A Preliminary Study of the Solubility of Copper in Water Vapor
-
摘要: 近年来地质证据和少量的实验研究证实, 相当量的铜可以在气相中迁移, 人们认识到铜在气相中迁移是一种重要的地球化学过程, 但目前关于铜在气相中溶解反应机理的研究还相当缺乏.本文通过溶解度法, 在310~350℃, 压力为4.2~10MPa的条件范围内, 实验研究了铜在不饱和水蒸气相中的溶解度.结果表明: 水蒸气的存在大大增强了铜在气相中的溶解度; 恒定温度下, 铜在气相中的溶解度随着水蒸气压的增加而增大; 气相中铜可能以水合物的形式存在, 铜在气相中的溶解可由以下反应表述: CuClmsolid+nH2O gas=CuClm·(H2O)ngas(m=1, 2), 其中水合数随着温度升高而下降, 温度为310℃水合数n为~6, 330℃为~5, 350℃为~4.研究结果明确显示, 气体溶剂H2O与铜之间的反应可大大增强铜在气相中的溶解和迁移能力.Abstract: In recent years, geological evidence and the available experimental data have shown that a significant quantity of copper can be transported in vapor. It has been recognized that the transport of copper in vapor may be an important geochemical process. But, up to now, little work has been done on the mechanisms of dissolution of copper in vapor. In this paper, the solubility of copper in undersaturated water vapor was investigated experimentally at temperatures of 310 to 350℃and pressures from 4. 2 to 10 MPa. Results of these experiments show that the presence of water vapor increases the concentration of Cu in the gas. At the same temperature, the solubility of copper increases with the increase of water vapor pressure. Copper may exist as hydrated gaseous particles in the vapor phase. The dissolution process can be described by the reaction: CuClmsolid +nH2O gas=CuClm·(H2O)ngas(m=1, 2). The hydration number decreases with increasing temperature, varying from -6 at 310 ℃, to -5 at 330 ℃ and -4 at 350℃. The results show that the interactions between gas-solvent H2O and copper significantly enhance the capacity of dissolution and transport of copper in the gas phase.
-
Key words:
- copper /
- vapor phase /
- solubility /
- experimental study
-
图 2 温度为310℃、压力为4.84 MPa条件下, 铜在气相中的溶解度与时间的关系
Fig. 2. Solubility of copper in the vapor phase as a function of time, at 310℃, pH2O =4.84 MPa
图 3 在310℃、330℃、350℃条件下log XCu对log fH2O的关系
Fig. 3. Plots of log XCu versus log fH2O at 310℃, 330℃, 350℃
表 1 铜在气相中的溶解度和摩尔分数
Table 1. Solubility and mole fraction of copper in the vapor phase
-
[1] Archibald, S.M., Migdisov, A.A., Williams-Jones, A. E., 2001. The stability of Au-chloride complexes in water vapor at elevated temperatures and pressures. Geochimica et Cosmochimica Acta, 65(23): 4413-4423. doi: 10.1016/S0016-7037(01)00730-X [2] Archibald, S.M., Migdisov, A.A., Williams-Jones, A. E., 2002. An experimental study of the stability of copper chloride complexes in water vapor at elevated temperatures and pressures. Geochimica et Cosmochimica Acta, 66(9): 1611-1619. doi: 10.1016/S0016-7037(01)00867-5 [3] Barnes, H.L., 1997. Geochemistry of hydrothermal ore deposits. 3rd edition. Jonh Wiley and Sons, New York. [4] Brewer, L., Lofgren, N., 1950. The thermodynamics of gaseous cuprous chloride, monomer and trimer. J. Am. Chem. Soc., 72: 3038-3045. doi: 10.1021/ja01163a066 [5] Dienstbach, F., Emmenegger, F.P., Schlaepfer, C.W., 1977. Vaporization of copper(Ⅱ)chloride and the structure of vapor studied using UV/visible and Raman spectroscopy. Inst. Anorg. Anal. Chem. Helv. Chim. Acta, 60: 2460-2470. doi: 10.1002/hlca.19770600732 [6] Gemmell, J. B., 1987. Geochemistry of metallic trace elements in fumarole condenstates from Nicaraguan and Costa Rican volcanoes. Journal of Volcanology and Geothermal Research, 33: 161-181. doi: 