The stability of Au-chloride complexes in water vapor at elevated temperatures and pressures

被引:107
作者
Archibald, SM [1 ]
Migdisov, AA [1 ]
Williams-Jones, AE [1 ]
机构
[1] McGill Univ, Dept Earth & Planetary Sci, Montreal, PQ H3A 2A7, Canada
基金
加拿大自然科学与工程研究理事会;
关键词
D O I
10.1016/S0016-7037(01)00730-X
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
The solubility of gold in liquid-undersaturated HCl-bearing water vapor was investigated experimentally at temperatures of 300 to 360 degreesC and pressures up to 144 bars. Results of these experiments show that the solubility of gold in the vapor phase is significant and increases with increasing f(HCl), and f(H2O). This behavior of gold is attributed to formation of hydrated gold-chloride gas species, interpreted to have a gold-chlorine ratio of 1: 1 and a hydration number varying from 5 at 300 degreesC to 3 at 360 degreesC. These complexes ld are proposed to have formed through the following reaction: Au-solid + m.HClgas + n.H2Ogas = AuClm.(H2O)(n)(gas) + m/2.H-2(gas), (A1) which was determined to have log K values of -17.28 +/- 0.36 at 300 degreesC, -18.73 +/- 0.66 at 340 degreesC, and -18.74 +/- 0.43 at 360 degreesC. Gold solubility in the vapor was retrograde, i.e., it decreased with increasing temperature, possibly as a result of the inferred decrease in hydration number. Calculations based on our data indicate that at 300 degreesC and f(O2)-pH conditions, encountered in high sulfidation epithermal systems, the vapor phase can transport up to 6.6 ppb gold, which would be sufficient to form an economic deposit (e.g,, Nansatsu, Japan; 36 tonnes) in similar to 30,000 yr. Copyright (C) 2001 Elsevier Science Ltd.
引用
收藏
页码:4413 / 4423
页数:11
相关论文
共 45 条
[1]   SOLUBILITY OF SODIUM-CHLORIDE AND SULFATE IN SUBCRITICAL AND SUPERCRITICAL WATER-VAPOR FROM 450-550-DEGREES-C AND 100-250 BAR [J].
ARMELLINI, FJ ;
TESTER, JW .
FLUID PHASE EQUILIBRIA, 1993, 84 :123-142
[2]  
ARRIBAS A, 1995, MAGMAS FLUIDS ORE DE, V13, P419
[3]  
Barnes H., 1997, Geochemistry of Hydrothermal Ore Deposits, V3rd, P699
[4]   Hydrosulphide complexing of Au(I) in hydrothermal solutions from 150-400 degrees C and 500-1500bar [J].
Benning, LG ;
Seward, TM .
GEOCHIMICA ET COSMOCHIMICA ACTA, 1996, 60 (11) :1849-1871
[5]   CONDENSATION OF VOLATILE ELEMENTS IN HIGH-TEMPERATURE GASES OF MOUNT ST HELENS [J].
BERNARD, A ;
LEGUERN, F .
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH, 1986, 28 (1-2) :91-105
[6]  
Biltz W, 1928, Z ANORG ALLG CHEM, V176, P121
[7]   THE SYSTEM NACL-H2O - RELATIONS OF VAPOR-LIQUID NEAR THE CRITICAL-TEMPERATURE OF WATER AND OF VAPOR-LIQUID-HALITE FROM 300-DEGREES-C TO 500-DEGREES-C [J].
BISCHOFF, JL ;
ROSENBAUER, RJ ;
PITZER, KS .
GEOCHIMICA ET COSMOCHIMICA ACTA, 1986, 50 (07) :1437-1444
[8]   How long can a hydrothermal system be sustained by a single intrusive event? [J].
Cathles, LM ;
Erendi, AHJ ;
Barrie, T .
ECONOMIC GEOLOGY AND THE BULLETIN OF THE SOCIETY OF ECONOMIC GEOLOGISTS, 1997, 92 (7-8) :766-771
[9]  
COOKE DR, 2000, REV EC GEOL, V12, P221
[10]   CHEMICAL EVOLUTION AND MINERAL DEPOSITION IN BOILING HYDROTHERMAL SYSTEMS [J].
DRUMMOND, SE ;
OHMOTO, H .
ECONOMIC GEOLOGY, 1985, 80 (01) :126-147