Fraunhofer Institute for Wood Research Bio-based circular economy: Fraunhofer WKI researches the reutilization of wood
Researchers at the Fraunhofer WKI are pursuing the goal of creating alternatives to the use of fossil raw materials. Through their work, they are laying important foundations for a circular bioeconomy – from raw resources, through the development of innovative materials and their utilization, and on to recycling. Within the framework of the federal ministry of agriculture’s call for funding applications “Recyclinggerechte Verwendung von Holz” (Recycling-friendly utilization of wood), the Fraunhofer WKI is involved in five of the six research projects. The focus of the projects is aimed at the development of cross-sector solutions for the resource-efficient use of wood, the circular economy and climate protection.
The construction industry is one of the most resource-intensive sectors of the economy. In particular, the production of concrete and steel consumes enormous quantities of finite raw materials and releases huge amounts of CO2. In order to create resource-conserving and climate-friendly buildings, the construction industry is increasingly relying on wood. However, even plant-based raw materials are not infinitely available, or they require time to grow back. Solutions that enable wood and other renewable raw materials to be recycled and re-used after their first utilization, for example as a construction material in a building, are therefore becoming increasingly important. This is the goal of a circular bio-economy.
The highest possible level of recyclability after use is therefore already taken into account by the researchers at the Fraunhofer WKI during the development of new materials. In addition, they design bespoke recycling processes for existing products that contain wood or other plant-based materials - for example wooden components, waste wood or balsa wood from wind-turbine rotor blades. The aim of the work at the Fraunhofer WKI is to enable the utilized raw resources or base materials to be used multiple times (cascade utilization) and thus to reduce the demand for new resources.
Project »Holztafel 2.0.«:
How can prefabricated wooden panels be made recyclable?
Timber frame construction is a very resource-efficient and technically mature construction method and is therefore by far the most common method in timber construction. However, the material mix of metallic, organic and mineral components makes it difficult to separate the individual components by type. Researchers at the Fraunhofer WKI, in collaboration with the Technische Universität Braunschweig, the Ruhr-Universität Bochum and four industrial partners (Otto Baukmeier Holzbau-Fertigbau GmbH & Co. KG, Sto SE & Co. KGaA, Fermacell - James Hardie Europe GmbH, and ALBA Braunschweig GmbH), want to change this. By the end of 2026, the project team wants to have developed wood panels that are significantly easier to recycle by type. The raw materials recovered during the recycling process can be used as starting materials for new products. At the end of the project, a number of demonstrators are intended to demonstrate the feasibility of the “Design for Recycling” of the wooden panel, the recycling processes and the reutilization of the recovered raw materials in new products.
Project »DANSIZ«:
How can waste wood be better sorted and processed in order to make it usable as a material?
Researchers at the Fraunhofer WKI and the Fraunhofer IOSB, in collaboration with the Pallmann company, want to find ways to increase the material recycling of waste wood. Up until now, a large proportion of waste wood has only been thermally recycled, as incorrectly sorted waste results in critical contaminants entering the waste-wood material stream. In order to be able to remove these contaminants reliably and automatically in future, the project team is developing an innovative sorting process on the basis of near-infrared (NIR) sensor technology. As a result, large quantities of waste wood can be used for higher-value applications. The development of waste-wood-specific shredding processes is intended to further improve the quality of the raw material. Both processes should make the use of waste wood significantly more attractive for the wood-based materials industry. As an application example, the project team would like to develop particle boards or wood-plastic composites on the basis of waste wood.
Project »Recycling for Reuse«:
How can pollutants and metal residues be removed from waste wood?
Researchers from the Fraunhofer WKI, in collaboration with the Technische Universität Braunschweig, the Leipzig University of Applied Sciences and the industrial partners Ing.-Holzbau Schnoor GmbH, Rinntech-Metriwerk GmbH & Co. KG and Schumann analytics want to find out how waste wood can be processed in such a way that it is suitable for re-use in the manufacture of components. The challenge lies in the fact that waste wood is often contaminated with harmful substances, for example through the use of wood preservatives or coatings. In order to be able to re-use waste wood, it must therefore first be cleaned to such an extent that it is considered harmless in accordance with the Waste Wood Ordinance. In collaboration with industrial partners, the scientists first want to determine the quantities in which potentially recyclable waste wood is accrued. In addition, they are developing mechanical processes in order to detect and remove metallic foreign bodies (nails and screws) and wood preservatives from waste wood. The aim is to develop classification rules for the re-use of the construction material and a holistic re-use concept in the form of a schematized process plan.
Project »AltholzAerogel«:
Is waste wood suitable for the production of aerogels?
Aerogels are highly porous, feather-light materials with exceptional properties: extremely low thermal conductivity, low sound transmission and high adsorption capacity for volatile organic compounds. They are ideally suited both for lightweight construction and as a filter material and are therefore regarded as the material of the future. In collaboration with the German Aerospace Center (DLR) and eight industrial partners, researchers at the Fraunhofer WKI are developing a process for the production of aerogels on the basis of waste wood. The project partners are using the aerogels to produce prototypes of insulation materials and pollutant-adsorbing room-air filters that can be utilized in buildings and vehicles. Furthermore, transfer possibilities for applications in exhaust-gas purification will be identified. A further project objective is the recovery of the raw materials required for the manufacture of the aerogels from the products.
Project »ReKonFu«:
How can furniture be recycled more easily?
Hinges for modular furniture are currently predominantly made of metal. In collaboration with the Institut für Holztechnologie Dresden gemeinnützige GmbH (IHD) and business partner Topp Textil GmbH, the Fraunhofer WKI is developing an adjustable and detachable textile hinge on the basis of natural fibers for wooden furniture. The aim is to reduce the consumption of metals and, at the same time, improve the recyclability of the furniture. Up until now, the metal hinges, which are often screwed or pressed in, have had to be separated from the waste wood during the recycling process. This separation is time-consuming and can require complex plant technology. The new textile fittings are not firmly attached to the wooden construction and can therefore be adjusted and removed. This flexibility also enables them to be utilized in the field of cash-and-carry and flat-pack furniture. Furthermore, components – particularly the furniture doors – can be easily replaced. This facilitates repairs or the adaptation of the furniture to new color trends and, consequently, increases the service life of the furniture carcasses. The recyclability of the textile hinge itself will also be evaluated within the framework of the project. Upon successful completion of the project, a new type of hinge will be available that has been developed with “Design for Recycling” in mind and that represents a sustainable alternative to conventional metal fittings.
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