Microencapsulation of phosphogypsum into a sulfur polymer matrix: Physico-chemical and radiological characterization


The aim of this work is to prepare a new type of phosphogypsum-sulfur polymer cements (PG-SPC) to be utilised in the manufacture of building materials. Physico-chemical and radiological characterization was performed in phosphogypsum and phosphogypsum-sulfur polymer concretes and modeling of exhalation rates has been also carried out. An optimized mixture of the materials was obtained, the solidified material with optimal mixture (sulfur/phosphogypsum = 1:0.9, phosphogypsum dosage = 10–40 wt.%) results in highest strength (54–62 MPa) and low total porosity (2.8–6.8%). The activity concentration index (I) in the PG-SPC is lower than the reference value in the most international regulations and; therefore, these cements can be used without radiological restrictions in the manufacture of building materials. Under normal conditions of ventilation, the contribution to the expected radon indoor concentration in a standard room is below the international recommendations, so the building materials studied in this work can be applied to houses built up under normal ventilation conditions.

Additionally, and taking into account that the PG is enriched in several natural radionuclides as 226Ra, the leaching experiments have demonstrated that environmental impact of the using of SPCs cements with PG is negligible.


► Microencapsulation of phosphogypsum residues into a sulfur polymer matrix. ► Inertization of a waste material. ► Radiological characterization of the as built new material (phosphogypsum plus sulfur polymer matrix).



phosphate rock


portland cement clinker

sulfur polymer concrete

phosphogypsum-sulfur polymer concrete

sulfur modified

external risk index

equivalent radium concentration
Ac (%)

coefficient of absorption with respect to the pH
Lc (%)

leaching coefficient for 238U and 210Po at the different pHs