How ALS2 Recovers Palladium from Aerospace Brazing Alloy Scrap
Aerospace manufacturers rely on high-temperature brazing alloys to bond turbine blades, heat exchangers, and structural honeycomb panels. Many of these alloys contain palladium as a critical alloying element because of its resistance to oxidation, its catalytic behaviour, and its ability to wet nickel-based superalloys at service temperatures above 1100 °C. When components reach end-of-life, the palladium locked inside those joints is rarely recovered through conventional recycling routes — a gap that the ALS2 acidless separation process is built to close.
For recyclers and processors working in Australia, the opportunity is significant. The country imports the vast majority of its platinum-group metals, and the nation's aerospace sector — from Boeing Australia's facility in Fishermans Bend (Melbourne) to the maintenance hubs around Brisbane Airport — generates a steady flow of nickel-palladium brazed scrap. Recovering that palladium domestically would reduce import dependence while creating a new revenue line for the local e-waste and WEEE value chain.
The Brazing Alloys Used in Aerospace Components
Nickel-palladium, palladium-cobalt, and palladium-silver brazes are favoured in jet engine hot zones because they maintain strength under thermal cycling. A typical high-temperature braze joint contains between 5% and 25% palladium by weight, and the surrounding substrate is usually Inconel, Haynes, or another nickel superalloy. That layered, dissimilar metal structure makes mechanical separation almost impossible; chemical separation is required, yet the alloy's robustness means aggressive leaching agents were traditionally necessary.
End-of-life streams include turbine vane repairs scrapped during scheduled engine overhauls, rocket nozzle coupons, honeycomb panels from retired airframes, and service tooling contaminated with braze residue. In Australia, several Tier 1 approved maintenance organisations handle these flows under CASA-approved procedures, sending significant volumes to overseas refiners rather than processing them locally.
The complexity of these multi-metal scrap types is similar to what processors face when recovering gold from ceramic CPU packages with ALS2, where a robust but selective leach is required without dismantling the substrate. Both feedstocks demand a chemistry that can discriminate between precious and base metals while respecting the integrity of the surrounding materials.
Why Palladium Recovery Matters in Australia
Australia produces almost no primary palladium; the country's output comes mainly as a by-product of nickel mining at sites like Kambalda and across the broader Western Australian goldfields. According to Geoscience Australia figures, domestic production covers only a small fraction of national demand, and the gap is filled by imports from Russia and South Africa. Strategic materials lists maintained by the Australian Government have repeatedly flagged palladium as a supply-risk commodity.
E-waste is the most realistic secondary source on home soil. The Australian Bureau of Statistics estimates electronic waste generation continues to climb well past 20 kg per capita, and state-level landfill bans in New South Wales, Victoria, South Australia, and the ACT have redirected circuit boards, sensors, and rejected aerospace components into formal recycling channels. Each kilogram of palladium recovered offsets roughly 200,000 kilograms of ore that would otherwise need to be mined, processed, and smelted overseas.
That argument resonates with regulators drafting extended producer responsibility schemes in Queensland and Western Australia. Embedded palladium in aerospace components is not currently captured by any national take-back scheme, but the same infrastructure being designed for lithium-ion batteries and solar panels could plausibly be expanded to cover industrial WEEE.
Inside the ALS2 Acidless Separation Process
ALS2 is built on a chloride-based leaching medium that operates without mineral acids. The medium is formulated to dissolve platinum-group metals selectively while leaving base metals such as nickel, iron, and chromium behind in their solid state. Because no nitric acid or aqua regia is required, the process avoids the toxic nitrogen oxide fumes that have historically made precious-metal refining one of the dirtiest activities in the metallurgical sector.
A key feature is temperature staging. The leach runs in a closed vessel at controlled temperature, with sequential dissolution steps that respond to the electrode potentials of palladium, platinum, and rhodium. Selectivity comes from redox couples already present in the spent aerospace components — the chromium and iron content shifts the solution chemistry so that palladium and other precious targets ionise first while the alloy substrate remains intact.
According to ALS2 consortium briefings and Horizon 2020 dissemination materials, recovery rates above 95% have been recorded on pilot feedstocks that mimic turbine blade scrap. The closed-vessel approach also reduces occupational exposure to acid mists, an important consideration under Australian Work Health and Safety regulations for hazardous chemicals.
Step-by-Step: From Scrap to Pure Palladium
Pre-treatment begins with mechanical size reduction — typically shredding and screening — followed by magnetic removal of steel contaminants. The non-ferrous fraction, now concentrated in nickel-palladium and similar high-temperature alloys, enters the ALS2 leach. Residence times are around two to four hours depending on particle size and braze composition.
