ALS2 and Tungsten-Carbide Tool Scrap: A Cleaner Path to Gold Recovery

Australia has long been defined by its relationship with gold, from the historic boomtowns around Kalgoorlie and Boulder in Western Australia to modern precious-metals refineries serving the country's mining sector. That heritage is now taking a fresh direction, as industrial scrap streams become an increasingly important secondary source of the metal. Tungsten-carbide tool inserts, drill bits and cutting tools used in mining, construction and machining all carry measurable gold deposits on their surfaces, often applied as wear-resistant coatings or concentrated in brazed joints. Treating those deposits efficiently is a challenge that traditional chemistry has handled with mixed results, and one that a new European-backed technology is being designed to address.

The ALS2 project, coordinated by Italy's Ikoi S.p.A. and supported through the European Union's Horizon 2020 research and innovation programme, is developing an acidless separation process engineered for precious-metals recovery from complex waste streams. Unlike conventional aqua regia or cyanide leaching, ALS2 uses non-corrosive chemistry and controlled electrical potential, allowing operators to recover gold, silver and platinum-group metals from substrates like tungsten-carbide without dissolving the tool itself. The result fits comfortably into compact recovery plants, including the kind of mid-sized facilities emerging across Australia's e-waste and scrap-metal sectors.

Tungsten-Carbide Scrap as a Hidden Gold Reservoir

Mining remains one of Australia's most resource-intensive industries, and tungsten-carbide tools play a steady role in drill strings, grinding mills and high-pressure roll crushers across operations from the Pilbara to Mount Isa. As these tools wear, fragments and end-of-life inserts accumulate in scrap yards in Perth, Brisbane and regional smelting hubs. The metallic coatings on these components often contain gold in the range of a few grams per kilogram of substrate, sometimes concentrated where the carbide tip meets the steel body of the original tool.

The challenge with this kind of scrap is structural. Tungsten-carbide is extraordinarily hard and chemically stable, which is exactly why the tools are valuable, yet the same qualities make it resistant to the aggressive acids normally used to liberate precious metals. Conventional refiners therefore tend to either grind the entire insert into powder and leach it whole, which wastes the carbide, or pre-roast the material to crack the matrix. Both routes consume substantial energy and generate liquid waste streams that require careful treatment under Australian environmental compliance frameworks.

ALS2 approaches the same problem from a different angle. Rather than attacking the substrate, the process targets the surface deposits where gold sits, exploiting differences in electrochemical potential between the coating and the underlying carbide. That selectivity makes the technology appealing for recovery operators who want to keep the tungsten-carbide intact, either for resale into cutting-tool reclamation or for downstream recycling into cemented carbide feedstocks.

The Acidless Separation Mechanism

At the heart of the ALS2 flow sheet is a series of non-corrosive aqueous solutions paired with controlled electrical potential. Scrap parts are loaded into a reaction chamber where a mild electrolyte dissolves the precious-metal layer while the carbide substrate remains passive. The dissolved gold is then collected through selective electrowinning, producing a high-purity deposit on stainless-steel cathodes without the noxious off-gases associated with nitric acid or chlorine chemistry.

Because no aqua regia or cyanide is present, the working environment shifts noticeably. Operators in a compact plant in Sydney or Adelaide can run the process under far simpler ventilation and personal-protection regimes than a traditional refinery, and the waste streams leaving the site are easier to characterise and treat. Spent electrolytes can be reused across multiple batches, reducing both water consumption and the volume of effluent that needs downstream processing.

Selective recovery is another important feature. Gold, silver and the platinum-group metals respond at slightly different potentials, so the system can be tuned to plate them sequentially rather than as a mixed precipitate. For a recycler handling a mix of tungsten-carbide inserts, PCB connectors and catalytic substrates, this flexibility removes the need for repeated re-dissolution and re-precipitation steps that dominate acid-based flowsheets.

Comparing ALS2 to Conventional Acid-Based Refining

The differences between ALS2 and traditional refining become clearer when laid side by side. The comparison below summarises the key operational and environmental factors that drive refiner decisions in Australia and similar regulated markets.

