Spent alkaline and zinc-carbon batteries secondary resource
End-of-life non-button alkaline and zinc-carbon batteries, represented by a mixed AA-cell powder after dismantling, electrolyte washing and drying. This secondary resource is distinct from the curated watch/button-cell powder, nickel-metal-hydride batteries and lithium-ion battery black mass. The selected experiment treats the two primary-cell chemistries together; it does not establish separate chemistry-specific performance or a universal battery composition. Constituent-element criticality is not inherited.
Microbial & Biochemical Mechanisms (2)
Indirect leaching with a sulfur-oxidizing culture medium
bioleaching
Microbial
Associated Organisms:
Acidithiobacillus thiooxidans (NCBITaxon:930)
Sulfur-grown Acidithiobacillus thiooxidans DSM 11478 produced an acidified, polythionate-containing medium in a separate air-lift reactor. This medium mobilized Zn and Mn from prepared mixed AA battery powder. Microbial involvement is upstream lixiviant production; direct cell attack on the battery powder and an isolated polythionate-specific causal effect were not demonstrated. Removal or inactivation of all cells before the leaching stage was not established.
Experimental Context & Analytical Limits:
Methods II.B–F, pp.124–125: mixed spent AA alkaline and Zn-C cells of different brands were opened; casing, ferrous components, plastic and paper were separated, powder was washed with distilled water and dried overnight at a printed 150 degrees without an explicit temperature-unit letter. Figure 1 also separates a zinc can. Table 1 reports mixed-powder compositions both with and without that can, without transparently binding one of those assays to every extraction denominator. No absolute whole-cell inventory is reconstructed. The culture was maintained at 30 degrees C and 180 rpm in mineral salts medium, initially pH 2.5 with 1% m/V elemental sulfur. The 26.5-L total-volume air-lift reactor held sulfur as substrate and attachment support, was maintained at 30 degrees C and was inoculated once; acidified liquid was replaced with fresh mineral medium without reinoculation. The conclusion selects 8 kg sulfur, 10 L medium, 138 L/h air and a 350 mM proton endpoint. These are acid-production settings, not a claim of 10 L battery-leaching volume. The separate 50-L leaching vessel contained 2 kg prepared powder and 28 L biological medium at pH near 0.4, stirred at 200 rpm. Medium was replaced when pH and dissolved-metal measurements plateaued. Leaching-stage temperature and a full sampling/mass-balance correction were not specified. The authors call the integrated apparatus a pilot plant; the stated vessel and feed scales do not establish commercial deployment.
Methods II.B–F, pp.124–125: mixed spent AA alkaline and Zn-C cells of different brands were opened; casing, ferrous components, plastic and paper were separated, powder was washed with distilled water and dried overnight at a printed 150 degrees without an explicit temperature-unit letter. Figure 1 also separates a zinc can. Table 1 reports mixed-powder compositions both with and without that can, without transparently binding one of those assays to every extraction denominator. No absolute whole-cell inventory is reconstructed. The culture was maintained at 30 degrees C and 180 rpm in mineral salts medium, initially pH 2.5 with 1% m/V elemental sulfur. The 26.5-L total-volume air-lift reactor held sulfur as substrate and attachment support, was maintained at 30 degrees C and was inoculated once; acidified liquid was replaced with fresh mineral medium without reinoculation. The conclusion selects 8 kg sulfur, 10 L medium, 138 L/h air and a 350 mM proton endpoint. These are acid-production settings, not a claim of 10 L battery-leaching volume. The separate 50-L leaching vessel contained 2 kg prepared powder and 28 L biological medium at pH near 0.4, stirred at 200 rpm. Medium was replaced when pH and dissolved-metal measurements plateaued. Leaching-stage temperature and a full sampling/mass-balance correction were not specified. The authors call the integrated apparatus a pilot plant; the stated vessel and feed scales do not establish commercial deployment.
Curated Evidence Points:
Support
Source:
falco2014
Figures 1–4 and Methods II.B–C distinguish culture-based acid production from subsequent powder treatment. Figure 4 reports protons, sulfate, polythionates and free cells during the reactor time course. Results III.B, p.127 and Figure 6 report 100% Zn and 65% Mn extraction after two fresh-medium loads. These are source-reported percentages for prepared powder, not isolated-product or whole-battery yields. Figure 6 plots metal-extracted percent despite its concentration caption; the first- and second-load bars are not summed here, and cumulative accounting is not independently reconstructed. The abstract instead reports 67% Mn, an unresolved difference retained without harmonization.
Partial
Source:
falco2014
Methods II.F and Results III.B describe S1 commercial sulfuric acid and S2 biological medium at the same stated acid concentration. The prose reports 60% more extracted Mn and 40% more Zn in S2 relative to S1, but does not supply the underlying numerical series, uncertainty, matched evolving pH/composition or a sterile sulfur-reactor control. These relative increases are not extraction percentages or evidence that live-cell contact was necessary. Equation 6 is a proposed generalized polythionate reaction, not a separately tested molecular pathway. Reactor productivity errors elsewhere refer to successive steps rather than independent battery-leaching replicates.
