Pyrite-roasting cinder secondary resource
Solid residue generated by roasting or calcining pyrite-bearing feed, also described as pyrite ash. The curated experiments concern calcined waste supplied by the Eti Mining Bandırma Borax Plant, Turkey, and a separately characterized, weathered pyrite-ash sample from São Domingos, Portugal. This processing residue is distinct from natural pyrite, unroasted mine tailings, smelting slag and spent sulfuric-acid-production catalyst. Its composition varies with feed, processing and weathering; neither study establishes a uniform mineral formula or commercial product specification. No criticality-list designation is inferred from constituent elements.
Microbial & Biochemical Mechanisms (2)
Sulfur solubilization in yeast and acetic-acid-bacterium incubations
bioleaching
Microbial
Associated Organisms:
Saccharomyces cerevisiae (NCBITaxon:4932), Acetobacter aceti (NCBITaxon:435)
Sulfate was detected after incubating pyrite ash with source-identified S. cerevisiae alone or with A. aceti and organic substrates. These laboratory observations provide partial evidence for a culture-associated desulfurization treatment. The study does not separate biological action from acid-driven dissolution, demonstrate an iron-oxidizing phenotype, or establish a purified iron product or recovery of constituent metals.
Experimental Context & Analytical Limits:
The Bandırma calcined ash was reported to contain 61.08% iron and 0.59% total sulfur. Five-percent pulp suspensions, without a stated mass/volume basis, were incubated for eight weeks at 25, 30 and 35 degrees C. The five treatments combined ash with glucose and yeast; glucose and both organisms; glucose, ethanol and both organisms; ethanol, acetic acid and both organisms; or all three organic additions and both organisms. The isolates came from commercial baker's yeast and vinegar, with no sequence, deposit or strain-specific identification supplied. Species CURIEs resolve the reported names only. Methods call the medium sulfur-free but do not give its complete recipe, substrate concentrations, inoculum quantity, working volume, ash pretreatment, sterilization, shaking rate, replication or uncertainty. No matched uninoculated or killed-cell treatment is reported. Glucose, ethanol and added acetic acid are experimental inputs, not measured microbial metabolite yields. No industrial microbial operation was demonstrated.
The Bandırma calcined ash was reported to contain 61.08% iron and 0.59% total sulfur. Five-percent pulp suspensions, without a stated mass/volume basis, were incubated for eight weeks at 25, 30 and 35 degrees C. The five treatments combined ash with glucose and yeast; glucose and both organisms; glucose, ethanol and both organisms; ethanol, acetic acid and both organisms; or all three organic additions and both organisms. The isolates came from commercial baker's yeast and vinegar, with no sequence, deposit or strain-specific identification supplied. Species CURIEs resolve the reported names only. Methods call the medium sulfur-free but do not give its complete recipe, substrate concentrations, inoculum quantity, working volume, ash pretreatment, sterilization, shaking rate, replication or uncertainty. No matched uninoculated or killed-cell treatment is reported. Glucose, ethanol and added acetic acid are experimental inputs, not measured microbial metabolite yields. No industrial microbial operation was demonstrated.
Curated Evidence Points:
Partial
Source:
ermurat2013
Methods page 2 and Results pages 4–5 describe weekly pH/redox measurements and spectrophotometric sulfate measurement after eight weeks. Figure 1 is a light micrograph of the mixed culture with ash; attachment does not establish the sulfur reaction's cause. Page 5 reports a highest dissolved-sulfur/total-sulfur ratio of 0.5 for the treatment containing glucose, ethanol, acetic acid and both organisms. Figure 5 displays separate 25 and 35 degrees C series as stacked segments: their combined column height is not one treatment's sulfur-removal fraction. It provides no 30-degree series or error bars. Without an abiotic comparator, the reported ratio cannot establish the biological contribution or synergism.
Partial
Source:
ermurat2013
Equations 1–10, Table 1 and Figures 2–4 derive ferric/ferrous ratios and quantities termed specific growth or iron-utilization rates from pH and redox observations. They are model predictions, not independent iron-speciation measurements or measured cell-growth rates. The source reports only modest pH/redox changes and discusses limited oxygen as a possible explanation. These results do not establish enzymatic iron oxidation by either source-reported isolate. No sulfur balance including biomass or gas, residual-solid sulfur assay, product purity, yield or ironmaking test is supplied.