The pregnant leach solution, now carrying palladium-chloride complexes, is separated from the residue and passed through a selective precipitation train. A staged reagent addition drops palladium as a pure sponge, while platinum and rhodium stay in solution for downstream recovery. The sponge is washed, calcined, and reduced under hydrogen to yield a black powder assaying above 99.95%.
From there, secondary producers can melt, granulate, or redissolve the powder for re-entry into the aerospace braze supply chain. The solid residue from the leach — rich in nickel oxides — is itself a saleable by-product for stainless steel producers in Port Kembla or Whyalla, turning a problematic waste stream into a circular input for domestic metallurgical industries.
How ALS2 Stacks Up Against Traditional Refining
The acidless route differs from incumbent methods on several operational parameters. The table below compares typical figures from published pilot data and conventional refinery disclosures.
| Parameter | Conventional Aqua Regia | Pyrometallurgical Copper Collection | ALS2 Acidless Process |
|---|---|---|---|
| Reagent toxicity | High — nitric acid, HCl | Low to moderate — lead, fluxes | Low — chloride salt medium |
| NOx / SOx emissions | Significant | Moderate (furnace off-gas) | Negligible |
| Typical palladium yield | 90–94% | 85–92% | 95–99% |
| Energy intensity | Medium | High | Medium-low |
| By-product handling | Liquid waste requiring treatment | Slag and matte streams | Recoverable nickel-rich residue |
| Suitability for small plants | Poor | Very poor | Strong |
The figures make clear that ALS2 is particularly well-suited to decentralised processors and urban recycling hubs. A facility in Geelong or an industrial estate in Sydney's west could integrate the system without the stack permits or acid neutralisation infrastructure that pyrometallurgical and aqua regia routes demand.
The same flexibility has already attracted interest from teams looking at cash out pontoon economics for high-value scrap streams that prize low-overhead, modular recovery. Capital and operating cost profiles matter as much as yield when recyclers weigh up site selection in capital cities where property and labour expenses continue to climb.
Sustainability Gains for Local Recyclers
Environmental performance is where ALS2 scores most consistently for Australian operators. Because the chemistry avoids strong mineral acids, atmospheric releases of nitrogen oxides fall to near zero. Water consumption is closed-loop through the leach-precipitation cycle, and the only consumables are chloride salts and small reagent additions for selective precipitation.
For a recycler operating under the Environment Protection Authority in Victoria or the NSW Environment Protection Authority, the permitting pathway is considerably simpler than for a traditional refinery. Smaller stack and discharge permits mean shorter approval timelines and reduced ongoing monitoring cost, both of which cut into the unit economics of palladium recovery.
There is also a downstream materials story. The aluminium honeycomb residue recovered from airframe scrap can be fed back into local smelters, while the nickel-iron oxide residue provides a feedstock for Australian stainless producers who currently depend on imported ferro-nickel. Closing those loops aligns with the Critical Minerals Strategy released by the Department of Industry, Science and Resources, and with the National Waste Policy Action Plan target of recycling 80% of e-waste by 2030.
Industrial Scale-Up and Horizon 2020 Support
ALS2 is moving from pilot to demonstration under the European Union's Horizon 2020 research and innovation programme. Ikoi S.p.A., the technology owner, has partnered with research institutes and downstream metallurgical specialists to validate the process on real industrial scrap streams, including aerospace braze residues. Milestones over the next 18 months include a 250-kilogram batch demonstration and the publication of a full life-cycle assessment.
For Australian companies, the most practical near-term move is technology transfer collaboration: partnering with the ALS2 consortium on feedstock characterisation, integrating the leach into existing WEEE lines, or supplying certified aerospace scrap into a regional demonstration plant. Discussions with the CSIRO's critical minerals team could also accelerate validation on local feedstocks, given their existing work on nickel and platinum-group metal extraction.
Equipment manufacturers may eventually produce containerised ALS2 modules suitable for deployment near scrap sources in Brisbane, Melbourne, or Perth. Such distributed refining would shrink transport footprints, reduce exposure to shipping disruptions observed along the Australia–Asia trade routes, and bring the benefits of palladium recovery closer to the operations where the scrap is generated.
If your organisation generates nickel-palladium brazing scrap from aerospace maintenance or processes nickel superalloys through Australian facilities, reach out to the ALS2 team to explore pilot feedstock trials, licence arrangements, and consortium partnership opportunities under the Horizon 2020 framework.