Djurleite mineral
Djurleite is the monoclinic copper sulfide mineral Cu31S16, distinct from chalcocite, digenite, covellite, copper element and a mixed copper ore. The September 2026 IMA list records approved status A and 1967 s.p.; the special-procedure notation is not a numbered approval accession. A natural djurleite-rich separate supports a qualified laboratory culture-associated copper-mobilization observation. Its associated copper minerals, missing uninoculated comparator and inconsistent inoculum reporting prevent a pure-phase extraction yield or an independently isolated microbial effect.
Microbial & Biochemical Mechanisms (1)
Culture-associated copper mobilization from a djurleite-rich separate
bioleaching
Microbial
Associated Organisms:
Acidithiobacillus ferrooxidans (NCBITaxon:920)
Fu et al. report copper entering solution during incubation of a djurleite-rich natural separate with a living culture identified as Acidithiobacillus ferrooxidans Atf.6. Inoculum and ferrous-iron series, together with a separate cell-attachment assay, support a conditional culture-associated observation. They do not distinguish direct enzymatic attack from chemical oxidation or establish that all copper came from djurleite. The source-reported 95.12% endpoint is a bulk-specimen copper extraction index, not an isolated-product recovery or phase conversion.
Experimental Context & Analytical Limits:
Laboratory shake-flask experiments on handpicked material from Bofang copper mine, Hunan, China. The paper reports XRD identification of djurleite with small amounts of chalcocite, bornite and quartz, but publishes no diffraction trace or quantitative phase refinement. Table 1 reports 71.94% Cu, 1.22% Fe and 20.53% S, and labels purity 90.65% without explaining its calculation. The material was milled in porcelain below 74 micrometres and stored under nitrogen. Culture Atf.6 was isolated from a Daye copper mine and adapted in stages; no collection accession or sequence authentication is supplied. Late-logarithmic cells were grown in optimized 4.5 K medium containing, per litre, 2.0 g (NH4)2SO4, 0.25 g K2HPO4, 0.25 g MgSO4.7H2O, 0.1 g KCl and 22.0 g FeSO4.7H2O. Leaching used 250 mL flasks with 100 mL working solution, 20 g/L solids, initial pH 2, 30 degrees C, 160 rpm and 48 days. Distilled water replaced evaporation. Inoculum series used 0.5, 1.0 and 1.5 x 10^8 cells at nominal zero initial Fe(II); the iron series used 0, 1.5, 2.5 and 4.5 g/L initial Fe(II). Culture-medium carryover into nominal zero-iron leaching is not resolved; washing is described for the separate attachment assay, not clearly for leaching. Page 666 identifies 1.0 x 10^8 cells as best for djurleite, whereas page 669 calls 0.5 x 10^8 cells optimal for the combined assay. This conflict is retained, and the Figure 3 endpoint is not assigned a uniquely verified inoculum. Dissolved copper was measured by atomic absorption spectroscopy and cells counted with a hemocytometer; counting alone does not verify viability. No matched uninoculated leaching time course, sterilization check, replication count, uncertainty estimates, explicit extraction equation or cumulative sampling correction is reported. The outcome is solution mobilization in a laboratory, without a closed copper mass balance or isolated copper product.
Laboratory shake-flask experiments on handpicked material from Bofang copper mine, Hunan, China. The paper reports XRD identification of djurleite with small amounts of chalcocite, bornite and quartz, but publishes no diffraction trace or quantitative phase refinement. Table 1 reports 71.94% Cu, 1.22% Fe and 20.53% S, and labels purity 90.65% without explaining its calculation. The material was milled in porcelain below 74 micrometres and stored under nitrogen. Culture Atf.6 was isolated from a Daye copper mine and adapted in stages; no collection accession or sequence authentication is supplied. Late-logarithmic cells were grown in optimized 4.5 K medium containing, per litre, 2.0 g (NH4)2SO4, 0.25 g K2HPO4, 0.25 g MgSO4.7H2O, 0.1 g KCl and 22.0 g FeSO4.7H2O. Leaching used 250 mL flasks with 100 mL working solution, 20 g/L solids, initial pH 2, 30 degrees C, 160 rpm and 48 days. Distilled water replaced evaporation. Inoculum series used 0.5, 1.0 and 1.5 x 10^8 cells at nominal zero initial Fe(II); the iron series used 0, 1.5, 2.5 and 4.5 g/L initial Fe(II). Culture-medium carryover into nominal zero-iron leaching is not resolved; washing is described for the separate attachment assay, not clearly for leaching. Page 666 identifies 1.0 x 10^8 cells as best for djurleite, whereas page 669 calls 0.5 x 10^8 cells optimal for the combined assay. This conflict is retained, and the Figure 3 endpoint is not assigned a uniquely verified inoculum. Dissolved copper was measured by atomic absorption spectroscopy and cells counted with a hemocytometer; counting alone does not verify viability. No matched uninoculated leaching time course, sterilization check, replication count, uncertainty estimates, explicit extraction equation or cumulative sampling correction is reported. The outcome is solution mobilization in a laboratory, without a closed copper mass balance or isolated copper product.
