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Mineral wool waste back to loop with advanced sorting, pre-treatment, and alkali activation

Periodic Reporting for period 3 - WOOL2LOOP (Mineral wool waste back to loop with advanced sorting, pre-treatment, and alkali activation)

Période du rapport: 2021-12-01 au 2022-11-30

The theoretical maximum of mineral wool that could unlocked for exploitation is 2.5 Mt/year (the current formation rate) – that is also the amount of material, which strongly underexploited. Although this is only 0.2% of all CDW, it takes disproportionally large space due to low density and landfilling is getting increasingly expensive (expected cost will generally exceed 100 €/t of landfilled waste in the near future). Furthermore, the amount of mineral wool waste is expected to keep increasing worldwide, due to more stringent energy regulations: better insulation is one of the easiest ways to reduce the total environmental impact of buildings in cold and warm climates alike. The WOOL2LOOP project aimed to close this material loop by introducing novel technologies, adopting new concepts and value chain collaboration to CDW sorting, pre-treatment, and processing up to novel construction materials, such as:.
• pre-demolition audit
• on-site analysis with time-gated Raman spectroscopy and handheld XRF technology
• smart robotized demolition
• compression, baling, shredding, pre-processing milling technologies to achieve needed particle size
• alkali-activation (i.e. geopolymerization) technology to convert reactive silica and alumina of the mineral wool into new building material products.


The overall objective of the WOOL2LOOP project was and is still to divert mineral wool as CDW from landfilling and to develop its utilization into novel applications, meanwhile securing the access to sustainable, alternative, circular raw materials for the construction industry in the future.

A broad selection of products were produced in large-scale pilots from relatively low to high value products: precast concrete elements, pavement slabs, facade elements, acoustic panels, dry concrete, floor screed and 3D-printing equipment. Geographically consortium covered 9 countries within the EU and 14 partners from global large construction material producers, research institutes and innovative SME. Environmental, health, safety (EHS) and economic aspects were considered throughout the project. There is a strong business potential in the WOOL2LOOP concept, not only because of constantly increasing landfilling costs of mineral wool as economic driver for the project, construction material industry is more active than ever in adoption of alternative circular raw materials replacing CO2 -intensive binder systems like OPC. The key impacts of the project beyond academic outputs are 6 patent applications and industrial partners’ conviction to WOOL2LOOP circular concept. Product manufacturers are investing, investigating the concept up-scaling in their own industrial set-up as well testing and finalizing final recipes while also addressing learned (by today resolvable) challenges. The project started on 1st June 2019 and ended on 30th of November 2022.
Project ended without major failures. In the light of project objectives rmain results can be described as below;

One critical aspect of mineral wool wastes is their organic resin content and resin type, second critical aspect is ammonia emissions during alkali activation.
Although VR technology is present in everyday life it was not easy to develop a system that would survive conditions on site and enables to work efficiently.
Guidelines for pre-demolition audits with mineral wool involved were created.
The optimal pre-treatment consist of machinery or system combining compression, shredding, ball milling and if not ball mill available additional sieving and/or air classification in addition to screw or disc milling. Commercial technology exists, it is just about specifying the most feasible local cost-efficient solution.
All demonstrations completed with actual next steps reflecting each industrial partners’ own set up, investments, further testing and fine-tuning.
EHS aspect and risks have been widely prevented, studied and tested on mineral wool sourcing, pre-treatment and actual production of novel AAM products. Final products EHS aspects have been covered partly. Further work is needed and will take place.
Five different companies have produced five different products: pavement slabs, facade elements, reinforced wall panels, dry mix concrete and acoustic panels.
Communication, dissemination, clustering and other awareness creation and networking activities will exceed original plan. 8 peer-reviewed articles published and still 9 peer-reviewed articles to be published within WOOL2LOOP. Remarkable visibility within the industry in Finland.

It can be concluded that there is a great potential for AAM concrete as a supplement to the large OPC production worldwide, which is a major source of greenhouse gas emissions, and at the same time avoiding valuable secondary raw materials ending up at landfills. When investigating the internal and external barriers and opportunities with geopolymer concrete, five key barriers were discovered: Shortage of GGBFS/slags, lack of infrastructure to collect and treat SRM, lack of building codes, investments in upscaling, and the fact that the concrete market can be quite conservative.
We can conclude the main drivers identified of direct importance for the WOOL2LOOP concept originates from climate policies and the obligations to the Paris agreement of reducing GHG emissions by 40% in 2030 and to become climate neutral by 2050. Operationalisation of the Paris Agreement has for the EU resulted in several policies, circular road maps and initiatives such as the Green Deal, the Circular Economic Action Plan, etc. All with the overall aim to reduce CO2 emissions and decouple economic activities from the depletion of natural capital.

The main policy recommendations
• Encourage use of secondary raw materials, either through taxes on virgin materials or landfilling, or by making LCA and/or carbon footprint compulsory for all building products.
• Initiate demonstrations to convince key stakeholders that low-carbon cement types can replace many traditional OPC applications, e.g. pavement stones, façade panels, dry mix concrete etc.
• A shift towards more performance-based building standards.
• To encourage stakeholders: architects, civil engineering, construction companies, certification schemes, etc. to consider low carbon cements through more demonstrations/reference projects, training and communication and green public procurement.
• New EU initiatives such as the New BAUHAUS initiative or movements as well as the EU Taxonomy for sustainable activities are both likely to provide for bold drivers towards the green and circular transition and thereby an important driver for the uptake of new green building materials such as the WOOL2LOOP type products.

WOOL2LOOP has also aimed to progress approval and standardization of novel construction materials and their main components. Also progressing circularity of material streams traditionally claimed as "waste only", there is a need and future market for "wasterials".
Built environment is built for the people. No sub-optimizing can take place in progressing low carbon, carbon neutral, circular and resource efficient built environment. People health and well-being comes first. Multiple criteria need to be considered e.g. economic
viability, safety, health, longevity, aesthetics and so on.
WOOL2LOOP Project Meeting 8 Ljubljana, Slovenia
WOOL2LOOP Final Conference 26th of October 2022, Lisbon, Portugal
WOOL2LOOP Final Report