title: Microencapsulation of phosphogypsum into a sulfur polymer matrix: physico-chemical and radiological characterization.
abstract: 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 (226)Ra, the leaching experiments have demonstrated that environmental impact of the using of SPCs cements with PG is negligible.
authors.affiliation: Centro Nacional de Investigaciones Metalúrgicas (CENIM), CSIC, Avda. Gregorio del Amo, 8, 28040 Madrid, Spain. flopez@cenim.csic.es
authors.forename: Félix A
authors.initials: FA
authors.lastname: López
authors.forename: Manuel
authors.initials: M
authors.lastname: Gázquez
authors.forename: Francisco José
authors.initials: FJ
authors.lastname: Alguacil
authors.forename: Juan Pedro
authors.initials: JP
authors.lastname: Bolívar
authors.forename: Irene
authors.initials: I
authors.lastname: García-Díaz
authors.forename: Israel
authors.initials: I
authors.lastname: López-Coto
mesh_terms: D002133:Calcium Sulfate / Q000737:chemistry*; D004339:Drug Compounding; D008855:Microscopy, Electron, Scanning; D010758:Phosphorus / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: C077769:phosphogypsum; D010758:Phosphorus; D013455:Sulfur; D002133:Calcium Sulfate