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Geochemistry of Acid Mine Waste
Published in William J. Deutsch, Groundwater Geochemistry, 2020
Pyrite (FeS2) and other sulfide minerals form under reducing conditions where sulfide (S[II]) is the dominant redox form of sulfur. Sulfide minerals are not stable in the presence of molecular oxygen (O2); therefore they will oxidize and dissolve if exposed to earth surface conditions or groundwater with dissolved oxygen (DO). Figure 12-1 is a pH-Eh diagram of the Fe–S–H2O system that shows the stability fields of pyrite and the Fe(III) minerals ferrihydrite (Fe[OH]3) and jarosite (KFe3[SO4]2[OH]6). Under reducing conditions pyrite is stable, but as the system becomes more oxidizing ferrihydrite replaces pyrite as the stable iron mineral. Ferrihydrite is stable over a very wide range of pH and Eh conditions, which is the reason it is such a common weathering product of primary iron-bearing minerals. Under acidic, highly oxidizing conditions, with sufficient sulfate present, jarosite becomes the stable iron mineral. The fields for Fe2+ and Fe3+ on Figure 12-1 represent regions where the iron minerals are relatively soluble at dissolved concentrations greater than 10−6 mol/L.
Microbe-mineral interactions at a Portuguese geo-archaeological site
Published in Cesareo Saiz-Jimenez, The Conservation of Subterranean Cultural Heritage, 2014
A.Z. Miller, A. Dionisio, M.E. Lopes, M.J. Afonso, H.I. Chamine
FESEM images of a stalactite fragment revealed small rhombohedral or pseudocubic crystals, <5 μm (Fig. 5A), on a slimy matrix (Fig. 5B). Similar crystals were reported by Jamieson et al. (2005) accumulated in stalactites and fine-grained mud from the Richmond mine (Iron Mountain, California). They were characterised as jarosite-group minerals, which are secondary minerals formed from the oxidation of sulfide deposits and commonly associated with acid rock-drainage at acid-mine waste sites (Basciano < Peterson 2007). The oxidation of sulfide minerals is exacerbated by the presence of Fe- and S-oxidising bacteria such as Leptospirillum ferrooxidans and Acidithiobacillus thiooxidans, respectively (Ziegler et al. 2009, 2013, Jones et al. 2012). Ziegler et al. (2009) described jarosite embedded in snottites from an abandoned pyrite mine in the Harz Mountains in Germany. These snottites were found to be dominated by Leptospirillum ferrooxidans. In addition, archaea belonging to uncultured Thermoplasmatales, as well as ARMAN (Archaeal Richmond Mine Acidophilic Nanoorganism) were identified in the snottites from the German pyrite mine (Ziegler et al. 2013). Microbial cells were not evidenced in the mucolite-like stalactites from the Aveleiras mine by FESEM. However, the jarosite-like crystals seemed to be embedded in an organic matrix, probably of EPS, which points out to a biogenic origin.
Mines: Acidic Drainage Water
Published in Brian D. Fath, Sven E. Jørgensen, Megan Cole, Managing Water Resources and Hydrological Systems, 2020
Wendy B. Gagliano, Jerry M. Bigham
Goethite is a crystalline oxyhydroxide that occurs over a wide pH range, is relatively stable, and may represent a final transformation product of other mine drainage minerals.[8] Ferrihydrite is a poorly crystalline ferric oxide that forms in higher pH (>6.5) environments. Schwertmannite is commonly found in drainage waters with pH ranging from 2.8 to 4.5, and with moderate to high sulfate contents. It may be the dominant phase controlling major and minor element activities in most acid mine drainage. Jarosite group minerals form in more extreme environments with pH < 3, very high sulfate concentrations, and in the presence of appropriate cations like Na and K.
Leaching of coal fly ash with sulphuric acid for synthesis of wastewater treatment composite coagulant
Published in Canadian Metallurgical Quarterly, 2022
M. Clotilde Apua, B. Diakanua Nkazi
It is observed from the XRD patterns in Figure 13 that the characteristics of the mineral matter in the pre-leached CFA sample were revealed in the post-leached CFA. Nevertheless, throughout reaction with varying times a secondary mineral phase, jarosite (2Fe3(OH)6(SO4)2), was formed. It is established that the formation of jarosite is based on the presence of iron in sulphate environment and the tendency for iron sulphate to hydrolyse inside pH less than 3 and temperatures between 20 and 200°C [64]. Therefore, in H2SO4 medium containing CFA, jarosite precipitate can be formed according to reaction in Equation 12 [64,65]. The XRD results of the post-leached CFA are consistent with the results in Figure 11. where X is the hydronium ion.
Comparative investigation of bio-beneficiation of Kasnau-Matasukh lignite using native microorganisms
Published in International Journal of Coal Preparation and Utilization, 2022
Aniruddha Kumar, Pramod K Rajak, Asha Lata Singh, Rajesh Kumar, K N Singh, Prakash K Singh
The mineralogical phase variations due to bacterial activity was studied through XRD analysis of the treated and raw (untreated) lignite (Fig. 6). It was observed that various minerals such as quartz, pyrite, kaolinite were present in the raw lignite, which are also observed througth FTIR analsysis at the band range of 1600–400 cm−1 & 3015–3616 cm−1. Major changes were observed in the lingite samples with the formation of new peaks and reduction in the peak intensity after bacterial treatment. After treament, peaks of minerals like pyrite disappeared due to interaction between lignite and bacteria wherein an alternate phase change of jarosite appeared along with other sulfate like lonecreekite (NH4Fe(SO4)2.12H2O) and laumontite (CaAl2Si4O12.4(H2O) (Martini 1983; Singh et al. 2015b). Jarosite is believed to have been formed by dissolving ferric iron under sulfate-rich environment, especially (Baron and Palmer 1996; Welch et al. 2008). The mechanism of jarosite formation is shown in the following equation of Blowes et al. (2003) and Basciano (2008).
Prediction of compressive and flexural strengths of jarosite mixed cement concrete pavements using artificial neural networks
Published in Road Materials and Pavement Design, 2021
Extraction of zinc metal from its sulphide ore can be done by two processes: hydrometallurgy and pyrometallurgy. Jarosite is the waste generated when zinc is extracted by hydrometallurgical processes and has been categorised as hazardous. India has four zinc smelters, thus making it the 7th largest zinc producer in the world. Two zinc smelters (Debari Zinc Smelter, Udaipur and Chanderiya Zinc Smelter, Chittorgarh) are situated in the Rajasthan owing to the largest zinc mines reserve (Rampura-Agucha, Rajpura-Dariba, Zawar and Sindesar Khurd). Hydrometallurgical process is used for the extraction of zinc at Debari Zinc smelter thus releasing hazardous by-product jarosite. Debari zinc smelter, Rajasthan, India produces around 48 MTPA of zinc. Because of the huge quantity of waste, it causes a disposal problem in the landfills of smelters and also cause contamination of water, soil and air and hence, affecting the environment. In order to achieve some long-term benefit from this waste, it should be put to proper reuse/recycle for preparing the sustainable concrete (Mehra, Gupta, & Thomas, 2016; Mehra, Kumar, Thomas, & Gupta, 2018).