Utilisation of By-Product Phosphogypsum Through Extrusion-Based 3D Printing

Area of Science:

• Construction Materials Science
• Waste Valorization
• Additive Manufacturing

Background:

• Phosphogypsum (PG) is a low-utilization byproduct of phosphate fertilizer production.
• PG contains calcium sulfate, offering potential as a binder, but acidic impurities limit its use.
• 3D printing technology offers advantages in the construction sector.

Purpose of the Study:

• To develop a 3D-printable construction material utilizing phosphogypsum (PG).
• To investigate the effect of 3D printing on the mechanical properties of PG-based paste.
• To overcome challenges associated with PG impurities for construction applications.

Main Methods:

• Calcination of PG to produce the binding material (β-CaSO₄·0.5H₂O).
• Neutralization of acidic impurities in PG using quicklime.
• Formulation of a 3D-printable paste using PG binder and sand aggregate.

Main Results:

• 3D printing improved the mechanical properties of the PG-based material compared to cast samples.
• The highest compressive strength of 950 kPa was achieved in the [u] direction for 3D-printed specimens.
• Cast specimens exhibited 17% lower compressive strength (810 kPa) than the optimal 3D-printed samples.

Conclusions:

• 3D printing is a viable method for enhancing the mechanical performance of phosphogypsum-based construction materials.
• The developed PG-based mixture shows promise for sustainable construction applications.
• Further research into densification could further optimize the properties of 3D-printed PG materials.