CMMMech
CMMMech > Secondary resource > Coal beneficiation waste

Coal beneficiation waste secondary resource

Heterogeneous discarded material generated by coal beneficiation, represented by gravity/flotation processing dumps of the Lviv-Volyn coal basin and the Chervonogradska central concentrating factory. This secondary resource is distinct from natural coal, coal combustion ash, mine-drainage treatment solids, a particular germanium mineral and elemental germanium. The studies describe native-community-associated laboratory leaching and an enlarged experimental cascade using selected dump samples; their compositions and outcomes are not universal waste properties. Constituent criticality, selective metal products and industrial deployment are not inferred.

Microbial & Biochemical Mechanisms (5)

Native-community-associated leaching of coal beneficiation dumps

bioleaching Microbial

Blayda and colleagues treated dump material containing an indigenous acidophilic sulfur-oxidizing community with acidic mineral media and different added substrates. The reported transfer of germanium and other metals into solution supports a community-associated leaching observation. Acid dissolution and reagent chemistry were not separated from biological contributions, and the study does not establish a particular organism, enzyme or microbial enhancement.

Experimental Context & Analytical Limits:
The 2012 feed came from dumps of the Lviv Coal Company central beneficiation factory, generated by gravity and flotation processing of coal from the Lviv-Volyn basin. Table 1 reports 25.8 mg/kg Ge and 12.1 mg/kg Ga in the selected waste. Leaching used 0.5 L flasks at 30.0 plus or minus 2.0 degrees C, solid:liquid ratio 1:10 and pH about 1.8 maintained by addition of 0.5 mol/L sulfuric-acid reagent; that concentration is not the final slurry acid concentration. Medium 9K without an added energy source was solution 1; solutions 2-5 added Fe(II), sodium thiosulfate, thiourea and sulfur, respectively. The paper does not specify their doses, leaching endpoint duration, working liquid volume, agitation, particle pretreatment, biological replicate count or a strain accession. The native community is not an authenticated pure culture. Solid analyses used emission spectrometry; solution Ge used extraction-photometry as a germanomolybdate complex with prior impurity separation. Other dissolved metals were measured by atomic absorption.
Curated Evidence Points:
Table 2 labels its values as percentages transferred from dump material into solution. It reports 99.9 percent Ge for the basal, Fe(II), thiourea and sulfur treatments, versus 55.0 percent for thiosulfate. Ga is reported as 99.9 percent for basal and Fe(II), 90.5 percent for thiosulfate and thiourea, and 70.6 percent for sulfur. These are reported leaching fractions, not isolated-metal yields. Ge already reaches the same reported value without an added energy source; the table does not demonstrate a Ge advantage from adding Fe(II), thiourea or sulfur.
The basal medium treatment contains the native community and is not a sterile abiotic control. No matched sterilized feed, killed biomass or acidity-matched cell-free leach is displayed. The paper provides neither a calculation formula nor a closed solution/residue mass balance for the percentages, and supplies no leaching error bars or biological replicate count. Repeated 99.9 values are not evidence of complete recovery beyond their reported precision. Introduction-level mineral proportions are not a phase analysis of each treated aliquot, and no germanium host phase or dissolved oxidation state is demonstrated.
Figures 1 and 3 concern a separate three-day wheat germination assay, not the leaching duration or a microbial control. Figure 3 plots values above 100 on an axis labelled seed germination percent and differs from Figure 1 for untreated dump material. The text does not resolve that normalization. Table 1's Mn value also differs markedly from the introductory bulk MnO description. The broad detoxification and economic claims are therefore not adopted as verified safety, field restoration or commercial feasibility.

Reagent-dependent leaching in native-community flotation waste assays

bioleaching Microbial

The separate 2016 study compared iron and sulfur-reagent treatments of coal-flotation dump material containing a mesophilic acidophilic chemolithotrophic community. Germanium appeared in the leach liquor with different time courses. Greater reported dissolved Ge in the higher-ferric treatment coincided with little or no reported liquid culture growth, whereas ferrous treatment supported much greater growth. This contrast does not establish that microbial growth caused the higher Ge release or that a direct-contact pathway operated.

