ZnS deposition

The influence of Zn-deposition on Cu(lll) surfaces on methanol synthesis by hydrogenation of CO2 shows that Zn creates sites stabilizing the formate intermediate and thus promotes the hydrogenation process [2.44]. Further publications deal with methane oxidation by various layered rock-salt-type oxides [2.45], poisoning of vana-dia in VOx/Ti02 by K2O, leading to lower reduction capability of the vanadia, because of the formation of [2.46], and interaction of SO2 with Cu, CU2O, and CuO to show the temperature-dependence of SO2 absorption or sulfide formation [2.47]. 

Innocent M, Pezzatini G, Fomi F, Foresti ML (2001) CdS and ZnS deposition on Ag(l 11) by electrochemical atomic layer epitaxy. J Electrochem Soc 148 C357-C362... 

Figure 14.8 (a) A voltage oscillation obtained for Zn electrodeposition from an ultra-thin electrolyte, (b) SEM images of the Zn deposit obtained under the voltage oscillation. (Reprinted from Ref [27] with permission from John Wiley, Sons Ltd.)... 

Epithermal base-metal vein-type deposits are distributed in the Green tuff region (Southwest Hokkaido, Northeast Honshu) (Fig. 1.62). The distribution area of this type of deposits is nearly same as that of Kuroko deposits. For example, large deposits (Osarizawa Cu-(Au) Ani Cu-Au Hosokura Pb-Zn deposits) occur in Northeast Honshu, but are more widely distributed in the Green tuff region than Kuroko deposits. 

Orebody zoning (Park and Macdiarmid, 1963) is observed in Cu-Pb-Zn deposits. For example, in Osarizawa deposit, which is one of the largest Cu-Pb-Zn deposits in Japan, ore metal zoning from deeper to shallower parts is Cu —> ZnPb —> AuAg. 

Quartz is the most abundant gangue mineral. It occurs commonly in Au-Ag and Pb-Zn deposits but is scarce in Cu deposits. Chalcedonic quartz coexisting with Au-Ag minerals occurs abundantly in Au-Ag deposits. Amethyst is generally rare and occurs as a late-stage mineral in Au-Ag and Pb-Zn deposits. 

The occurrence of other Mn-Ca silicates such as johannsenite, bustamite, rhodonite, pyroxmangite, tephroite, and penwithite has been reported from Au-Ag and Pb-Zn deposits, but these minerals are not common. They have not been reported from Cu deposits. 

Chlorite is abundant in Cu-Pb-Zn-rich deposits but is scarce in Au-Ag-rich deposits. Fe chlorite is the most common and Fe-Mg chlorite is subordinate (Shirozu, 1969). Almost all of the chlorite is classified as orthochlorite which can be regarded as part of the clinochlore-daphnite solid solution series. In general, chlorite is intimately associated with sulfide minerals such as sphalerite, galena, pyrite, chalcopyrite, and pyrrhotite. A 7 A septechlorite was reported from the Toyoha Pb-Zn deposits (Sawai, 1980). Interstratified chlorite-smectite and vermiculite-saponite are rather common minerals in Au-Ag deposits (e.g., Yoneda and Watanabe, 1981), but they have not yet been reported from other deposits. 

As mentioned already, small amounts of electrum occur in epithermal base-metal vein-type deposits. Electrum is not observed in the epithermal base-metal vein-type deposits in which pyrrhotite occurs (e.g., Toyoha-Soya, Oizumi, and Hosokukura Pb-Zn deposits). However, electrum is found in epithermal base-metal vein-type deposits in which hematite is commonly observed (e.g., Osarizawa and Ani Cu-Pb-Zn deposits). This indicates that electrum precipitates in relatively high /s2 and /oj condition. 

S values of epithermal base metal deposits are higher than those of the epithermal Au-Ag deposits and range mostly from - -3%c to -f-7%o (Fig. 1.111). Although most of 8 " S values for base-metal deposits lie in this range, 8- " S of composite sample of sulfides from the Motokura Cu-Pb-Zn deposits, Ohmori Cu-Ag deposits, Hosokura Pb-Zn deposits, Sasayama Cu-Pb-Zn deposits and Imai-lshizaki Cu-Pb-Zn deposits are low, that is, -1-0.1, -1-1.8, -1-2.2, —0.9 and —2.1%o, respectively (Shikazono, 1987b Shikazono and Shimizu, 1993). 

Shikazono, N. (1974b) Physico-chemical properties of ore-forming solutions responsible for the formation of Toyoha Pb-Zn deposits, Hokkaido, Japan. Geochem, J., 8, 37-46. 

Resch, R. Prohaska, T. Friedbacher, G. Grasserbauer, M. Kanniainen, T. Lindroos, S. Leskela, M. Niinisto, L. Broekaert, J. A. C. 1998. In-situ investigation of ZnS deposition on mica by successive ionic layer adsorption and reaction method as studied with atomic force microscopy. Fresenius J. Anal. Chem. 353 772-777. 

