of the whole recycling value chain could solve this problem, with proper and more accurate sorting techniques being particularly crucial.

Mechanical short-term and long-term properties of PP recyclate blends
© Lehrstuhl fĂĽr Abfallverwertungstechnik und Abfallwirtschaft der Montanuniversität Leoben (11/2022)
The amount of recycled material in new products should be increased in the next few years. By adding virgin material, the mechanical properties of the pure recyclate can be improved. In this work, 10 % and 40 % post-consumer recyclate was added to a virgin material and analyzed. Both raw materials were also tested. The short-term as well as the long-term properties decrease with increasing recyclate content. The recyclate has a higher influence on the young’s modulus, yield stress and slow crack growth resistance than on the notched impact toughness.

Estimation of Recycling Potential of Multilayer Films in Austria
© Lehrstuhl fĂĽr Abfallverwertungstechnik und Abfallwirtschaft der Montanuniversität Leoben (11/2022)
It is impossible to imagine today’s society and economy without plastic and plastic packaging is in particular focus. Worldwide, 368 million tons of plastic were produced in 2019, of which 57.9 million tons in the European Union (EU). They account for more than a third of all plastic products in Europe and are particularly conspicuous because of their short lifespan and ubiquitous distribution in the environment worldwide. (Plastic Europe 2020) According to Eurostat, plastic packaging is accountable for 15.4 million tons or 177.4 kg of waste plastic packaging per citizen in 2019 (Eurostat 2021). Hence, the proliferation of plastic in all areas of life has become an increasingly visible issue and its impact on the environment is the subject of heated debate.

Fundamental drying experiments with processed residual municipal solid waste materials
© Lehrstuhl fĂĽr Abfallverwertungstechnik und Abfallwirtschaft der Montanuniversität Leoben (11/2022)
Waste management companies and municipalities in southwestern Hungary aim the fulfillment of the EU’s target, namely to decrease landfilling below 10 % and increase recycling above 65 % of municipal solid wastes. However selective collection is continuously improved there is still high amount of residual MSW is generated. A new mechanical RMSW processing plant (20 t/h) and an experimental RDF pyrolysis plant (200 kg/h) had been built (Faitli et al. 2020) and now extensive research is being carried out to solve the local utilization of the bio-fraction and the RDF. This is the reason why this fundamental drying research was necessary. Dryer classification and the selection of the best solid waste drying techniques vary significantly due to the vast range of waste to be dried and the inherent challenges of dealing with non-standardized systems. In general, biomass dryers may be categorized according to their heat transmission technique and the physical qualities of wet particles.

Refine the circular economy by rethinking it - a holistic approach for the advanced circular economy
© Lehrstuhl fĂĽr Abfallverwertungstechnik und Abfallwirtschaft der Montanuniversität Leoben (11/2022)
The Circular Economy is a recent economic approach aiming to transform the linear economy into a sustainable system including the economic, ecological, and social dimensions. The transformation faces various barriers and obstacles, each in a different field inside the value system. Three different (sub-system) approaches were developed independently to address those hurdles and provide solutions to mitigate them. The paper will briefly describe those approaches, including their strengths and weaknesses. Out of each of the three individual sub-systems, these sub-systems are combined in a holistic approach and presented as the Advanced Circular Economy. The system is developed on a meta-level. Nevertheless, a very crucial example, namely traction batteries for electric vehicles, will be given to show the relevance of the system within the current economic surroundings and explain the overall system of the Advanced Circular Economy.

The AHOY-Project: Waste Wood Sorting with X-ray Technology
© Lehrstuhl fĂĽr Abfallverwertungstechnik und Abfallwirtschaft der Montanuniversität Leoben (11/2022)
Waste wood is a valuable resource, but is hardly recycled despite increasing demand, predicted supply gaps (Mantau et al. 2010), and galloping wood prices since 2020 (Trading Economics 2022). In Germany alone around 10 million tons of waste wood accumulated in 2016. Only a minor part (1.7 million tons) is substantially reused in the production of chipboards. The majority (7.7 million tons) is fed into energy recovery, i.e., burned in one of the 80 German waste wood power plants (BMUV 2021), and is thus lost, while the supply of fresh wood is limited by slow growth cycles and finite acreage. In view of current environmental regulations, climate change and massive tree mortality, waste wood should be kept permanently in the circular economy as a high-quality raw material in the future.

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