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Chalcopyrite-enargite concentrate primary resource

Mixed copper-sulfide mineral concentrates represented by the D3, Eb and Ea feeds in Oyama et al. (2021), distinct from the constituent chalcopyrite and enargite mineral species, the nearly pure model chalcopyrite tested separately in that paper, and the DC-I/DC-II/DC-III enargite-pyrite concentrates examined in Okibe et al. (2022). Figure 1 reports chalcopyrite/enargite/pyrite contents of 12/21/30 wt% for D3, 17/6.7/36 wt% for Eb and 8/24/10 wt% for Ea; bornite, chalcocite, geerite and other phases also occur. The displayed Ea phase labels total 97%, so the figure is not treated as a closed compositional balance. Mine, batch and beneficiation details are not established; the acknowledgments identify an academic supplier for Ea. This owner denotes concentrated geological feed, not a documented discarded residue, a pure phase or a traded product specification. No mineral identifier or constituent criticality designation is inherited.

Microbial & Biochemical Mechanisms (1)

Feed-dependent carbon-assisted mixed-culture copper dissolution

bioleaching Microbial

Associated Organisms: Acidithiobacillus caldus (NCBITaxon:33059)

Laboratory inoculated concentrate assays showed feed-dependent associations between activated-carbon dose, solution redox trajectory and dissolved copper. For Eb, Section 3.2.1 reports day-30 soluble-copper fractions of 74%, 92% and 100% without carbon, with 0.05% w/v carbon and with 0.3% w/v carbon, respectively. For D3, the carbon-free curve plateaued just above 60%, whereas 0.05% carbon approached complete dissolution by day 35. For Ea, the carbon-free endpoint was reported as 54%; 0.3% carbon improved early dissolution but 0.05% gave the higher final soluble-copper outcome. These are source-reported mixed-feed dissolved fractions, referenced to copper in each feed, not isolated-metal yields or measured extraction of individual mineral phases. Parallel no-added-cell comparisons and evolving redox/pH profiles constrain the interpretation; the experiment does not establish a universal carbon optimum or a causal effect of the chalcopyrite/enargite ratio alone.

