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Special Issue "State-of-the-Art Materials Science in Belgium 2017"

A special issue of Materials (ISSN 1996-1944).

Deadline for manuscript submissions: closed (30 June 2018)

Special Issue Editor

Guest Editor
Prof. Dr. Dirk Poelman

Lumilab, Department of Solid State Sciences, Ghent University, Krijgslaan 281-S1, B-9000 Gent, Belgium
Website 1 | Website 2 | E-Mail
Interests: lighting, vision, luminescence, displays; thin film optics, photocatalysis, medical imaging, structural characterization

Special Issue Information

Dear colleagues,

Belgium is a small country. The days of minerals and ores from the former colony Congo have long passed by, and the last coal mine was closed 25 years ago. So, Belgium has hardly any physical resources which can be exploited in materials research and development, or industry. This drawback is compensated by focussing on highly technological fields of research, not requiring vast amounts of raw materials. This approach includes the development of new analytical methods for the characterization of materials, research into new advanced functional materials as well as finding new industrial processes utilizing existing materials.

This special issue aims at collecting an overview of materials research activities in Belgium. Research topics include, but are not limited to:

  • Methods for the synthesis of new materials in powder, bulk or thin film form.
  • Surface modification or functionalization of materials.
  • Optical, electrical, mechanical or magnetic properties of materials.
  • New methods for materials characterization.
  • Material degradation and protection.
  • Applications of advanced functional materials.
  • Technologies for separation and recycling.

It is my pleasure to invite you to submit manuscripts on the subject “State-of-the-Art Materials Science in Belgium” for this Special Issue. Full papers, communications, as well as comprehensive reviews are welcome. Please feel free contact me as guest editor in case of further questions.

Prof. Dr. Dirk Poelman
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • synthesis; characterization
  • coatings; functional materials
  • degradation; protection; recycling; circular economy

Published Papers (12 papers)

