2024-12-16_REVISION - M1977410 (26)

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ADS-RPT-2021-14 ESS-Nederland Mine _ 60 November 4, 2021 200 Lake Drive, Glasgow, DE 19702 302.731.1700 Fax 302.731.1701 www.gravertech.com Proprietary and Confidential Page 5 of 8 concentration of these samples was not near the initial concentration of either Cd or Zn, the capacities are likely to be larger than the reported values. These equilibrium batch isotherm tests serve as guidance to initial capacity estimates. They do not factor in or correct for capacity changes with respect to kinetic or other engineering effects. The best way to gauge the capacity of the media is to perform a pilot test and get the real capacity of the media under actual process conditions. 4.3 Kinetic Testing Evaluation Kinetic evaluations of the media were conducted by extracting a small amount of water out of a single reaction at specific intervals. For the sake of this test, samples were taken at 1 minute, 5 minutes, 10 minutes, 60 minutes and overnight (equilibrium contact). After careful evaluation, the results appear best in the V/m ratio of 1000 mL/g. At this ratio, there is sufficient contact with the media during the kinetic testing that an effect can be evaluated. The cadmium data show that only about slightly more than 0% of the Cd is removed at 5 minutes of contact. At 10 minutes of contact, the removal percentage goes up to about 10% (Figure 1). At 60 minutes of contact, the removal is over 70%. The actual reduction should be higher, but the calculation is limited by the ICP-MS detection limit. The data from the Zn analysis shows that less than 40% of the Zn is removed at 10 minutes. At 60 minutes, the percent removal increases to 86% (Figure 2). The media appears kinetically hindered for both Zn and Cd removal. The Cd is probably hindered due to the lower concentrations; it takes longer for the ions to find the surface of the media and to be sufficiently adsorbed.