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Wulfenite mineral

Wulfenite is the lead molybdate mineral species PbMoO4, distinct from elemental lead or molybdenum, the tungstate endmember stolzite and an unspecified lead-bearing ore or precipitate. The Handbook of Mineralogy identifies its tetragonal structure and documents W-bearing compositions. Gracanin and colleagues (2024) characterized natural tabular and bipyramidal crystals from Mezica, Slovenia: single-crystal diffraction assigned both examined forms to I41/a, while microscopy showed inclusions within the otherwise compositionally wulfenite host. Their environmental growth reconstruction is an inference, not a monitored precipitation experiment. The publisher correction repairs the legends of Figures 1-6; the updated figures and Tables 1-4 are used here. The separately studied Xinjiang material underwent abiotic sodium-sulfide treatment in the laboratory. This record does not establish a microbial mechanism, an isolated-metal recovery yield or industrial deployment. Criticality is unrecorded.

Microbial & Biochemical Mechanisms (1)

Abiotic sulfidization and aqueous molybdenum mobilization

other

In Cai2024, sodium-sulfide treatment of a characterized natural wulfenite preparation released molybdenum into the aqueous fraction and produced solid-state signals assigned to PbS alongside residual PbMoO4. The authors interpreted the combined leaching, diffraction, Raman, XPS and microscopy evidence as interface-coupled dissolution and precipitation with a porous PbS product layer. The reaction sequence and diffusion-controlled later stage are mechanistic interpretations; the schematic core-shell model is not a direct time-resolved measurement of reaction fronts. At the source's molar Na2S:PbMoO4 ratio of 1 and selected 30-minute endpoint, Figure 1b and Section 2.1 report Mo leaching ratios of 59.44% at 25 degrees C and 94.43% at 90 degrees C. These are solution-assay fractions of the starting Mo inventory, not isolated molybdenum product yields.

Experimental Context & Analytical Limits:
Laboratory chemical treatment, with no cells or microbial reagent production. Natural square plate-like material from Xinjiang, China was hand selected, dry ground and screened to 38-72 micrometres. Table 1 reports 54.64 wt.% Pb and 25.43 wt.% Mo, corresponding to calculated PbMoO4 purities of 96.83% and 97.32% on the respective elemental bases; Section 3.1 also reports 0.42 wt.% WO3 and 0.56 wt.% CaO. These estimates and the lack of detected impurity diffraction peaks do not prove absolute phase purity. Each assay used 0.755 g powder and 20 mL Na2S solution made with analytical Na2S.9H2O in a covered 50 mL glass bottle, a thermostated bath and magnetic stirring. The dose series in Figure 1a is at 25 degrees C; the temperature series in Figure 1b holds the molar ratio at 1. Section 3.3's washed, vacuum-dried solids were treated for 30 minutes at 25 degrees C; those characterizations are not automatically the 90-degree leach residue. Untreated material is shown in Figures 2-5. Dissolved Mo was assayed by thiocyanate spectrophotometry, with the source's Equation 1 normalizing concentration times liquid volume against sample mass and Mo content. The methods do not specify the solid-liquid separation cutoff, initial/final pH, agitation speed, replicate number or analytical uncertainty for these leaching runs. Figure S1 falls between 30 and 40 minutes; without replicate/error information, this does not establish a significant decline or a monotonic approach to equilibrium. The paper contains inconsistent statements about PbS solubility; this contradiction is retained as a limit, not used to infer a unique kinetic model. Flotation optimization and grinding-assisted leaching are proposed implications; neither a flotation campaign nor industrial deployment is demonstrated by this experiment.
Curated Evidence Points:
Support Source: cai2024
Sections 2.1-2.4 and Figures 1-5 support aqueous Mo mobilization, PbS-assigned product signals and residual wulfenite after chemical treatment. Sections 3.1-3.3 and Table 1 define the feed, conditions and assay denominator. Figure 1a's 64.15% endpoint is at a different dose from Figure 1b's 59.44% at ratio 1; they are not treated as contradictory measurements of one run.
Partial Source: cai2024
Section 2.5 and Figure 6 propose coupled dissolution-precipitation and a diffusion-limiting product shell; no direct time-resolved reaction-front series or isolated-product mass balance is shown. The same section first describes PbS as less soluble than PbMoO4 but later calls it more soluble. Figure 3's intermediate optical and Raman panels are both labelled with molar ratio 0.05. Solubility ordering, shell transport and industrial implications require additional evidence beyond the bounded observation.
Figure S1 supports a finite sampled time series with the largest plotted value at 30 minutes and a lower 40-minute value; the main text selects 30 minutes because later leaching does not increase significantly, without reported replicate uncertainty. Table S1 contains thermodynamic calculations, not observed rates or product yields. Neither artifact establishes a universal optimum, a microbial contribution or industrial performance.

