Simonkolleite mineral
Simonkolleite is the zinc hydroxide chloride hydrate mineral, ideal Zn5(OH)8Cl2.H2O, accepted by IMA as 1983-019. It is distinct from zinc metal, zincite, hydrozincite and the reagent betaine hydrochloride. The curated primary study concerns a synthetic analogue made from purchased zinc grains and its thermal conversion, not a microbial experiment or a demonstrated scrap-metal recycling operation. No criticality designation is inherited from its zinc constituent.
Microbial & Biochemical Mechanisms (2)
Abiotic simonkolleite precipitation from zinc metal in aqueous betaine hydrochloride
other
Laboratory reaction of metallic zinc with aqueous betaine hydrochloride produced a recoverable white powder with a diffraction pattern assigned to simonkolleite and hexagonal flakes observed by SEM. Concentration, duration and temperature were associated with different particle morphologies. Precursor complexation, Ostwald ripening and oriented attachment are proposed explanations of these observations, not independently established molecular pathways. This chemical synthesis does not establish microbial involvement, zinc recovery efficiency or commercial production.
Experimental Context & Analytical Limits:
Qu2023 Methods and Table 1 describe purchased 99.8% zinc grains, 20-35 mesh, used as supplied. The lower-temperature experiment used nominal 10 or 40 mass% aqueous betaine hydrochloride, 3 g zinc and 200 rpm at 40 degrees C. Methods give 15 mL solution whereas Table 1 labels the amount 15 g; no unreported density conversion is assumed. The listed time series is 1, 3, 5, 7 and 15 days, but the diffraction exemplar is explicitly a ten-day 10% product, and the first recovered 40% product is labelled day 2. A separate 160 degrees C, 24-hour autoclave arm used 40% solution and 2 g zinc, with 10 mL in Methods versus 10 g in Table 1. Unreacted grains were left in the reactor while the suspended product was settled overnight, decanted, washed with deionized water using 1000 rpm centrifugation for three minutes, finally washed with methanol and dried in a fume hood. No matched zinc-free, betaine-free or pH-matched control series, independent synthesis-replicate count or complete zinc balance is reported. The study's n=200 refers to measured crystal side lengths, not 200 independent reaction replicates.
Qu2023 Methods and Table 1 describe purchased 99.8% zinc grains, 20-35 mesh, used as supplied. The lower-temperature experiment used nominal 10 or 40 mass% aqueous betaine hydrochloride, 3 g zinc and 200 rpm at 40 degrees C. Methods give 15 mL solution whereas Table 1 labels the amount 15 g; no unreported density conversion is assumed. The listed time series is 1, 3, 5, 7 and 15 days, but the diffraction exemplar is explicitly a ten-day 10% product, and the first recovered 40% product is labelled day 2. A separate 160 degrees C, 24-hour autoclave arm used 40% solution and 2 g zinc, with 10 mL in Methods versus 10 g in Table 1. Unreacted grains were left in the reactor while the suspended product was settled overnight, decanted, washed with deionized water using 1000 rpm centrifugation for three minutes, finally washed with methanol and dried in a fume hood. No matched zinc-free, betaine-free or pH-matched control series, independent synthesis-replicate count or complete zinc balance is reported. The study's n=200 refers to measured crystal side lengths, not 200 independent reaction replicates.
Curated Evidence Points:
Support
Source:
qu2023
Product characterisation, Figure 4 and Figure 5 (repository PDF pages 5-6) show the recovered ten-day 10% product's powder diffraction compared with the simonkolleite reference labelled COD 9004683, together with hexagonal flakes and their side-length distribution. These establish a simonkolleite-assigned crystalline product, without a quantitative phase fraction, impurity detection limit or isolated zinc recovery yield.
Support
Source:
qu2023
The Reaction time section and Figures 8-10 (PDF pages 8-11) retain a useful negative result: no recoverable precipitate was reported for the 40% solution after one day; Figure 9 starts with a two-day sample. The authors observed narrower distributions and less aggregation for 40% than 10% at early times, but aggregation appeared in both by day 15. Figure 12 (PDF page 12) shows more varied morphologies at 160 degrees C. These are within-study morphology observations, not evidence that every particle or every arm was independently phase quantified.
Partial
Source:
qu2023
Methods/Table 1 (PDF page 4) and the labelled Figures 4, 8-10 and 14 do not provide a single consistent run inventory: days 2 and 10 appear in results despite their omission from the listed series. The Methods heading says room temperature but both its actual temperature and Table 1 say 40 degrees C. The Introduction describes recycled scrap zinc, whereas Methods specify purchased reagent grains; the Conclusion also says zinc oxide oxidation despite the metallic feed in Methods. The record retains the explicitly documented reagent experiment rather than assigning waste provenance or silently repairing these source inconsistencies.
Partial
Source:
qu2023
Figures 6-11 and the accompanying discussion (PDF pages 6-11) infer precursor supersaturation, Zn-betaine complexes, capping and competing growth pathways from morphology. No direct precursor concentration time series or intervention isolating these pathways is reported. Figure 16 (PDF page 14) shows substantial washing-dependent thermal mass losses, with an organic-complex impurity proposed by the authors. The qualitative high-purity claim and absence of obvious extra diffraction peaks do not establish absolute chemical purity or a closed process mass balance.
