ALS2 treatment of gold from encoder disks in servo motors
ALS2 treatment of gold from encoder disks in servo motors addresses a small but valuable part of the electronic-waste stream. Encoder disks use optical surfaces to report shaft position and speed; some contain gold-bearing coatings or components. Once a drive is removed from a machine, those discs are easy to overlook, yet their material value can justify careful recovery when they are collected before the surrounding motor is shredded.
Ikoi S.p.A.’s ALS2Project develops an acidless separation technology for recovering precious metals from electronic waste and waste electrical and electronic equipment (WEEE). The project presents the technology as a safer, cleaner alternative to acid-based refining, with applications in compact precious-metals recovery plants. For Australian partners, the opportunity is to connect targeted dismantling with high-value metal recovery rather than rely on unsorted motor scrap.
Gold in servo-motor scrap does not arrive as a ready-made doré bar. It may be dispersed through coated discs, adhesives, laminates, steel, copper and mixed fines. A credible process therefore starts with dependable feed preparation, representative sampling and controlled pre-concentration. ALS2 should operate on a characterised fraction instead of expecting an entire bin of obsolete motors to produce a uniform result.
Australian relevance is strongest where industrial automation, maintenance and e-waste logistics meet. Servo motors leave automated production and warehouse systems in Sydney, Melbourne, Brisbane and regional manufacturing centres, while state and territory collection rules shape how old equipment reaches recyclers. This article examines the technical pathway, commercial questions and controls needed before ALS2 treatment moves from project development to dependable operation.
Why encoder disks hold recoverable value
The encoder disk is the feedback element that lets a servo controller know where a motor shaft is and how fast it turns. Selected optical encoders use finely patterned reflective surfaces, including gold-coated layers, while other designs use magnetic or etched components. Any gold-bearing part is vulnerable to mixing during dismantling. Its value depends on identifying the right motors and separating the relevant discs before fine shredding turns them into difficult-to-sort material.
The quantity can be modest beside copper and steel, but the economics may improve because gold has high value per unit mass. This makes encoder recovery a classic urban-mining opportunity: a concentrated, traceable stream can outperform a diffuse search through low-grade electronic waste. It also creates a practical destination for parts that might otherwise be treated as negligible motor scrap.
Australian workshops give the stream a recognisable context. A maintenance fitter may call the component an “encoder disc”, “feedback unit” or “position sensor”, while procurement teams search for “servo replacement parts”. Integrators servicing robotic cells, CNC machines and conveyor drives can identify high-value discs if collection procedures preserve them. That local language and maintenance knowledge can support a reverse-logistics scheme built around equipment audits rather than blind collection.
What acidless separation changes
ALS2Project’s core proposition is selective separation without the mineral-acid leaching circuits commonly associated with conventional hydrometallurgical refining. In an acid-based route, gold may be dissolved from a prepared feed and later recovered from solution. An acidless route seeks to separate the valuable fraction through a different combination of process conditions, reducing dependence on large volumes of corrosive liquid and the wastewater handling they require.
“Acidless” describes the core separation principle; it does not mean inert, automatic or impact-free. Mechanical preparation, dust control, heating, reagents and residual waste still need review. The commercial advantage should be demonstrated through measured chemical consumption, worker-exposure controls, effluent characteristics and operating labour rather than inferred from the name alone.
The project’s reported support from the European Union’s Horizon 2020 research and innovation programme provides a foundation for continued technical development. It also creates a clear standard for Australian evaluation: imported laboratory performance should be checked with local encoder-derived feed, local water and energy conditions, and the mixed quality of material received from municipal and commercial streams.
Preparing a reliable gold-bearing feed
Targeted dismantling comes first. Servo motors should be removed from obsolete drives, then opened far enough to separate encoder discs from windings, magnets, bearings, gears and housings. This recovery effort protects both the gold-bearing component and higher-value parts of the motor. A dismantling station can use visual checks, part markings and maintenance records to identify encoder-equipped units without opening every motor.
Only after this separation should size reduction occur. Shredding can release the disc coating or fragment the disc, but indiscriminate shredding can scatter small components through steel, copper and plastic fines. Screens, magnets, density separation and targeted manual picking can create a richer feed. The objective is a consistent encoder-derived fraction with a known gold grade and minimal contamination, not maximum tonnage at any cost.
Sampling then determines whether the route is viable. A plant needs a defensible assay method, clean laboratory digestion or fusion procedures, metal mass balances and checks for interfering elements. Gold content can vary by encoder design and source, so results from one batch should not be scaled automatically to all WEEE. A feed map linked to collection partners is more useful than an impressive result from a hand-picked sample.
