title: Fractionation and fluxes of metals and radionuclides during the recycling process of phosphogypsum wastes applied to mineral CO₂ sequestration.
abstract: The industry of phosphoric acid produces a calcium-rich by-product known as phosphogypsum, which is usually stored in large stacks of millions of tons. Up to now, no commercial application has been widely implemented for its reuse because of the significant presence of potentially toxic contaminants. This work confirmed that up to 96% of the calcium of phosphogypsum could be recycled for CO2 mineral sequestration by a simple two-step process: alkaline dissolution and aqueous carbonation, under ambient pressure and temperature. This CO2 sequestration process based on recycling phosphogypsum wastes would help to mitigate greenhouse gasses emissions. Yet this work goes beyond the validation of the sequestration procedure; it tracks the contaminants, such as trace metals or radionuclides, during the recycling process in the phosphogypsum. Thus, most of the contaminants were transferred from raw phosphogypsum to portlandite, obtained by dissolution of the phosphogypsum in soda, and from portlandite to calcite during aqueous carbonation. These findings provide valuable information for managing phosphogypsum wastes and designing potential technological applications of the by-products of this environmentally-friendly proposal.
authors.affiliation: Department of Applied Physics, University of Huelva, Campus 'El Carmen', 21071 Huelva, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Contreras
authors.affiliation: Department of Geology, University of Huelva, Campus 'El Carmen', 21071 Huelva, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Pérez-López
authors.affiliation: Department of Applied Physics, University of Huelva, Campus 'El Carmen', 21071 Huelva, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Gázquez
authors.affiliation: Institute of Materials Science of Seville (CSIC-US), Av. Américo Vespucio, 49, 41092 Seville, Spain; Department of Condensed Matter Physics, University of Seville, Av. Reina Mercedes, 41012 Seville, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Morales-Flórez
authors.affiliation: Department Earth Sciences, University of Cádiz, Campus del Río San Pedro, Av. República Saharaui, 11510 Puerto Real, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Santos
authors.affiliation: Institute of Materials Science of Seville (CSIC-US), Av. Américo Vespucio, 49, 41092 Seville, Spain; Department of Condensed Matter Physics, University of Seville, Av. Reina Mercedes, 41012 Seville, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Esquivias
authors.affiliation: Department of Applied Physics, University of Huelva, Campus 'El Carmen', 21071 Huelva, Spain. Electronic address: bolivar@uhu.es.
authors.forename: J P
authors.initials: JP
authors.lastname: Bolívar
mesh_terms: D002119:Calcium Carbonate / Q000737:chemistry; D002133:Calcium Sulfate / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry*; D005591:Chemical Fractionation; D008670:Metals / Q000737:chemistry*; D008903:Minerals / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry*; D011868:Radioisotopes / Q000737:chemistry*; D059027:Recycling / Q000379:methods*; D018505:Waste Management / Q000379:methods*
chemical_list: D008670:Metals; D008903:Minerals; D011868:Radioisotopes; C077769:phosphogypsum; D002245:Carbon Dioxide; D010758:Phosphorus; D002119:Calcium Carbonate; D002133:Calcium Sulfate
keywords: CO(2) sequestration; Calcite; Industrial waste; Metals; Phosphogypsum; Radionuclides