Fig. 4. Histogram of 634S values for sphalerite grains from NW Alberta till samples, the Pine Point Pb-Zn deposit and other Pb-Zn deposits in the Rocky and Mackenzie mountains (Paradis et al. 2006).

In this case study, 11 different extraction methods (Table 1) were applied to a 1000 m line of 15 B/C-horizon soil samples (<0.25 mm) across the Talbot VMS Cu-Zn deposit in northern Manitoba, Canada (Fig. 1), followed by ICP-MS analysis. Student s t test and minimum t probability statistics provide a tool to rank the exploration performance of each method (Stanley 2003 Stanley Noble 2008). By... 

To track the sources of the geochemical anomalies of heavy metals in suspended matters along the Shun an River basin (one of the main tributary basins of the Anhui section of the Yangtze River basin), a rock survey was conducted on typical ore deposits and outcrops of main strata and geological bodies along the Shun an River basin. The results shown in Table 3 indicate the largest source of Cd in suspended matters on the Shun an River basin is endogenetic deposits, especially Pb-Zn deposits. 

The results of source tracking show that the endogenic deposits, especially Pb-Zn deposits, have been the largest supplier of Cd. 

Figure 11 is a series of voltammograms for the deposition of Zn on atomic layers of Te, Se, and S. A definite trend in the Zn UPD peak potentials is evident, going up the periodic table. Zn is hardest to deposit on the Te atomic layer, where deposition is not initiated until -0.7 V. A well-defined Zn UPD peak is evident on the Se layer, initiated near -0.5 V, while Zn deposition on the S atomic layer begins near -0.3 V. These numbers are consistent with differences in the free energies of formation of the three compounds -115.2, -173.6, and -200.0 kJ/mole for ZnTe, ZnSe, and ZnS respectively [310]. For a two-electron process, these differences in the stabilities of the compounds correspond to 0.30 V and 0.14 V, respectively, in line with the shifts observed in Fig. 11. 

Figure 16 is a graph of Zn and Se coverages per cycle for ZnSe deposits as a function of the Zn potential. The Se deposition was carried out by first depositing two monolayers at -0.9 V and then reducing off the excess at -0.9 V. The drop in coverage above -0.8 V is due to decreased stability of the Zn (Fig. 11). A plateau in both the Zn and Se coverages is evident between -1.2 and -0.9 V, however, the Zn coverage per cycle is nearly 3/4 ML, while the Se remains at 1/2 ML. The standard potential for Zn deposition is about -1.0 V (vs. Ag/AgCl), and given that a mM solution of ZnS04 was used, bulk deposition would not be expected until -1.1 V. The reason for the disparity between the Zn and Se in the...

FIG. 17. Zinc and tellurium coverages, per cycle, after four ECALE cycles, as a function of the Zn-deposition potential. Te atomic layers were formed by initial deposition of a couple of ML of Te at —0.8 V, followed by reductive dissolution of the excess Te at -1.1 V. 

Figure 11.3. Schematic diagram showing the reactions that take place during Zn deposition via a Zn(OH)2 layer (A) metal-hydroxide interface (B) hydroxide-electrolyte interface. (From Electrochemically Deposited Thin Films II, M. Paunovic, ed., Electrochemical Society, Pennington, NJ, 1995, with permission from the Electrochemical Society.)...

Walters, S., Skrzeczynski, B., Whiting, T., Bunting, F., Arnold, G. 2002. Discovery and geology of the Cannington Au-Pb-Zn deposit, Mount Isa Eastern Succession, Australia development and application of an exploration model for Broken Hill-type deposits. Special Publication (Society of Economic Geologists U.S.), 9, 95-118. 

Gilliss, M.L., Al, T.A., Blowes, D.W., Hall, G.E.M., MacLean, B. 2004. Geochemical dispersion in groundwater from a weathered Cu-Zn deposit in glaciated terrain. Geochemistry-Exploration Environment Analysis, 4, 291-305. 

Lawrie, K.C. Hinman, M.C. 1998. Cobar-style polymetallic Au-Cu-Ag-Pb-Zn deposits. AGSO Journal of Australian Geology and Geophysics, 17,169-187. 

Figure 3.12 presents 5 C and 5 0-values of hydrothermal carbonates from the Pb-Zn deposits of Bad Grund and Lautenthal, Germany. The positive correlation between and 0/ 0-ratios can be explained either by calcite precipitation... 

Zheng YF, Hoefs J (1993) Carbon and oxygen isotopic vovariations in hydrothermal caicites. Theoretical modeling on mixing processes and application to Pb-Zn deposits in the Harz Mountains, Germany. Miner Deposita 28 79-89... 

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