Separation Mechanisms

Acidic, metal- and sulfate-bearing drainage generated when mining exposes sulfide-bearing materials to oxidation. This record denotes the heterogeneous liquid mine-derived feed, distinct from natural ore, individual dissolved elements, coal-mine-drainage treatment solids, and isolated precipitate phases. The characterized Brazilian copper-mine and South African mining-facility waters below are separate source-specific samples, not a universal composition or interchangeable reactor feed. No constituent criticality designation or industrial recovery performance is transferred to this resource.

Alabandite is the cubic manganese sulfide mineral, ideal formula MnS, grandfathered in the September 2026 IMA list. It is distinct from the MnS polymorph rambergite, elemental manganese and a whole polymetallic ore. The accepted experiment identifies alabandite as one component of natural Talvivaara black shale and measures its content in fractions from laboratory flotation with freeze-dried bacterial biomass. This is not pure-mineral testing, proof of a microbial surface mechanism, manganese product recovery or a criticality designation inherited from Mn.

• Staphylococcus carnosus

Salt-flux-bearing mixed slag from aluminium scrap remelting, containing process salts and oxide-rich solids. The accepted study sampled a rotary furnace batch from a Brazilian recycler using NaCl/KCl flux. This resource is defined by salt-flux remelting origin, distinct from the existing post-metal-recovery secondary aluminium dross specimen, generic smelting slag, bauxite residue, elemental aluminium or a single mineral. Laboratory water leaching and recovered salt crystals are documented; microbial action, inherited criticality and industrial deployment of this recipe are not.

Steelmaking slag identified by primary studies as basic-oxygen-furnace (BOF), or Linz-Donawitz converter, slag. The separately studied feeds are a December 2016 sample from Yarborough, Scunthorpe, UK, and a sample supplied by an unnamed Austrian steelmaking company in the 2022 study. This process-defined secondary resource is distinct from electric-arc-furnace slag or dust, blast-furnace residues, copper smelter slag, constituent elements and individual mineral species. These heterogeneous samples do not define all BOF slags. No inherited elemental identifier or criticality designation is assigned.

Cassiterite is the mineral species with IMA-approved formula SnO2. The September 2026 IMA list records grandfathered status G and original description year 1832; that year is not an IMA approval identifier. The mineral is distinct from elemental tin, a tin commodity, and a cassiterite-bearing experimental feed. The curated separation study used a Brazilian mineral sample reported as 84.7% pure by X-ray fluorescence, rather than a demonstrated pure SnO2 phase. No criticality designation is inherited from tin.

• Rhodococcus opacus

Mixed slag generated during smelting of chromite-bearing feed to produce ferrochrome alloy. The curated experiment used waste supplied by Zimasco at Kwekwe, Zimbabwe. This processing-derived resource is distinct from chromite ore, physical beneficiation tailings, chromite ore processing residue from chemical chromium extraction, the ferrochrome alloy product and individual slag mineral phases. Composition varies with feed and process; the selected sample is not a universal specification. No constituent criticality designation or mineral identifier is inherited.

Liquid residual streams generated by wet flue-gas desulfurization and associated wastewater treatment, distinct from solid FGD gypsum, coal ash, elemental selenium and natural mineral resources. The accepted experiment concerns a particular coal-power-plant effluent after physical/chemical pretreatment and dilution, not an invariant composition or all FGD streams. Its selenium-bearing residuals were investigated for treatment; no marketable recovered selenium product or inherited criticality is asserted.

Fluorite is the calcium fluoride mineral CaF2, listed with grandfathered status G in the IMA-CNMNC September 2026 mineral list. Its original-description year is unresolved in that list; no numbered approval accession is asserted. The Handbook of Mineralogy describes cubic fluorite and natural hydrothermal, sedimentary and igneous occurrences. This mineral owner is distinct from the traded fluorspar commodity and elemental fluorine. The experiments below use ground natural crystals reported as 99% CaF2 and concern bacterial-cell-associated flocculation and settling. They establish neither mineral dissolution nor production of a specified fluorspar grade. No criticality designation is inherited from the commodity or element, and no industrial deployment is claimed.

• Corynebacterium xerosis

Löllingite, commonly written loellingite, is the orthorhombic iron arsenide mineral with ideal formula FeAs2. The September 2026 IMA list records it as grandfathered, with original-description year 1845. It is distinct from arsenopyrite, skutterudite, elemental arsenic and a mixed arsenic-bearing ore. Natural compositions need not be exact endmembers. The accepted microbial experiment concerns a quantified loellingite-arsenopyrite feed mixed with pyrite, not purified loellingite. Its flotation response does not establish dissolved-metal extraction, an isolated loellingite product or industrial deployment. No constituent-element criticality is inherited.