Partial
Source:
falco2014
Table 1 and Figure 5 establish heterogeneous Zn/Mn-containing feed, including residual K in the EDS spectrum despite electrolyte washing. Results III.B characterize remaining solid as Mn/O-rich; the reported Mn2O3 diffraction assignment concerns material calcined at 500 degrees C, not a directly established as-leached crystalline phase. Partial Mn extraction remains explicit. Figure 4 also shows free-cell counts declining late in the acid-production run; acid production is not evidence of unrestricted culture tolerance or indefinite performance.
Context_only
Source:
dsm11478
The current DSMZ record assigns DSM 11478/Tth04 to Acidithiobacillus thiooxidans and records mine-drainage provenance. This corroborates the reported culture-collection label, without independent authentication of cells used in the 2014 experiment.
Context_only
Source:
ncbi930
The species-level NCBI identifier identifies A. thiooxidans; it does not encode the experimental strain or prove its causal contribution.
Separate electrolysis of the biologically generated leachate
recovery
An externally powered electrolysis stage deposited a source-assigned metallic Zn cathodic solid and a Mn-oxide anodic solid from an aliquot of the preceding leachate. This stage is electrochemical, not demonstrated microbial electrodeposition. Deposits and source-reported leachate recovery are documented, but the experiment does not establish a closed whole-battery recovery yield, battery-grade products or commercial production.
Experimental Context & Analytical Limits:
Methods II.G–H, p.125 used 6.5 L leaching liquor, two stainless-steel electrodes separated by 25 cm, average current density 100 A/m2, atmospheric pressure and room temperature. Bath samples were analyzed by atomic absorption and pH, and end-of-run solids by acid digestion/atomic absorption, SEM-EDS, diffraction and BET methods. The article does not provide a complete deposit-mass and metal-inventory reconciliation across washing, leaching, liquid replacement, sampling and electrolysis.
Methods II.G–H, p.125 used 6.5 L leaching liquor, two stainless-steel electrodes separated by 25 cm, average current density 100 A/m2, atmospheric pressure and room temperature. Bath samples were analyzed by atomic absorption and pH, and end-of-run solids by acid digestion/atomic absorption, SEM-EDS, diffraction and BET methods. The article does not provide a complete deposit-mass and metal-inventory reconciliation across washing, leaching, liquid replacement, sampling and electrolysis.
Curated Evidence Points:
Support
Source:
falco2014
Results III.C, pp.127–128 reports 36% Mn and 66% Zn recovery from leaching solution after 68 hours, with metallic Zn described at the cathode and brown Mn oxide at the anode. These leachate-stage percentages are not multiplied by leaching percentages to infer overall recovery. Figure 7 shows the anodic solid's laminar morphology, not a quantitative purity or phase determination.
Partial
Source:
falco2014
Current efficiency for both deposits was below 10%. The bath became green and the anode lost mass; the authors attribute the principal Fe impurity to electrode corrosion. The reported Zn deposit purity is 90%; Mn-oxide purity is 82% in Results and 85% in Conclusions. The final electrolysis pH is described as 1.8 and later 1.5. These unresolved differences and low efficiencies are preserved. The Mn2O3 assignment again follows 500-degree-C calcination; it cannot establish an identical crystalline phase in the untreated anodic deposit. Claimed economic and ecological advantages were not a demonstrated full process cost or life-cycle assessment.
Sources & References
-
falco2014: Falco, Martínez, Di Nanno, Thomas and Curutchet (2014). Study of a pilot plant for the recovery of metals from spent alkaline and zinc-carbon batteries with biological sulphuric acid and polythionate production. Latin American Applied Research 44(2):123–129. DOI 10.52292/j.laar.2014.429; complete seven-page publisher PDF, Methods II.A–H, Results III.A–C, Figures 1–7 and Table 1.
https://doi.org/10.52292/j.laar.2014.429 (accessed 2026-10-12) -
dsm11478: DSMZ catalogue: Acidithiobacillus thiooxidans DSM 11478, strain Tth04. Collection identity does not authenticate the experimental stock.
https://www.dsmz.de/collection/catalogue/details/culture/DSM-11478 (accessed 2026-10-12) -
ncbi930: NCBI Taxonomy 930: Acidithiobacillus thiooxidans, species identity.
https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=930&mode=Info (accessed 2026-10-12)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-12T13:19:52.376103+00:00 |
Codex (GPT-6; codex) | CREATE | Created the mixed spent AA alkaline/zinc-carbon resource from full primary evidence, distinguishing upstream biological medium production, qualified powder leaching and separate electrolysis while retaining source and mass-balance limits. |
Record source: data/records/spent-alkaline-zinc-carbon-batteries.yaml