Context_only
Source:
ima_2026_09
The exact Simonkolleite row and the introductory definitions identify an approved mineral with ideal Zn5(OH)8Cl2.H2O and IMA number 1983-019. They establish mineral identity, not the experimental sample's purity, microbial formation or a criticality classification.
Context_only
Source:
handbook_simonkolleite
The complete identity entry describes natural simonkolleite associated with weathering of zinc-bearing slag at Richelsdorf, Germany. That mineral occurrence does not turn the purchased zinc-grain experiment into a secondary-resource recovery trial.
Thermal transformation of synthetic simonkolleite to zinc oxide
other
Heating the study's synthetic simonkolleite produced zinc oxide through intermediate chloride-bearing solids. Staged diffraction supports transformation of the crystalline phases, and SEM shows retention of a broadly hexagonal external shape with cracks. It does not establish quantitative zinc retention, pure product recovery or a demonstrated gas-evolution mechanism.
Experimental Context & Analytical Limits:
The Characterisation Methods (repository PDF page 5) specify approximately 15 mg samples under nitrogen at 20 mL/min, heating from 30 to 800 degrees C at 1 degree C/min, holding for 30 minutes and cooling at 5 degrees C/min. The calcination Results and Figure 13 instead describe an endpoint of 900 degrees C; Figure 14a also extends to 900 degrees C. These incompatible maximum-temperature descriptions remain unresolved. Figure 14's staged diffraction series labels unheated 25 degrees C and products at 100, 250, 400 and 600 degrees C from a ten-day 10% synthesis, whereas the Figure 13 SEM example is explicitly from a 15-day 10% synthesis. Those panels are not treated as measurements on one demonstrably identical aliquot. The staged runs' individual heating/hold details are not separately specified.
The Characterisation Methods (repository PDF page 5) specify approximately 15 mg samples under nitrogen at 20 mL/min, heating from 30 to 800 degrees C at 1 degree C/min, holding for 30 minutes and cooling at 5 degrees C/min. The calcination Results and Figure 13 instead describe an endpoint of 900 degrees C; Figure 14a also extends to 900 degrees C. These incompatible maximum-temperature descriptions remain unresolved. Figure 14's staged diffraction series labels unheated 25 degrees C and products at 100, 250, 400 and 600 degrees C from a ten-day 10% synthesis, whereas the Figure 13 SEM example is explicitly from a 15-day 10% synthesis. Those panels are not treated as measurements on one demonstrably identical aliquot. The staged runs' individual heating/hold details are not separately specified.
Curated Evidence Points:
Support
Source:
qu2023
Simonkolleite calcination, Figures 13-14 (PDF pages 11-13) distinguish the external morphology from the phase evidence. Figure 14b shows little change between unheated and 100-degree patterns, ZnO plus beta-Zn(OH)Cl assigned at 250 and 400 degrees C, and only ZnO-assigned diffraction peaks at 600 degrees C. The absence of visible simonkolleite peaks is not a quantified complete-conversion measurement. Figure 13 shows fractured but broadly hexagonal calcined flakes in a separately labelled synthesis example.
Partial
Source:
qu2023
The Decomposition process discussion and Figures 14-16 (PDF pages 12-14) compare thermal mass losses with proposed water, hydrogen chloride and zinc chloride loss pathways. The approximately 67% remaining mass cited in the text is a thermal residue fraction of the starting solid, not a percentage recovery of feed zinc. Competing gas-loss pathways were proposed without direct evolved-gas analysis here; washing altered the mass-loss curves. The 800-versus-900-degree endpoint discrepancy and the separate ten-day/15-day panel provenance preclude a unified, precisely reproduced thermal protocol or an overall metal-yield claim.
Sources & References
-
ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026: definitions on PDF page 1 and Simonkolleite row on PDF page 200. Previously acquired original re-inspected on the access date; approved status A, number 1983-019.
https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-15) -
handbook_simonkolleite: Handbook of Mineralogy, Simonkolleite, page 511: complete one-page formula, powder-diffraction and natural-occurrence description.
https://handbookofmineralogy.org/pdfs/simonkolleite.pdf (accessed 2026-10-15) -
qu2023: Qu, Hadjittofis, Malaret, Hallett, Smith and Sedransk Campbell (2023). Controlling simonkolleite crystallisation via metallic Zn oxidation in a betaine hydrochloride solution. Nanoscale Advances 5:2437-2452. Complete published-version article from White Rose, PDF pages 2-17 after repository cover, plus official JATS and Figures 1-16; Table 1.
https://doi.org/10.1039/d3na00108c (accessed 2026-10-15)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-15T03:51:25.419453Z |
codex (GPT-6; codex) | CREATE | Added the simonkolleite mineral identity and qualified abiotic zinc-grain precipitation and thermal transformation, preserving source protocol conflicts, no microbial attribution, and unquantified purity and recovery. |
Record source: data/records/simonkolleite.yaml