Topic
Kaňkite
About: Kaňkite is a research topic. Over the lifetime, 9 publications have been published within this topic receiving 241 citations. The topic is also known as: IMA1975-005.
Papers
TL;DR: The authors in this paper found that the mineralogy of As in weathered tailings is highly variable, with aggregates of more than one Asbearing phase common in a given sample, and major differences in As mineralogy in the tailings are mainly controlled by factors that influence the weathering history ( e.g., presence or absence of mill concentrates, degree of water saturation, and abundance of relict carbonate minerals).
Abstract: The mineral form, grain size and texture of As-bearing particles are important factors influencing the risk to human health associated with exposure to As-contaminated soils, sediments and mine wastes. Mining of arsenopyrite-bearing gold ores in Nova Scotia in the late 1800s and early 1900s has left a legacy of weathered, As-rich tailings deposits in more than 60 gold districts across the province. Fourteen samples of near-surface tailings and one of soil from several former gold mines frequented by the public were sieved to 20% As) mill concentrates exposed at the surface within the tailings deposits are dominated by a single As mineral, fine-grained scorodite (FeAsO4·2H2O) in one case, and massive unweathered arsenopyrite in the other. In the tailings (0.7 to 7% As), scorodite and amorphous hydrous ferric arsenate (HFA) are the most common As-bearing major components, occurring as discrete grains or grain coatings on gangue minerals. Other major As phases identified in the tailings include As-bearing amorphous hydrous ferric oxyhydroxides (HFO), kaňkite (FeAsO4·3.5H2O), pharmacosiderite [KFe4(AsO4)3(OH)4·6–7H2O], yukonite [Ca7Fe12(AsO4)10(OH)20·15H2O], amorphous Ca–Fe arsenates, and arsenopyrite. Minor or trace constituents include: As-bearing ferric oxyhydroxides with up to 10% As (HFO, goethite, lepidocrocite and akaganeite), As-bearing sulfates (jarosite [(K,Na,H3O)Fe3(SO4)2(OH)6], tooeleite [Fe6(AsO3)4(SO4)(OH)4·4H2O]) and realgar (As4S4). Arsenic-bearing HFO (2.5% As) and goethite (0.08% As) were identified in the single B-horizon soil sample. This study is part of a broader coordinated effort by a multi-department federal and provincial advisory committee formed to coordinate the study of ecosystem and human health risks associated with historical gold mine sites in Nova Scotia. Our study shows that (i) the mineralogy of As in weathered tailings is highly variable, with aggregates of more than one As-bearing phase common in a given sample, and (ii) major differences in As mineralogy in the tailings are mainly controlled by factors that influence the weathering history ( e.g. , presence or absence of mill concentrates, degree of water saturation, and abundance of relict carbonate minerals). The variable solubility of these primary and secondary As-bearing minerals influences both the environmental mobility and the bioaccessibility of As in near-surface tailings and soil samples.
128 citations
TL;DR: In this paper, the authors measured the thermodynamic properties of scorodite, its polymorph parascorodite and the mineral kaňkite by a combination of calorimetric techniques, thus avoiding the inherent uncertainties of solubility experiments.
70 citations
TL;DR: It is demonstrated that combined application of X-ray diffraction, electron microscope/microprobe analysis, and Raman microspectroscopy is an available and powerful approach for identification and characterization of iron arsenate minerals in complex environmental samples.
Abstract: In this paper, we demonstrate that combined application of X-ray diffraction (XRD), electron microscope/microprobe analysis (EMPA), and Raman microspectroscopy is an available and powerful approach for identification and characterization of iron arsenate minerals in complex environmental samples. Arsenic-rich material from the medieval mining dump close to the Giftkies mine in the Jachymov ore district (Czech Republic) has been studied. Scorodite, kaňkite, amorphous iron arsenate (pitticite), and, to a lesser extent, native sulfur were determined in the studied samples as products of low-temperature arsenopyrite weathering. Scorodite and kaňkite form mixed nodules and crusts, which are locally coated by hardened gel-like amorphous pitticite. Pitticite also borders fractures in the mineralized rock fragments in the dump. Native sulfur, in microscopic crystals and grainy aggregates, originates directly in places with dissolved arsenopyrite and forms pseudomorphs. The Raman spectra presented in the paper can serve as comparative data for phase identification in other contaminated areas. New Raman data for the hydroxyl stretching region of scorodite (important bands: 3514, 3427, and 3600 cm−1) and the whole Raman spectrum for pitticite (important bands: 472, 831, 884, 2935, 3091, 3213, 3400, and 3533 cm−1) are a valuable output of this paper.
