Radiological and leaching assessment of an ettringite-based mortar from ladle slag and phosphogypsum. (February 2020)

• Record Type: Journal Article
• Authors: Gijbels, Katrijn; Nguyen, Hoang; Kinnunen, Paivo; Samyn, Pieter; Schroeyers, Wouter; Pontikes, Yiannis; Schreurs, Sonja; Illikainen, Mirja
• Is Part Of: Cement and concrete research. Volume 128(2020)
• Publication Date: 2020-02
• Subjects: Ladle slag -- Phosphogypsum -- Ettringite -- Naturally occurring radionuclides -- Leaching; Cement -- Periodicals; Cement -- Research -- Periodicals; Concrete -- Periodicals; Concrete -- Research -- Periodicals; Ciment -- Périodiques; Béton -- Périodiques; Cement; Concrete; Periodicals; 620.135
• DOI: 10.1016/j.cemconres.2019.105954
• Languages: English
• ISSNs: 0008-8846

Abstract

Abstract: In this investigation, ettringite-based mortars were synthesized from ladle slag (LS) and phosphogypsum (PG), promoting the concept of a circular economy. However, the reuse of naturally occurring radioactive materials (NORM), such as PG, requires radiological investigation. Also, the immobilization degree for contaminants contained in PG should be evaluated. The former was investigated using gamma spectroscopy and radon exhalation/emanation tests, while the latter was assessed using an up-flow percolation column test according to the CEN/TS 16637-3. The produced mortars comply with current legislation on naturally occurring radionuclides (NOR) in building materials, proving that they can be safely used for building purposes. The radon emanation decreased upon increasing the Polish PG content, which was mainly determined by the microporosity. The specific surface areas were 20–30 times lower than conventional cement, and the immobilization degree for contaminants was generally high (>90%). This investigation demonstrates high potential for PG reuse in ettringite-based mortars. Highlights: Ettringite-based mortars were produced from ladle slag and phosphogypsum. The mortars comply with the legislation on naturally occurring radionuclides in building materials. The radon emanation was mainly dependent on the microporosity when using Polish phosphogypsum. Specific surface areas were 20–30 times lower than conventional cement. The mortars show a high degree of immobilization for contaminants contained in phosphogypsum.