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Research

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Open AccessArticle Introducing Obliquely Perforated Phononic Plates for Enhanced Bandgap Efficiency
Materials 2018, 11(8), 1309; https://doi.org/10.3390/ma11081309
Received: 6 June 2018 / Revised: 19 July 2018 / Accepted: 25 July 2018 / Published: 28 July 2018
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Abstract
Porous phononic crystal plates (PhPs) that are produced by perpendicular perforation of a uniform plate have well-known characteristics in selective manipulation (filtration, resonation, and steering) of guided wave modes. This paper introduces novel designs of porous PhPs made by an oblique perforation angle.
[...] Read more.
Porous phononic crystal plates (PhPs) that are produced by perpendicular perforation of a uniform plate have well-known characteristics in selective manipulation (filtration, resonation, and steering) of guided wave modes. This paper introduces novel designs of porous PhPs made by an oblique perforation angle. Such obliquely perforated PhPs (OPhPs) have a non-uniform through-the-thickness cross section, which strongly affects their interaction with various wave mode types and therefore their corresponding phononic properties. Modal band analysis is performed in unit-cell scale and variation of phononic bandgaps with respect to the perforation angle is studied within the first 10 modal branches. Unit-cells with arbitrary perforation profile as well as unit-cells with optimized topology for maximized bandgap of fundamental modes are investigated. It is observed that the oblique perforation has promising effects in enhancing the unidirectional and/or omnidirectional bandgap efficiency, depending on the topology and perforation angle of OPhP. Full article
(This article belongs to the Special Issue State-of-the-Art Materials Science in Belgium 2017)
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Open AccessFeature PaperArticle Thickness Characterization Toolbox for Transparent Protective Coatings on Polymer Substrates
Materials 2018, 11(7), 1101; https://doi.org/10.3390/ma11071101
Received: 30 May 2018 / Accepted: 26 June 2018 / Published: 28 June 2018
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Abstract
The thickness characterization of transparent protective coatings on functional, transparent materials is often problematic. In this paper, a toolbox to determine the thicknesses of a transparent coating on functional window films is presented. The toolbox consists of a combination of secondary ion mass
[...] Read more.
The thickness characterization of transparent protective coatings on functional, transparent materials is often problematic. In this paper, a toolbox to determine the thicknesses of a transparent coating on functional window films is presented. The toolbox consists of a combination of secondary ion mass spectrometry and profilometry and can be transferred to other transparent polymeric materials. A coating was deposited on designed model samples, which were characterized with cross-sectional views in transmission and in scanning/transmission electron microscopy and ellipsometry. The toolbox was then used to assess the thicknesses of the protective coatings on the pilot-scale window films. This coating was synthesized using straightforward sol-gel alkoxide chemistry. The kinetics of the condensation are studied in order to obtain a precursor that allows fast drying and complete condensation after simple heat treatment. The shelf life of this precursor solution was investigated in order to verify its accordance to industrial requirements. Deposition was performed successfully at low temperatures below 100 °C, which makes deposition on polymeric foils possible. By using roll-to-roll coating, the findings of this paper are easily transferrable to industrial scale. The coating was tested for scratch resistance and adhesion. Values for the emissivity (ε) of the films were recorded to justify the use of the films obtained as infrared reflective window films. In this work, it is shown that the toolbox measures similar thicknesses to those measured by electron microscopy and can be used to set a required thickness for protective coatings. Full article
(This article belongs to the Special Issue State-of-the-Art Materials Science in Belgium 2017)
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Open AccessArticle Pair Distribution Function Analysis of ZrO2 Nanocrystals and Insights in the Formation of ZrO2-YBa2Cu3O7 Nanocomposites
Materials 2018, 11(7), 1066; https://doi.org/10.3390/ma11071066
Received: 24 May 2018 / Revised: 19 June 2018 / Accepted: 20 June 2018 / Published: 23 June 2018
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Abstract
The formation of superconducting nanocomposites from preformed nanocrystals is still not well understood. Here, we examine the case of ZrO2 nanocrystals in a YBa2Cu3O7−x matrix. First we analyzed the preformed ZrO2 nanocrystals via atomic pair distribution
[...] Read more.
The formation of superconducting nanocomposites from preformed nanocrystals is still not well understood. Here, we examine the case of ZrO2 nanocrystals in a YBa2Cu3O7−x matrix. First we analyzed the preformed ZrO2 nanocrystals via atomic pair distribution function analysis and found that the nanocrystals have a distorted tetragonal crystal structure. Second, we investigated the influence of various surface ligands attached to the ZrO2 nanocrystals on the distribution of metal ions in the pyrolyzed matrix via secondary ion mass spectroscopy technique. The choice of stabilizing ligand is crucial in order to obtain good superconducting nanocomposite films with vortex pinning. Short, carboxylate based ligands lead to poor superconducting properties due to the inhomogeneity of metal content in the pyrolyzed matrix. Counter-intuitively, a phosphonate ligand with long chains does not disturb the growth of YBa2Cu3O7−x. Even more surprisingly, bisphosphonate polymeric ligands provide good colloidal stability in solution but do not prevent coagulation in the final film, resulting in poor pinning. These results thus shed light on the various stages of the superconducting nanocomposite formation. Full article