38 citations
TL;DR: In this paper, the authors determined principal secondary arsenic mineral phases and their environmental stability in a waste rock pile at the Kaňk site near Kutna Hora, Slovenia, and found that the most stable minerals from viewpoint of As-binding appear to be scorodite and beudantite.
Abstract: The arsenic mineralization in historical waste rock pile at Kaňk site near Kutna Hora developed over a period of about 500 years. The objective of this study was to determine principal secondary arsenic mineral phases and their environmental stability. The only common primary As-bearing mineral – arsenopyrite - occurs in the mineral assemblage of Kutna Hora base-metal deposit together with quartz, pyrite, sphalerite, and pyrrhotite. Most of arsenic is bound in supergene minerals (scorodite, jarosite-beudantite, bukovskýite, pitticite), which are relatively stable under oxidizing conditions prevailing in the pile. The Kaňk site is a type locality for bukovskýite, kaňkite, zýkaite, and parascorodite. In long-term perspective, the most stable minerals from viewpoint of As-binding appear to be scorodite and beudantite. A higher mobility was observed for As incorporated into jarosite and poorly crystalline to amorphous phases (FeIII -oxyhydroxides, pitticite). This study has not confirmed significant mobility of arsenic within the pile and water infiltrating in recharge periods of the year (late winter-early spring) should not mobilize arsenic at a significant rate. However, monitoring of the stability of secondary As-phases and dissolved arsenic in the environment around the pile is required to avoid future migration of arsenic out of the pile.
18 citations
TL;DR: Secondary arsenic minerals (SAM) formed recently in abandoned adits of the former Au-As mine at Zloty Stok (SW Poland) constitute two assemblages.
Abstract: Secondary arsenic minerals (SAM) formed recently in abandoned adits of the former Au-As mine at Zloty Stok (SW Poland) constitute two assemblages. The first consists of two types of scorodite, pitticite, kaňkite, hornesite, picropharmacolite and minor amounts of jarosite and gypsum. Formation of the Fe arsenates took place under acidic conditions (pH ~3–4) as a result of lollingite, arsenopyrite and pyrite oxidation. Hornesite and picropharmacolite crystallized as products of interactions between acidic arsenic-rich pore solutions with Mg-Ca carbonates from rocks that surround the ore mineralisation. The interaction of carbonates with acid pore solutions caused a rapid increase in pH that reached neutral or weakly alkaline values. The chemical compositions of hornesite and picropharmacolite correspond well to their ideal compositions: (Mg 3.17 Ca 0,07 ) Σ3.24 (AsO 4 ) 1.90 × 8H 2 O and Ca 4.31 Mg 0.92 (HAsO 4 ) 1.91 [(AsO 4 )1.99(SO 4 )0.01] Σ2.00 × 11H 2 O, respectively. The second assemblage of SAM comprises exclusively the Mg-enriched erythrite [(Co 1.66 Mg 1.03 Ni 0.28 Ca 0.05 Zn 0.02 ) Σ3.03 (AsO 4 )1.99 × 8H 2 O)] – annabergite [(Ni 1.48 Mg 0.94 Co 0.66 Ca 0.12 Fe 0.01 Zn 0.01 ) Σ3.20 (AsO 4 )1.92 × 8H 2 O] series. These minerals crystallized from slightly acidic (pH ~5–6) to neutral media. Dissolution of SAM and other secondary phases (e.g., schwertmannite) causes the release of arsenate and sulphate ions into mine waters. These ions can be reduced under anaerobic conditions by different strains of bacteria. The product of this process is orpiment
8 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2018 | 1 |
| 2017 | 1 |
| 2015 | 3 |
| 2012 | 1 |
| 2009 | 2 |
| 1984 | 1 |