Cassiterite-polymetallic sulfide ore primary resource
A heterogeneous natural tin-bearing geological feed containing cassiterite and sulfide minerals, represented here by the Myanmar ore studied by Wang et al. (2025). The crushed experimental ore contained source-assigned pyrite, cassiterite, quartz, tourmaline and mica. Its mine and deposit are not specified. Crushing does not establish a processing-waste origin. This resource is distinct from cassiterite or pyrrhotite mineral species, elemental tin, a tin commodity and a produced concentrate. The study does not establish extraction from a pure mineral or properties of all ores described by this name. No criticality designation is inherited from tin.
Microbial & Biochemical Mechanisms (1)
Culture-associated sulfide alteration and iron mobilization from mixed tin ore
bioleaching
Microbial
Associated Organisms:
Leptospirillum ferriphilum (NCBITaxon:178606), Sulfobacillus thermosulfidooxidans (NCBITaxon:28034), Acidithiobacillus caldus (NCBITaxon:33059)
Growing mixed and single bacterial cultures were associated with iron mobilization, acidification and altered pyrite-bearing ore residues during laboratory pretreatment. The mixed culture showed an earlier increase in the iron-based dissolution proxy than either iron-oxidizing single culture. This supports conditional biological pretreatment of the mixed feed. It does not establish a sulfur mass balance, a specific molecular route, a sustained final advantage over both single cultures, selective tin recovery or a purified product.
Experimental Context & Analytical Limits:
The three named acid-mine-drainage isolates were held by the authors' Central South University laboratory; strain and sequence accessions are not supplied. The species IDs do not identify these isolates or independently verify their community proportions. The Myanmar ore was crushed and sieved below 1 mm and autoclaved at 115 degrees C for 30 min. Iron-free modified 9K medium contained, in g/L, (NH4)2SO4 3, Na2SO4 2.1, MgSO4.7H2O 0.5, K2HPO4 0.05, KCl 0.1 and Ca(NO3)2 0.01, at initial pH 2. The source specifies 10% pulp density, 10% v/v inoculum and a 1:1:1 mixed-culture ratio. Mid-log cells were centrifuged and washed twice with sterile water acidified to pH 2 before resuspension. The stated 2e7 cells/mL is described as the population in the inoculation, not unambiguously a final reactor concentration. Assays used 5 L flasks at 45 degrees C and 170 rpm, in triplicate, with figures extending to 20 days. Working volume is unresolved: Section 2.2 describes 150 mL medium, Section 2.4 collects 200 mL culture, and Section 2.5 describes a 100 mL sample from a stirred-tank reactor. These descriptions are not harmonized into a verified reactor scale. Figures include a control and the three single cultures; the control preparation is incompletely described. No killed-cell or pH-trajectory-matched chemical comparison is provided. ICP total iron was measured every two days. The source defines its desulfurization percentage as the measured total-iron concentration divided by the total-iron concentration obtained by aqua-regia digestion of ore. This is an iron-based proxy, not directly measured sulfur removal or isolated tin yield; the concentration and sampling basis does not establish a closed cumulative mass balance.
The three named acid-mine-drainage isolates were held by the authors' Central South University laboratory; strain and sequence accessions are not supplied. The species IDs do not identify these isolates or independently verify their community proportions. The Myanmar ore was crushed and sieved below 1 mm and autoclaved at 115 degrees C for 30 min. Iron-free modified 9K medium contained, in g/L, (NH4)2SO4 3, Na2SO4 2.1, MgSO4.7H2O 0.5, K2HPO4 0.05, KCl 0.1 and Ca(NO3)2 0.01, at initial pH 2. The source specifies 10% pulp density, 10% v/v inoculum and a 1:1:1 mixed-culture ratio. Mid-log cells were centrifuged and washed twice with sterile water acidified to pH 2 before resuspension. The stated 2e7 cells/mL is described as the population in the inoculation, not unambiguously a final reactor concentration. Assays used 5 L flasks at 45 degrees C and 170 rpm, in triplicate, with figures extending to 20 days. Working volume is unresolved: Section 2.2 describes 150 mL medium, Section 2.4 collects 200 mL culture, and Section 2.5 describes a 100 mL sample from a stirred-tank reactor. These descriptions are not harmonized into a verified reactor scale. Figures include a control and the three single cultures; the control preparation is incompletely described. No killed-cell or pH-trajectory-matched chemical comparison is provided. ICP total iron was measured every two days. The source defines its desulfurization percentage as the measured total-iron concentration divided by the total-iron concentration obtained by aqua-regia digestion of ore. This is an iron-based proxy, not directly measured sulfur removal or isolated tin yield; the concentration and sampling basis does not establish a closed cumulative mass balance.
