Author:

Keywords:

Waste valorisation, Sustainability

Abstract:

Sustainable use of solid residues and carbon dioxide, the two largest and most important waste products from thermal processes, is an urgent issue both for the industry involved and society as a whole, considering the financial and environmental repercussions of their production. This Knowledge Platform focuses on three types of waste-to-product valorisation: production of a carbon sink, construction materials, or sorbents. Thermal processes constitute a bulk activity in metals production, waste incineration, glass industry, etc. They generally produce major amounts of solid waste materials, such as slag and fly ash, containing oxides of silicon, calcium, magnesium, aluminium and iron, together with a multitude of heavy metals, chlorides and/or sulphates. Rising prices of raw materials and growing awareness for environmental issues lead to a change in perception of these materials from waste to a potential product. Thermal processes also generate a vast amount of carbon dioxide which they emit into the atmosphere. The discussion concerning carbon dioxide is evolving rapidly, but it is clear that the emission of this greenhouse gas will become ever more regulated in the future. Mineral carbon sequestration is currently mainly investigated on primary materials such as olivine and serpentine. Sequestration in alkaline waste materials, however, provides an interesting alternative because of high reactivity, on-site production and low cost. In addition, the reaction with carbon dioxide stabilizes the waste materials and often improves environmental properties. The concept of producing construction materials from waste materials is only slowly coming of age despite the obvious benefit of transforming low-cost input materials into potentially high-value products. The production of another high-value product, a sorbent to remove pollutants from liquid streams, has only very recently been investigated for some of the waste materials studied in this project, and is a promising industrial application for in-house treatment of waste streams. A successful approach requires a broad consortium with relevant expertise for the scientific investigation, but which at the same time can be easily tailored to a particular valorisation option that emerges. The Platform aims at this dual objective by bringing together all expertise involved and by focusing on the challenging aim of valorising solid materials and/or carbon dioxide in high-value products by intensified processes and with clear prospects on the economic and legislative feasibility, ecological benefits and societal relevance.