Comparing the carbon footprint of mobile ALS2 units and centralised plants

The environmental cost of recovering precious metals from discarded electronics depends on far more than the refining reaction itself. Electricity, transport, chemical production, water use, wastewater treatment, plant construction and the fate of residual materials all contribute to the life-cycle footprint. For Australia, where material may travel thousands of kilometres between collection points and processing facilities, the location of recovery can be as important as the technology used.

Mobile or compact ALS2 units offer a different model from a large centralised hydrometallurgical plant. Instead of sending every circuit board or electronic fraction to one distant facility, processing can be placed closer to collection, dismantling or pre-treatment operations. The result may be lower transport emissions and a more responsive local recycling network, although the outcome depends on throughput, electricity supply and how efficiently each unit is operated.

Why location changes the emissions profile

A centralised hydrometallurgical plant benefits from scale. Large reactors, pumps, filtration systems and wastewater equipment can process substantial volumes continuously, spreading energy consumption and fixed infrastructure across tonnes of feedstock. High utilisation can reduce the carbon intensity per kilogram of recovered copper, silver, gold or other valuable metals.

That advantage can be weakened when feedstock is dispersed. Electronics collected in Perth, Darwin, regional Queensland or Tasmania may need to move through several logistics stages before reaching a major processing centre. Trucks, shipping containers, warehousing and back-haul arrangements add emissions before the material enters the plant. A mobile unit positioned near a transfer station, dismantling site or industrial estate can shorten those distances and reduce the need to transport low-value fractions containing only small concentrations of precious metals.

The comparison should therefore use a full system boundary rather than comparing electricity consumed inside two machines. A credible assessment includes collection, sorting, pre-treatment, internal handling, processing, residue management and the transport of recovered metals to their next market. It should also account for avoided production of primary metals, since the largest environmental benefit comes from displacing mining and refining of virgin resources.

Where ALS2 units can reduce carbon

ALS2 is designed around acidless separation for precious-metal recovery from electronic waste and WEEE streams. The acidless separation technology can support compact recovery plants, which creates the possibility of locating treatment closer to the source of suitable feedstock. Shorter supply chains can reduce diesel use, freight kilometres and the repeated handling associated with sending mixed e-waste to a distant refinery.

The benefit is particularly relevant in Australia’s urban corridors. A unit serving businesses and dismantlers around Sydney, Melbourne or Brisbane could receive concentrated fractions locally rather than sending every load interstate or overseas. It could also complement existing collection networks, where mobile phones, computers and small appliances are gathered at retail drop-off points, council facilities and commercial recycling depots. Fewer long-distance movements may lower emissions while improving traceability.

An acidless process may also reduce the carbon associated with manufacturing, transporting and managing strong mineral acids. This does not mean that a mobile unit has no chemical or energy footprint. Separation equipment still needs electricity, maintenance, consumables and trained operators, while recovered fractions and process residues need compliant downstream management. Its advantage must be demonstrated through measured consumption and recovery performance rather than assumed from the absence of conventional acids alone.

The scale advantage of a centralised plant

Large hydrometallurgical facilities can be efficient when they receive a steady, well-characterised stream. Continuous operation improves equipment utilisation, and centralised laboratories can monitor feed chemistry, recovery rates and residue quality. A single site may also have established systems for water treatment, heat recovery, emissions control and the sale of refined products.

Centralisation can reduce the number of duplicate machines and specialist services required across a region. If a mobile unit is run below capacity, its embodied carbon, maintenance travel and standby electricity can become significant per tonne processed. Moving equipment between locations may also create emissions that are overlooked when the analysis focuses only on the distance saved for the e-waste.

Feedstock quality is another important variable. A central refinery may have enough volume to blend different materials and maintain a stable operating profile. Smaller distributed units need reliable local supply and effective pre-sorting. Processing unsorted household electronics can increase energy demand, reduce recovery yields and create avoidable residues. A compact installation is most likely to perform well when it receives prepared fractions with known metal content.

Australian conditions that shape the result

Australia’s geography makes transport a decisive factor. A truck movement between Melbourne and Sydney is materially different from a route linking a regional community in Western Australia with a metropolitan refinery. Remote and regional councils often face limited recycling infrastructure, while freight may return empty after delivering goods. Locally deployed capacity could reduce this imbalance, provided the unit has enough feedstock and can meet state and federal environmental requirements.