• Leptospirillum ferrooxidans

Ludwigite ore denotes a heterogeneous boron-bearing iron ore or its beneficiated boron-iron concentrate, represented here by the mixed geological feed used by Liang et al. (2024). It is not the mineral species ludwigite, elemental boron or iron, a borates commodity specification, or the secondary residue left after processing. The experimental substrate for water leaching was a soda-ash-roasted derivative of that concentrate; its altered composition must not be assigned to the original ore. The paper's Table 2 reports 5.12 wt% B2O3 and 58.23 wt% total iron in this reduced feed, and Figure 9 identifies metallic iron, sodium magnesium silicate, sodium silicate and magnesium-ferrous oxide. Its bulk-feed result cannot establish which individual original boron mineral supplied the dissolved boron. The exact mine/sample identifier and original batch mineral proportions are not established in the inspected 2024 article, which refers to earlier work for the ore characterization. No constituent's criticality designation is transferred to this resource.

The element Pr, distinct from dissolved Pr(III), its salts and oxides, Pr-containing magnet alloys and ore or waste resources. The US2025 designation applies to the named praseodymium mineral commodity. Evidence below concerns cell-free protein chromatography of a synthetic binary solution, not microbial growth on an ore or industrial recovery.

• Methylobacterium sp. 13MFTsu3.1M2

This collective commodity family follows Australia's 20 February 2024 rare-earth-elements entry: yttrium and all fifteen lanthanides, including promethium. Scandium has a separate entry in that list. This sixteen-member economic grouping differs from the broader seventeen-element chemical definition, which also includes scandium, and from the EU 2020 assessment's fifteen-member light/heavy split, which excludes both scandium and promethium. Inclusion of promethium preserves the Australian source's stated membership and does not assert an ordinary mined promethium supply. This family overlaps individual element records and narrower rare-earth commodity groups; it is not one mineral, alloy or fixed mixture. The mechanism below concerns only a synthetic neodymium/dysprosium solution and does not establish recovery of every family member or treatment of ore, magnets or industrial waste.

• Hansschlegelia quercus

Source-labelled samarium-cobalt magnet scrap supplied by the Defence Metallurgical Research Laboratory, Hyderabad, India. Its preceding service history and manufacturing-waste category were not disclosed, so the feed is not asserted to be end-of-life devices. It is distinct from NdFeB magnet waste, the broad rare-earth permanent-magnet commodity grouping, pure Sm2Co17 and its constituent elements. The characterized preparation includes oxide phases as well as a Sm2Co17 assignment. No criticality designation or microbial recovery is inherited from the feed's constituents.

The element Sc, distinct from dissolved Sc(III), scandium chloride, scandium oxide, Sc-bearing minerals and waste feedstocks. The US2025 designation concerns the named scandium mineral commodity. Laboratory evidence below uses an immobilized bacterial protein and synthetic dissolved-metal mixtures; it does not demonstrate living-cell extraction.

• Methylorubrum extorquens

Heterogeneous residual aluminium dross after an earlier recovery of metallic aluminium from primary dross by screening or flux-assisted remelting. This source-defined secondary dross is narrower than the umbrella aluminium-dross category; the accepted specimen came from an aluminium remelting plant in Guangxi, China. It contains metallic aluminium, aluminium oxides and nitride, magnesium-aluminium spinel, and other oxides and process salts. It is not a mineral species, elemental aluminium, bauxite residue, spent potlining, or an automatically equivalent feed to an unspecified aluminium-smelting slag. Laboratory chemical extraction is documented without a microbial mechanism, inherited criticality designation, or demonstrated industrial deployment.

Used CuO-ZnO-Al2O3 catalyst material from synthesis-gas processing, including low-temperature carbon monoxide conversion. This composition-defined secondary resource is distinct from fresh catalyst, its constituent oxides, elemental copper/zinc and spent refinery hydroprocessing catalysts. The selected Polish-market sample had 35.1 wt% Cu, 29.9 wt% Zn and 9.2 wt% Al by AAS; these are sample measurements, not a universal formulation. Its plant and service history are unspecified. No constituent criticality is inherited.

Used iron-molybdate catalyst from methanol oxidation for formaldehyde production. This process-defined secondary resource contains iron molybdate and excess molybdenum oxide, with feed-specific impurities and amorphous material. It is distinct from molybdenite, elemental molybdenum, fresh catalyst and spent Ni/Co-Mo refinery catalysts. Two primary studies examine different spent feeds; their compositions and yields are not interchangeable. No mineral identifier or constituent-element criticality is assigned.

Used nickel-bearing catalyst from primary steam reforming, represented by a spent nickel-oxide/alumina formulation supplied by an unnamed fertilizer plant. This use-defined secondary resource is distinct from vegetable-oil hydrogenation catalyst, platinum petroleum-reforming catalyst, fresh catalyst and elemental nickel. The selected feed composition does not define every steam-reforming formulation. No constituent criticality or mineral identifier is inherited.

Used platinum-bearing catalyst from petroleum reforming, represented by a source-described monometallic Pt/Al2O3 catalyst. This use-defined secondary resource is distinct from automotive converters, nickel steam-reforming catalysts, refinery hydroprocessing catalysts, fresh catalyst and elemental platinum. The selected feed composition does not define every reforming formulation. No constituent criticality or mineral identifier is inherited.