Experimental Context & Analytical Limits:
The source identifies Chervonogradska central concentrating factory flotation waste from the Lviv-Volyn basin; Table 1 reports Ge 26.0 plus or minus 0.1 mg/kg. Waste was crushed to 1-3 mm. Leaching used a 9K mineral background, 0.5 L laboratory vessels and reported solid:liquid ratio 1:10. Methods specify pH at or below 2.0 and one to four weeks; displayed time courses span seven days and show pH rising above 2.0. The nominal ferrous-salt treatment is given as 44.5 g/L in Methods but 44.4 g/L in captions, with 8.96 g/L Fe(II) stated in Methods. Ferric-sulfate additions were nominally 3, 6, 9 and 15 g/L; the sulfur-reagent treatment was 5 g/L. Salt hydration and the source's parenthetical elemental-iron equivalents are not independently reconciled. The medium's calcium-nitrate dose, incubation temperature, mixing rate, inoculum preparation and biological replication are not supplied. The community is described by microscopy and dilution counts without a taxon or strain accession. Solution metals were measured by atomic absorption.
Curated Evidence Points:
Figure 2 shows approximately 1.5 mg/L Ge after seven days for nominal 15 g/L ferric sulfate, versus approximately 0.5 mg/L for the ferrous treatment. These are approximate plotted solution concentrations, not recovery percentages. The lower ferric additions produce different trajectories. Page 50 reports strong growth with ferrous iron but no observed growth in the ferric liquid phase, despite reporting nonzero cell counts. The latter is not a sterile arm or proof that cells attached to mineral surfaces.
No matched sterile ferric, ferrous, sulfur-reagent or acid-only time course isolates a microbial effect. The authors describe mechanisms as disputed and not finally established. Proposed contact, sulfur-inclusion, iron-redox and mineral-destruction explanations are not direct measurements of causality or germanium phase conversion. Ferric chemistry, acidity and matrix effects remain alternatives. No purified germanium product, sampling-corrected mass balance or industrial operation is shown.
The abstract prints Na2S2O5, Figure 1 labels Na2S2O3 and the Figure 2 caption prints Na2S3O5 while the prose calls the reagent thiosulfate. Figure 2's sulfur-labelled curve eventually exceeds the ferrous curve despite the broad low-efficiency sulfur claim. The reported 15.0 percent extraction statement on page 48 is not reconciled with the displayed concentration trajectories and Figure 1 percentage comparisons. Eh axes and prose use mV for values around 0.25-0.65, without a resolved reference or unit correction; initial pH and Eh prose also differ from the graphs. No unified extraction percentage, corrected reagent formula or calibrated redox potential is inferred from these conflicts.
Context_only Source: blayda2012
The earlier paper concerns the same regional waste family and overlapping authors, but different reported feed compositions, treatment sets and incompletely specified endpoints. Its 99.9 percent Ge results cannot be pooled with or used to calibrate the 2016 concentration graphs. Sample identities and independence of the feed batches are unresolved; these papers are not presented as independent replication of a uniform process yield.

Medium-dependent germanium leaching in native-community dump assays

bioleaching Microbial

The 2017 study measured germanium transferred into solution from coal-beneficiation dump material containing its native acidophilic chemolithotrophic community while varying nutrient and iron/sulfur reagent composition. The observed association is retained separately from the authors' proposed microbial-growth and indirect iron-redox explanations. The experiment does not isolate a microbial advantage, verify a pure strain or validate the claimed optimum recipe.

