How ALS2 recovers gold from lead-free BGA solder joints
Ball grid array (BGA) packages are common in processors, memory modules, mobile devices and network equipment. Their solder balls connect packages to circuit boards, while fine gold wire, gold-plated pads and other metallisation carry much of the precious-metal value. In most lead-free assemblies, the solder is tin-silver-copper rather than gold, so the recovery challenge is to release the solder-bearing package without losing the minute gold-bearing components around it.
Acid-based refining can dissolve exposed metal, but it also creates corrosive reagents, hazardous liquid effluent and handling risks. ALS2Project offers an acidless separation route that uses physical and thermal liberation before targeted concentration. For Australian e-waste operators, that combination could make compact precious-metals recovery plants more practical at regional sorting and reprocessing hubs.
Why BGA packages are a valuable e-waste fraction
Lead-free solder has a lower processing temperature than traditional leaded solder, with common tin-silver-copper grades melting or fully becoming fluid at approximately 217–220°C. Gold has a much higher melting point, so a carefully controlled heat treatment can liquefy the solder without melting the gold-bearing wires, pads or plating. The thermal window must still be managed because each package combines different polymers, laminates and metals.
Fine components are easily lost during shredding. If a BGA package is mixed with plastics, aluminium, copper and other board materials, conventional density or magnetic separation may direct the valuable fraction to the wrong output. A successful process must first liberate the package and its metallisation, then prevent gold-bearing fines from becoming an untraceable part of the bulk residue.
Inside the ALS2 separation route
ALS2 begins with feed preparation rather than a leaching tank. BGA-rich boards and components are identified, removed from larger WEEE streams and prepared so that metal-bearing pieces remain physically distinguishable. This stage can combine careful dismantling, size reduction and the removal of obvious contaminants without exposing workers to the entire mixed WEEE stream.
The project’s BGA application centres on controlled, acid-free thermal treatment. Heat softens or melts lead-free solder while the gold-bearing metallisation remains solid. This creates a selective liberation step in which package, board and solder-rich material can be separated instead of being dissolved together. ALS2 is therefore best understood as a physical separation process that prepares concentrated feed for final refining, rather than a direct method for converting mixed electronic scrap into pure bullion.
Following liberation, physical concentration can divide the material into useful streams. Screens, density separation and targeted sorting help recover solder-rich particles and separate discrete gold-bearing components. Because tin-silver-copper solder also contains silver, the solder fraction may carry both precious- and base-metal value. Further refining of the relevant concentrates can then recover these metals under controlled metallurgical conditions.
Turning liberated parts into a valuable concentrate
Liberation is only half of the economic challenge. Additional size reduction can expose the gold, while excessive crushing may smear soft metal and make it harder to separate. Dust control, fire prevention and careful mass balances are therefore essential when handling fine electronic material. ALS2’s value lies in combining this controlled preparation with a route that avoids a bulk chemical dissolution stage.
| Recovery consideration | ALS2 acidless separation | Bulk acid refining | Mechanical sorting alone |
|---|---|---|---|
| Primary approach | Controlled thermal liberation followed by physical concentration | Chemical dissolution of exposed metals | Shredding, screening and density-based sorting |
| Treatment of BGA material | Releases solder-bearing parts and gold-bearing metallisation separately | Can dissolve exposed gold but also consumes metal-bearing residues | May leave fine gold attached to mixed components |
| Chemical requirement | No bulk acid leach within the acidless route | Strong acids and other lixiviants require controlled handling | Low reagent use, but limited chemical selectivity |
| Main operating risks | Heat management, dust and variable feed composition | Corrosion, hazardous gas and liquid-effluent control | High material throughput and potentially poor concentrate grade |
| Potential plant role | Compact modular recovery beside a WEEE sorting facility | Larger wet-processing installation with extensive safeguards | Useful pre-processing stage that still needs downstream recovery |
The distinction between recovery and refining is important. A separated BGA component or solder concentrate can have measurable gold content without yet meeting bullion specifications. Representative sampling and assay results determine whether it proceeds to an accredited refiner, an ingot producer or another metal-recovery route. This clear handover helps Australian operators avoid valuing an unverified concentrate as though it were finished gold.
Safety and sustainability gains
An acidless flow reduces the risk of workers handling concentrated acids, cyanide-bearing solutions or other aggressive lixiviants. It can also lower demand for corrosion-resistant equipment and reduce the volume of liquid waste requiring neutralisation. Those benefits are especially valuable for compact sites operating near urban collection depots or industrial parks, where a smaller wet-chemical plant would add permits, monitoring and operating complexity.
Acidless does not mean impact-free. Heated treatment still consumes energy, fine components can create combustible dust, and any thermal off-gas must be managed. Residues also require testing for hazardous constituents rather than being assumed harmless because no acid was used. A credible sustainability assessment should compare reagent consumption, water use, energy demand, recovery yield and verified final destination for all remaining fractions against the chosen acid-based benchmark.
Australian deployment considerations
Australian deployment begins with waste classification and permits. Used electrical and electronic equipment shipped for recycling may require export consent, movement documents and Basel Convention codes, with Border Force declarations reflecting waste status. Waste controls apply regardless of the general AUD 45,000 commercial-value threshold, so a sample cannot be treated as an ordinary low-value parcel. A licensed waste contractor should verify its classification and approved destination before a BGA-rich stream is imported or moved interstate.
Opportunity is strongest where device waste, manufacturing expertise and bullion markets coexist. Melbourne has substantial electronics manufacturing and repair activity, Sydney produces dense consumer and data-centre equipment streams, Brisbane has expanding infrastructure replacement cycles, and Perth connects advanced hardware supply chains with a mature bullion sector. A compact ALS2 installation at a licensed hub near these volumes could reduce freight to offshore refiners and generate a locally assayable concentrate. Collection rights, feedstock contracts and state stewardship coverage remain essential because arrangements differ across televisions, computers, phones, batteries and component boards.
ALS2’s European research background adds useful transparency, including information published in AA Europe project resources. Support from the European Union’s Horizon 2020 research and innovation programme can strengthen technical documentation and stakeholder confidence, but an Australian pilot still requires local feed characterisation, safety validation, residue testing and a documented route to an accredited refiner.
Building an Australian recovery partnership
A credible pilot should begin with one controlled feedstock, such as BGA-rich material from depopulated boards or a specialist processor. The trial needs a measured input mass, representative sampling at every stage and separate collection of liberated solder, gold-bearing components and residual board material. Those results establish actual recovery rates rather than relying on theoretical content or a single laboratory assay.
The commercial case should track plant footprint, energy consumption, labour requirements, concentrate value and residue treatment cost. Compact equipment becomes attractive when a regional facility can process enough material to cover transport, maintenance and analytical expenses. Partnerships between Ikoi, licensed Australian e-waste organisations, universities and accredited metal refiners would also help adapt the process to local regulations and customer requirements.
Start by reviewing the ALS2Project background, then contact Ikoi and an Australian processing partner to scope a feed trial, residue assay and compact-plant deployment study.