Curated Evidence Points:
Support
Source:
wang2025
Sections 2.1-2.3 and 3.1, Figures 1-5 and Table 1 support culture-associated iron mobilization and alteration of the mixed ore. The mixed culture and the two iron-oxidizing single cultures have substantially higher iron signals than the control and the Acidithiobacillus caldus single culture. SEM and XRD show altered residues and decreased pyrite signals. The caldus-only arm has little iron mobilization and less evident residue alteration; its presence in the mixed inoculum alone does not demonstrate its independent causal contribution. Figure 2 shows an early mixed-culture advantage, subsequent convergence of the iron-oxidizing cultures and declining late iron signals.
Partial
Source:
wang2025
The abstract and conclusion report a 90% proxy value within ten days, whereas Section 3.1 describes the mixed-culture maximum iron signal at day 12. These refer to a threshold and a maximum and are not treated as identical endpoints. Section 3.1 says single cultures reached the same percentage at day 14, but the conclusion says six additional days after the ten-day mixed endpoint. Figure 1 also places the mixed cell-count peak later than the day-8 peak stated in the prose. These conflicts, changing pH, secondary precipitation and incompletely specified concentration normalization prevent adoption of an exact biological desulfurization yield or validated kinetic advantage.
Partial
Source:
wang2025
Original Figure 5 and Tables 1-2 support a changed residue composition but contain unreconciled quantitative problems. Table 1's control phase percentages sum to 115.37%; its mixed residue has 5.74% jarosite, whereas Table 2 lists only 0.005% total Fe for that residue. The source's cassiterite phase percentages and elemental Sn percentages are also inconsistent with one another on a common whole-residue basis. The prose claims single-culture jarosite exceeds 6.43%, but Table 1 lists 6.34% and 5.86%. Reported zero pyrite values lack a stated detection limit and do not prove absolute removal. Table 2's Sn change from 3.66% in the control to 4.781% in mixed-culture residue is relative composition, not recovered Sn mass or retention yield. No table is silently repaired or converted into a closed phase, iron, sulfur or tin balance.
Context_only
Source:
wang2025
Figure 6 reports community and extracted extracellular-polymer patterns, while Figure 7 is a proposed mechanism diagram. Community proportions, electron-transfer proteins, sulfur intermediates and extracellular-polysaccharide explanations do not independently establish molecular causality in this experiment. The sequencing Methods describe a V4 target but list 27F/1492R primers and provide no sequence accession. The source's abstract claims a 30-50% caldus proportion, which does not describe all Figure 6A time points. Section 4.2 and the Conclusions place flotation and practical application in future work. No downstream flotation result, isolated tin product, product-grade assay or industrial deployment is demonstrated.
Sources & References
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wang2025: Wang M, Zeng W, Yan Z, Shen L, Yu R, Wu X, Li J, Qiu G, Streit W and Liu Y (2025). The Bio-Desulfurization of Cassiterite-Polymetallic Sulfide Ores Enhanced by a Consortium of Moderately Thermophilic Bacteria. Separations 12(3):61. DOI 10.3390/separations12030061; complete 13-page publisher PDF and XML, Sections 2-5, Figures 1-7 and Tables 1-2.
https://doi.org/10.3390/separations12030061 (accessed 2026-10-12) -
ncbi_ferriphilum: NCBI Taxonomy 178606, Leptospirillum ferriphilum, species; official live taxonomy page. Species mapping does not identify the experimental isolate.
https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=178606&mode=Info (accessed 2026-10-12) -
ncbi_thermosulfidooxidans: NCBI Taxonomy 28034, Sulfobacillus thermosulfidooxidans, species; official live taxonomy page. Species mapping does not identify the experimental isolate.
https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=28034&mode=Info (accessed 2026-10-12) -
ncbi_caldus: NCBI Taxonomy 33059, Acidithiobacillus caldus, species; official live taxonomy page. Species mapping does not identify the experimental isolate.
https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=33059&mode=Info (accessed 2026-10-12)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-12T05:23:55Z |
codex (GPT-6) | CREATE | Added a distinct natural mixed tin-ore resource and narrowly scoped laboratory bioleaching pretreatment after complete primary PDF/XML and original-graphics inspection. Preserved control, normalization, composition and reactor-description limits; adopted no recovery yield. |
Record source: data/records/cassiterite-polymetallic-sulfide-ore.yaml