TY - JOUR
T1 - Phosphate's second life
T2 - Upcycling phosphogypsum and clay by-product through acid geopolymer technology
AU - Oubaha, Said
AU - Charai, Mouatassim
AU - Beniddar, Hamza
AU - Mabroum, Safaa
AU - El Machi, Aiman
AU - Mghazli, Mohamed Oualid
AU - Taha, Yassine
AU - Hakkou, Rachid
PY - 2024
Y1 - 2024
N2 - The present study explores the repurposing of large amounts of phosphoric acid by-products, specifically phosphogypsum (PG), by evaluating its effectiveness as a precursor in acid-activated geopolymer technology. Geopolymers were elaborated using PG and calcined clays, activated with phosphoric acid. The research focused on evaluating the mechanical properties and microstructure of these geopolymers after a 28-day curing period. X-ray diffraction (XRD) analysis revealed the formation of new crystalline phases, including brushite, newberite, and berlinite. Fourier-transform infrared (FTIR) spectroscopy confirmed the presence of P-O and Si-O-Al bonds, indicative of successful geopolymerization. Scanning electron microscopy (SEM) imaging demonstrated a dense, cohesive microstructure in optimized samples. Based on the response surface methodology, the study identified optimal conditions for maximum compressive strength: 28.83 % PG content, 14.39 mol/L phosphoric acid concentration, and a curing temperature of 72.45°C. This optimized formulation produced a dense, cohesive microstructure with a notable compressive strength of 21.46 MPa. The leaching test confirmed that no harmful substances were released from the geopolymer samples. These results suggest that PG can be effectively recycled through geopolymer technology for use in the construction industry.
AB - The present study explores the repurposing of large amounts of phosphoric acid by-products, specifically phosphogypsum (PG), by evaluating its effectiveness as a precursor in acid-activated geopolymer technology. Geopolymers were elaborated using PG and calcined clays, activated with phosphoric acid. The research focused on evaluating the mechanical properties and microstructure of these geopolymers after a 28-day curing period. X-ray diffraction (XRD) analysis revealed the formation of new crystalline phases, including brushite, newberite, and berlinite. Fourier-transform infrared (FTIR) spectroscopy confirmed the presence of P-O and Si-O-Al bonds, indicative of successful geopolymerization. Scanning electron microscopy (SEM) imaging demonstrated a dense, cohesive microstructure in optimized samples. Based on the response surface methodology, the study identified optimal conditions for maximum compressive strength: 28.83 % PG content, 14.39 mol/L phosphoric acid concentration, and a curing temperature of 72.45°C. This optimized formulation produced a dense, cohesive microstructure with a notable compressive strength of 21.46 MPa. The leaching test confirmed that no harmful substances were released from the geopolymer samples. These results suggest that PG can be effectively recycled through geopolymer technology for use in the construction industry.
KW - Phosphogypsum
KW - Geopolymer
KW - Recycling
KW - Acid-activation
KW - Mine by-product
KW - Construction industry
U2 - 10.1016/j.conbuildmat.2024.138829
DO - 10.1016/j.conbuildmat.2024.138829
M3 - Journal article
SN - 0950-0618
VL - 451
JO - Construction and Building Materials
JF - Construction and Building Materials
M1 - 138829
ER -