Using ALS2 for platinum recovery from thermocouple protection tubes
Using ALS2 for platinum recovery from thermocouple protection tubes turns a niche industrial waste stream into a candidate urban-mining feed. Spent thermocouples come from furnaces, kilns, boilers, smelters and high-temperature test rigs. Their small size and mixed construction make them awkward to sort, while noble-metal sensing elements can carry meaningful recoverable value.
ALS2 is Ikoi S.p.A.’s acidless separation technology for recovering precious metals from electronic waste and WEEE recycling streams. It offers an alternative to a conventional acid-based refining route, with less dependence on strong mineral acids during primary separation and a design suited to compact precious-metals recovery plants. ALS2Project also highlights its support from the European Union’s Horizon 2020 research and innovation programme.
For Australia, the interest is practical rather than abstract. There is no large domestic mined-platinum industry, yet platinum-bearing thermocouples are imported and used in mineral processing, cement and lime production, power generation and specialist manufacturing. Sites from the Pilbara and Kalgoorlie to Melbourne, Adelaide and Mount Isa generate maintenance waste that is often mixed into broader e-waste loads.
A credible project still starts with evidence, not a headline metal price. Operators need to establish what each collected stream contains, separate genuinely platinum-bearing items from low-value ceramics, and define where the recovered fraction will go. The most useful route combines laboratory assay, a controlled ALS2 trial, clear mass-balance measurements and a credible buyer for the metal-rich product.
Understanding what the waste actually contains
The term thermocouple protection tube can conceal an important distinction. Many tubes are ceramic alumina, mullite or silicon carbide and contain little or no platinum. Platinum is more often found in the sensing wire or contacts of certain Type R, Type S and Type B assemblies, especially where a process requires stable temperature measurement at very high heat.
Used industrial inventories also contain Type K or Type J units built around nickel, chromel, alumel or iron, together with stainless-steel sheaths, terminal blocks and insulation. A mixed bin can therefore have a modest platinum content even when individual assemblies look valuable. Treating every discarded tube as a platinum feed without sampling can make the economics look better than they are.
Start with chain-of-custody records and a representative assay, using XRF for rapid screening and ICP methods where precise quantification is needed. Technicians can dismantle known assemblies, separate obvious steel and ceramic pieces, and retain the platinum-bearing fraction for a trial. This careful preparation is what allows an acidless separation process to deliver a reliable recovery rate rather than merely a clean-looking residue.
How ALS2 changes the recovery route
Traditional hydrometallurgical refining commonly uses nitric, hydrochloric or sulphuric acid, sometimes in combination, to dissolve the feed. Those flows require acid-resistant tanks and linings, controlled heating, reagent storage and treatment of liquid effluents. If multiple metals dissolve together, the plant must also separate a low concentration of platinum from larger volumes of iron, nickel, copper or other constituents.
Ikoi’s ALS2 technology is designed to recover precious metals without relying on acid-based refining in the primary separation stage. For thermocouple waste, complex mixed feed can be processed toward a concentrated precious-metal fraction rather than dispersed into a large volume of acidic solution. The fraction can then be evaluated as an input to a specialist refiner, where further treatment may still be needed to meet the buyer’s specification.
Acidless does not mean impact-free. Fine ceramic and metal dust, electrical insulation, residues and possible rhodium remain safety and environmental management issues. The advantage is a different separation route with lower corrosive-reagent demand, not permission to relax controls. The Horizon 2020 association provides evidence of structured European research and innovation support, while site-specific trials remain essential before commercial deployment.
From collected waste to a marketable fraction
A workable Australian programme begins at the maintenance bay. Label and weigh thermocouples by source, record whether each unit is a platinum-bearing type, and keep them separate from general electrical waste where practical. Aggregators can combine small loads from electrical contractors, cement plants, foundries and laboratories. This creates enough feedstock for a pilot without requiring every waste holder to install a recovery plant.
Before treatment, the selected material should be sampled and prepared to the consistency required by the ALS2 equipment. A pilot should measure input mass, metal grades, recovered mass and the grade and destination of every major residue. Those checks matter because a high gross recovery percentage can still be unprofitable if too much value is left in material sent to smelting or disposal.
