How ALS2 Supports Zero-Liquid-Discharge Precious Metals Refining

Electronic waste contains valuable gold, silver, palladium and other metals, yet recovering them can create a difficult environmental problem. Conventional refining routes often depend on acids, large volumes of process water and complex wastewater treatment. A zero-liquid-discharge approach aims to change that balance by keeping water within the facility and preventing contaminated liquid effluent from leaving the site.

ALS2, developed by Ikoi S.p.A., addresses this need through acidless separation for precious-metals recovery from electronic waste and WEEE streams. Its relevance extends beyond the recovery of valuable materials: the technology supports compact plants, lower chemical dependency and a more controlled path towards circular manufacturing. For Australia, where e-waste volumes are rising across cities and regional communities, these features have practical importance.

Why liquid discharge matters in precious-metals recovery

Refining printed circuit boards and other electronic components produces more than a metal-bearing fraction. Traditional hydrometallurgical processes can generate acidic solutions containing dissolved metals, salts and treatment residues. These liquids require neutralisation, monitoring and compliant disposal, and the associated infrastructure can be difficult to justify for smaller or decentralised recycling operations.

Zero liquid discharge, commonly shortened to ZLD, is a process design objective in which wastewater is treated and reused rather than released as a routine effluent. Water may be recovered for washing, separation or cooling, while the remaining concentrated solids are managed as a material for further recovery or controlled disposal. The goal is therefore broader than simply using less water: it is to close the liquid loop and reduce the risk of transferring pollution from one medium to another.

For Australian operators, this matters because environmental approvals can vary between states and territories, while water security remains a significant operational concern. A plant in Melbourne, Sydney or Brisbane may face different local requirements from a facility near Perth or Adelaide, but avoiding a continuous liquid discharge can simplify the environmental profile of a proposed recycling site.

ALS2 and the acidless separation principle

ALS2 is built around the recovery of precious metals without relying on the acid-based chemistry associated with many conventional refining systems. By reducing the use of aggressive reagents, the process can limit the creation of acidic wastewater at its source. That source reduction is essential to ZLD: it is more efficient to prevent a difficult liquid stream than to treat it after it has been produced.

The technology is intended for precious-metals recovery from electronic scrap and WEEE feedstocks, including materials whose composition can vary from one batch to the next. A compact process configuration can support local or regional treatment, reducing the need to transport low-value, mixed e-waste over long distances before it reaches a specialist refinery. This is especially relevant in Australia, where equipment collected in regional Queensland, Western Australia or the Northern Territory may otherwise travel hundreds or thousands of kilometres to reach processing infrastructure.

Acidless operation should not be interpreted as the absence of all process controls. Feed preparation, dust management, thermal conditions, separation performance and residue handling still require careful engineering. The benefit is that ALS2 can help shift the environmental focus from large volumes of hazardous liquid chemistry towards controlled solid fractions and recoverable metal outputs.

Building a closed-loop water system

A ZLD plant normally combines several stages: collection of process water, separation of suspended solids, recovery of dissolved or fine contaminants, concentration of residual moisture and reuse of treated water. ALS2 can fit within this type of system by limiting the chemical load entering the water circuit and making internal reuse more manageable.

Water used for equipment cleaning or material preparation can be captured rather than sent directly to a drain. After suitable treatment, it may return to an approved process step. The exact arrangement depends on the feedstock, plant design and local licence conditions, but the principle remains consistent: water is treated as an operational resource rather than a disposable by-product.

The final concentrated residue must be handled responsibly. ZLD does not eliminate waste; it changes its form and concentrates it. Recoverable metal-bearing solids can return to the refining circuit, while non-recoverable residues require classification and lawful disposal. This distinction is important for transparent environmental reporting and for demonstrating that water closure has not simply created an unmanaged solid-waste burden.

Relevance to Australia’s e-waste market

Australians replace smartphones, computers, televisions and household appliances at a steady rate, while workplaces regularly retire servers, monitors and networking equipment. Collection patterns are concentrated around major cities such as Sydney, Melbourne, Brisbane and Perth, but regional councils and community recycling centres also receive significant volumes. The National Television and Computer Recycling Scheme has helped establish public expectations that electronics should be collected and processed through responsible recycling channels.

A compact precious-metals recovery plant could complement these collection networks by placing treatment closer to feedstock generation. Shorter transport routes can reduce fuel use and improve the economics of handling low-volume, high-value material. The approach also fits Australia’s interest in developing domestic critical-minerals and advanced-manufacturing capabilities instead of exporting every valuable fraction for overseas processing.

Market conditions remain important. E-waste is often collected as a mixed stream, and the value of a shipment depends on its composition, contamination, labour costs and logistics. ALS2’s potential value lies in combining resource recovery with a lower liquid-waste burden, which may help operators assess smaller distributed facilities alongside larger centralised plants.

Compliance, safety and community confidence

Australian recycling businesses operate within a framework shaped by state and territory environmental protection laws, workplace health and safety duties, waste transport rules and national product stewardship arrangements. A project may need to address requirements for emissions, hazardous materials, contaminated residues, storage, fire safety and community consultation. Reducing acid use can support safer handling, but it does not replace a full risk assessment or regulatory approval process.

The Basel Convention also influences the international movement of hazardous and other controlled wastes, including some electronic scrap shipments. Domestic processing can reduce reliance on overseas routes and provide better visibility over where metals, residues and reusable components end up. For local councils and businesses, traceability is increasingly important when selecting a recycler, particularly where procurement policies require evidence of lawful and environmentally sound treatment.

Public acceptance depends on understandable evidence. Operators should be able to explain what enters the facility, which metals are recovered, how water is reused, where residues go and how incidents are controlled. The project updates from ALS2 provide useful context for following the technology’s development, research activity and sustainability objectives under the European Union’s Horizon 2020 programme.

From pilot development to industrial deployment

Moving from a technology project to a commercial refining operation requires more than proving that precious metals can be separated. Developers must test a representative range of feedstocks, measure recovery rates, examine energy consumption and confirm the quality of recovered products. Long-term operation also reveals practical issues such as feedstock variability, maintenance intervals, operator training and the performance of water-recycling equipment.

The most effective deployment model may combine pre-sorting with targeted recovery. Reusable devices and components should be removed before treatment, while circuit boards and other metal-bearing fractions can be prepared for separation. Better sorting reduces contamination, improves process stability and helps ensure that the ZLD system is treating a predictable stream rather than an uncontrolled mixture of plastics, batteries, ceramics and metals.

For a country as geographically dispersed as Australia, modularity could be a major advantage. A compact facility near an urban collection hub may serve metropolitan volumes, while a regional operation could process selected high-value fractions before sending refined products to downstream manufacturers. In each case, the design should balance water closure, energy demand, transport distance, recovery yield and the cost of managing concentrated residues.

ALS2 can contribute to a refining model in which environmental performance is measured through several connected outcomes: precious metals recovered, virgin mining displaced, acids avoided, water retained within the process and residues safely managed. This broader assessment is more meaningful than judging a facility by metal yield alone.

Australian recyclers, councils, manufacturers and technology developers can help accelerate this model by evaluating acidless separation alongside their existing collection and processing arrangements. Examine the ALS2 approach, follow its technical development and identify where a low-liquid-discharge recovery plant could strengthen local e-waste infrastructure and the circular use of precious metals.