Covellite mineral
Covellite is the CuS mineral species, listed as grandfathered with original description year 1832 in the September 2026 IMA list. It is distinct from elemental copper, dissolved copper, mixed copper ores and an unspecified manufactured copper sulfide. The experiment below identifies a covellite crystalline phase in a laboratory precipitate made from mine drainage using biologically generated sulfide; it does not demonstrate microbial leaching of natural covellite or establish the purity of the whole precipitate. No criticality designation is inherited from copper.
Microbial & Biochemical Mechanisms (1)
Covellite-phase precipitation using sulfide generated by a separate consortium
biomineralization
Microbial
Gas from a sulfidogenic bioreactor inoculated with an acidophilic sulfate-reducing consortium was delivered to a separate bottle of real copper-bearing mine drainage. Collected solids after 48 or 96 hours exhibited diffraction peaks assigned to covellite and sheet-like crystalline aggregates. The microbial contribution is upstream sulfide generation; the downstream copper-sulfide precipitation is chemical. The study does not establish direct cell contact with the product, a species-specific causal role, a microbial advantage over matched chemical sulfide, or a quantified copper recovery yield.
Experimental Context & Analytical Limits:
The consortium originated from anaerobic sediment in an acidic river in northern Chile; this paper gives no strain accession or community composition that can identify its active members. Biomass was immobilized on 1-2 mm porous glass beads occupying 40% of a 2.3 L working-volume continuous-flow reactor. Reported reactor conditions were pH 4.5, 30 degrees C and 40 rpm, with a 150 mL/min N2/CO2 stream at 70/30%. The sterile synthetic feed lacked copper, had pH 2.5 and 13.86 mM sulfate in Table 1, and received 5 mM glycerol plus 0.01% w/v yeast extract. Feed addition responded to rising reactor pH. These are upstream reactor conditions, not independently specified temperature or mixing settings for the downstream bottle. The off-line bottle contained 1 L of drainage from an unnamed copper mine in Para State, Brazil, initially pH 5.1 and reported Cu 325, Mn 10.50 and Zn 0.12 mg/L. Biogenic H2S carried by the gas stream was sparged for 48 or 96 hours. Solids were vacuum-filtered and dried overnight at 60 degrees C. Inoculum density, reactor hydraulic residence time, quantified H2S delivery and independent experimental replicate numbers are not reported. The two exposure durations are treatment conditions, not proof of replication. This is a laboratory synthesis experiment using a mining effluent, not industrial deployment.
The consortium originated from anaerobic sediment in an acidic river in northern Chile; this paper gives no strain accession or community composition that can identify its active members. Biomass was immobilized on 1-2 mm porous glass beads occupying 40% of a 2.3 L working-volume continuous-flow reactor. Reported reactor conditions were pH 4.5, 30 degrees C and 40 rpm, with a 150 mL/min N2/CO2 stream at 70/30%. The sterile synthetic feed lacked copper, had pH 2.5 and 13.86 mM sulfate in Table 1, and received 5 mM glycerol plus 0.01% w/v yeast extract. Feed addition responded to rising reactor pH. These are upstream reactor conditions, not independently specified temperature or mixing settings for the downstream bottle. The off-line bottle contained 1 L of drainage from an unnamed copper mine in Para State, Brazil, initially pH 5.1 and reported Cu 325, Mn 10.50 and Zn 0.12 mg/L. Biogenic H2S carried by the gas stream was sparged for 48 or 96 hours. Solids were vacuum-filtered and dried overnight at 60 degrees C. Inoculum density, reactor hydraulic residence time, quantified H2S delivery and independent experimental replicate numbers are not reported. The two exposure durations are treatment conditions, not proof of replication. This is a laboratory synthesis experiment using a mining effluent, not industrial deployment.
Curated Evidence Points:
Support
Source:
silva2019
Sections 2.1-2.3 and Figure 1 distinguish the inoculated sulfide-generating reactor from the gas-fed drainage bottle. Figures 2-3 show collected precipitate and diffraction patterns; Section 3.2 and Table 2 assign covellite with corresponding lattice parameters. Figure 5 shows sheet-like and hexagonal crystalline aggregates. This supports the reported covellite-phase product under the stated coupled process, without proving a pure bulk product or a particular enzymatic route.
Partial
Source:
silva2019
No uninoculated reactor, gas-only drainage blank or matched reagent-H2S precipitation control is reported. The study therefore does not isolate the necessity or superiority of biological sulfide production. Section 3.1 reports final drainage pH 2.1 at both exposure times, but a color change, settling and acidification do not quantify copper removal or identify all proposed transient polysulfide species. The study supplies no final dissolved-copper concentration, isolated solid mass, closed copper balance or measured product recovery percentage.
Partial
Source:
silva2019
Table 3 labels EDXRF entries as wt% but reports Cu/S values of 87.67/73.99 for CuS48 and 70.97/106.08 for CuS96. Each pair already exceeds 100%, and one sulfur entry exceeds 100% alone. The text's ratios of 1.18 and 0.67 are ratios of those reported mass entries, whereas the abstract and conclusion describe molar ratios. These unresolved normalization and ratio-basis problems do not establish stoichiometry, quantified purity or a sulfur/copper balance. Values are retained only to expose the inconsistency, not as accepted composition observations. Absence of other assigned XRD peaks has an unspecified detection limit and cannot prove absence of all minor or amorphous constituents.
Partial
Source:
silva2019
Table 4 and Figure 4 report volume-distribution Dv90 values of 43.4 micrometers after 48 hours and 22 micrometers after 96 hours, following ultrasonic dispersion. These are particle-size quantiles, not crystallite dimensions or a recovery fraction. Figure 5 instead shows selected submicrometer-to-micrometer sheets and aggregates; its morphology does not supply a representative particle-size distribution or prove the whole product is nanoscale. Methods, figure labels and tables consistently specify 96 hours; the isolated CuS98 token in Section 3.1 is a source-label inconsistency and is not treated as a third experimental arm.
Sources & References
-
ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. Covellite row, PDF page 50; column definitions and distribution terms on pages 1-2.
https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-11) -
silva2019: Silva, Lucheta, Bitencourt, do Carmo, Nancucheo Cuevas, Siqueira, de Oliveira and Alves (2019). Covellite (CuS) Production from a Real Acid Mine Drainage Treated with Biogenic H2S. Metals 9(2), 206. Complete nine-page publisher PDF and XML; Sections 2-3, Figures 1-5 and Tables 1-4.
https://doi.org/10.3390/met9020206 (accessed 2026-10-11)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-11T20:31:36.869961+00:00 |
codex (GPT-6; codex) | CREATE | Created mineral identity and phase-formation evidence from biogenic sulfide and real drainage, retaining separate process stages, unresolved composition and control limitations, and no quantified product recovery claim. |
Record source: data/records/covellite.yaml