654 Table 5 presents the p-value of the Pjs model terms. All terms were found to be statistically significant, at a 95% confidence level. Table 5 – P-values for Pjs model terms Term P-Value Constant < 0.001 Jg < 0.001 Baffling < 0.001 Jg2 0.037 Jg*Baffling < 0.001 The statistical analysis indicates that both baffle configuration and superficial gas velocity (Jg) have significant main effects on the specific power draw at Njs. Higher Jg, as well as the use of the stator, led to increased Njs values. The faster impeller speeds produced a corresponding increase in power consumption (Figure 4). This trend aligns with the observations of Tabosa (2012), who reported that specific power consumption in a mechanical flotation cell increases with impeller speed. Figure 4 – Main effects of baffling (0: Stator only, 1: Baffles only) and Jg on mean Pjs The stator also promotes intense turbulent energy dissipation, which contributes to larger specific power draw values (Schubert, 2008; Kim et al., 2023). Conversely, although aeration is generally expected to reduce power draw (Arbiter et al., 1976; Nienow, 1997), this effect typically occurs when air is introduced at a constant impeller speed. In this study, the impeller speed was increased to reach Njs, which more than offset any potential power savings from aeration. Consequently, the overall effect of increasing Jg was an increase in Pjs. Baffling and Jg exhibited a strong interactive effect on Pjs, consistent with the interaction observed for Njs. This relationship is expected, as variations in power draw can be largely attributed to changes in impeller speed. Increasing Jg raises Njs, and consequently, Pjs increases as well. Because power scales exponentially with impeller speed (Newell & Grano, 2007), the sensitivity of Pjs to Jg depends strongly on the baffling configuration (Figure 5).
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