Electricity intensity also varies by location and time. A unit connected to a grid with a high share of renewable generation, or supported by properly managed rooftop solar and storage, may have a lower operational footprint than an equivalent installation relying heavily on coal-fired electricity or diesel generation. Melbourne, Adelaide and Canberra have different grid conditions from mining and remote industrial regions, so a national average can conceal meaningful local differences.

Australian regulation affects both the logistics and the carbon calculation. The Recycling and Waste Reduction Act 2020 and the National Television and Computer Recycling Scheme shape how covered electronics are collected and processed. State and territory waste rules, transport licences, workplace controls and facility approvals also influence where treatment can occur. Compliance may add monitoring and infrastructure, yet it provides the chain-of-custody evidence needed to show that materials are recovered safely rather than diverted to disposal.

Everyday habits matter as well. Australians replace mobile phones, laptops and household appliances frequently, but small devices often remain in drawers instead of entering formal collection channels. Improving participation in take-back schemes can increase the volume available to a local unit and reduce the carbon per item collected. Better separation at retail stores, offices and council depots is usually more valuable than simply adding processing capacity.

Measuring the footprint fairly

A comparison should begin with a functional unit, such as the carbon dioxide equivalent required to recover one kilogram of gold-bearing fraction, one tonne of printed circuit boards or a specified quantity of saleable precious metals. Measuring only tonnes of incoming e-waste can be misleading because two streams may contain very different concentrations of gold, silver, palladium, copper and contaminants.

The assessment should then gather primary data from both systems. Relevant measurements include electricity per tonne, fuel for transport and mobile deployment, water consumption, reagent production, maintenance, replacement parts, packaging, residue treatment and final product logistics. Recovery yield is essential: a process that uses slightly more electricity but recovers substantially more metal may have the lower footprint once avoided mining is included.

Transport modelling should reflect real Australian routes rather than a generic distance. It should compare collection-to-plant movements, intermodal freight, local transfer operations and the return journey for recovered products or residues. Scenarios can test a dense metropolitan network, a regional hub and a remote service area. This approach reveals where mobile capacity delivers the greatest reduction and where a large plant remains more efficient.

Embodied emissions deserve attention too. A mobile unit requires steel, electrical equipment, pumps, controls and installation work. A central facility carries a much larger construction burden, including buildings, tanks, laboratories and wastewater infrastructure. Allocating those impacts over the facility’s expected lifetime and throughput prevents a new compact unit from being judged against a mature plant with its construction emissions already in the past.

Building a lower-carbon recovery network

The strongest model may not be a choice between entirely mobile and entirely centralised processing. Compact ALS2 units could perform local separation of suitable high-value fractions, while central facilities handle specialist finishing, complex residues or materials that require larger-scale treatment. This hub-and-spoke arrangement can retain some economies of scale while reducing unnecessary transport of low-volume, high-value feedstock.

A practical Australian network could place units near major metropolitan collection zones and regional aggregation hubs. Sydney, Melbourne, Brisbane, Perth and Adelaide generate substantial commercial and household e-waste, while regional centres could serve wider catchments where long freight distances currently dominate the footprint. The appropriate location would depend on feedstock contracts, grid intensity, local approvals, operator availability and access to downstream buyers.

Carbon performance should be reported transparently after commissioning. Operators can track kilograms of CO₂ equivalent per kilogram of recovered metal, electricity from renewable sources, litres of water used, transport kilometres avoided and the share of residues sent to beneficial recovery or approved treatment. Publishing these indicators helps councils, recyclers, manufacturers and producer-responsibility schemes compare options on evidence rather than marketing language.

For electronics manufacturers and retailers, local recovery can also strengthen material security. Recovered precious metals can re-enter manufacturing supply chains with clearer provenance, while shorter routes make it easier to audit handovers and identify losses. In a market where customers increasingly expect responsible disposal, a visible Australian recovery pathway can support participation without pretending that every device must travel to a single national refinery.

Businesses assessing a new recovery pathway should model their own feedstock, transport routes, electricity mix and operating schedule before selecting a plant configuration. Engage with the ALS2 project to examine whether a compact acidless unit can reduce freight emissions, improve local precious-metal recovery and fit the compliance requirements of the Australian site.