Geopolymerization: a generic solution for the valorisation of high-temperature residues

The project considers the valorisation of historically landfilled and fresh residues from high-temperature processes. The residues considered in the study originate from non-ferro industries or residue from gas-plasma gasification of municipal solid waste, which are not commercially valorised yet today. Such residues have been proven to be valuable resources in inorganic polymer synthesis, because of their silica (+ iron, aluminium, calcium…) content and predominantly glassy nature. An additional benefit of these inorganic polymers, apart from the waste valorisation, is the low energy input upon manufacture.

As the knowledge on the mechanism and structure of inorganic polymers from the residues mentioned above is limited, past research has been reactive, inefficient, and did not enable full control of the physico-chemical properties. More knowledge on the formation, structure and the link of raw materials, processing, structure, and properties should enable pro-active research and open doors to higher added value applications. This project aims to gather that knowledge.

A combination of state of the art methodology and novel experimental techniques will be used for obtaining kinetic information and monitor the structural evolution. The necessity of novel techniques originates from the difference between the residues, predominantly ferrosilicates, and common precursors for inorganic polymer synthesis, aluminosilicates. State of the art techniques fail in probing the role of iron in the structure. These novel techniques, accompanied by complementary state of the art techniques, will be used to perform a parametric study, linking the kinetic and structural information with the properties of the material. This link will be quantitative. Therefore, depending on the chemistry and mineralogy of a certain residue, a near-optimal processing and mix design can be proposed to obtain a wanted product. This is needed for efficient future research as well as full control on the processing in the transition to the market.

Using the fundamental knowledge gained from the above mentioned actions, the application of iron-rich inorganic polymers in higher added-value products is investigated. Fibre reinforcement is investigated, taking into account the alkaline environment of the fresh and hardened inorganic polymer.