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Chalcopyrite mineral

Chalcopyrite is the mineral species with IMA-approved formula CuFeS2. The September 2026 IMA list records status G (grandfathered) and the uncertain original-description year 1725 ?. That year is not an IMA approval number. This mineral species is distinct from elemental copper, the copper commodity, and an impure flotation concentrate. The curated bioleaching experiment concerns an Aitik concentrate; its copper-element representation in cmmmech:copper is the same experiment, not an independent replication. No constituent-element criticality is inherited.

Microbial & Biochemical Mechanisms (1)

Culture-dependent leaching of chalcopyrite concentrate

bioleaching Microbial

Associated Organisms: Acidithiobacillus caldus (NCBITaxon:33059), Sulfobacillus thermosulfidooxidans (NCBITaxon:28034), Leptospirillum ferriphilum (NCBITaxon:178606)

Living defined acidophile cultures promoted copper release from chalcopyrite concentrate in laboratory flasks. The initial Acidithiobacillus caldus plus Sulfobacillus thermosulfidooxidans pair gave the largest reported released-copper concentration. Cultures containing the stronger iron oxidizer Leptospirillum ferriphilum reached higher redox potentials, without maximizing copper release. This supports conditional bioleaching of a mineral-bearing feed; it does not establish a purified copper yield, quantitative chalcopyrite-phase conversion, or deployment of the defined consortium.

Experimental Context & Analytical Limits:
Aitik-mine flotation concentrate contained 29.5% Cu. The authors report greater than 98% purity from aqua-regia digestion and elemental analysis, and note that bornite accompanies chalcopyrite at the deposit. Elemental analysis does not independently establish single-phase purity. The 50-100 micrometre fraction was washed with 0.1 M EDTA in 0.4 M NaOH, washed three times with acetone, dried overnight at 60 degrees C and heated for 10 h at 120 degrees C under nitrogen. Living A. caldus DSM 8584, S. thermosulfidooxidans DSM 9293 and L. ferriphilum DSM 14647 from separate axenic continuous cultures were tested singly and in every pair and three-species combination, alongside uninoculated controls. Four flasks per treatment contained 100 mL MAC medium initially at pH 1.8 and 2% w/v concentrate in 250 mL flasks, at 38 +/- 2 degrees C and 120 rpm. Inoculation was 10^7 cells/mL per species, so total cell loading differed among mixtures. Inoculated endpoints were 14 days after redox potential exceeded 400 mV versus Ag/AgCl, totaling 14-20 elapsed days. The heated HCl slurry-digest/AAS assay counted released copper in dissolved and precipitated fractions. Species identifiers below do not replace the experimental strain designations.
Curated Evidence Points:
Bioleaching results and Figure 1C report 14.2 +/- 0.3 mM total released Cu for the initial A. caldus/S. thermosulfidooxidans pair, versus 2.4 +/- 0.3 mM for uninoculated controls at 15 days; Figure 1 reports means +/- SD, n=4. Every binary mixture outperformed the three-species mixture in that experiment. Different elapsed endpoints preclude treating this comparison as a common-time leaching rate.
Marginal leaching and late iron oxidation in A. caldus-only flasks were attributed to possible surviving environmental contaminants. Figure 2 and the repeated pair experiments reached 593 +/- 15 mV, so the lower initial redox values do not establish a universal 550 mV ceiling. Proposed passivation, attachment, transient chalcocite formation and candidate iron-oxidation genes are not demonstrated molecular causes or phase-specific mass balances. Large-scale testing remains future work in the source.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. PDF page 40, Chalcopyrite row; page 1, column definitions; page 2, distribution terms.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-11)
  2. christel_2018: Christel et al. (2018). Weak Iron Oxidation by Sulfobacillus thermosulfidooxidans Maintains a Favorable Redox Potential for Chalcopyrite Bioleaching. Frontiers in Microbiology 9:3059. DOI 10.3389/fmicb.2018.03059. Mineral and Bioleaching Experiments Methods; Bioleaching of Chalcopyrite Concentrate results; Figures 1-2.
    https://doi.org/10.3389/fmicb.2018.03059 (accessed 2026-10-11)
  3. taxonomy_caldus: NCBI Taxonomy 33059, Acidithiobacillus caldus, species; DSM 8584 listed as type strain.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=33059&mode=Info (accessed 2026-10-11)
  4. taxonomy_thermosulfidooxidans: NCBI Taxonomy 28034, Sulfobacillus thermosulfidooxidans, species; DSM 9293 listed as type strain.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=28034&mode=Info (accessed 2026-10-11)
  5. taxonomy_ferriphilum: NCBI Taxonomy 178606, Leptospirillum ferriphilum, species; DSM 14647 listed as type strain.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=178606&mode=Info (accessed 2026-10-11)

Curation History

Timestamp Curator Action Summary
2026-10-11T04:56:10Z codex (GPT-6) CREATE Added IMA-grounded chalcopyrite identity and primary concentrate bioleaching evidence with assay, purity, timing, controls and scale limits. Distinguished the mineral from copper and identified shared experimental evidence without double-counting replication.

Record source: data/records/chalcopyrite.yaml