Subsequent batch assays in KMD medium (20% pulp) revealed that inoculated systems with Kobold A (30 °C) and Kobold B (45 °C), significantly outperformed uninoculated controls. By day 35, the flasks inoculated with Kobold B achieved cobalt recovery rates exceeding 90% (Fig.1), confirming the high catalytic potential of the selected consortia. Figure 1 – Cobalt extraction flask assays. 3.3.2. Minicolumn Bioleaching Preliminary evaluations focused on assessing glomerulus formation [19] and the efficiency of bio-oxidation were done using syringes packed with "Cola Scavenger" and quartz, which demonstrated favorable glomerulus stability and minimal mineral carryover into the pregnant leach solution (PLS). Five bioleaching campaigns were executed in 30cm. minicolumns to determine optimal operational parameters for scalable application. Variables included microbial consortia, pH, temperature, acid curing intensity, and inoculation protocols. The most robust performance was observed in columns operated at 45 °C using the Kobold B consortium. Under optimized conditions—comprising a pH of 1.5, 80% acid curing, an inoculum density of 1x107 cells g⁻¹, and post-curing inoculation—cobalt recovery surpassed 90% by day 120 (Fig.2). Figure 2 – Cobalt extraction in minicolumns assays. 3.3.3. Polymetallic recovery potential In addition to cobalt recovery, the systems were monitored for the solubilization of other
RkJQdWJsaXNoZXIy MTM0Mzk2