Chalcocite mineral
Chalcocite is the Cu2S mineral species listed as grandfathered, with original description year 1751, in the September 2026 IMA list. It is distinct from copper element, covellite, digenite, bornite, mixed copper ore and manufactured copper-sulfide reagents. The natural mineral separate used below is not established as a pure endmember. No criticality designation is inherited from copper.
Microbial & Biochemical Mechanisms (1)
Reported community-associated leaching of a natural chalcocite separate
bioleaching
Microbial
The study reports higher copper leaching indices after inoculating a 1:2 mass mixture of chalcocite and pyrite separates with a mine-derived community, alongside a higher solution potential. The uninoculated arm also shows substantial reported copper leaching, and inoculation raises the reported iron leaching index as well. Ferric-mediated attack, sulfur oxidation and galvanic interactions are the authors' interpretations, not isolated organism-specific or molecular mechanisms. The source's percentage equation is inconsistent with its stated solution-concentration definition, so no verified extraction fraction or product-recovery yield is adopted here.
Experimental Context & Analytical Limits:
Laboratory experiment using natural material from Zijinshan Copper Mine, Fujian, China. Chalcocite and pyrite separates were prepared by hand sorting, gravity separation and flotation, then ground below 0.074 mm. Table 2 gives the chalcocite separate 68.42 wt% Cu, 2.53 wt% Fe, 23.98 wt% S and 0.11 wt% SiO2, with a source-labelled purity of 92.40%. This elemental table does not establish a quantitatively verified endmember phase fraction; other copper-bearing phases are not excluded. Living community inoculum came from the mine's heap sump, followed by four to five days of laboratory cultivation/adaptation on 9K medium. Source genus profiles include Leptospirillum, Acidithiobacillus and Sulfobacillus; no authenticated strain or species-specific causal role is assigned. The mixed-separate assay used 30 degrees C, 14 days, initial pH 1.8 and inoculum-to-pulp volume ratio 1:10. Methods describe initial pH adjustment with 20% v/v sulfuric acid and an initial inoculated cell density of 2 x 10^7 cells/mL, without resolving its basis across the different inoculum ratios. Flask working volume, solid mass, agitation, exact 9K recipe, inoculum washing and subsequent pH-control details are not supplied. No mineral sterilization or verification of sterility in the uninoculated comparator is described. Copper and total iron in supernatant were measured by ICP-OES; potential was measured against Ag/AgCl and reported on the hydrogen scale. The paper states at least three repetitions with means and standard-deviation error bars. Sampling replacement and cumulative mass correction are not specified. A separate raw-ore stirred-reactor arm uses different conditions; its 5% pulp loading and 120 rpm are not assigned to these flask assays.
Laboratory experiment using natural material from Zijinshan Copper Mine, Fujian, China. Chalcocite and pyrite separates were prepared by hand sorting, gravity separation and flotation, then ground below 0.074 mm. Table 2 gives the chalcocite separate 68.42 wt% Cu, 2.53 wt% Fe, 23.98 wt% S and 0.11 wt% SiO2, with a source-labelled purity of 92.40%. This elemental table does not establish a quantitatively verified endmember phase fraction; other copper-bearing phases are not excluded. Living community inoculum came from the mine's heap sump, followed by four to five days of laboratory cultivation/adaptation on 9K medium. Source genus profiles include Leptospirillum, Acidithiobacillus and Sulfobacillus; no authenticated strain or species-specific causal role is assigned. The mixed-separate assay used 30 degrees C, 14 days, initial pH 1.8 and inoculum-to-pulp volume ratio 1:10. Methods describe initial pH adjustment with 20% v/v sulfuric acid and an initial inoculated cell density of 2 x 10^7 cells/mL, without resolving its basis across the different inoculum ratios. Flask working volume, solid mass, agitation, exact 9K recipe, inoculum washing and subsequent pH-control details are not supplied. No mineral sterilization or verification of sterility in the uninoculated comparator is described. Copper and total iron in supernatant were measured by ICP-OES; potential was measured against Ag/AgCl and reported on the hydrogen scale. The paper states at least three repetitions with means and standard-deviation error bars. Sampling replacement and cumulative mass correction are not specified. A separate raw-ore stirred-reactor arm uses different conditions; its 5% pulp loading and 120 rpm are not assigned to these flask assays.
Curated Evidence Points:
Support
Source:
wu2019
Section 2.2 and original Figures 4-5 show the inoculated and uninoculated mixed-separate arms. Reported copper indices are similar at day 2, then higher with inoculation; the reported iron index also rises with inoculation. Figure 5 shows higher later solution potential in the inoculated arm. These support the reported community-associated assay observation, conditional on the unresolved quantitative normalization, rather than exclusive microbial dissolution or a copper-only selective recovery process.
Partial
Source:
wu2019
Printed Equation 2 on page 18286 subtracts a concentration-volume term from 1, although its surrounding text defines C as solution metal concentration. Its direction is inconsistent with interpreting increasing dissolved metal as increasing extraction; the units and molecular-weight convention are not specified. Original solution concentrations, masses and volumes are unavailable for reconstruction. Plotted leaching percentages are therefore source-reported indices, not independently verified feed-mass yields or chalcocite conversion.
Partial
Source:
wu2019
Figure 6 gives genus-level relative sequence abundances from separate mineral assays; it does not measure the contributions of individual taxa to the mixed-separate outcome. Sections 2.3.1-2.3.2 describe attached material while Figure 6 and the DNA methods describe solution samples, so attachment-specific attribution is unresolved. No matched dynamic-potential or pH control isolates an effect beyond community-associated changes in solution chemistry. The calculated electronic structures, vacancies and proposed two-stage separation scheme are interpretations, not measured enzymatic activity, demonstrated phase-selective conversion or industrial deployment.
Sources & References
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ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. Chalcocite row on PDF page 40; status and year definitions on page 1, distribution terms on page 2. Same-day retained original rechecked rather than downloaded anew.
https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-11) -
wu2019: Wu, Yang, Wen and Wang (2019). Semiconductor-Microbial Mechanism of Selective Dissolution of Chalcocite in Bioleaching. ACS Omega 4(19), 18279-18288. Complete original main, especially Sections 2.1-2.3 and 4.1-4.5, Tables 1-2, Figures 1-8 and printed Equation 2; model context in Section 2.4, Figures 9-12 and Tables 3-5.
https://doi.org/10.1021/acsomega.9b02294 (accessed 2026-10-11)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-11T20:29:59Z |
codex (GPT-6; codex) | CREATE | Created the chalcocite mineral record and a qualified natural-specimen community-associated leaching observation, retaining ambiguous percentage accounting, uninoculated release, incomplete specimen purity and unresolved causal and deployment claims. |
Record source: data/records/chalcocite.yaml