(This article belongs to the Special Issue State-of-the-Art Materials Science in Belgium 2017)
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Open AccessArticle Understanding the Interaction between a Steel Microstructure and Hydrogen
Materials 2018, 11(5), 698; https://doi.org/10.3390/ma11050698
Received: 2 April 2018 / Revised: 23 April 2018 / Accepted: 24 April 2018 / Published: 28 April 2018
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Abstract
The present work provides an overview of the work on the interaction between hydrogen (H) and the steel’s microstructure. Different techniques are used to evaluate the H-induced damage phenomena. The impact of H charging on multiphase high-strength steels, i.e., high-strength low-alloy (HSLA), transformation-induced
[...] Read more.
The present work provides an overview of the work on the interaction between hydrogen (H) and the steel’s microstructure. Different techniques are used to evaluate the H-induced damage phenomena. The impact of H charging on multiphase high-strength steels, i.e., high-strength low-alloy (HSLA), transformation-induced plasticity (TRIP) and dual phase (DP) is first studied. The highest hydrogen embrittlement resistance is obtained for HSLA steel due to the presence of Ti- and Nb-based precipitates. Generic Fe-C lab-cast alloys consisting of a single phase, i.e., ferrite, bainite, pearlite or martensite, and with carbon contents of approximately 0, 0.2 and 0.4 wt %, are further considered to simplify the microstructure. Finally, the addition of carbides is investigated in lab-cast Fe-C-X alloys by adding a ternary carbide forming element to the Fe-C alloys. To understand the H/material interaction, a comparison of the available H trapping sites, the H pick-up level and the H diffusivity with the H-induced mechanical degradation or H-induced cracking is correlated with a thorough microstructural analysis. Full article
(This article belongs to the Special Issue State-of-the-Art Materials Science in Belgium 2017)
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Open AccessArticle Highly Efficient Low-Temperature N-Doped TiO2 Catalysts for Visible Light Photocatalytic Applications
Materials 2018, 11(4), 584; https://doi.org/10.3390/ma11040584
Received: 22 February 2018 / Revised: 29 March 2018 / Accepted: 6 April 2018 / Published: 10 April 2018
Cited by 1 | PDF Full-text (34347 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, TiO2 prepared with an aqueous sol-gel synthesis by peptization process is doped with nitrogen precursor to extend its activity towards the visible region. Three N-precursors are used: urea, ethylenediamine and triethylamine. Different molar N/Ti ratios are tested and the
[...] Read more.
In this paper, TiO2 prepared with an aqueous sol-gel synthesis by peptization process is doped with nitrogen precursor to extend its activity towards the visible region. Three N-precursors are used: urea, ethylenediamine and triethylamine. Different molar N/Ti ratios are tested and the synthesis is adapted for each dopant. For urea- and trimethylamine-doped samples, anatase-brookite TiO2 nanoparticles of 6–8 nm are formed, with a specific surface area between 200 and 275 m2·g−1. In ethylenediamine-doped samples, the formation of rutile phase is observed, and TiO2 nanoparticles of 6–8 nm with a specific surface area between 185 and 240 m2·g−1 are obtained. X-ray photoelectron spectroscopy (XPS) and diffuse reflectance measurements show the incorporation of nitrogen in TiO2 materials through Ti–O–N bonds allowing light absorption in the visible region. Photocatalytic tests on the remediation of water polluted with p-nitrophenol show a marked improvement for all doped catalysts under visible light. The optimum doping, taking into account cost, activity and ease of synthesis, is up-scaled to a volume of 5 L and compared to commercial Degussa P25 material. This up-scaled sample shows similar properties compared to the lab-scale sample, i.e., a photoactivity 4 times higher than commercial P25. Full article
(This article belongs to the Special Issue State-of-the-Art Materials Science in Belgium 2017)
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Open AccessFeature PaperArticle LaAlO3:Mn4+ as Near-Infrared Emitting Persistent Luminescence Phosphor for Medical Imaging: A Charge Compensation Study
Materials 2017, 10(12), 1422; https://doi.org/10.3390/ma10121422
Received: 10 November 2017 / Revised: 5 December 2017 / Accepted: 9 December 2017 / Published: 12 December 2017
Cited by 2 | PDF Full-text (3653 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Mn4+-activated phosphors are emerging as a novel class of deep red/near-infrared emitting persistent luminescence materials for medical imaging as a promising alternative to Cr3+-doped nanomaterials. Currently, it remains a challenge to improve the afterglow and photoluminescence properties of these
[...] Read more.
Mn4+-activated phosphors are emerging as a novel class of deep red/near-infrared emitting persistent luminescence materials for medical imaging as a promising alternative to Cr3+-doped nanomaterials. Currently, it remains a challenge to improve the afterglow and photoluminescence properties of these phosphors through a traditional high-temperature solid-state reaction method in air. Herein we propose a charge compensation strategy for enhancing the photoluminescence and afterglow performance of Mn4+-activated LaAlO3 phosphors. LaAlO3:Mn4+ (LAO:Mn4+) was synthesized by high-temperature solid-state reaction in air. The charge compensation strategies for LaAlO3:Mn4+ phosphors were systematically discussed. Interestingly, Cl/Na+/Ca2+/Sr2+/Ba2+/Ge4+ co-dopants were all found to be beneficial for enhancing LaAlO3:Mn4+ luminescence and afterglow intensity. This strategy shows great promise and opens up new avenues for the exploration of more promising near-infrared emitting long persistent phosphors for medical imaging. Full article
(This article belongs to the Special Issue State-of-the-Art Materials Science in Belgium 2017)
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Review

