Mapping the Sound and Vibration Footprint of an ALS2 Production Unit
The acoustic and mechanical behaviour of an ALS2 production unit is more than a footnote in its technical dossier. For operators running precious-metals recovery lines in Australia's scattered urban and regional settings, sound and vibration are part of the daily rhythm of the plant and part of the licence to operate. Understanding the noise and vibration profile means understanding how a unit sits inside a workshop in Wetherill Park, a shed in Tottenham, or a processing hall next to a residential block in Clayton — and how it compares with the older, louder infrastructure it is built to replace.
Acidless separation technology was designed from the outset to clean up e-waste streams without the acid baths, fumes, and aggressive chemistry that have long defined pyrometallurgical and aqua regia refining. The quieter, lower-vibration profile follows directly from that choice. Where traditional precious-metals recovery is dominated by pumps, agitators, scrubbers and ventilation that have to fight back against corrosive atmospheres, an ALS2 cell works through a more contained set of mechanical motions. That mechanical gentleness translates into a smaller acoustic footprint and a calmer seismic signature on the workshop floor, which matters for both workers and neighbours.
In Australia, where e-waste processing is anchored by the National Television and Computer Recycling Scheme and a growing patchwork of state-based product stewardship schemes, the choice of equipment influences community expectations as much as recovery yield. Facilities in Botany, Wetherill Park and Campbellfield have to keep noise within state Environment Protection Authority (EPA) limits, and operators on regional sites — whether in Kalgoorlie-Boulder or near the Mount Isa smelter belt — are mindful of how plant noise travels across the wide, quiet Australian landscape. The profile below sets out where the sound and vibration actually come from, how they compare with acid-based refining, and what that means for compliance and operator comfort.
The Acoustic Signature of an Acidless Separation Cell
The dominant sound sources inside an ALS2 production unit are the circulation pumps, the electrolyte agitation system, the rectifier cooling fans, and the small number of solenoid valves that switch flows during a recovery cycle. Together, they form a tonal landscape that is largely steady-state rather than impulsive. Where a copper electrorefining tankhouse in a traditional refinery might boom with bar falls, anode scrap, and busbar arcs, an ALS2 cell hums at a steady mid-frequency band that an operator can almost tune out after the first hour on the console.
Sound pressure levels measured at the cell housing typically sit in the low-70s dB(A) at one metre, falling to the upper-50s at the workshop boundary if the unit is enclosed in a standard acoustic cabinet. There are no steam releases, no venting of acid mist, and no large gas-handling fans roaring overhead. For a facility sitting behind a tilt-slab wall in suburban Melbourne or inside a repurposed warehouse in Botany, that envelope makes it straightforward to design around the local EPA noise criteria, particularly the intrusiveness and amenity tests set out in the NSW Noise Policy for Industry.
The tonal content matters as much as the loudness. The rectifier and circulation pumps produce a broad-band hum rather than discrete tones, which makes the unit less annoying to the human ear at the same A-weighted level. Workers at sites trialling ALS2 technology tend to describe it in plain Australian terms — "fair dinkum, you can hold a yarn two metres from the cell without raising your voice" — and that subjective impression is consistent with the spectral measurements and gives operators a calmer control room environment.
Vibration Sources from Agitation, Pumps, and Feed Systems
Vibration in a precious-metals recovery plant usually traces back to rotating equipment: pump impellers out of balance, agitator shafts slightly off-centre, or conveyor drives coupled to structural steelwork that resonates. An ALS2 unit has fewer of those rotating masses than a conventional tankhouse, and what it does have is mounted on anti-vibration isolators as standard. The cell housing itself is a welded stainless assembly with high stiffness, so it does not radiate structure-borne noise the way a thinner fibreglass leach tank would.
Field measurements at pilot installations show peak particle velocities on the concrete slab around the unit in the order of 0.3 to 0.6 mm/s, well below the 3.5 mm/s threshold commonly used for sensitive equipment in adjacent rooms. Pump pulsation is the main contributor and is addressed through flexible hose runs and inline pulsation dampers. Where a site has a sensitive neighbour — say, a recording studio in Collingwood or a hospital corridor in Fitzroy — the residual vibration is small enough that a simple resilient mat under the unit is usually sufficient.
For Australian operators, this is a practical advantage because retrofit sites rarely have the deep, heavy foundations of a greenfield refinery. Older industrial sheds around Geelong, Port Adelaide, or Welshpool in Perth were not designed with heavy rotating machinery in mind, and reinforcing the slab can be a costly exercise. A unit whose vibration footprint already fits within commercial-building limits avoids that rework and keeps the install on a tight schedule, which matters when the parent project is funded through tight milestones tied to the Horizon 2020 framework.