Experimental Context & Analytical Limits:
The feed was gravity/flotation waste from Chervonogradska coal preparation plant, Lviv Coal Company, derived from Lviv-Volyn coal and stored in dumps for one year. Methods describe predominantly 5-7 mm particles and 2.60 times 10^-3 percent Ge in this feed. Stationary seven-day laboratory cultivation used solid:liquid ratio 1:10, pH at or below 2.0 and 30.0 plus or minus 2.0 degrees C. A 16-condition Greco-Latin-square design varied four factors at four levels: KH2PO4 at 0, 1, 2 or 3 g/L; K2HPO4 at 0, 0.5, 1 or 1.5 g/L; (NH4)2SO4 at 0, 2, 3 or 5 g/L; and a reagent factor consisting of FeSO4.7H2O at 44.0 g/L, Fe2(SO4)3.7H2O at 15.0 g/L, Na2S2O3 at 5.0 g/L, or Fe2(SO4)3.7H2O at 30.0 g/L. Methods specify fixed KCl 1.0, MgSO4 0.5 and NH4Cl 0.9 g/L. Reagent identity and dose change together in the fourth factor. Germanium in solution was measured by atomic absorption. The extraction ratio is defined as the amount transferred into solution divided by the original amount in solid feed, expressed as a percentage. Native community densities quoted from an earlier study are not current assay counts; no taxon or strain accession, working volume, inoculum preparation, biological replicate count or measured pH trajectory is supplied for this design.
Curated Evidence Points:
Tables 1-3 map experiment 10 to A3B2C4D3: KH2PO4 2, K2HPO4 0.5, (NH4)2SO4 5 and Na2S2O3 5 g/L, with the Methods' fixed additives. Table 3 reports 93.50 percent Ge transferred into solution on both days 4 and 5, then 80.25 and 70.00 percent on days 6 and 7. Experiment 5, A2B1C2D3, instead has KH2PO4 1, no added K2HPO4, (NH4)2SO4 2 and Na2S2O3 5 g/L; its corresponding values are 82.60, 62.18, 86.87 and 76.34 percent. These are reported solution-transfer fractions on a source-defined feed denominator, not an isolated germanium-product yield or a cumulative recovery trajectory. The paper provides no closed residue/solution balance or explanation of the later decreases.
The abstract, Table 6's day-4 ranking and conclusions recommend A2B1C2D3, but the conclusion assigns 93.5 percent in four days to that recipe while Table 3's matching experiment 5 gives 82.60 percent. The displayed 93.50 value belongs to experiment 10 with different phosphate and ammonium-sulfate levels. The recommended recipe also gives KCl 0.1 and NH4Cl 0.5 g/L, unlike Methods' fixed 1.0 and 0.9 g/L. No separate confirmatory dataset resolves these differences; a reproducible optimum or improvement over the earlier studies is not established by the displayed results.
The sole Figure summarizes daily maxima and means across the 16 conditions, rather than a single optimized treatment followed against an abiotic control. Its significance caption names control (0) without identifying a matched sterile or killed-cell arm. No measured biomass time course establishes the proposed adaptation, growth or iron/sulfur-oxidation phases. Acid/reagent chemistry and matrix effects remain alternative contributions. Tables 4 and 5 also disagree on the dominant day-7 factor: Table 4 gives D the largest Fisher statistic, whereas Table 5 assigns A 73.1 percent influence and D only 4.71 percent. The variance-analysis interpretation is not treated as verified biochemical causality, and no industrial process is demonstrated.
Context_only Source: blayda2017
The paper explicitly cites the 2016 study and other work from the same research group and waste locality. Its 16-condition design, particle description and endpoints are distinct reported observations, but sample-batch independence and reuse of any earlier measurements cannot be established. The 2012 and 2016 mechanisms remain separate; their percentages, solution concentrations and community descriptions are not pooled into a shared yield, authenticated strain or independent replication.

Strain and native-community comparisons in aged coal-waste leaching

bioleaching Microbial

Associated Organisms: Acidithiobacillus ferrooxidans (NCBITaxon:920)

The 2018 paper reports metal leaching by locally identified Acidithiobacillus ferrooxidans cultures, a named type-strain culture and the native community of an aged coal-beneficiation dump. Seven-day plotted treatments exceed the displayed sterile controls. This supports a conditional culture-associated leaching difference; it does not distinguish direct microbial attack from biologically altered acidity and iron chemistry or establish a universal strain ranking.

