CMMMech
CMMMech > Secondary resource > Spent silver-oxide–zinc button-cell batteries

Spent silver-oxide–zinc button-cell batteries secondary resource

Discarded button cells identified by the primary source as silver-oxide–zinc batteries, distinct from zinc–manganese button cells, other battery chemistries, elemental silver or zinc and isolated recovered products. The accepted experiment used powder manually removed from market-collected waste cells, not intact batteries or an authenticated pure oxide feed. It supports laboratory metal mobilization with a filtered fungal culture medium, with unresolved experimental-condition and yield conflicts.

Microbial & Biochemical Mechanisms (1)

Metal mobilization by an Aspergillus niger culture filtrate

bioleaching Microbial

Associated Organisms: Aspergillus niger (NCBITaxon:5061)

Filtered spent medium from a source-named Aspergillus niger culture mobilized zinc, silver and a much smaller fraction of mercury from waste-cell powder. Organic-acid action is the authors' explanation, but this experiment does not isolate citric acid from other medium constituents or demonstrate a microbial increment over a matched sterile-medium or chemical-acid control. Cells were removed before leaching; this is not evidence of fungal growth at the leaching temperatures or of a live-cell uptake mechanism. Solution analysis does not establish purified-metal recovery.

Experimental Context & Analytical Limits:
The culture came from FIRDI, Hsinchu, Taiwan, without a strain accession. The referenced earlier tin-removal paper's 34770 strain is not assigned to this assay. Sucrose medium contained 100 g/L sucrose plus nitrate, phosphate, magnesium sulfate, potassium chloride and yeast extract. Section 2.3 describes both 30 and 25 degrees C cultivation at 120 rpm for ten days, then 0.22 micrometre filtration. It reports pH 1.97 and 20 g/L citric acid while citing an earlier study; no independent metabolite assay is described here. Collected cells were manually dismantled and their powder dried at 60 degrees C. Brand, battery model, discharge state, particle-size distribution and phase authentication are not supplied. Aqua-regia digestion and ICP-OES provide the Table 1 feed assay, including Zn 290 mg/g and Ag 35.86 mg/g; these are digested elemental concentrations, not phase abundances or whole-device inventories. The time series used 0.10 g powder in 100 mL filtrate in 250 mL flasks at 30 degrees C and 150 rpm for up to eight hours. Separate temperature, agitation and filtrate-volume series varied these conditions. Experiments were triplicate and leachates were analyzed by ICP-OES; sample-volume correction, complete mass balances and the meaning of plotted error bars are not specified. Laboratory assays alone are documented.
Curated Evidence Points:
Sections 2.1–2.5 and Figure 1 support the feed preparation and filtrate-leaching observation. At six hours in the 30 degrees C time-series arm, the Results report approximately 80% Zn and 41% Ag extraction, but only 2% Hg; Figure 1 shows little additional release at eight hours. These are the paper's solution-based extraction estimates, not independently reconciled yields or recovered-product masses. The incomplete mercury release is preserved rather than claiming comprehensive metal removal or detoxification.
Figure 4 and the conclusion report 100% Zn and Ag with 0.10 g powder and 15 mL filtrate at 60 degrees C, 100 rpm and six hours. However, Section 2.4 specifies 150 rpm and eight hours for the volume series, and eight hours for the agitation series whereas Figures 3–4 say six. Figure 2 shows 100% Zn and Ag at 60 degrees C, 150 rpm and six hours, while Figure 3 shows roughly 70% at the same nominal temperature, speed, time and 100 mL volume. The Results' claimed temperature range of 20–60 degrees C and shaking range of 50–200 rpm also differ from the displayed 30–60 degrees C and 0–150 rpm series. These conflicts preclude treating the combined optimum as a verified reproducible protocol. Low mercury release persists in these arms. No reconciled quantitative observation is imported.
The source attributes leaching to citric acid and contrasts it with ferric supernatant in an earlier 2013 study, but neither a matched acid comparison nor a fresh assay of that earlier bacterial arm is presented here. The prior study's Table 2 summary is not independent replication or proof that oxidized zinc can never dissolve in an acidic ferric medium. No source-supported industrial scale, life-cycle advantage, isolated product purity or criticality designation follows from this experiment.
Context_only Source: ncbi_5061
The current authority resolves the source's species name to NCBITaxon:5061. It does not identify the experimental stock, its metabolites or a species-wide leaching phenotype.

Sources & References

  1. jadhav_2018: Jadhav U, Su C-H, Chakankar M, Hocheng H (2018). Leaching of Metals from Waste Silver Oxide-Zinc Button Cell Batteries by Aspergillus niger. Batteries 4(4):51. DOI 10.3390/batteries4040051; complete seven-page original, Sections 2–4, Tables 1–2 and Figures 1–4.
    https://doi.org/10.3390/batteries4040051 (accessed 2026-10-14)
  2. ncbi_5061: NCBI Taxonomy 5061, current species name Aspergillus niger. Species-level name context only; not authentication of the unnamed FIRDI culture used in the experiment.
    https://www.ncbi.nlm.nih.gov/datasets/taxonomy/5061/ (accessed 2026-10-14)

Curation History

Timestamp Curator Action Summary
2026-10-14T18:01:44.920258Z Codex (GPT-6; codex) CREATE Created the source-qualified secondary-resource owner; preserved conflicting conditions, incomplete balances, controls, null results and laboratory scope.

Record source: data/records/spent-silver-oxide-zinc-button-cell-batteries.yaml