Radiological and non-radiological leaching assessment of alkali-activated materials containing ground granulated blast furnace slag and phosphogypsum

Katrijn Gijbels; Sheldon Landsberger; Pieter Samyn; Remus Ion Iacobescu; Yiannis Pontikes; Sonja Schreurs; Wouter Schroeyers

doi:10.1016/j.scitotenv.2019.01.089

Radiological and non-radiological leaching assessment of alkali-activated materials containing ground granulated blast furnace slag and phosphogypsum

Sci Total Environ. 2019 Apr 10:660:1098-1107. doi: 10.1016/j.scitotenv.2019.01.089. Epub 2019 Jan 10.

Authors

Katrijn Gijbels¹, Sheldon Landsberger², Pieter Samyn³, Remus Ion Iacobescu⁴, Yiannis Pontikes⁵, Sonja Schreurs⁶, Wouter Schroeyers⁷

Affiliations

¹ Hasselt University, CMK, Nuclear Technological Centre, Agoralaan, Gebouw H, 3590 Diepenbeek, Belgium. Electronic address: katrijn.gijbels@uhasselt.be.
² Nuclear Engineering Teaching Lab, University of Texas at Austin, Pickle Research Campus, Austin, TX 78712, USA. Electronic address: s.landsberger@mail.utexas.edu.
³ Hasselt University, IMO, Applied and Analytical Chemistry, Agoralaan, Gebouw D, 3590 Diepenbeek, Belgium. Electronic address: pieter.samyn@uhasselt.be.
⁴ KU Leuven, Department of Materials Engineering, Kasteelpark Arenberg 44, 3001 Leuven, Belgium. Electronic address: remusion.iacobescu@kuleuven.be.
⁵ KU Leuven, Department of Materials Engineering, Kasteelpark Arenberg 44, 3001 Leuven, Belgium. Electronic address: yiannis.pontikes@kuleuven.be.
⁶ Hasselt University, CMK, Nuclear Technological Centre, Agoralaan, Gebouw H, 3590 Diepenbeek, Belgium. Electronic address: sonja.schreurs@uhasselt.be.
⁷ Hasselt University, CMK, Nuclear Technological Centre, Agoralaan, Gebouw H, 3590 Diepenbeek, Belgium. Electronic address: wouter.schroeyers@uhasselt.be.

PMID: 30743907
DOI: 10.1016/j.scitotenv.2019.01.089

Abstract

Alkali-activated materials (AAMs) based on ground granulated blast furnace slag (GGBFS) and phosphogypsum (PG) were investigated in order to quantify leaching of naturally occurring radionuclides (NOR) and inorganic non-radiological elements according to an up-flow percolation column test as described in CEN/TS 16637-3. Gamma spectroscopy and neutron activation analysis (NAA) were applied for radiological characterization, inductively coupled plasma optical emission spectrometry (ICP-OES) and ion-chromatography (IC) for chemical characterization. Upon leaching, ²³⁸U, ²²⁶Ra, ²¹⁰Pb, and ²²⁸Ra were retained very well. Both for ²³²Th and ⁴⁰K, a decrease in activity concentration was observed due to leaching and their release was influenced by the use of different alkali activators, which was also the case for the leaching of non-radiological elements. Only a small amount of Al (0.5-0.8%), Ca (0.1-0.2%) and Si (0.1-0.3%) was mobilized, while highest release was observed for K (56-94%), Na (49-88%) and S (71-87%). At first glance, drinking water is not endangered by leaching of NOR following the requirements of the European Drinking Water Directive. From the results for porosity, obtained with mercury intrusion porosimetry (MIP), it was concluded that both the porosity and formation of multiple leachable and non-leachable complexes are determining factors for the release of elements from AAMs.

Keywords: Alkali-activated material; Ground granulated blast furnace slag; Leaching; Naturally occurring radionuclides; Phosphogypsum.