Acidophilic consortium assay with no established leaching advantage
bioleaching
Microbial
Associated Organisms:
Sulfobacillus thermosulfidooxidans (NCBITaxon:28034), Leptospirillum ferriphilum (NCBITaxon:178606), Acidithiobacillus caldus (NCBITaxon:33059)
The São Domingos ash was tested with the SLA acidophilic consortium under conditions transferred from an optimization model for a different, crushed-pyrite feed. The author concluded that this transfer failed and did not establish useful microbial enhancement of ash leaching. The result is specific to this feed and nine-day assay; it does not establish that all pyrite-roasting residues resist biological treatment.
Experimental Context & Analytical Limits:
SD-BIO-2 was collected from native-sulfur and black layers and supplied and characterized by LNEG. The source identifies it as roasted pyrite ash below 250 micrometers, with original roasting equipment and temperature unknown. It is distinct from the study's SD-BIO-1 slag and SD-BIO-3 partly leached crushed pyrite. Tables 4.8–4.9 report a heterogeneous, sulfate-rich ash including gypsum, anglesite, beudantite and quartz, with uncertain minor assignments; portable-XRF composition is sample-specific. The SLA culture came from the Freiberg working group's collection and is reported as S. thermosulfidooxidans DSM 9293T, L. ferriphilum DSM 14647 and A. caldus DSM 8584. Catalogue-name correspondence does not independently authenticate the experimental stocks or establish an individual species' contribution. Adaptation used 3% wt/vol feed, 1% wt/vol elemental sulfur and 20 mM ferrous iron for seven days at 42 degrees C and 120 rpm. The ash assay used the 100 mL batch setup, 10% vol/vol inoculum, 2% wt/vol ash, 1% wt/vol sulfur, nominal initial pH 1.66, 54 mM added ferrous iron and 42 degrees C for nine days. Shaking speed is explicit for adaptation but not separately restated for this assay. HBS medium and trace salts contained several measured metals; their blank subtraction is not documented. The comparison is called abiotic, but feed sterilization and ash-control sterility verification are not established. Cells in controls of the separate crushed-pyrite and slag experiments are explicitly reported; that observation is not assigned to the ash arm.
SD-BIO-2 was collected from native-sulfur and black layers and supplied and characterized by LNEG. The source identifies it as roasted pyrite ash below 250 micrometers, with original roasting equipment and temperature unknown. It is distinct from the study's SD-BIO-1 slag and SD-BIO-3 partly leached crushed pyrite. Tables 4.8–4.9 report a heterogeneous, sulfate-rich ash including gypsum, anglesite, beudantite and quartz, with uncertain minor assignments; portable-XRF composition is sample-specific. The SLA culture came from the Freiberg working group's collection and is reported as S. thermosulfidooxidans DSM 9293T, L. ferriphilum DSM 14647 and A. caldus DSM 8584. Catalogue-name correspondence does not independently authenticate the experimental stocks or establish an individual species' contribution. Adaptation used 3% wt/vol feed, 1% wt/vol elemental sulfur and 20 mM ferrous iron for seven days at 42 degrees C and 120 rpm. The ash assay used the 100 mL batch setup, 10% vol/vol inoculum, 2% wt/vol ash, 1% wt/vol sulfur, nominal initial pH 1.66, 54 mM added ferrous iron and 42 degrees C for nine days. Shaking speed is explicit for adaptation but not separately restated for this assay. HBS medium and trace salts contained several measured metals; their blank subtraction is not documented. The comparison is called abiotic, but feed sterilization and ash-control sterility verification are not established. Cells in controls of the separate crushed-pyrite and slag experiments are explicitly reported; that observation is not assigned to the ash arm.