10.1016/0377-0273(87)90059-X [7] Heinrich, C.H., Ryan, C.G., Mernagh, T.P., et al., 1992. Segregation of ore metals between magmatic brine and vapor: A fluid inclusion study using PIXE microanalysis. Economic Geology, 87: 1566-1583. doi: 10.2113/gsecongeo.87.6.1566 [8] Heinrich, C.A., Günther, D., Audétat, A., 1999. Metal fractionation between magmatic brine and vapor, determinded by microanalysis of fluid inclusions. Geology, 87: 755-758. [9] Kestin, J., Sengers, J. V., Kamgar-Parsi, B., et al., 1984. Thermophysical properties of fluid H2O. J. Phys. Chem. Re f. Data, 13: 175-183. doi: 10.1063/1.555707 [10] Lowenstern, J. B., Mahood, G. A., Rivers, M. L., et al., 1991. Evidence for extreme partitioning of copper into a magmatic vapor phase. Science, 252(7): 1405-1409. [11] Migdisov, A.A., Williams-Jones, A.E., Suleimenov, O.M., 1999. Solubility of chlorargyrite(AgCl) in the water vapor at elevated temperature and pressures. Geochimica et Cosmochimica Acta, 63(22): 3817-3827. doi: 10.1016/S0016-7037(99)00213-6 [12] Peterson, D.E., 1973. Sublimation thermodynamics and kinetics of cuprous-chloride. Part Ⅰ : Vacuum balancetorsion experiments. PartⅡ : Mass-spectrometer experiments(Dissertation). University of Kansas, Kansas, 484. [13] Pokrovski, G.B., Zakirov, I.V., Roux, J., et al., 2002. Experimental study of arsenic speciation in vapor phase to 500℃ : Implications for As transport and fractionation in low-density crustal fluids and volcanic gases. Geochimica et Cosmochimica Acta, 66(19): 3453 3480. doi: 10.1016/S0016-7037(02)00946-8 [14] Seward, T.M., Henderson, C.M., Charnock, J.M., et al., 1996. An X-ray absorption(EXAFS) spectroscopic study of aquated Ag+ in hydrothermal solutions to 350℃. Geochim. Cosmochim. Acta, 60: 2273-2282. doi: 10.1016/0016-7037(96)00098-1 [15] Sheller, B., 1976. A transpiration-mass spectrometric technique for the determination of the thermodynamic properties of chloride vapor transport reactions(Dissertation). Colorado School of Mines, Golden, Colorado, 197. [16] Taran, Y. A., Bernard, A., Gavilanes, J. C., et al., 2000. Native gold in mineral precipitates from high temperature volcanic gases of Colima volcano, Mexico. Applied Geochemistry, 15: 337-346. doi: 10.1016/S0883-2927(99)00052-9 [17] Ulrich, T., Günther, D., Heinrich, C.A., 1999. Gold concentrations of magmatic brines and the metal budget of porphyry copper deposits. Nature, 399(17): 676-679. [18] Williams-Jones, A.E., Migdisov, A.A., Archibald, A.M., et al., 2002. Vapor-transport of ore metals. Water-Rock Interactions, Ore Deposits, and Envrionmental Geochemistry, 7: 279-305. [19] Xiao, Z., 1999. Experimental and theoretical studies of the solubility of copper in liquid and vapor in the system NaCl-HCl-H2O (Dissertation). Mcgill University, Montreal. [20] Zakaznova-Iakovleva, V. P., Migdisov, A. A., Suleimenov, O.M., et al., 2001. An experimental study of stibnite solubility in gaesous hydrogen sulphside from 200 to 320℃. Geochimica et Cosmochimica Acta, 65(2): 289 298. doi: 10.1016/S0016-7037(00)00523-8 [21] Zhang, R.H., Hu, S., 2002. A case study of the influx of upper mantle fluids into the crust. Journal of Volcanology and Geothermal Research, 118: 319-338. doi: 10.1016/S0377-0273(02)00300-1 -
下载:
点击查看大图
图(3) / 表(1)
计量
- 文章访问数: 3440
- HTML全文浏览量: 139
- PDF下载量: 1
- 被引次数: 0
