CMMMech > Secondary resource > Traction-battery hydrometallurgical residue

Traction-battery hydrometallurgical residue secondary resource

Residual solids from acid leaching in wet recovery of nickel or cobalt from waste traction-battery cathode materials and other recycled wastes. The curated study used separate nickel-line and cobalt-line residues from an unnamed Chinese enterprise; their compositions are not pooled. The source calls these residues slags, but does not establish molten-slag origin. They are downstream processing residues, distinct from mechanically prepared battery black mass, intact batteries, a pure cathode compound and isolated nickel or cobalt products. Exact incoming battery chemistries and the contribution of other wastes are unspecified. No constituent-element criticality is inherited.

Microbial & Biochemical Mechanisms (1)

Acidophile culture-associated release from separate nickel and cobalt residues

bioleaching Microbial

Associated Organisms: Acidithiobacillus ferrooxidans (NCBITaxon:920), Leptospirillum ferriphilum (NCBITaxon:178606), Acidithiobacillus thiooxidans (NCBITaxon:930), Acidithiobacillus caldus (NCBITaxon:33059), Sulfobacillus thermotolerans (NCBITaxon:338644)

Living acidophilic cultures were associated with increased dissolved-metal release from separate acid-leached nickel-line and cobalt-line residues. Single cultures and mixtures were compared. Iron and sulfur metabolism is a proposed explanation; the experiment does not isolate a unique cellular pathway or establish the contribution of each mixture member. The claim is laboratory solution release rather than isolated-product recovery or industrial deployment.

Experimental Context & Analytical Limits:
Sections 2.1–2.3: source-reported stocks were A. ferrooxidans ATCC 23270 (Af), L. ferriphilum AS1 6358 (Lf), historical Thiobacillus thiooxidans BJMCC 01101 (Tt), A. caldus CGMCC 1.15711 (Ac) and S. thermotolerans DSM 17362 (St). Seven days of preculture preceded residue addition in 3-L beakers with a 2-L 9K-medium system, 200 mL culture and initial pH 1.9. Stirring suspended the solids; evaporated water was replenished daily and filtered samples analyzed by ICP-MS through day 12. Initial 10% loading denotes 200 g solids per 2 L; 20–50% arms used 400–1000 g. Af, Lf, Tt and the blank CK were tested at 30 degrees C, Ac/St at 40 degrees C; mixtures used 30, 40 or 45 degrees C. MC45-40AS contained equal starting volumes of all five cultures at 45 degrees C; MC40-25St contained equal Af/Lf/Tt/St volumes at 40 degrees C. Starting inoculum proportions do not demonstrate post-growth community composition. No matched 40/45-degree abiotic series, pH/iron-matched controls, replication count or error definition is reported. The text mentions optimization of sulfur and ferrous sulfate without complete final amounts.

Curated Evidence Points:

Support Source: lu2025

Sections 3.1.1–3.1.4 and Figures 1–4 show higher source-defined leaching ratios in inoculated arms than the 30-degree blank, with mixture composition, temperature and loading affecting the curves. Only the 30-degree single-culture comparison shares the blank temperature. Increasing solids loading generally lowered the final released fraction. Neither an independent temperature effect nor synergy among members is established by all comparisons. No percentage is adopted as a verified whole-process recovery yield.

Partial Source: lu2025

Section 2.1 reports 0.8214% Ni in nickel residue and 0.4998% Co in cobalt residue, whereas original SI Table S1 reports 7209 ± 56 PPM Ni and 4093 ± 40 PPM Co for those respective feeds. The basis of the disagreement and uncertainty terms is unexplained. No reconciled inventory, normalized concentration observation or corrected extraction yield is inferred. Tables 1–2 and Figure 2 label MC40-25Ac, while portions of the prose and caption call it MC40-25AS; these are not treated as an additional consortium.

Partial Source: lu2025

The abstract/conclusion assign 75.4% Co release to MC40-25St, Section 3.1.2 states 79.6%, and the loading discussion gives 82.9% at 10% loading. The text also claims a 1.18-fold improvement over a 72.3% single-culture result without consistent arithmetic. These source discrepancies preclude selection of a definitive optimized Co yield. Ni kinetics report 88.4%, while the separate BCR presentation reports 90.3% leached; the record does not silently equate these endpoints.

Partial Source: lu2025

Section 2.4 and Figures 5–6 use operational BCR acid-soluble, reducible, oxidizable and residual fractions alongside a leached fraction. These are extraction categories, not verified mineral phases or oxidation states. No closed mass balance, recovered solid product, product purity, independent consortium authentication or industrial reactor performance is demonstrated. The supplier being industrial does not change the laboratory deployment scope.

Context_only Source: ncbi20261012

Live species nodes resolve the five organism CURIEs and the historical Thiobacillus thiooxidans name to A. thiooxidans. ATCC 23270 and DSM 17362 appear among the respective type-strain links, but those links do not authenticate the cultures used. AS1 6358, BJMCC 01101 and CGMCC 1.15711 remain source-reported stock labels without an asserted collection CURIE or inferred causal assignment.

Sources & References

lu2025: Lu, H., Zhang, H., Chen, X., Wang, L. and Yan, X. (2025). Bioleaching of sludge from acid-leached waste traction batteries used in electric vehicles for the extraction of Ni and Co using optimized microbial consortia. RSC Advances 15, 45979–45985. DOI 10.1039/D5RA07472J; complete Europe PMC XML, Sections 2–3, Tables 1–2, original Figures 1–6 and two-page SI Table S1.
https://doi.org/10.1039/D5RA07472J (accessed 2026-10-12)
ncbi20261012: NCBI Taxonomy, live species nodes accessed 2026-10-12: Acidithiobacillus ferrooxidans 920, Leptospirillum ferriphilum 178606, Acidithiobacillus thiooxidans 930, Acidithiobacillus caldus 33059 and Sulfobacillus thermotolerans 338644. Species mappings, not authentication of experimental stocks.
https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?command=show&id=178606&mode=node (accessed 2026-10-12)

Curation History

Timestamp	Curator	Action	Summary
`2026-10-12T14:49:44.531130+00:00`	Codex (GPT-6; codex)	CREATE	Created the distinct downstream wet-processing residue from complete original evidence, retaining feed/yield conflicts, separate residue arms and comparative-control limitations.

Record source: data/records/traction-battery-hydrometallurgical-residue.yaml