652 Table 2 – Metrics of the Njs regression model Indicator Value R2 98.3 R2 adjusted 97.0 Standard Error (RPM) 36.1 Observations 10 Table 3 presents the p-value of the Njs model terms. Terms with p<0.05 (95% confidence) were considered statistically significant. Table 3 – P-values for Njs model terms Term P-Value Constant < 0.001 Jg < 0.001 Baffling 0.054 Jg2 0.008 Jg*Baffling 0.010 At the 95% confidence level, the regression model indicates that baffling arrangement does not have a statistically significant main effect on coarse particle suspension. However, it is significant with 94.6% confidence and is also present in the interactive term which had a significance of 99% and was therefore retained in the model. Moreover, previous studies strongly suggest that replacing the stator with baffles can significantly modify suspension performance. The stator converts a substantial portion of impeller energy into turbulence, which is detrimental to particle suspension (Nagata, 1975; Fallenius, 1987). In contrast, baffles promote mean flow, enhancing solids suspension efficiency (Nguyen & Schulze, 2003; Paul et al., 2004; Mesa, 2020). Consequently, operation with baffles resulted in a lower Njs than with the stator (Figure 2). Figure 2 – Main effects of baffling (0: Stator only, 1: Baffles only) and Jg on mean Njs It can also be concluded from Figure 2 that superficial gas velocity (Jg) exhibited a strong influence on coarse particle suspension. This agrees with previous studies in both mechanical flotation cells and mixing tanks, which have shown that aeration affects solids suspension (Rewatkar et al., 1991; Kraume, 1992; Mavros, 1992; Van der Westhuizen, 2004; Zheng et al., 2005; Lima et al., 2009). Air introduction decreases
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