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the mehdi abad zinc - lead deposit , wich is located in central iran, is one of the largest zinc .....

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The oxidation of sulfide minerals in coal and mine's waste materials produce acid mine drainage. The evaporation, oxidation, dilution and neutralization of this acid drainage lead to formation of secondary minerals. Due to having broad surface spreading these minerals have the potential of maintaining sulfates and many of the metallic elements. In order to carry out mineralogical and geochemical studies on environmental minerals formed, the sampling has been done in the dumping site of the Vatani coal washing factory and coal mine of Galand-rud on 2008. On the basis of X-ray diffraction results the minerals identified are epsomite, hexahyrate, gypsum, halite, goethite, hematite, dolomite, siderite, kaolinite, montmorillonite, illite and quartz as major minerals and jarosite as a minor mineral. The geochemical analyses indicate the enrichment of MgO, SO₃ and trace elements of Cr, Pb, Co, Rb in secondary minerals relative to the mine's coal and dumped materials. On the other hand, the environmental minerals are enriched in Ni, Zn, pb, Cu, Cr, Co up to levels more than the Clarke abundance and average of China, America & world coal mines. On the basis of Gibb's diagrams the cations and anions present in mine’s drainages are originate from parent materials. According to hydrogeochemistry saturation index model in acid drainage of dumping area of Vatani coal washing factory, goethite, Iron, hydroxides, calcite, dolomite are in saturated, while iron sulfates melanterite and jarosite are under saturated.

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In this research, Cu_0.5Zn_0.5Fe₂O₄ nanoparticles were prepared by citrateprecursormethod and under air-ambient annealing at 200, 400, 600^°C. The structural features of samples were investigated by X-ray powder diffraction and FT-IR spectroscopy. The structural characterization of compounds, using X’Pert package and Fullprof program, is evidence for formation of a cubic structure (Fd-3m space group) with no presence of impurity phase that is emphasized by FT-IR data. Calculated values of crystallite size and unit cell parameter show a minimum for the sample annealed at temperature 200˚C. Band gap energies of samples have been estimated using absorption coefficient. under similar reaction conditions, the catalytic results show that the sample annealed at temperature 200˚C is the best catalyst for the CO and C₂H₆ oxidation due to smaller crystallite size.

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Newly minerals could be formed as a result of oxidation, hydrolysis, precipitation and dehydration processes in acid mine drainage (AMD) environment. The occurrence of secondary minerals within the dump No. 7 from Miduk copper mine was studied using mineralogical approaches including X-ray diffraction (XRD), Scanning Electron Microscope (SEM-EDS) and Raman Spectroscopy (RS). Geochemical invetigations, including saturation index and speciation, were conducted on pore water of the dump which simulated from paste pH test. Acidic pH value (ranges from 1.47 to 4.23), a high concentration of SO₄^2- (ranges from 3.95 to 286 g/L) and a high level of Fe (varies from 120.9 to 70860 mg/L) of the waste leached indicate that sulphide oxidation especially pyrite occurs within the dump. Complex FeSO₄⁺ was dominant species of ferric iron in the leached solution phase. According to mineralogical and geochemical studies, newly formed minerals including coquimbite, ferricopiapite, plumbojarosite, rozenite, alunogen and brochantite were identified within the dump. Retention of As, Pb and Cu by iron sulphate, especially coquimbite, were confirmed in the dump. The results of the present study could be employed to develop a comperehensive environmental management program at the mining sites.