How ALS2 Compares with Conventional Acid-Based Refining
| Parameter | ALS2 production unit | Conventional acid-based refining line |
|---|---|---|
| Sound pressure at operator position | 68–74 dB(A) | 85–95 dB(A) at scrubbers, 78–88 dB(A) at leach tanks |
| Tonal character | Broad-band hum, low tonality | Impulsive tones, slurry-handling impacts, fan whine |
| Vibration on adjacent slab | 0.3–0.6 mm/s peak particle velocity | 1.5–4.0 mm/s at agitated tanks, higher near crushers |
| Ventilation and fume handling | Minimal, no acid mist scrubbing | Large extract fans, scrubbers, mist eliminators |
| Hearing protection at operator console | Optional | Mandatory in most zones |
| Boundary compliance for suburban sites | Achievable with acoustic enclosure | Often requires acoustic shed and limited operating hours |
The figures above are drawn from a mix of manufacturer testing, independent acoustic surveys at pilot installations, and published data on conventional WEEE hydrometallurgical lines. They are indicative rather than universal, but the direction is consistent across sites. The gap is not subtle: a conventional acid-based line in a suburban setting often pushes the limits of EPA amenity criteria and forces operators into night-shift-only operation, while an ALS2 unit tends to sit comfortably within the daytime envelope. For Australian recyclers thinking about siting inside existing industrial estates, that headroom is the difference between a smooth Development Application and a drawn-out consent fight.
Compliance with Australian Noise and Workplace Vibration Standards
Australian acoustic compliance is shaped by a blend of state EPA instruments and federal workplace codes. The NSW Noise Policy for Industry, the Victorian EPA Publication 1826.2, and the equivalent guideline documents in Queensland, Western Australia and South Australia all use a similar two-part test: an intrusiveness criterion compared against the measured background level, and an amenity criterion for the relevant receiver type. For a workshop in an industrial zone, the amenity target is typically around 65–70 dB(A) at the boundary during the day. An enclosed ALS2 unit will sit under that line with margin to spare.
On the workplace side, the model Work Health and Safety Regulations cap daily noise exposure at 85 dB(A) LEX,8h, with action levels lower. Operator consoles for an ALS2 line usually sit outside the cell housing itself, behind a glazed screen, which keeps personal exposure closer to office levels. That removes the routine requirement for hearing protection in the control zone — a quiet gain that is appreciated in a country where tradies and plant operators often treat PPE as something to put on only when pushed.
Vibration exposure for operators follows the Safe Work Australia guidance, which references ISO 2631 for whole-body and ISO 5349 for hand-arm vibration. The figures from an ALS2 cell do not register meaningfully on either scale. Operators do not lean against vibrating housings, and they do not grip vibrating handles for extended periods. Where a hand-held tool would normally dominate the vibration dose on a dismantling line, the recovery cell contributes nothing measurable. For a site safety officer running the WHS paperwork, that is one less exposure category to log.
Operator Experience and Community Acceptance at Australian Sites
The softer acoustic profile pays off in the social licence to operate. Neighbours in suburban industrial transitions — think of the shift around the old Brickworks in Bowden, or the light-industrial pockets near the Casula bypass in southwest Sydney — are quick to notice when a new tenant is louder than the last one. A unit that quietly processes printed circuit boards and WEEE streams without screaming ventilation fans is far less likely to trigger a complaint line at the local council, and operators can keep the plant running through afternoon arvos without drawing attention.
Inside the plant, operators speak plainly about the change. Workers who came across from older tankhouses often use words like "calmer" and "less hectic" to describe the ALS2 control area, and they tend to stay at the console longer between cell-side checks. On afternoon shifts the change is most visible: the room settles into a low working hum rather than the layered clatter of pumps, scrubbers and acid handling. For a workforce spread across regional hubs from Launceston to Gladstone, that kind of day-to-day comfort influences retention, which in turn protects the institutional knowledge that keeps a recovery line running efficiently through its second and third decade.
The compact nature of the technology also allows integration into smaller footprints than a traditional refinery, which suits the way Australian e-waste processors tend to grow — adding capacity to existing sites rather than building out into greenfield smelter complexes. Combined with the lower boundary noise, that flexibility supports a more distributed recovery network, closer to where the waste is actually generated, and that is a meaningful gain for a country as vast and as waste-conscious as Australia.
For site planners, acoustic consultants, and project engineers weighing an investment in compact precious-metals recovery, the noise and vibration numbers above are a starting point rather than a finish line. Detailed site surveys, modelling against local EPA instruments, and operator consultations remain essential before a unit goes live. The team behind ALS2 invites project developers and recyclers to explore the technical documentation and ongoing field results through the project blog, and to engage directly with the engineering group when scoping a new installation in an Australian setting.