Curated Evidence Points:
Partial
Source:
pereira2025
Sections 4.2–4.4 and 5.1.4.1.2, printed pages 15–22 and 33–34, with Figures 5.12–5.14: after nine days there was no visible color distinction, pH/redox trajectories largely overlapped the control, and the author reported very low overall metal leaching without a demonstrated biological advantage. This is a negative result for transferring the crushed-pyrite model, not validation of an ash-specific optimum. Solution measurements do not establish isolated-metal recovery. The separate slag's favorable recoveries and the crushed-pyrite model predictions are not ash outcomes.
Partial
Source:
pereira2025
Printed page 34 says Mn and Sb leaching was no higher than the chemical control, yet Figure 5.14 shows the day-nine inoculated Sb bar visibly above the control and a smaller difference for Mn. No error bars or ash-specific significance analysis reconcile this discrepancy; the record retains the author's limited conclusion without asserting exact equality or a statistically proven null. Figure 5.13B also shows a large day-two ferrous-iron excursion, whereas the nominal addition was 54 mM. Equation 5 reverses the concentration/absorbance variable description relative to the calibration axes in Figure 4.4. Equation 7's leach-liquor mg/g basis and solid-composition denominator are incompletely specified; its Table 4.11 reference and the ash section's Table 4.10 reference do not match the actual composition Table 4.9. No exact ash recovery percentage or independently validated mass balance is adopted.
Sources & References
-
ermurat2013: Ermurat Y (2013). Modeling the kinetics of pyrite ash biodesulfurization by Saccharomyces cerevisiae and Acetobacter aceti in liquid state bioreactors. Electronic Journal of Biotechnology 16(2). DOI 10.2225/vol16-issue2-fulltext-1. Complete 12-page SciELO original, especially Methods page 2, Table 1 and Figures 1–5. PDF publication date is 15 March 2013; Crossref gives 7 March 2013.
https://doi.org/10.2225/vol16-issue2-fulltext-1 (accessed 2026-10-12) -
pereira2025: Pereira da Luz MV (2025 deposit). Statistical optimization of parameters for bioleaching of mine wastes from São Domingos Mine, Portugal. SINReM master's thesis, Microbiology and Biohydrometallurgy Working Group, TU Bergakademie Freiberg; public author-deposited Scriptiebank copy, complete 101-page PDF including appendices. The pyrite-ash arm is SD-BIO-2, with Tables 4.3–4.9 and Figures 5.12–5.14; this is a thesis experiment, not an independently peer-reviewed journal article.
https://scriptiebank.be/file/21588/download?token=QIzLpVs8 (accessed 2026-10-12) -
thesis_deposit: Scriptiebank author and 2025 deposit record for Pereira da Luz's SINReM master's thesis. Establishes the public PDF's provenance and deposit year; its popular summary is not an additional experiment.
https://scriptiebank.be/scriptie/2025/statistical-optimization-parameters-bioleaching-mine-wastes-sao-domingos-mine (accessed 2026-10-12) -
ncbi_yeast: NCBI Taxonomy 4932, Saccharomyces cerevisiae, species; not authentication of the baker's-yeast isolate.
https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=4932&mode=Info (accessed 2026-10-12) -
ncbi_aceti: NCBI Taxonomy 435, Acetobacter aceti, species; not authentication of the vinegar isolate.
https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=435&mode=Info (accessed 2026-10-12) -
ncbi_sulfobacillus: NCBI Taxonomy 28034, Sulfobacillus thermosulfidooxidans, species; DSM 9293 is listed as a type-strain designation.
https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=28034&mode=Info (accessed 2026-10-12) -
ncbi_leptospirillum: NCBI Taxonomy 178606, Leptospirillum ferriphilum, species; DSM 14647 is listed as a type-strain designation.
https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=178606&mode=Info (accessed 2026-10-12) -
ncbi_caldus: NCBI Taxonomy 33059, Acidithiobacillus caldus, species; DSM 8584 is listed as a type-strain designation.
https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=33059&mode=Info (accessed 2026-10-12)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-12T14:02:33Z |
codex (GPT-6; codex) | CREATE | Created the processing-residue owner from complete primary originals, with qualified culture-associated sulfur solubilization and a separate limited-response ash assay; retained source contradictions, taxon scope and missing controls without importing abstract-only recovery claims. |
Record source: data/records/pyrite-roasting-cinder.yaml