Experimental Context & Analytical Limits:
June 2014 samples came from the surface layer, to 50 plus or minus 5 cm depth, of Lviv-Volyn gravity/flotation dumps stored for over five years. The reported feed contained Ge 30.0 plus or minus 0.1 and Ga 22.4 plus or minus 0.1 g/t. Native-community densities are cited to an earlier study. Methods specify solid:liquid 1:10, pH at or below 2.0, 30.0 plus or minus 2.0 degrees C and periodic mixing. The 9K mineral background contains (NH4)2SO4 3.0, MgSO4 0.5, KCl 0.1 and K2HPO4 0.5 g/L, with calcium nitrate named without its dose. Ferrous and ferric treatments use nominal FeSO4.7H2O 44.5 and Fe2(SO4)3.7H2O 15.0 g/L, respectively. Local labels are Lv red 9, Lv black 37, Lad 5, Lad 27 and DTV 1; the comparator is ATCC 23270. Non-native cultures were reportedly preadapted to substrate in 9K at 1:10 for 72 hours. Control K* is described as sterile substrate with medium but without cultures. Sterilization procedure, initial inoculum dose, vessel working volume, matched pH/redox trajectories and biological replicate count are not supplied. Three repeated analytical measurements and relative standard deviation 0.03-0.05 do not establish three biological runs.
Curated Evidence Points:
Figure 2 on p30 plots seven-day Ge leaching at approximately 40-85 percent across ATCC 23270, Lv black 37, Lv red 9 and the native association, while corresponding K* bars are approximately 1-5 percent. Its caption does not name the iron reagent, but adjacent p31 prose identifies the seven-day comparison as ferrous treatment. These are approximate plotted leaching percentages, not exact tabulated yields. Figure 1 separately compares five-day ferrous and ferric treatments for Ge, Ga and Al without displaying K* bars. Neither figure demonstrates isolated product recovery.
The paper gives no explicit percentage calculation or closed solution/residue balance. Sterile K* does not establish matched post-incubation acidity, ferric concentration or substrate alteration by sterilization. Figure 3 compares four-day native-community treatments with different reagents or imposed Eh 0.65 V; its reference electrode is not specified, and no sterile matched-redox series is displayed. It cannot isolate a biological contribution to the redox-treatment advantage. The four-day, five-day and seven-day endpoints must not be ranked as equal-duration outcomes.
The recommended medium repeats the 2017 A2B1C2D3 recipe and 93.5 percent four-day Ge claim without its original 16-row dataset. The 2018 p31 fixed KCl 1.0 and NH4Cl 0.9 g/L again differ from the p32 recommended 0.1 and 0.5 g/L. Its optimization subsection gives 30.0 plus or minus 0.5 degrees C, whereas general Methods give plus or minus 2.0. These differences are preserved, not harmonized into a validated recipe or independent replication.
Context_only Source: blayda2017
The existing 2017 Table 3 assigns 93.50 percent to experiment 10, not recommended experiment 5, which reports 82.60 percent on day 4. The later repetition does not resolve that discrepancy. Shared authors, waste family, factors and outcome claims leave measurement reuse and sample-batch independence unresolved despite the 2018 aged-feed description differing from the 2017 one-year storage. No percentage is pooled across the 2012, 2016, 2017 and 2018 studies.
The verified identifier names the species reported for the isolate treatments, not an authenticated Lv strain or the whole native community. No sequence or collection accession is asserted for Lv red 9, Lv black 37, Lad 5, Lad 27 or DTV 1.
The catalogue confirms the named type-strain identity but gives acid bituminous-coal mine effluent as its origin, unlike the paper's brown-coal wording. This provenance discrepancy is not resolved by assuming the experimental stock was independently authenticated.
Figure 7B of this same-year companion displays the same pattern of strain, native-community and control bars for red dump material as Figure 2 of the technological paper. This is apparent overlapping evidence, not an additional independent replication. Companion Methods supply different adaptation and temperature detail and describe physiological and PCR-based identification without a deposited sequence accession for these local isolates. Those details are not silently transferred into the technological assay. Its Table 1 calls the Lv black 37 origin red dumps, while later adaptation prose calls black dumps its native substrate. Exact stock provenance and reused raw measurements remain unresolved.

