The solubility of molybdenum dioxide and trioxide in HCl-bearing water vapour at 350°C and pressures up to 160 bars

Rempel, Kirsten U.; Williams‐Jones, Anthony E.; Migdisov, Artas

doi:10.1016/j.gca.2008.04.015

Cited by 49 publications

(24 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The studies of Stein (1985), Rempel et al (2006) and Hannah et al (2007) suggest that molybdenite crystallizes from a vapor phase by reaction of hydrated molybdate species with H 2 S as oxygen fugacity falls below the SO 2 -H 2 S buffer with declining temperature. With increasing f(HCl), the Mo speciation changes from hydrated oxide to oxychloride, and this may explain the variable association of molybdenite with either sericitic or potassic alteration in porphyry Mo ore deposits (Rempel et al 2008). Hannah et al (2007) modeled Mo concentration and isotopic variations in molybdenite by Rayleigh distillation.…”

Section: Mechanism For the Deposition Of Rementioning

confidence: 99%

RHENIUM-RICH MOLYBDENITE AND RHENIITE IN THE PAGONI RACHI Mo-Cu-Te-Ag-Au PROSPECT, NORTHERN GREECE: IMPLICATIONS FOR THE Re GEOCHEMISTRY OF PORPHYRY-STYLE Cu-Mo AND Mo MINERALIZATION

Voudouris¹,

Melfos²,

Spry³

et al. 2009

The Canadian Mineralogist

View full text Add to dashboard Cite

The porphyry-type Pagoni Rachi Mo-Cu-Te-Ag-Au prospect, in northern Greece, is a porphyry-epithermal system hosted by an Oligocene dacite porphyry and quartz-feldspar porphyry dikes. The rare mineral rheniite (ReS 2 ) and molybdenite, with very high contents of Re (up to 4.7 wt% Re), occur in quartz veins along with Fe-Cu sulfides, Pb-, Sn-, and Cl-bearing oxides, hematite, ilmenite and tellurides of Bi; these veins are spatially related to sericitic and transitional sericitic-sodic-potassic alteration. Earlier-formed gold-bearing quartz and magnetite veins with sodic-potassic-calcic alteration and late precious-metal telluride-rich carbonate-quartz veins with argillic alteration contain only minor amounts of molybdenite. The composition of rheniite ranges from almost pure, stoichiometric rheniite with low Mo content to rheniite with up to 5.99 wt% Mo. Petrographic, scanning electron microscope, and structural studies suggest that the high Re content of molybdenite from Pagoni Rachi is the result of the isovalent Re-for-Mo substitution in molybdenite. This fact is corroborated by the progressive shortening of the Mo-S mean bond-distance (from 2.414 Å in pure molybdenite to 2.355 Å), as well as by the isotropic decrease of the unit-cell values with the increase of the Re:Mo ratio. The structural analysis of four molybdenite crystals, with the highest Re content ever reported in nature, demonstrates that they crystallize as the 2H polytype and not the 3R polytype, as previously hypothesized, thus suggesting that Re concentration does not correlate with a specific polytype. The fluid inclusions in quartz in the Re-bearing molybdenite-rheniite veins at Pagoni Rachi show that they homogenize to either the liquid or vapor phases (354 to 428°C) or by halite dissolution at 317 to 585°C, which equates to salinities of 40 to 59 wt% NaCl equiv. Rheniite and molybdenite likely precipitated as temperatures fell below 400°C during phase separation under relatively oxidizing conditions, at elevated chlorine activity, and from relatively acid hydrothermal solutions. However, the presence of Pb oxides, Sn-bearing minerals and tellurides § E-mail address: voudouris@geol.uoa.gr 1014 thE CanaDian MinERalogist is compelling evidence that rheniite and Re-rich molybdenite may have formed directly from the vapor as sublimates, in a manner similar to the way they are deposited at the Kudriavy volcano, Kurile Islands.Keywords: porphyry-epithermal deposit, rheniite, Re-rich molybdenite, polytype, phase separation, tellurides, sublimates, Pagoni Rachi, Greece.soMMaiRE L'indice minéralisé en Mo-Cu-Te-Ag-Au de Pagoni Rachi, de type porphyre, situé dans le nord de la Grèce, est un système épithermal encaissé par un porphyre dacitique oligocène et des filons de porphyre quartzofeldspathique. Nous y avons trouvé la rhéniïte (ReS 2 ), espèce rare, et la molybdénite très enrichie en Re (jusqu'à 4.7% Re, poids), dans des veines de quartz avec des sulfures de Fe-Cu, des oxydes contenant Pb, Sn, et Cl, l'hématite, l'ilménite et des tellurure...

show abstract

Section: Mechanism For the Deposition Of Rementioning

confidence: 99%

RHENIUM-RICH MOLYBDENITE AND RHENIITE IN THE PAGONI RACHI Mo-Cu-Te-Ag-Au PROSPECT, NORTHERN GREECE: IMPLICATIONS FOR THE Re GEOCHEMISTRY OF PORPHYRY-STYLE Cu-Mo AND Mo MINERALIZATION

Voudouris¹,

Melfos²,

Spry³

et al. 2009

The Canadian Mineralogist

View full text Add to dashboard Cite

show abstract

“…In water vapour, owing to the near-total association of ions, speciation is dominated by charge-neutral complexes (Smith et al, 1987;Driesner et al, 1998;Camp and Patey, 1999;Chialvo and . The primary Mo species in the vapour is therefore most probably that derived from experiments on the solubility of MoO 3 in water vapour, i.e., the hydrated trioxide, MoO 3 ÅnH 2 O(g) (Glemser and Haeseler, 1962;Belton and Jordan, 1965;Glemser et al, 1966;Buiten, 1968;Rempel et al, 2006Rempel et al, , 2008. This conclusion is supported by the observation that the concentrations of Mo in ammonium-bearing vapour (in coexistence with liquid) are the same, within error, as those in pure water vapour (vapour-only experiments; Rempel et al, 2006), as shown in Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Concentrations measured by Ulrich et al (1999) were averaged by the authors, and n was not given. Rempel et al, 2008 between aqueous liquid and vapour at up to 450°C and vapour-saturated pressure. This autoclave was fitted with capillary tubes which allowed the sampling of liquid and vapour from opposite ends of the vessel at quasi-isobaric conditions, as well as an inner cell which allows the liquid and vapour to be trapped separately at the temperatures and pressures of the experiments.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…doi:10. 1016/j.gca.2009.03.004 which has been found to be relatively soluble in water vapour and may exhibit strong vapour fractionation (Glemser and Haeseler, 1962;Belton and Jordan, 1965;Glemser et al, 1966;Buiten, 1968;Rempel et al, 2006Rempel et al, , 2008.…”

Section: Introductionmentioning

confidence: 99%

“…The concentrations of Mo in aqueous liquid (Ivanova et al, 1975;Kudrin, 1985;Wood et al, 1987;Cao, 1989;Gu, 1993) and vapour (Glemser and Haeseler, 1962;Belton and Jordan, 1965;Glemser et al, 1966;Buiten, 1968;Rempel et al, 2006Rempel et al, , 2008 have been measured separately in a number of experimental studies, and a vapour-liquid distribution coefficient (K V=L D ) might, in principle, be calculated from these data (i.e., using the Mo concentrations measured in the vapour and liquid). However, the solubility measurements in liquid and vapour were made under significantly different chemical conditions, and thus do not represent chemical equilibrium between the two phases (Tables 2 and 3 The objective of this study was to measure the concentration of molybdenum(VI) in coexisting H 2 O vapour and liquid, at 300-370°C and vapour-saturated pressure.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations