Radon exhalation study of manganese clay residue and usability in brick production

摘要

The reuse of by-products and residue streams is an important topic due to environmental and financial aspects. Manganese clay is a residue of manganese ore processing and is generated in huge amounts. This residue may contain some radionuclides with elevated concentrations. In this study, the radon emanation features and the massic exhalation rate of the heat-treated manganese clay were determined with regard to brick production. From the manganese mud depository, 20 samples were collected and after homogenization radon exhalation characteristics were determined as a function of firing temperatures from 100 to 750 degrees C. The major naturally occurring radionuclides K-40, Ra-226 and Th-232 concentrations were 607 +/- 34, 52 +/- 6 and 40 +/- 5 Bq kg(-1), respectively, comparable with normal clay samples. Similar to our previous studies a strong correlation was found between the internal structure and the radon emanation. The radon emanation coefficient decreased by similar to 96% from 0.23 at 100 degrees C to 0.01 at 750 degrees C. The massic radon exhalation rate of samples fired at 750 degrees C reduced by 3% compared to samples fired at 100 degrees C. In light of the results, reusing of manganese clay as a brick additive is possible Without any constraints. (C) 2016 Elsevier Ltd. All rights reserved.