Sources & References

  1. handbook_wulfenite: Handbook of Mineralogy, Wulfenite, PbMoO4; Mineral Data Publishing version 1, copyright 2001-2005. One-page identity sheet: crystal data, cell data, chemistry and occurrence. W-bearing analyses are specimen compositions, not a separate element or commodity identity.
    https://www.handbookofmineralogy.org/pdfs/wulfenite.pdf (accessed 2026-10-15)
  2. gracanin2024: Gracanin N, Podlogar M, Semsari Parapari S, Boulet P, Ruiz-Zepeda F, Sturm S and Rogan Smuc N (2024). Formation mechanisms and environmental influences on the crystal growth of wulfenite. Scientific Reports 14, 9234. DOI 10.1038/s41598-024-60043-4. Updated twelve-page primary PDF: analytical methods, Tables 1-4 and corrected Figures 1-6 inspected; I41/a characterization and inclusions are observations, whereas the three-stage growth history and environmental concentrations are inferred.
    https://doi.org/10.1038/s41598-024-60043-4 (accessed 2026-10-15)
  3. gracanin2024_correction: Gracanin and colleagues (2024). Publisher Correction: Formation mechanisms and environmental influences on the crystal growth of wulfenite. Scientific Reports 14, 10090, published 2 May 2024. DOI 10.1038/s41598-024-60770-8. Corrects inadvertently switched legends for Figures 1-6; this is a correction to the same study, not independent experimental evidence.
    https://doi.org/10.1038/s41598-024-60770-8 (accessed 2026-10-15)
  4. cai2024: Cai Z, Li J, Ning S and Liu R (2024). Mechanistic Insights into the Reaction of Wulfenite with Aqueous Sodium Sulfide Solution and Its Industrial Implications. Molecules 29(22), 5404. DOI 10.3390/molecules29225404. Complete twelve-page original: Sections 2.1-2.5, Figures 1-6, Table 1 and Sections 3.1-3.3. Mineral preparation, aqueous Mo assay, solid characterization and proposed interface-coupled dissolution-precipitation distinguished.
    https://doi.org/10.3390/molecules29225404 (accessed 2026-10-15)
  5. cai2024_supplement: Cai and colleagues (2024), supplementary material to DOI 10.3390/molecules29225404. Original two-page PDF in the publisher ZIP: Figure S1 time series and Table S1 thermodynamic values. These belong to the same experiment as cai2024, not a replication.
    https://mdpi-res.com/d_attachment/molecules/molecules-29-05404/article_deploy/molecules-29-05404-s001.zip (accessed 2026-10-15)

Curation History

Timestamp Curator Action Summary
2026-10-15T05:08:57.241476+00:00 codex (GPT-6; codex) CREATE Added primary-backed wulfenite identity and abiotic sulfidization evidence, retaining the publisher correction, source dose and solubility inconsistencies, and laboratory/product-yield limits.
2026-10-15T05:17:36.996996Z codex (GPT-6; codex) EDIT Corrected the Figure 3 intermediate-dose transcription after independent review: both panels read 0.05. Preserved the initial CREATE and native F1 plus remaining source limitations.

Record source: data/records/wulfenite.yaml