Undissolved Ilmenite Mud from TiO₂ Production-Waste or a Valuable Addition to Portland Cement Composites?

Area of Science:

• Materials Science
• Civil Engineering
• Waste Management

Background:

• Ilmenite mud (MUD) from titanium dioxide (TiO2) production via the sulphate method is a hazardous waste.
• A modified, rinsed R-MUD exhibits reduced acidity and heavy metal content.
• Rinsing increases silica (SiO2) concentration, imparting pozzolanic potential.

Purpose of the Study:

• To evaluate the pozzolanic activity of R-MUD as a Portland cement additive.
• To compare R-MUD's performance against established pozzolanic materials.
• To assess the impact of R-MUD on cement hydration and microstructure.

Main Methods:

• R-MUD was prepared by rinsing and filtering ilmenite mud.
• Pozzolanic activity was tested using thermal analysis techniques.
• Calorimetric tests measured heat of hydration in cement composites.

Main Results:

• R-MUD demonstrated pozzolanic activity comparable to silica fume at 3 days.
• Its activity surpassed fly ash by 28 days and matched it by 180 days.
• Calorimetry confirmed R-MUD's high reactivity, similar to silica fume and pure cement at 72 hours.

Conclusions:

• R-MUD is a viable, reactive pozzolanic substitute for Portland cement.
• Its addition promotes the formation of C-S-H phases, crucial for cement microstructure.
• Utilizing R-MUD offers a sustainable approach to managing industrial waste in construction materials.