This technical demonstration outlines a hydrometallurgical electrowinning process utilizing a cation exchange membrane to separate cathodic metal deposition from anodic acid regeneration. The system circulates a 10–15% hydrochloric acid feedstock through a mag-drive pump, passing over a polarized titanium cathode and linseed-oil-treated graphite anode. Operational parameters run at 45 A and 6 V (~135 W input), targeting an oxidation-reduction potential (ORP) exceeding 1,500 mV to maximize precious metal dissolution from galena-dominant ore. The protocol yields approximately 85 g of mixed-metal concentrate (primarily lead with embedded PGMs and gold) within a 30–40 minute batch cycle. Economic modeling calculates raw material value at ~15¢ against ~2¢ in electrical costs, while explicitly acknowledging significant current efficiency losses and thermodynamic inefficiencies at this prototype scale. The workflow emphasizes strict hazard mitigation, including active chlorine scrubbing, secondary containment sized at 2x fluid volume, and OSHA/EPA ventilation compliance. Future development prioritizes continuous vacuum filtration integration, injection-molded cell manufacturing, and industrial tonnage scaling.
Key Highlights & Timestamps
0:17 Continuous Mining Demonstration: Showcases a batch-to-continuous electro-mining unit extracting ~2 oz of metallic concentrate using approximately 2 cents of electrical energy.
2:19 Fluid Dynamics & Process Loop: Leach solution circulates from the anode regeneration chamber through a bypass into the cathode compartment, returning depleted fluid for acid restoration via a cation exchange membrane.
3:02 Membrane & Electrode Architecture: Deploys an open-sourced cation exchange membrane paired with boiled graphite gouging rods to chemically regenerate the leaching agent on the positive side.
4:17 Reagent Formulation: Mixes 32% stock HCl to achieve a 10–15% working solution; restricts sodium chloride addition to under 5 g/L to prevent gold complexation and cathodic plating inhibition.
6:39 Hazard & Containment Protocols: Mandates outdoor operation, active ventilation, halogen scrubbing, and secondary liquid containment systems sized at 2x the working fluid volume to mitigate toxic gas and chemical spill risks.
12:29 Electrochemical Cell Assembly: Utilizes a mag-drive pump, titanium cathode plates, and a polarized titanium collection bolt to precipitate metals as powder while preventing oxidative re-dissolution.
15:28 Process Monitoring & ORP Targets: Employs pH indicators and chlorine dioxide meters; targets oxidation-reduction potential exceeding 1,500 mV to ensure efficient precious metal dissolution.
18:33 Feedstock Analysis & Deposition: Processes galena-dominant ore; observes lead sponge formation on cathodes, with secondary membranes deployed to prevent cross-contamination.
22:46 Post-Extraction Processing: Implements vacuum filtration and sodium bicarbonate neutralization washes to halt acidic re-dissolution and isolate dry concentrate.
24:36 Energy Economics & Output Yield: Generates 85 g of concentrate over 30–40 minutes at 45 A and 6 V (~135 W); calculates raw material value at ~15 cents against 2 cents in power costs, noting severe current efficiency losses.
26:06 Analytical Verification: Presents third-party ICP-MS data confirming co-extraction of gold, rhodium, platinum, palladium, and iridium, supplemented by XRF detection of rare earth elements and base metals.
28:22 Industrial Scaling Roadmap: Outlines progression to ton-per-day throughput via continuous vacuum filtration drums, injection-molded cell manufacturing, and extended catalyst/membrane lifespans.
33:25 Commercial & Operational Constraints: Clarifies that economic viability requires industrial-scale feedstock tonnage, rejects retail-scale profitability, and offers technical consultation and feedstock validation services.