The commercial objective is usually an enriched platinum-bearing intermediate, not a finished kilogram of 99.99 per cent metal in the kerb-side bin. A refiner or trader should review the product against an agreed assay and accept the material under a clear settlement formula. Obtaining preliminary buyer feedback before the trial helps the operator optimise recovery for value, rather than treating laboratory purity as the only goal.
Why the Australian market is a suitable fit
Industrial demand gives the project a credible source of feed. Thermal control is essential in mineral roasters and kilns, cement and lime plants, metal smelters, glass production and large boilers. Australian crews often call damaged units “burnt thermocouples” or “spent probe assemblies”, and local suppliers understand the maintenance schedules that create a predictable return flow. That local knowledge is useful when designing take-back and segregation.
Australian e-waste markets are already shaped by licensed collectors, council drop-off points, manufacturers, electrical wholesalers and specialist metal traders. Thermocouples may reach these channels alongside cable, motors, instrumentation and printed circuit boards. A dedicated take-back arrangement can recover a valuable stream before it becomes diluted in mixed WEEE, while giving importers and maintenance firms a simple route to document responsible disposal.
Geography strengthens the case for modular equipment. A compact ALS2 installation near a collector hub in a capital city can process bulky, low-value material close to the source. A mobile or containerised system may also suit regional industrial clusters, reducing freight and handling costs while avoiding the need to transport every spent assembly long distances to a central refinery.
Commercial viability, scale-up and compliance
The business case should be built around contained platinum value, expected recovery, treatment cost, residue disposal and revenue timing. Because spent thermocouples are small and can be contaminated, sorting and freight can consume the margin quickly. ALS2’s acidless separation and compact plant profile may improve that equation, but no operator should rely on spot platinum prices or generic waste fees until representative batches have been tested.
A sensible scale-up path uses three gates: analytical validation, a continuous pilot campaign, and a commercial module linked to an accredited assay and an offtake agreement. Track recovery, product grade, labour, consumables, residue classification and maintenance across each gate. This gives Australian partners evidence for investment and avoids scaling equipment around an unverified feed composition.
Regulatory planning matters too. State environmental authorities may regulate waste classifications, discharges and residue movement, while workplace and dangerous-goods rules still apply to transport, dust and certain chemical products. An acid-free primary process can simplify acid storage and spill planning, but it does not remove the need for permits, contracts, training and a defensible chain of custody.
| Factor | Conventional acid-based refining route | ALS2-enabled separation route |
|---|---|---|
| Core separation | Strong acids dissolve the feed into a mixed-metal solution | Acidless primary separation targets a concentrated precious-metal fraction |
| Equipment profile | Acid-resistant tanks, linings, pumps, heating and reagent-control systems | Compact modular separation equipment can suit smaller recovery sites |
| Operator exposure | Acid handling, fumes, spills and large liquid flows create added risks | No primary acid-mixing circuit, although dust, insulation and residues still require controls |
| Waste profile | Acidic liquor, neutralisation requirements and potentially contaminated sludge | Reduced acid-bearing liquid burden, with solid residues requiring proper testing and classification |
| Metal product | Platinum may remain diluted among other dissolved metals | Platinum-rich intermediate can be sent for downstream refining and assay settlement |
| Best operational fit | Concentrated, homogeneous feeds with established acid infrastructure | Distributed mixed-waste streams where lower reagent handling and modular deployment are valuable |
Start with a controlled platinum recovery pilot
The first step for an Australian operator, collector or technology partner is to assemble a representative feedstock and a complete material balance. Identify the thermocouple types, document their industrial origin, conduct laboratory analysis and establish what ALS2 can recover from the actual stream. A trial should then compare the recovered fraction with the residue so that value, safety and disposal impacts can be assessed together.
Engage Ikoi S.p.A. and the ALS2Project team with the assay results, proposed scale and Australian logistics, then build the pilot around an independent refiner or metal buyer. Contact Ikoi to arrange technical scoping, equipment suitability review and a test programme for platinum recovery from thermocouple protection tubes. A compact, measured pilot is the clearest route from mixed industrial waste to a safer and more valuable recovery stream.