Red mud Heat treatment Radon exhalation By product Building material

Fig. 4. Cumulative pore volume in function of pore size between 1 and 100 nm.Figure optionsDownload full-size imageDownload as PowerPoint slide
However, CX-5461 strong correlation was found between the mezo-pores and the massic exhalation features; the elevated massic exhalation capacity in the case of the 200°C-treated samples pointed to an elevated pore volume range, which also had the biggest effect on the amount of emanated radon and exhaled radon.
This elevated pore volume range was found to be between 60 and 90 nm, where the cumulated pore volume was the highest (see Fig. 5).
Fig. 5. Cumulative pore volume in function of pore size between 50 and 100 nm.Figure optionsDownload full-size imageDownload as PowerPoint slide
3.2.1. Emanation vs. internal structure
The specific surface of all heat-treated samples and the pore volume were calculated according to BET theory (Brunauer et al., 1938). The obtained results were compared with calculated emanation factors (Fig. 6) to find connection between them.