Upcycling processes for primary and secondary resources

General theme: Process development, from concept to fully-operational pilot-plan scale, for the transformation of residues into novel engineered materials that society needs. Focus is on hydrometallurgical (e.g. bauxite residue, also known as “red mud”) and pyrometallurgical residues (e.g. ferrous and non-ferrous metallurgy slags), and attention is given to the metallurgical process itself so that it delivers a more promising precursor. In view of the high volumes, the end-materials are typically used in construction.

Flagship topics:

Valorisation of bauxite residue

A process has been proposed and the proof-of-concept has been validated at the laboratory scale, currently being up-scaled towards a production of 1 tonne/day. The process involves thermal treatment of bauxite residue and subsequently mixing with as-produced residue that contributes in the alkali-activation. By optimising additives, shaping and curing, compressive strength of end-materials is higher than 100 MPa. A follow-up process that involves a unique curing step while providing unique properties is being patented

Valorisation of non-ferrous slags

SIM² KU Leuven scanned the whole quaternary phase diagram of FeO-CaO-Al2O3-SiO2 and has identified best possible chemistries to provide a highly reactive amorphous precursor. Based on that, SIM² KU Leuven coined the term Extraordinary Leuven Cement (ELCE), and it is developing a whole series of blended cements with high-end performance, including fire resistance. Hybrid cements are where SIM² KU Leuven currently focuses.

Porous, functional, inorganic polymers

By combining different resources SIM² KU Leuven has succeeded in forming tailored porosity in a fibrous zeolite microstructure. This open a range of possibilities, from heat and sound insulating to applications in catalysis and absorption for the uptake of metals/pollutants. SIM² KU Leuven currently upscales to monoliths of 50 x 50 cm2

Modelling

By combining computational work in MD, ab initio MD and DFT, with experimental data from synchrotron facilities SIM² KU Leuven tries to understand the atomic configuration of a range of slags and eventually predict properties (e.g. reactivity). From a different starting point, SIM² KU Leuven tries to answer the same question by statistics and high-throughput experimentation. Eventually, SIM² KU Leuven wants to understand the behaviour of the atoms during processing and how that affects the performance of the resulting final materials. If it succeeds, SIM² KU Leuven will be in position to predict performance of inorganic polymers by merely knowing the chemistry of the starting slag precursor. The database for the slags and other anthropogenic raw materials is online here: http://sreway.info/web/.

Other areas

In addition to the above SIM² KU Leuven is currently active in microwave processing, valorisation of ashes, durability assessment and non-destructive-testing, including X-ray tomography, as well as immobilisation of radioactive sources and how our new binders interact with them.

The Team

The leading members in this research line are:

Prof. Yiannis Pontikes
Prof. Yiannis Pontikes
Yiannis is the Research Line Leader and the coordinator of Secondary Resources for Engineered Material (SREMat) research group at MTM (https://www.mtm.kuleuven.be/Onderzoek/sremat/). Yiannis is work package leader or project coordinator in approximately 10 projects dealing with the valorisation of bauxite residue (red mud), slags from ferrous and non-ferrous metallurgy, and vitrified residues from municipal solid wastes, ranging from fundamental to competitive work and from bilateral Flemish ones, to multi-actor international projects. Yiannis and the SREMat group have an expertise on ceramic, cement and inorganic polymer (geopolymer) processing from binder to full scale prototypes
Prof. Özlem Cizer
Prof. Özlem Cizer
Prof. Özlem Cizer is conducting research at the Civil Engineering Department in the field of sustainable construction materials with a focus on mineral-based binders (lime- and cement-based materials), alkali-activated materials, and their early-age properties and durability. She is an MC member of a wide European network group of COST Action TU1404 on cement-based materials and structures, and coordinating the work on chemical and microstructure characterization. She is a member of RILEM and the Editor-in-Chief of the international journal of Restoration of Buildings and Monuments.
Prof. Koen Van Balen
Prof. Koen Van Balen
Prof. Koenraad Van Balen is a civil engineer.
Dr. Lubica Kriskova
Dr. Lubica Kriskova
Dr. Lubica Kriskova is a post-doctoral researcher experienced in the field of valorisation of ferrous and non-ferrous slags . Her main expertise domain is synthesis of cement based binders and solid as well as porous inorganic polymers.
Prof. Lucie Vandewalle
Prof. Lucie Vandewalle
Prof. Lucie Vandewalle is a civil engineer and her research focuses on the technology and structural behaviour of concrete. Her main research topics are fibre reinforced concrete, selfcompacting concrete, high early strength concrete, creep and shrinkage of concrete and shear capacity of prestressed concrete beams. She is convenor of FIB TG4.1 “Fibre Concrete” and of CEN/TC104/WG11 “Polymer fibres”.
Prof. Jan Elsen
Prof. Jan Elsen
Prof. Jan Elsen is a geologist and his research focuses on the mineralogical characterisation and use of industrial minerals (clays, cement minerals and zeolite deposits with pozzolanic properties). Techniques used include Quantitative X-Ray Diffraction, petrography, electron microscopy and thermal and chemical analysis.
Prof. Valerie Cappuyns
Prof. Valerie Cappuyns
Prof. Valerie Cappuyns is senior lecturer in environmental science and technology. Her research interests include environmental geochemistry (solid-phase characterisation and leaching of heavy metals from soils, sediments and waste materials), sustainable management of contaminated sites, life cycle analysis, and eco-efficiency.