Safety and plant considerations
Acid-based refining brings particular occupational risks through corrosive solutions, toxic fumes, splashing and wastewater chemistry. ALS2 is intended to reduce those acid-handling demands, which can benefit small sites that lack the infrastructure of a large metallurgical refinery. Lower reagent intensity may also simplify transport and storage, provided every remaining chemical and process step is documented and assessed.
A compact recovery plant still needs sound separation equipment, guarding, dust extraction, ventilation, fire controls and emergency procedures. Encoder discs can contain coatings, adhesives and laminates whose thermal behaviour must be understood. Operators need training for the specific ALS2 equipment, and maintenance schedules must cover moving parts, sensors and metering accuracy. Safety performance should be compared under like-for-like throughput and feed conditions.
Environmental claims should likewise rest on measured data. A local life-cycle assessment can include electricity, water, consumables, recovered-metal credits and the final destination of non-valuable residues. Inland Australia makes the water question particularly important: a process suitable for Perth or Kalgoorlie should not obscure the value of low-water operation in a water-constrained region. Reduced acid use is meaningful, yet no separation route should be described as having zero impact.
Building a case in Australia
Potential feedstock partners include industrial automation suppliers, machine-tool service firms, robotics integrators, original-equipment manufacturers, IT asset-disposal companies and licensed e-waste recyclers. A practical Australian model could use regional collection hubs in Melbourne, Sydney and Brisbane, with small ALS2 modules positioned near high-grade industrial streams. Municipal household e-waste is less predictable, so commercial and industrial segregation may offer the cleaner first market.
The operating environment differs by jurisdiction. Australia’s states and territories use different waste classifications, facility licences, transport rules and product-stewardship arrangements, so a processor must check the requirements of each collection route. Chain-of-custody records should identify the motor source, dismantling batch, final gold fraction and responsible refiner. Recovered precious metal also requires assay discipline and documentation that satisfy Australian scrap-metal and trading controls.
Western Australia adds a useful parallel. Gold expertise around Kalgoorlie and other mining centres is substantial, and that workforce understands assay accuracy and precious-metal accountability. Yet urban electronic waste differs from ore: the grade is lower, the feed is less homogeneous and the material has already passed through several manufacturers. ALS2 treatment of gold from encoder disks should therefore be presented as a specialised recycling stream, not as a miniature version of mining extraction.
From validation to commercial deployment
Scale-up evidence should separate a successful batch from a repeatable process. The familiar distinction between weather and climate offers a useful parallel: a favourable commissioning assay is a moment, while consistent recovery, product quality and uptime across feeds and shifts form the longer-term pattern. Investors, recyclers and regulators need both kinds of evidence, properly interpreted.
A local feasibility programme should begin with a few hundred kilograms of documented encoder-disc fraction, or another quantity justified by feed availability. It should test pre-concentration, ALS2 recovery, tail composition, consumable use and maintenance access. Data should cover variability by motor type and collection source, including stoppages, operator workload and the route for residues. If the process performs well, larger trials can then test seasonal supply, transport distance and commercial throughput.
The comparison below focuses on likely design differences, while leaving the final verdict to site-specific evidence.
| Measure | Acid-based refining | ALS2 acidless separation |
|---|---|---|
| Core chemistry | Often uses mineral-acid leaching and dissolution | Avoids reliance on mineral-acid leaching in the core separation stage |
| Process infrastructure | May require corrosion-resistant tanks, reagent systems and wastewater treatment | Designed for a more compact plant with fewer acid-handling demands |
| Occupational profile | Greater potential for corrosive exposure, fumes and liquid handling | Lower acid exposure potential, with mechanical, dust and residual-reagent risks still controlled |
| Feed strategy | Can process selected complex feeds when chemistry is tightly controlled | Benefits from a characterised, gold-bearing fraction prepared upstream |
| Commercial test | Recovery, reagent consumption, effluent, labour and throughput | The same measures, plus consistency across realistic batches and maintenance cycles |
The comparison highlights where ALS2 could provide value, yet head-to-head trials remain essential. Acid-free separation could lower complexity for some sites, while a conventional refinery might remain better suited to a different feed or product specification. For encoder-derived material, the decision should rest on net recovered value, safe operating conditions, verified residue management and the quality of the final gold product.
Move the next stage from technical promise to a defined test: contact Ikoi S.p.A. or the ALS2Project consortium, request an encoder-disc sample and assay plan, and agree the mass-balance and safety metrics for a local feasibility run. That gives Australian suppliers, recyclers and industrial partners a practical way to evaluate acidless precious-metal recovery and, if the results hold, build it into a durable circular supply chain.