Three-stage experimental leaching of coal-beneficiation waste

bioleaching Microbial

Associated Organisms: Acidithiobacillus ferrooxidans (NCBITaxon:920)

The 2018 paper describes an enlarged experimental cascade processing coal-beneficiation waste with a native community and a preparation containing source-identified A. ferrooxidans Lv black 37 and Lv red 9. Stage liquors contain measurable Ge and several accompanying metals. This is an experimental apparatus observation, with unseparated biological and reagent contributions, rather than industrial deployment or demonstrated purification of a germanium product.

Experimental Context & Analytical Limits:
Figure 4 and pp33-34 describe three thermostated cylindrical vessels, each 8 dm diameter and 12 dm high, with 20 kg of 5-7 mm dump material per vessel. The first receives 194 L of the recommended medium and 6 L bacterial preparation, giving nominal 200 L and solid:liquid 1:10. The medium is stated as KH2PO4 1.0, (NH4)2SO4 2.0, KCl 0.1, MgSO4 0.5, NH4Cl 0.5 and Na2S2O3 5.0 g/L, retaining the fixed-additive discrepancies described separately. The preparation is reported as (223.6 plus or minus 3.79) times 10^8 CFU/cm3 and optical density 0.95 plus or minus 0.05, without wavelength or detailed counting protocol. Each stage lasts seven days at 30.0 plus or minus 2.0 degrees C. Liquor passes to successive vessels and is made up with fresh medium; later stages also receive 6 L inoculum. The order of volume adjustment relative to those later inoculum additions is unclear. After cycle 1, residues are mixed with untreated dump material for a second cycle; the mixing fraction is unspecified. Later liquor recycling is described at no more than 30 volume percent. Table 2 reports solution concentrations, not a cumulative extraction balance. Ge is measured by extraction-photometry as germanomolybdic acid after impurity separation; other solution metals use atomic absorption, with Ga separately measured by rhodamine-C colorimetry. No isotope or oxidation-state speciation is shown.
Curated Evidence Points:
Table 2 on p34 gives cycle-1 stage I, II and III Ge as 0.78 plus or minus 0.02, 1.81 plus or minus 0.03 and 3.05 plus or minus 0.05 mg/L. Cycle-2 values are 0.54 plus or minus 0.02, 0.98 plus or minus 0.02 and 1.36 plus or minus 0.03 mg/L. These exact table values are retained as solution concentrations; the second cycle's lower stage-III concentration is not erased. The Al column uses g/L while the other metal columns use mg/L. Transferred liquor, newly contacted feed, make-up solution and mixed residues prevent interpreting stage concentrations as a closed whole-feed yield or summing them as independent recoveries.
A medium-only cascade is said to reproduce laboratory results, and the inoculum addition is said to improve efficiency, but corresponding side-by-side numerical controls are not shown. The experimental feed composition is referred to nonexistent Table 6; this complete paper contains only Tables 1 and 2. The reported final liquor pH 1.7-2.4 also extends above the general pH-at-or-below-2 condition. No complete feed/solution/residue inventory, biological replication or matched sterile cascade is supplied. The claims of enhanced efficiency and safety are therefore not accepted as quantified treatment effects.
The reported liquor is proposed for subsequent ion-exchange processing, but no isolated concentrate, purity or downstream recovery measurement is presented. Figure 5 shows changed particle appearance without mineral diffraction, sterile matched photographs or a phase-specific transformation measurement. No post-treatment residual-metal table, toxicity assay or regulatory comparison establishes ecological safety or suitability for land restoration. Neither the apparatus size nor a flowsheet demonstrates an operating commercial plant. Named isolates do not establish strain-specific causality within the native-community and added-preparation mixture.

