A by-product of wood-wool cement panel manufacturing, known as sanding dust (SD), has been successfully reactivated into a viable low-carbon binder.
A study published in Scientific Reports details a thermal process that transforms this complex organic-mineral residue into a material with significantly enhanced performance, opening the door for its use in sustainable construction materials.
Reactivation Through Heat
Researchers heated raw sanding dust at 450°C for 5 hours, a process designed to selectively dehydrate portlandite without releasing carbon dioxide from carbonated phases. The transformation was characterized using X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy.
The heat treatment yielded substantial physical and chemical improvements:
- Particle size was reduced from an average of 29.21 µm to 19.11 µm.
- Blaine surface area increased from 2420 to 2996 cm²/g.
- Mineralogical analysis confirmed the decomposition of hydrated phases and the formation of larnite, a key indicator of successful reactivation.
- Setting time dropped dramatically, from over 9 hours to just 40 minutes.
- 28-day compressive strength surged from 1.59 MPa to 13.05 MPa.
A life cycle assessment highlighted a major environmental benefit: a 63% reduction in global warming potential compared to commercial CEM II cement.
Biocomposite Performance
The reactivated binder was then tested in low-density biocomposites.
By adjusting the binder-to-filler ratio from 2 to 4, the material's density dropped from 415 kg/m³ to 369 kg/m³, and thermal conductivity decreased from 0.075 to 0.068 W/(m·K).
Compressive strength reached up to 185 kPa, and the biocomposites demonstrated significantly lower emissions, ranging from 10 to 42 kg CO₂ eq., further underscoring their potential as a sustainable building material.