Influence of the addition of phosphogypsum on some properties of ceramic tiles

Phosphogypsum (PG) is a waste from phosphoric acid production, and this work evaluates the use of PG as an additive in ceramic manufacturing. Ceramic samples were produced by adding different concentrations of PG (5, 7.5, and 10 wt%) to natural clay, and sintering at 950, 1050, and 1150 °C. Technological and mechanical properties of the obtained ceramics were evaluated. Moreover, the U.S. EPA's toxicity characteristic leaching procedure, Index “I”, and the effective radium activity were calculated to evaluate the environmental risks. The use of PG improves the sintering behaviour and the bending strength, while also the environmental impact is negligible.
This research has been partially supported by the Spanish Government Department of Science and Technology (MINECO), by the project “Fluxes of radionuclides emitted by the PG piles located at Huelva; assessment of the dispersion, radiological risks and remediation proposals” (Ref.: CTM2015-68628-R). PhD student M. Contreras would like to express his gratitude for the research contract granted to him through the Fellowship Training Program of the University Teaching Staff (Ref.: AP2010-2746), financed by the Spanish Ministry of Education, Culture and Sport (MECD). This research has been partially supported by São Paulo Research Foundation (FAPESP) (Ref.: 2013/07296-2) in the Center for the Development of Functional Materials (CDMF), Laboratory of Ceramic Materials (LaMaC/UNESP), Campus of Presidente Prudente, São Paulo, Brazil.