Radioactive nuclides in phosphogypsum from the lowveld region of South Africa

Authors

  • Xolani Msila Sasol Dyno Nobel, Bronkhorstspruit, South Africa
  • Frans Labuschagne Sasol Dyno Nobel, Bronkhorstspruit, South Africa
  • Werner Barnard Sasol Technology Research and Development, Sasolburg, South Africa
  • David G. Billing School of Chemistry, University of the Witwatersrand, Johannesburg, South Africa

DOI:

https://doi.org/10.17159/sajs.2016/20150102

Keywords:

apatite, radium equivalent, radiation hazard indices, Anderson–Darling, secular equilibrium

Abstract

We evaluated the suitability of phosphogypsum from the Lowveld region of South Africa (LSA), for the manufacturing of building materials, with reference to (1) the National Nuclear Regulator Act 47 of 1999 and (2) the radioactivity associated risks as quantified in terms of the external and internal hazard indices, the activity concentration index and the radium equivalent. The distribution of radioactive nuclides in the LSA phosphogypsum was also examined. Analyses of 19 samples of the phosphogypsum show that phosphogypsum contains lower activity concentrations of naturally occurring radioactive nuclides of uranium and thorium and their progeny than the 500 Bg/kg limit set for regulation in South Africa. The potassium-40 (40K) activity concentration was below the minimum detectable amount of 100 Bq/kg. The values obtained for external and internal hazard indices and the activity concentration index were: 2.12 0.59, 3.44 0.64 and 2.65 0.76 respectively. The calculated radium equivalent Raeq was 513 76Bq/kg. The final decision regarding phosphogypsum’s suitability for use as a building material should consider scenarios of use.

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Published

2016-02-01

How to Cite

Msila, X., Labuschagne, F., Barnard, W., & Billing, D. G. (2016). Radioactive nuclides in phosphogypsum from the lowveld region of South Africa. South African Journal of Science, 112(1/2), 5. https://doi.org/10.17159/sajs.2016/20150102

Issue

Section

Research Article