Factor	Acid-Based Refining (aqua regia / cyanide)	ALS2 Acidless Separation
Primary reagents	Nitric acid, hydrochloric acid, sodium cyanide, aqua regia	Non-corrosive electrolytes, water-based
Operating temperature	Often elevated, with vigorous exotherms during aqua regia digestion	Moderate, near-ambient in most stages
Off-gas treatment	Nitrogen oxides, chlorine, HCN scrubbing required	Minimal acid fumes, low VOC load
Effluent handling	High-metal, high-acid waste; complex precipitation train	Lower acidity, easier metals recovery, reusable electrolyte
Substrate impact	Carbide matrix often attacked or dissolved	Carbide matrix preserved for resale or further use
Plant footprint	Large, with segregated acid and leaching halls	Compact, suitable for modular recovery units
Worker PPE	Acid-resistant suits, SCBA or supplied air in many tasks	Standard chemical PPE, lower respiratory risk
Regulatory burden	Heavy: hazchem licensing, cyanide permits, acid storage	Lighter chemical inventory, fewer restricted reagents

For an Australian operator weighing the cost of compliance, the comparison often swings the decision toward the acidless route. Hazchem licensing, cyanide permitting and acid storage all carry ongoing administrative and monitoring costs that smaller plants in regional centres struggle to absorb.

Sustainability and Worker Safety Benefits

Australia's mining and recycling sectors operate under some of the world's tighter environmental and occupational health frameworks, from the Environment Protection and Biodiversity Conservation Act through to state-level dangerous goods regulations. Any process that reduces the on-site inventory of restricted chemicals immediately lowers the compliance burden, which is one of the strongest arguments for adopting ALS2 in local recovery plants.

Worker safety is a related but distinct benefit. Acid refining requires sustained exposure controls: respirators, acid suits, emergency shower stations and continuously monitored air-handling systems. ALS2's chemistry sidesteps most of these requirements because the electrolytes used are far less aggressive. That matters in regions where skilled labour is scarce and where attracting trained metallurgists to remote facilities in Kalgoorlie, Tom Price or Gladstone is already a recruitment challenge.

Energy use is another piece of the sustainability picture. Because ALS2 operates near ambient temperature and uses electrical potential rather than thermal cracking, its energy footprint per ounce of recovered gold compares favourably with the multi-stage roasting and leaching routes used for hard-to-treat scrap. For organisations reporting under modern ESG frameworks and seeking verified secondary-source gold, the lower carbon profile of an ALS2-based plant is increasingly attractive.

Suitability for Compact Recovery Plants

A defining feature of the ALS2 design is that it scales down well. Pilot trials in Europe have demonstrated units small enough to fit inside a standard shipping container, opening the door to distributed recovery in places where shipping bulk scrap to a central refinery is uneconomic. Several Australian states, including Victoria and New South Wales, have invested in regional e-waste drop-off points, and a containerised ALS2 unit could in principle sit beside such a hub, recovering gold from locally generated tungsten-carbide tool waste before it leaves the region.

This decentralised model also shortens the supply chain for recovered metal. A precision-machining shop in Melbourne's industrial belt, for example, could send its worn inserts to a nearby ALS2 facility and receive back credit-grade gold without the long truck or rail journeys currently needed to reach centralised refiners. The same logic applies to mining-service workshops in the Hunter Valley, where drill-bit re-grinding operations already generate significant tungsten-carbide scrap.

Cost discipline matters as well. By avoiding expensive reagent consumption, slashing waste-handling overheads and producing a reusable carbide by-product, ALS2 changes the economics of recovering gold from what has historically been treated as a low-value, hard-to-process fraction. For a medium-sized recycler, that shift can move tungsten-carbide scrap from a cost line to a meaningful revenue contributor.

Integration with WEEE and Scrap Recycling Streams

The real strength of ALS2 emerges when it is plugged into a broader WEEE recycling line. Tungsten-carbide inserts rarely arrive alone. They come mixed with steel shavings, brazing residues, drill rods and the occasional contact-pin assembly containing its own small gold flash. An integrated recovery plant can therefore use the same ALS2 unit to process several infeeds: tungsten-carbide tool scrap, jewellery swarf, connector pins and small plated components.

Australia's National Television and Computer Recycling Scheme and the wider product-stewardship landscape continue to push volumes of small electrical appliances through accredited recyclers. Each of those appliances contains milligrams of gold on connector fingers and plating layers, and many also include cutting or grinding tools carrying tungsten-carbide. A single ALS2 cell positioned downstream of mechanical separation and sorting can address both streams with only modest reconfiguration between batches.

For scrap-metal merchants and WEEE processors alike, the technology offers a way to capture value that would otherwise be lost through blending or shipped overseas for processing. It also aligns with public expectations around circular-economy outcomes, expectations that have grown steadily stronger among Australian consumers, councils and procurement bodies over the past decade.

If your facility handles tungsten-carbide scrap or mixed WEEE streams and you would like to explore how ALS2 could fit into your recovery flowsheet, reach out to the project team to discuss pilot opportunities and integration pathways for Australian operations.