Exhausted aluminium-smelting cell lining containing variable proportions of carbonaceous cathode material, refractory cement and brick, and accumulated process salts. The accepted study used real mixed-cut waste supplied by Trimet Aluminium, Essen, Germany, with three visually selected grades from refractory-rich to mainly graphitic material. Exact cell and service histories were not resolved. This solid waste is distinct from aluminium dross, waste electrolyte, red mud, graphite as a mineral or commodity, and its constituent elements. Laboratory chemical extraction is documented without a microbial mechanism or an inherited criticality designation.

Used vanadia-tungsta/titania catalysts from coal-fired power-plant flue-gas denitrification, represented by separately characterized laboratory feeds. Niu and colleagues studied an arsenic-contaminated honeycomb catalyst from a Xinjiang plant; Su and colleagues separately studied gray and yellow regions of three spent honeycomb catalysts, S3–S5. This manufactured, heterogeneous secondary resource is distinct from refinery hydroprocessing, fluid catalytic cracking and sulfuric-acid-production catalysts, pure constituent oxides, mineral species and elemental vanadium or tungsten. V2O5-WO3/TiO2 is the sources' catalyst formulation notation, not proof of three separately quantified crystalline phases. Fresh catalysts S1–S2 in Su's study are comparators, not spent-resource observations. No criticality designation is inherited from the constituents.

• Acidithiobacillus thiooxidans ATCC 19377

Residual mineral solids generated by processing tungsten-bearing skarn ore. The curated case is historical tailings in the Smaltjärnen repository at the closed Yxsjöberg tungsten, copper and fluorspar mine in Sweden. The processing plant used gravity separation, magnetic separation and flotation. The characterized layered material contains scheelite among mixed silicate, carbonate, sulfide and other minerals; composition and particle liberation vary by sampled layer. This resource is distinct from tungsten as an element, pure scheelite, unprocessed ore, waste rock and a saleable concentrate. Hällström et al. document scheelite alteration, hydrous ferric oxide associations and tungsten transport in a field investigation of this repository; those geochemical observations do not establish microbial causation. No criticality designation is inherited from constituents, and the laboratory results below do not characterize all tungsten tailings.

Heterogeneous residual solids in uranium-mine tailings management areas, represented here by DT and RAT samples from two decommissioned Elliot Lake, Ontario sites. These are secondary mining residues, distinct from unprocessed uranium ore, individual uranium minerals, drainage water and purified elements. The original processing flowsheets and the expansions of the two sample-site abbreviations are not established by the curated study. Laboratory evidence concerns culture-associated metal solubilization and a separate resin screen; it does not establish industrial recovery or a resolved uranium extraction yield. No constituent-element criticality designation is inherited by these tailings.

Uranium (U), represented here as an element distinct from the dissolved U(VI) feed and electrode-associated material in a laboratory bioelectrochemical separation study. The United States 2025 designation applies to the named uranium commodity; it does not identify a uranium mineral species or establish the criticality of every uranium compound.

• Shewanella oneidensis MR-1

Vanadium (V), represented here as an element distinct from the dissolved V(V) feed and electrode-associated material in a laboratory bioelectrochemical separation study. The United States 2025 designation applies to the named vanadium commodity; it does not identify a vanadium mineral species or establish the criticality of every vanadium compound.

• Shewanella oneidensis MR-1

Discarded multilayer ceramic capacitor components, represented here by components removed from printed circuit boards of twenty post-consumer computers. This feed is distinct from whole printed circuit boards, tantalum capacitors, pure barium titanate and its constituent elements. The characterized batch contained ceramic and metallic phases; neither a universal capacitor composition nor a criticality designation is assigned. The accepted experiment uses chemical deep eutectic solvents and provides no microbial mechanism or industrial deployment evidence.

Used silver-bearing radiographic films obtained from medical facilities, comprising a gelatin-silver emulsion on a polymer base. The curated feeds are discarded X-ray films, not unused film stock, photographic processing liquids, elemental silver or all photographic wastes. Laboratory studies distinguish microbial-enzyme stripping of the emulsion from subsequent thermal production of silver metal. No constituent criticality designation or industrial deployment is inherited.

• Conidiobolus coronatus
• Bacillus spizizenii ATCC 6633 = JCM 2499

Mixed residual solids from acid leaching in zinc hydrometallurgy, including zinc retained in ferrite, sulfide and other specimen-dependent phases. The accepted studies used separate industrial residues from Hunan and Yunnan, China; their compositions and treatment outcomes are not interchangeable. This processing-generated resource is distinct from elemental zinc, a pure zinc-ferrite phase, zinc calcine before leaching, and zinc-purification waste. Two laboratory abiotic treatments are documented. No criticality designation, microbial mechanism, isolated zinc-product yield or deployment of these particular experimental protocols is inferred.

Mixed precipitated solids removed during the hot purification of zinc leach liquor, before the subsequent zinc-powder cementation stage. The accepted specimen is hot filter press cake (HFC) from the National Iranian Lead and Zinc Company in Zandjan, Iran, containing zinc, cobalt and manganese. This processing residue is distinct from zinc leach residue, cold purification filter cake, a pure oxide mineral, or elemental zinc. Its laboratory chemical leaching does not establish a microbial mechanism, a criticality designation, purified-metal production or industrial deployment of the tested treatment.