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Open AccessReview Recent Advances in Transmission Electron Microscopy for Materials Science at the EMAT Lab of the University of Antwerp
Materials 2018, 11(8), 1304; https://doi.org/10.3390/ma11081304
Received: 29 June 2018 / Revised: 25 July 2018 / Accepted: 26 July 2018 / Published: 28 July 2018
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Abstract
The rapid progress in materials science that enables the design of materials down to the nanoscale also demands characterization techniques able to analyze the materials down to the same scale, such as transmission electron microscopy. As Belgium’s foremost electron microscopy group, among the
[...] Read more.
The rapid progress in materials science that enables the design of materials down to the nanoscale also demands characterization techniques able to analyze the materials down to the same scale, such as transmission electron microscopy. As Belgium’s foremost electron microscopy group, among the largest in the world, EMAT is continuously contributing to the development of TEM techniques, such as high-resolution imaging, diffraction, electron tomography, and spectroscopies, with an emphasis on quantification and reproducibility, as well as employing TEM methodology at the highest level to solve real-world materials science problems. The lab’s recent contributions are presented here together with specific case studies in order to highlight the usefulness of TEM to the advancement of materials science. Full article
(This article belongs to the Special Issue State-of-the-Art Materials Science in Belgium 2017)
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Open AccessReview Advanced Chemical Looping Materials for CO2 Utilization: A Review
Materials 2018, 11(7), 1187; https://doi.org/10.3390/ma11071187
Received: 18 May 2018 / Revised: 29 June 2018 / Accepted: 6 July 2018 / Published: 10 July 2018
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Abstract
Combining chemical looping with a traditional fuel conversion process yields a promising technology for low-CO2-emission energy production. Bridged by the cyclic transformation of a looping material (CO2 carrier or oxygen carrier), a chemical looping process is divided into two spatially
[...] Read more.
Combining chemical looping with a traditional fuel conversion process yields a promising technology for low-CO2-emission energy production. Bridged by the cyclic transformation of a looping material (CO2 carrier or oxygen carrier), a chemical looping process is divided into two spatially or temporally separated half-cycles. Firstly, the oxygen carrier material is reduced by fuel, producing power or chemicals. Then, the material is regenerated by an oxidizer. In chemical looping combustion, a separation-ready CO2 stream is produced, which significantly improves the CO2 capture efficiency. In chemical looping reforming, CO2 can be used as an oxidizer, resulting in a novel approach for efficient CO2 utilization through reduction to CO. Recently, the novel process of catalyst-assisted chemical looping was proposed, aiming at maximized CO2 utilization via the achievement of deep reduction of the oxygen carrier in the first half-cycle. It makes use of a bifunctional looping material that combines both catalytic function for efficient fuel conversion and oxygen storage function for redox cycling. For all of these chemical looping technologies, the choice of looping materials is crucial for their industrial application. Therefore, current research is focused on the development of a suitable looping material, which is required to have high redox activity and stability, and good economic and environmental performance. In this review, a series of commonly used metal oxide-based materials are firstly compared as looping material from an industrial-application perspective. The recent advances in the enhancement of the activity and stability of looping materials are discussed. The focus then proceeds to new findings in the development of the bifunctional looping materials employed in the emerging catalyst-assisted chemical looping technology. Among these, the design of core-shell structured Ni-Fe bifunctional nanomaterials shows great potential for catalyst-assisted chemical looping. Full article
(This article belongs to the Special Issue State-of-the-Art Materials Science in Belgium 2017)
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Open AccessFeature PaperReview Spray-Drying of Electrode Materials for Lithium- and Sodium-Ion Batteries
Materials 2018, 11(7), 1076; https://doi.org/10.3390/ma11071076
Received: 31 May 2018 / Revised: 20 June 2018 / Accepted: 21 June 2018 / Published: 25 June 2018
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Abstract
The performance of electrode materials in lithium-ion (Li-ion), sodium-ion (Na-ion) and related batteries depends not only on their chemical composition but also on their microstructure. The choice of a synthesis method is therefore of paramount importance. Amongst the wide variety of synthesis or
[...] Read more.
The performance of electrode materials in lithium-ion (Li-ion), sodium-ion (Na-ion) and related batteries depends not only on their chemical composition but also on their microstructure. The choice of a synthesis method is therefore of paramount importance. Amongst the wide variety of synthesis or shaping routes reported for an ever-increasing panel of compositions, spray-drying stands out as a versatile tool offering demonstrated potential for up-scaling to industrial quantities. In this review, we provide an overview of the rapidly increasing literature including both spray-drying of solutions and spray-drying of suspensions. We focus, in particular, on the chemical aspects of the formulation of the solution/suspension to be spray-dried. We also consider the post-processing of the spray-dried precursors and the resulting morphologies of granules. The review references more than 300 publications in tables where entries are listed based on final compound composition, starting materials, sources of carbon etc. Full article