Sources & References

  1. blayda2012: Blayda, Baranov, Vasyleva, Vasyleva, Nemertsalov, Slyusarenko and Kamskaya (2012). Complex Assessment of the Waste Coal Beneficiation in Terms of Their Phytotoxicity, the Possibility of Recycling and Detoxification. Energotekhnologii i Resursosberezhenie 2:37-43. Complete original Russian article, Methods p39, Tables 1-2 and Figures 1-3. University repository item and original seven-page PDF; no DOI asserted.
    https://dspace.onu.edu.ua/items/1db891e3-f8fc-4e42-862f-520085833a0f (accessed 2026-10-12)
  2. vasyleva2016: Vasylieva, Blayda, Sliusarenko, Vasylieva and Chitrich (2016). Bacterial Leaching of the Metals from Waste Flotation of Coals with the Participation of Thiosulfate, Ferrous and Ferric Iron. Microbiology and Biotechnology 3(35):43-56, published 22 September 2016. DOI 10.18524/2307-4663.2016.3(35).77956; complete original article, Methods pp44-45, Table 1, Figures 1-4 and discussion pp50-52.
    https://doi.org/10.18524/2307-4663.2016.3(35).77956 (accessed 2026-10-12)
  3. blayda2017: Blayda, N. Yu. Vasylieva, T. V. Vasylieva and Sliusarenko (2017). Variance Analysis for Optimization of the Germanium Bioleaching Process from Coal Beneficiation Dumps. Biotechnologia Acta 10(4):44-52. DOI 10.15407/biotech10.04.044; complete official nine-page article, Methods pp45-46, Tables 1-7, sole Figure p48 and conclusions p51.
    https://doi.org/10.15407/biotech10.04.044 (accessed 2026-10-12)
  4. blayda2018: Blayda, Vasyleva, Slyusarenko, Barba and Vodzinskii (2018). Technological Parameters of Coal Mine Dumps Bioleaching for the Rare Metals Extraction. Kompleksnoe Ispolzovanie Mineralnogo Syra 307(4):28-37. DOI 10.31643/2018/6445.27; complete official ten-page original, Methods p29, Figures 1-5 and Tables 1-2; accepted 1 October 2018.
    https://doi.org/10.31643/2018/6445.27 (accessed 2026-10-12)
  5. ncbi_ferrooxidans_2026: NCBI Taxonomy species 920, Acidithiobacillus ferrooxidans, checked 12 October 2026. Species-name mapping only; does not authenticate the experimental local isolates or identify the native consortium.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=920 (accessed 2026-10-12)
  6. atcc_23270_2026: ATCC product 23270, Acidithiobacillus ferrooxidans type strain, NCIB 8455/DSM 14882, checked 12 October 2026. Catalogue gives acid bituminous-coal mine effluent as the isolation source; it does not authenticate a stock used in the 2018 experiment.
    https://www.atcc.org/products/23270 (accessed 2026-10-12)
  7. blayda2018_isolates: Blayda, T. Vasylieva, Sliusarenko, N. Vasylieva, Baranov and Shuliakova (2018). Isolation and Study of the Main Properties of Acidophilic Chemolithotrophic Bacteria Isolated from the Waste Dumps of Fuel-Energy Complex in Ukraine. Studia Biologica 12(3-4):3-16. DOI 10.30970/sbi.1203.570; original Methods pp4-6, Table 1 and Figure 7B p14 inspected for strain provenance and experiment overlap.
    https://doi.org/10.30970/sbi.1203.570 (accessed 2026-10-12)

Curation History

Timestamp Curator Action Summary
2026-10-12T02:37:05Z Codex (GPT-6) CREATE Created the secondary-resource owner from complete primary coal-beneficiation dump studies. Kept native-community association separate from proven microbial advantage, retained conflicting reagent/measurement descriptions and distinct experiments, and did not infer purified products or criticality.
2026-10-12T02:45:46Z Codex (GPT-6; codex) EDIT Corrected the wheat-assay figure locator to Figures 1 and 3 and the cited author spelling to Kamskaya after independent findings F1 and F2 in issue 143. Leaching measurements and mechanism scope are unchanged.
2026-10-12T03:19:10Z Codex (GPT-6; codex) EDIT Added the 2017 medium-composition experiment as a distinct qualified native-community observation, retaining exact assay denominators, recipe/table conflicts and control limits. Preserved the earlier source and mechanism fields, correction events and canonical history.
2026-10-12T03:56:15Z codex (GPT-6; codex) EDIT Added qualified 2018 strain/control and three-stage experimental leaching evidence, verified species authority, retained apparent companion-study overlap and recipe/mass-balance/scale limitations, and expanded the description for the experimental cascade.

Record source: data/records/coal-beneficiation-waste.yaml