Experimental Context & Analytical Limits:
D3, Eb and Ea were used as received without washing or sterilization, with reported D50 values of 39, 81 and 49 micrometres. Duplicate 500 mL flasks contained 200 mL heterotrophic basal salts medium, 1% w/v feed, 5 mM ferrous iron supplied as ferrous sulfate, 0.01% w/v elemental sulfur and 0.01% w/v yeast extract. Initial medium pH was 1.5; sulfuric acid readjustment to 1.5 occurred on days 2 and 3 for D3 and day 4 for Eb, with no readjustment for Ea. Cultures were shaken aerobically at 45 degrees C and 150 rpm. Four source-labelled early-stationary-phase cultures, Acidiplasma sp. Fv-Ap, Acidimicrobium ferrooxidans ICP (DSM 10331), Sulfobacillus sibiricus N1 (DSM 17363) and Acidithiobacillus caldus KU (DSM 8584), were harvested, washed and introduced at 10^7 cells/mL each, 4 x 10^7 cells/mL total. The structured taxon names one verified species member only; no terminal community or member-specific causal census was performed. Powdered Wako activated carbon was reported as 46.5 micrometres and 1400 square metres/g; D3 received 0 or 0.05% w/v, and Eb/Ea 0, 0.05 or 0.3% w/v. Figure 6 covers approximately 30-35 days depending on feed, rather than a shared endpoint across all feeds. ICP-OES measured total soluble Cu, As and Fe; ferrous iron was measured separately and planktonic cells counted directly. Source-derived percentages are not an independently reconstructed sampling-corrected mass balance. Added iron and sulfur, variable phase assemblages, size, acid dosing and possible unmeasured reagent carryover limit cross-feed comparisons.
Curated Evidence Points:
Sections 2.1-2.5 and 3.2, Figures 1, 5 and 6 and Figure S4 support the specified mixed-feed identity, inoculation and conditional copper dissolution. Eb favored 0.3% carbon at its endpoint, whereas Ea favored 0.05% at its endpoint despite faster early leaching at 0.3%. D3 tests plotted only 0 and 0.05%; the claim that higher doses did not improve D3 is explicitly attributed to unpublished data and is not adopted as an available measured dose-response. Figure 6 reports duplicate averages/error bars without establishing a statistical effect test.
Section 3.2 calls the controls sterile, but Section 2.1 explicitly states that the mixed concentrates were not sterilized. They are interpreted as no-added-cell comparators, not verified abiotic systems. Figure 6 includes substantial copper dissolution in control curves for D3 and Ea; low control redox potential does not prove zero dissolution or biological necessity. The article does not provide the same explicit control copper endpoints for every feed. Different pH trajectories and feed-specific acid adjustments prevent a clean estimate of microbial or carbon effects independent of chemistry.
Figure 5 calculates theoretical Cu atomic shares upon complete dissolution of each mineral, not observed phase-resolved extraction. The model Enormal is defined for chalcopyrite and is not independently validated for every phase in these mixed feeds. Electrochemical galvanic tests, detailed rate analyses, and residue XRD/SEM in Figures 2-4 and S1-S3 concern the separate model-chalcopyrite arm; they do not directly prove the same pathway or passivating phase for D3, Eb or Ea. Reported associations between redox behavior and feed composition are not a controlled mineral-ratio experiment.
Section 3.2.3 broadly describes roughly 60% arsenic leaching and proposes amorphous Fe-As precipitation for the rest. Figure S4 instead shows strongly arm-dependent soluble arsenic, including much lower values in several carbon-free and high-carbon conditions. No uniform 60% arsenic extraction or complementary immobilization yield is adopted. Dissolved total arsenic is not oxidation-state speciation; no mixed-feed secondary-phase identification or closed arsenic balance demonstrates the proposed precipitate. Source iron curves also contain initially added 5 mM Fe and cannot be read as mineral-derived iron alone. Suggested cell attachment, inhibition or flotation-chemical toxicity is not directly discriminated.
Context_only Source: ncbi_caldus
The current official species entry verifies NCBITaxon:33059 and lists DSM 8584 and KU as type-strain aliases. This does not authenticate the experimental culture or identify the remaining community members through the same accession.
Context_only Source: okibe_2022
The existing enargite-pyrite owner concerns different DC-I/DC-II/DC-III compositions at 20% w/v feed with six starting organisms and a 60-day design. The 2021 D3/Eb/Ea assays are not pooled with those results. The 2021 introduction's separate 2020 precursor with 37.4% enargite and 47.3% pyrite resembles nominal 2022 DC-II; it is not a D3/Eb/Ea composition or evidence of independent replication.

Sources & References

  1. oyama_2021: Oyama K, Takamatsu K, Hayashi K, Aoki Y, Kuroiwa S, Hirajima T and Okibe N (2021). Carbon-Assisted Bioleaching of Chalcopyrite and Three Chalcopyrite/Enargite-Bearing Complex Concentrates. Minerals 11(4):432, DOI 10.3390/min11040432. Complete official v2 PDF, 13 pages, Figures 1-6; original three-page supplement, Figures S1-S4. Sections 2.1-2.5 and 3.2 support the mixed-feed assays; model-mineral experiments are separate.
    https://doi.org/10.3390/min11040432 (accessed 2026-10-12)
  2. ncbi_caldus: NCBI Taxonomy 33059, Acidithiobacillus caldus, species; type-strain aliases DSM 8584 and KU. Identifier context only, not authentication of the experimental stock or proof of one member's causal contribution.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=33059&mode=Info (accessed 2026-10-12)
  3. okibe_2022: Okibe et al. (2022). Bioleaching of Enargite/Pyrite-Rich Dirty Concentrate and Arsenic Immobilization. Minerals 12(4):449, DOI 10.3390/min12040449. Sections 2-3, Table 1 and Figures 1-3; retained complete original inspected in the preceding curation and rechecked here for owner/experiment scope.
    https://doi.org/10.3390/min12040449 (accessed 2026-10-12)

Curation History

Timestamp Curator Action Summary
2026-10-12T11:44:52.561004Z Codex (GPT-6) create Created the distinct D3/Eb/Ea mixed-feed owner from complete official main and supplementary evidence, preserving control, quantitative, phase, version and experimental-overlap limits.

Record source: data/records/chalcopyrite-enargite-concentrate.yaml