Synthesis and Processing Routes of Porous Materials from Fe-rich Slags

Promovendus/a: Roberto Eduardo Murillo Alarcon

Promotor(en): Prof. dr. Yiannis Pontikes, Dr. Hubert Rahier

Every year, the metal industry generates millions of tons of by-products such as slags, which are often treated as waste. In this PhD, these Fe-rich slags were turned into new lightweight building materials that are full of small pores—like solid foams. Thanks to these pores, the materials are lighter, insulate heat and sound, and provide protection against fire.

The research showed three main achievements: (i) developing Fe-rich slag-based porous materials with densities between 400 and 1200 kg/m³, where the pore structure could be carefully controlled, and showing how processing and pore characteristics are directly linked to performance in terms of strength, insulation, sound absorption, and fire resistance; (ii) demonstrating that a special curing process, called hydrothermal curing, improves long-term stability by forming new crystalline phases; and (iii) introducing a fibre-stabilised foaming technique that makes production more scalable and closer to practical applications.

The resulting materials reached insulation and sound absorption values comparable to commercial products, while also withstanding fire for up to three to four hours. This demonstrates that industrial by-products can be upcycled into sustainable construction materials, helping to reduce waste, save resources, and build safer buildings for the future.