Curated Evidence Points:
Support
Source:
fu2014
Methods on page 665 and Figures 1a, 2a and 3a report increasing dissolved-copper extraction indices from the djurleite-rich specimen in inoculated flasks. Page 668 reports 95.12% after 48 days at 1.5 g/L initial Fe(II). Figure 2a also shows that higher initial iron was not uniformly beneficial. These are conditional specimen-level observations, not a universal optimum or a quantitative djurleite-only conversion.
Partial
Source:
fu2014
Page 665 reports 36.45% copper extraction when pH was adjusted to 2, before the reported incubation time course; Figure 1a starts near that value. Substantial initial chemical release and the absence of a matched uninoculated time course prevent attributing the full endpoint or its increment exclusively to microbial activity. Associated chalcocite and bornite are additional copper sources. The paper's direct-attack and ferric-regeneration explanations are proposed mechanisms, without selective inhibition, contact separation or chemistry-matched controls.
Partial
Source:
fu2014
Pages 666 and 669 conflict on the preferred djurleite inoculum (1.0 versus 0.5 x 10^8 cells). Figure 3c and its discussion label redox potential in eV, without an electrode reference, so no numerical redox threshold is adopted. Figure 3a does not reproduce the initial copper baseline depicted in Figures 1a and 2a; no reconciliation is supplied. The paper repeats Figure 2 on pages 667-668 and Table 1 on pages 665 and 671; repeated layouts are not independent experiments. Its cited Fu et al. 2013 djurleite paper is related same-group work and is not counted here as independent replication.
Partial
Source:
fu2014
The separate attachment assay on page 665 used washed cells in 50 mL of 0.001 mol/L KCl at pH 2, 30 degrees C and 120 rpm, with 0.5 g mineral of reported 50 micrometre size. Attachment was estimated by subtracting planktonic counts, and Figures 4-5 show attachment trends and cells on mineral surfaces. These conditions differ from leaching. Depletion, SEM attachment and adsorption-model fits do not demonstrate direct enzymatic dissolution or prove that attachment caused the copper endpoint.
Sources & References
-
ima_2026_09: IMA-CNMNC, The New IMA List of Minerals, September 2026; PDF pages 1-2 explain status and special procedures, page 58 lists Djurleite, Cu31S16, A, 1967 s.p.
https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-14) -
handbook_djurleite: Handbook of Mineralogy, Djurleite, version 1 (2001-2005); Cu31S16, monoclinic crystal data and association with other copper sulfides
https://handbookofmineralogy.org/pdfs/djurleite.pdf (accessed 2026-10-14) -
fu2014: Fu K, Lin H, Luo D, Jiang W and Zeng P (2014), Comparsion of bioleaching of copper sulphides by Acidithiobacillus ferrooxidans, African Journal of Biotechnology 13(5):664-672; methods page 665, Tables 1-2 and Figures 1-5, including the inoculum contradiction on pages 666 and 669
https://doi.org/10.5897/AJB2013.13023 (accessed 2026-10-14) -
ncbi_ferrooxidans: NCBI Taxonomy, Acidithiobacillus ferrooxidans, Taxonomy ID 920; species-level identity, not authentication of experimental strain Atf.6
https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=920&mode=Info (accessed 2026-10-14)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-14T15:41:35Z |
codex (GPT-6; codex) | CREATE | Created a distinct djurleite mineral owner and qualified natural-mixture culture-associated copper-mobilization observation, retaining chemical baseline release, missing controls, inoculum and figure inconsistencies, unresolved strain lineage and laboratory-only recovery scope. |
Record source: data/records/djurleite.yaml