2021-07-14_REVISION - M2012032 (4)

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FLSmidth USA,Inc. 7158 S FLSmidth Drive•Midvale • UT 84047-5559 • USA M ' D T H Next, the cake blow begins simulating cake drying. During the cake blow, filtrate production is measured with respect to time along with air pressure and the flow rate through the filter cake. Air flow is limited to applicable levels available on full-scale filters by adjusting air pressure. Figure 11 show the cake moisture over time during the cake blow step. FLSmidth calculates the full-scale filtration rate using the form time, a standard mechanical time of three and one half minutes, a standard pump time of one minute and the cake blow data for standard filter press testing. Full-scale filtration rate may vary depending on the size, pumping rate, and configuration of the filter press. 4.0 Received Samples FLSmidth's metallurgical lab generated the 30-gallons of the zinc rougher tailings sample for the solid-liquid separation test work. Table 1 summarizes the sample characterization. Table 2 summarizes the particle size analysis with the full results attached in Appendix C. Table 2: Sample Characteristic Summary Zn Ro Parameter Tails Suspended Solids wt% 27.3 Solids Specific Gravity, /mL 2.8 Liquor Specific Gravity, /mL 1.0 Table 3: Malvern Laser Diffraction Particle Size Analysis Percent Passing m D90 185 D80 141 D50 67 D10 2.8 5.0 Thickening Results 5.1 Flocculent Screening Table 4 summarizes the evaluated flocculants and their chemical characteristics. Table 4: Evaluated Flocculants Flocculent Charge Molecular Weight Charge Density SNF AN-905 Anionic Low — Medium Very Low SNF AN-913 Anionic Medium Low SNF AN-926VHM Anionic Very High Medium SNF AN-934VHM Anionic Very High High SNF AN-945VHM I Anionic Very High Very High Figure 4 shows SNF AN-926VHM provided the best settling rates and visually the best Page 1 10