How feed pre-shredding size affects ALS2 throughput

ALS2Project is developing a compact acidless separation technology for recovering precious metals from electronic waste and WEEE recycling streams. Led by Ikoi S.p.A. and backed by the European Union’s Horizon 2020 research and innovation programme, the project offers a safer, cleaner alternative to acid-based refining. That distinction matters because WEEE contains valuable metals alongside plastics, glass, coatings and hazardous components that make conventional processing demanding.

Throughput is the practical bridge between laboratory performance and a working recovery plant. For ALS2, gross feed rate cannot be judged separately from separation efficiency, because material entering quickly is not useful if valuable fractions remain in the residue. A sound assessment links tonnes per hour to recovery, product quality, operating stability and the mass balance of the entire plant.

Understanding the effect of feed pre-shredding size on ALS2 throughput requires attention to the complete particle-size distribution rather than a single nominal dimension. A coarser stream may move more tonnes through an intact conveyor while leaving encapsulated metals behind; a finer stream may expose valuable material but create losses, dust and handling problems. The best operating point is therefore equipment-specific and must be demonstrated with representative Australian feed.

Why particle size changes separation performance

Pre-shredding is the controlled size-reduction step before ALS2 separation. Its purpose is to open the feedstock without destroying the information needed to distinguish metal-bearing components from plastics, glass and residues. Achieving that requires more than reducing the largest item: excessive compression can smear or coat particles, while a feed consisting only of fine fragments can lose useful material during screening and cleaning.

Liberation is the central benefit of reducing particle size. When a printed circuit board, connector or contact is exposed and released from surrounding laminate or polymer, the downstream separation stages have a better chance of routing it to the appropriate fraction. Larger particles usually retain more encapsulating material, so a high gross feed rate can coexist with lower metal recovery. This is where feed preparation and separation performance become inseparable.

There is also a lower practical limit to useful pre-shredding. Excessively fine material can generate dust, cause conveyor and screen blinding, increase fire and explosion risks, and raise cleaning and maintenance requirements. Fine precious-metal fractions may be harder to capture, while the additional power needed for aggressive comminution can erode the economic benefit of a higher nominal capacity.

From feed sizing to a valid throughput trial

Screen apertures and the particle-size distribution around them determine whether the prepared material behaves predictably. A trial should therefore record the full size profile, including oversize pieces, fines and median particle size, rather than labelling every batch simply as “shredded”. Feed composition matters as well, since the same dimensions can behave differently in mixed household appliances, business IT equipment and telecommunications waste.

A useful trial compares coarse, medium and fine preparation bands selected around the actual equipment limitations. Each condition should use feed drawn from the same source and processed for a sufficient period to observe steady-state behaviour. Startup, blockage recovery and short peaks should be reported separately from sustained capacity, while mass-balance data shows whether the increased rate comes from better liberation or simply from accepting material that is poorly separated.

Throughput and recovered-metal output must be reported together. Gross throughput in tonnes per hour answers how quickly the plant accepts material; effective throughput describes the mass of saleable or recovered product generated per operating hour. The second measure is generally more useful for commercial evaluation because it accounts for valuable content left in residues. It also reveals when pre-shredding has shifted the bottleneck from feeding to screening, conveying or downstream recovery.

Designing an Australian pilot

An Australian pilot should sample feed at the receiving point rather than relying only on material prepared under ideal workshop conditions. In Sydney and Melbourne, apartment households often use council e-waste collection points or retailer take-back programs, adding appliances and mixed consumer electronics to the available stream. Samples should reflect those variations, including cables, mixed plastics, coated metals, displays and small appliances rather than a narrow fraction selected for convenience.

Local logistics also shape the feed specification. Facilities around Brisbane, Adelaide and Perth often face substantial transport distances between collection depots and processing centres. A compact modular system can reduce freight exposure, but only if feed preparation, separation, product handling and residue removal are designed as one route. Inadequate pre-shredding may solve a local transport problem while reducing the value delivered once material reaches the plant.

Operational safety must be addressed before size reduction begins. Australia’s second-hand and trade-in market extends the lives of phones, computers and household equipment, but obsolete batteries still enter waste streams. Damaged lithium batteries can ignite during compaction, conveying and shredding, particularly in mixed municipal e-waste. Remote battery removal, fire-resistant equipment design, inspection routines and suitable staff training are prerequisites for credible Australian trials.

Benchmarking should also be traceable and technically relevant. A figure copied from an unrelated commercial page on a reference site says nothing about ALS2 performance and should not enter an investment model. Comparisons need identified feed analyses, declared test conditions and independently reconciled input and output masses. Without that discipline, a favourable tonnes-per-hour figure may simply conceal lower recovery or unstable operation.

Sustainability and the Australian regulatory setting

The acidless separation route is intended to reduce reliance on the reagents and acid-bearing process waters associated with conventional precious-metals refining. Lower chemical use can improve operator safety and simplify water management, although a plant-level environmental case still requires measured energy consumption, residue characterisation and liquid balances. ALS2Project’s European research support provides a foundation for that evidence, while deployment in Australia would need local validation under Australian operating and regulatory conditions.

Waste policy is increasingly important to project design. Australia’s National Waste Policy prioritises prevention, resource recovery and circular approaches to materials, which align with recovering metals from equipment that would otherwise lose value. State and territory e-waste stewardship programs also influence where equipment is collected and how recyclers prepare material for downstream processing. A compact recovery unit can complement those systems by handling smaller, dispersed volumes near collection or sorting centres.

Environmental licensing may apply when treatment, storage or hazardous-waste activities fall within the relevant framework under the Environment Protection and Biodiversity Conservation Act. Operators should also check federal waste-export controls before moving unprocessed electrical equipment interstate or overseas. These checks are particularly important when imported used equipment is presented for recycling rather than direct reuse, since the classification of a shipment affects its lawful movement and environmental obligations.

The commercial market extends beyond large metropolitan plants. Australia’s dispersed population, long freight routes and variable volumes of e-waste make modular capacity attractive, provided the equipment can maintain separation quality across changing feed conditions. Energy prices, service labour, residue transport and the value recovered from each material fraction should be included in an Australian financial model. Recovery of precious metals must contribute to the business case alongside realistic assumptions about maintenance, consumables and plant availability.

Scaling from pilot evidence to commercial operation

A credible scale-up sequence begins with representative feed sampling, followed by baseline size analysis and controlled pre-shredding trials. The technical team should track gross throughput, effective throughput, recovery by valuable fraction, residue losses, energy use, dust generation and downtime. Testing should then repeat the preferred conditions with a second batch or season, because WEEE composition changes as consumer products, packaging and collection habits evolve.

The preferred feed condition should connect directly to the compact plant design. Conveyor capacities, screen apertures, dust controls, feed hoppers and downstream separation stages must all tolerate the selected material without creating a new bottleneck. A slightly lower gross rate may produce better economic results if it raises recovery, reduces rework and keeps more equipment available. Commercial planning should use sustained data from the pilot rather than a brief peak observed during commissioning.

ALS2Project can use these results to position ALS2 as a compact, safer and cleaner precious-metals recovery option for electronic waste and WEEE streams. Contact the project team to discuss a representative feed trial, define meaningful throughput measurements and build a defensible scale-up case for an Australian recovery plant.