Embedded in the SuMMa Policy Research Centre:

The Policy Research Centre – Sustainable Materials Management proves that the Science, Engineering and Technology Group can play an important role on the societal level. The Flemish government recently recognized a number of new Policy Research Centres. For the theme “Sustainable Materials Management” the candidacy of professor Karel Van Acker was selected. This recognition comes with a long-term structural funding for his research on the efficient use of raw materials, but also with an opportunity to contribute to the Flemish policy. The Policy Research Centre Programme was established by the Flemish government to provide a scientific basis for policy and enable a quick and proactive response to social developments and challenges. At the end of 2011 the government selected new research themes on the basis of its policy priorities. For each theme one candidacy was accepted to become a Policy Research Centre. These centres get structural research funding for a period of four years.

Professor Van Acker: “Sustainable Materials Management is a completely new theme. We will examine how we can be less dependent for our materials supply in Flanders and what is needed to get there. How can we build a more circular economy? How can we better close certain material loops? How can we ensure that we need less raw materials, become less dependent on supply from foreign countries and have less impact on the environment? We will study the current policy and its impact. We will translate the knowledge, gathered through our research, into specific recommendations for future policy of the Flemish government.

  • Interdisciplinary Research: “Our research for the Policy Research Centre is highly interdisciplinary. We do not only examine technological innovation, but we also study the economic instruments that the government can use to promote sustainable materials management, such as taxes, subsidies and standards. The legal framework is also part of our research. For instance, which laws make certain recycling opportunities impossible at this moment?  There are also people from organisation psychology involved, who will shed light on how the various actors can work together in a way that brings benefit to everyone.  We are used to primarily focus on the industrial valorisation of our research, but the Policy Research Centre really looks at the social valorisation.
  • Composition of the Policy Research Centre: “We have set up the Policy Research Centre as a matrix organisation which allows us to work closely together on specific cases throughout the various disciplines. In total, nine people are working in the centre. At the KU Leuven we have a postdoctoral researcher Materials Science who deals with life cycle costing and analysis, a doctoral student from the Faculty of Law who specializes in environmental law and a doctoral student from the Faculty of Business and Economics who looks into economic incentives. Furthermore there are people involved from VITO, UGent, UHasselt, UA and HUB. We mainly work on long-term fundamental research to provide a solid scientific base for the policy, but occasionally there are problem-driven short-term assignments, e.g. around topics from parliamentary questions.
  • Policy-relevant and independent: Can research that needs to be relevant to policy still be independent? “I’m not really worried about that”, says professor Van Acker, “The policy feels a serious shortage of scientific support. Many aspects of research in sustainable materials management are very new. We can really make a significant contribution in a very objective manner. The government expects focused policy advice for the long term, and therefore there is no value if we play up to them.” “Our work is followed by a large and diverse steering group committee, that will help to pursue objectivity. We, ourselves, have also proposed to establish an International Advisory Board that will monitor the scientific quality of the research. In addition, we will regularly organize sounding boards to get the industry and NGOs involved. We must ensure that all the different actors are drawn in and that we identify their needs. Managing this interdisciplinarity is our biggest challenge.”
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