Title: Comparison of spectrometry with arsenazo III and neutronic activation for U and Th determination in phosphogypsum

Authors: Maria Celia Siqueira, Kerley Oliveira, Antonio A. Mozeto, Maria Helena T. Taddei, Fabiana F. Dias

Addresses: Brazilian Nuclear Energy Commission (CNEN), Pocos de Caldas Laboratory (LAPOC), Rodovia Pocos de Caldas/Andradas, Km 13, 37701-970, Pocos de Caldas, MG, Brazil. ' Brazilian Nuclear Energy Commission (CNEN), Nuclear Research and Development Center (CDTN), Rua Professor Mario Werneck s/n – Pampulha, 31270-901 Belo Horizonte, MG, Brazil. ' Sao Carlos Federal University, Rodovia Washington Luiz, Km 235, Caixa Postal 676, 13565-905 Sao Carlos, SP, Brazil. ' Brazilian Nuclear Energy Commission (CNEN), Pocos de Caldas Laboratory (LAPOC), Rodovia Pocos de Caldas/Andradas, Km 13, 37701-970, Pocos de Caldas, MG, Brazil. ' Brazilian Nuclear Energy Commission (CNEN), Pocos de Caldas Laboratory (LAPOC), Rodovia Pocos de Caldas/Andradas, Km 13, 37701-970, Pocos de Caldas, MG, Brazil

Abstract: Phosphogypsum is a byproduct from the phosphoric acid industry which is formed by crystallisation during sulfuric acid attack on phosphate rocks. While the composition of phosphogypsum is dihydrated calcium sulphate, the material can contain high levels of impurities that exist in phosphate rocks, such as radionuclides from the 238U and 232Th series. The most common way of disposing of phosphogypsum is in piles in the environment around a phosphate ore processing plant. This could represent a risk to air, soil, and water, since this material has considerable 238U and 232Th radionuclide activities and their decay products.

Keywords: phosphogypsum; radionuclides; uranium; thorium; neutronic activation; arsenazo III; alpha spectrometry; environmental pollution.

DOI: 10.1504/IJNEST.2010.030302

International Journal of Nuclear Energy Science and Technology, 2010 Vol.5 No.1, pp.2 - 10

Published online: 14 Dec 2009 *

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