Zinc of Ireland’s ARGO Process Hits 99% Silver and 100% Lead Recovery Across Three Sites
Key Takeaways
- ARGO leach testing across three separate European zinc smelter feedstocks delivered average recoveries of 93% silver, 97% lead, and 80% copper — consistent results across independent sites, not a single outlier.
- The 12-month testwork program has been fast-tracked, with a TRL7 pilot plant targeted for early 2027 and technical partners SOLVOMET in Belgium and Core Resources driving the program.
- Critical minerals — germanium, gallium, and indium — have been confirmed to concentrate within the ARGO process flowsheet, with recovery results expected shortly and a full-scale installation design targeting 100,000+ tonnes per annum.
- VLAIO grant funding from an independent Belgian government body has been secured, providing external validation of the ARGO technology's commercial credibility.
- Zinc Leach Residue is currently a landfill-bound waste stream from zinc smelters — ARGO's ability to extract silver, lead, copper, and critical minerals from it creates a dual commercial and environmental value proposition.
ARGO technology delivers exceptional early-stage leach results
Zinc of Ireland Limited (ASX: ZMI) has released initial screening leach test results from its ARGO testwork program at Solvomet’s metallurgical research laboratory in Leuven, Belgium, and the numbers are hard to ignore. Testing of Zinc Leach Residue (ZLR) across three separate European smelter feedstocks delivered recoveries of up to 99% silver, 100% lead, and 91% copper.
What makes this result significant is consistency across three independent sites. A single strong result can be a data point. Three strong results from three separate feedstocks is a process signal.
The ARGO program is part of a major 12-month testwork program recently fast-tracked, with a pilot plant (TRL7) targeted for early 2027. The program is supported by VLAIO grant funding, providing external validation of the technology’s credibility.
Greg Ross, CEO
“To achieve these outcomes this early in the program is very exciting. This is the next step in the progress of the ARGO Technology since acquisition and provides further confirmation of its ability to treat one of the industries more difficult output streams and recover nearly the full value of what would previously lost metals.
ZMI is exceptionally well-positioned as we accelerate the ARGO testwork program, with a focus on critical minerals. Driven by strong industry interest and backed by VLAIO grant funding, our world-class technical partners including SOLVOMET and Core Resources which are working systematically to bring the ARGO pilot plant online by early 2027. …”
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Metal recovery across three smelter sites
The table below reproduces Table 1 from the announcement, showing recovery rates for each metal across the three smelter feedstocks tested.
| Metal | Site 1 | Site 2 | Site 3 | Average |
|---|---|---|---|---|
| Silver | 93% | 99% | 88% | 93% |
| Lead | 93% | 100% | 99% | 97% |
| Zinc | 35% | 70% | 69% | 58% |
| Copper | 68% | 91% | 81% | 80% |
Tests were performed on 500mL samples of ZLR from each of the three smelters, tested in triplicate, and run for 180 minutes at 25°C.
Zinc recovery averaged 58% across the three sites, which is lower than the other metals. That gap is worth contextualising: the ARGO process is primarily targeting silver, lead, and critical minerals rather than zinc itself, so this figure does not undermine the overall result.
The program also identified where critical minerals — germanium, gallium, and indium — concentrate within the ARGO process. That is a meaningful step. Knowing where these elements sit in the flowsheet is the prerequisite for extracting them efficiently, and ZMI has confirmed that pathway now exists for further testing.
What is Zinc Leach Residue and why does it matter?
Zinc Leach Residue (ZLR) is a solid waste by-product produced by zinc smelters during metal processing. Under conventional processing, ZLR typically ends up in landfill, taking with it trapped quantities of silver, lead, and copper that are never recovered.
ARGO is a low-temperature leaching technology designed to extract these metals from ZLR. That dual outcome — recovering commercially valuable metals while reducing industrial waste sent to landfill — is the core of the ARGO value proposition.
ZMI’s two metals technologies, ARGO and VOLTA, both target environmental and commercial gaps in the global zinc supply chain. ARGO addresses the waste-stream end: extracting value from material that would otherwise be discarded.
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Critical minerals and the road to pilot plant
Testing of critical minerals — germanium, gallium, and indium — is currently underway, with ZMI planning to report results shortly. These are not niche materials. Germanium and gallium are used in semiconductors and defence applications; indium is a key input for display screens and solar cells. Their presence in ZLR, and a confirmed pathway to recover them, adds a strategic dimension to the ARGO story beyond silver and lead.
The development pipeline from here runs as follows:
- Optimise leach test results and convert to element recovery trials
- Confirm final metal and element recovery percentages
- Incorporate results into simulation testing to develop a full circuit model
- Target full-scale installation design at 100,000+ tonnes per annum
- Pilot plant (TRL7) targeted for early 2027
Technical partners SOLVOMET in Belgium and Core Resources are working through this program systematically. VLAIO grant funding, announced the week prior to this release, supports the program and signals that an independent funding body has assessed the technology as credible.
For investors tracking ZMI’s ARGO development, the key signal from this announcement is straightforward: consistent, high recoveries of silver and lead across three independent European feedstocks at this early stage of testing is a meaningful de-risking outcome ahead of pilot plant development. The critical minerals layer, once confirmed, has the potential to add further weight to the project’s commercial case.
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