(This article belongs to the Special Issue State-of-the-Art Materials Science in Belgium 2017)
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Open AccessReview Fe-Based Nano-Materials in Catalysis
Materials 2018, 11(5), 831; https://doi.org/10.3390/ma11050831
Received: 5 April 2018 / Revised: 4 May 2018 / Accepted: 10 May 2018 / Published: 17 May 2018
Cited by 1 | PDF Full-text (29804 KB) | HTML Full-text | XML Full-text
Abstract
The role of iron in view of its further utilization in chemical processes is presented, based on current knowledge of its properties. The addition of iron to a catalyst provides redox functionality, enhancing its resistance to carbon deposition. FeOx species can be
[...] Read more.
The role of iron in view of its further utilization in chemical processes is presented, based on current knowledge of its properties. The addition of iron to a catalyst provides redox functionality, enhancing its resistance to carbon deposition. FeOx species can be formed in the presence of an oxidizing agent, such as CO2, H2O or O2, during reaction, which can further react via a redox mechanism with the carbon deposits. This can be exploited in the synthesis of active and stable catalysts for several processes, such as syngas and chemicals production, catalytic oxidation in exhaust converters, etc. Iron is considered an important promoter or co-catalyst, due to its high availability and low toxicity that can enhance the overall catalytic performance. However, its operation is more subtle and diverse than first sight reveals. Hence, iron and its oxides start to become a hot topic for more scientists and their findings are most promising. The scope of this article is to provide a review on iron/iron-oxide containing catalytic systems, including experimental and theoretical evidence, highlighting their properties mainly in view of syngas production, chemical looping, methane decomposition for carbon nanotubes production and propane dehydrogenation, over the last decade. The main focus goes to Fe-containing nano-alloys and specifically to the Fe–Ni nano-alloy, which is a very versatile material. Full article
(This article belongs to the Special Issue State-of-the-Art Materials Science in Belgium 2017)
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Open AccessFeature PaperReview Luminescent Lanthanide MOFs: A Unique Platform for Chemical Sensing
Materials 2018, 11(4), 572; https://doi.org/10.3390/ma11040572
Received: 19 March 2018 / Revised: 4 April 2018 / Accepted: 5 April 2018 / Published: 7 April 2018
Cited by 3 | PDF Full-text (29479 KB) | HTML Full-text | XML Full-text
Abstract
In recent years, lanthanide metal–organic frameworks (LnMOFs) have developed to be an interesting subclass of MOFs. The combination of the characteristic luminescent properties of Ln ions with the intriguing topological structures of MOFs opens up promising possibilities for the design of LnMOF-based chemical
[...] Read more.
In recent years, lanthanide metal–organic frameworks (LnMOFs) have developed to be an interesting subclass of MOFs. The combination of the characteristic luminescent properties of Ln ions with the intriguing topological structures of MOFs opens up promising possibilities for the design of LnMOF-based chemical sensors. In this review, we present the most recent developments of LnMOFs as chemical sensors by briefly introducing the general luminescence features of LnMOFs, followed by a comprehensive investigation of the applications of LnMOF sensors for cations, anions, small molecules, nitroaromatic explosives, gases, vapors, pH, and temperature, as well as biomolecules. Full article
(This article belongs to the Special Issue State-of-the-Art Materials Science in Belgium 2017)
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Open AccessFeature PaperReview The Use of Municipal Solid Waste Incineration Ash in Various Building Materials: A Belgian Point of View
Materials 2018, 11(1), 141; https://doi.org/10.3390/ma11010141
Received: 19 November 2017 / Revised: 2 January 2018 / Accepted: 3 January 2018 / Published: 16 January 2018
Cited by 1 | PDF Full-text (2419 KB) | HTML Full-text | XML Full-text
Abstract
Huge amounts of waste are being generated, and even though the incineration process reduces the mass and volume of waste to a large extent, massive amounts of residues still remain. On average, out of 1.3 billion tons of municipal solid wastes generated per
[...] Read more.
Huge amounts of waste are being generated, and even though the incineration process reduces the mass and volume of waste to a large extent, massive amounts of residues still remain. On average, out of 1.3 billion tons of municipal solid wastes generated per year, around 130 and 2.1 million tons are incinerated in the world and in Belgium, respectively. Around 400 kT of bottom ash residues are generated in Flanders, out of which only 102 kT are utilized here, and the rest is exported or landfilled due to non-conformity to environmental regulations. Landfilling makes the valuable resources in the residues unavailable and results in more primary raw materials being used, increasing mining and related hazards. Identifying and employing the right pre-treatment technique for the highest value application is the key to attaining a circular economy. We reviewed the present pre-treatment and utilization scenarios in Belgium, and the advancements in research around the world for realization of maximum utilization are reported in this paper. Uses of the material in the cement industry as a binder and cement raw meal replacement are identified as possible effective utilization options for large quantities of bottom ash. Pre-treatment techniques that could facilitate this use are also discussed. With all the research evidence available, there is now a need for combined efforts from incineration and the cement industry for technical and economic optimization of the process flow. Full article
(This article belongs to the Special Issue State-of-the-Art Materials Science in Belgium 2017)
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