Mechanism and kinetics of a mineral transformation under hydrothermal conditions: Calaverite to metallic gold

Jing, Zhao; Brugger, Joël; Grundler, Pascal V.; Xia, Fang; Chen, Guorong; Pring, Allan

doi:10.2138/am.2009.3252

Cited by 67 publications

(53 citation statements)

References 51 publications

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“…Negative molar volume changes, such as seen during the replacement of calaverite by gold ( Fig. 7a; Zhao et al 2009), are associated with porosity in the product phase. However, in systems exhibiting minor decreases in molar volume ( Fig.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

See 1 more Smart Citation

Textural and compositional complexities resulting from coupled dissolution–reprecipitation reactions in geomaterials

Altree-Williams

Pring

Ngothai

et al. 2015

Earth-Science Reviews

129

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Section: Accepted Manuscriptmentioning

confidence: 99%

“…Page 15/85 one must consider the relative solubilities of the parent and product phase and the mobility of species in solution when determining volume changes during solution-mediated mineral replacements (Pollok et al 2011;Putnis and Mezger 2004;Putnis 2009;Zhao et al 2009). (Table 1).…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Textural and compositional complexities resulting from coupled dissolution–reprecipitation reactions in geomaterials

Altree-Williams

Pring

Ngothai

et al. 2015

Earth-Science Reviews

129

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“…[37] Zhao and coworkers [38,39] found that Te could be effectively 'leached' from calaverite under hydrothermal conditions, leaving sponge- like porous gold (Fig. 6).…”

Section: Engineering Microtextures By Interface Coupled Dissolutionrementioning

confidence: 99%

A Novel Route for the Synthesis of Mesoporous and Low-Thermal Stability Materials by Coupled Dissolution-Reprecipitation Reactions: Mimicking Hydrothermal Mineral Formation

Brugger

McFadden

Lenehan

et al. 2010

Chimia

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Replacement reactions ('pseudomorphism') commonly occur in Nature under a large range of conditions (T 25 to >600 ˚C; P 1 to >5 kbar). Whilst mineral replacement reactions are often assumed to proceed by solid-state diffusion of the metal ions through the mineral, many actually proceed via a coupled dissolution and reprecipitation (CDR) mechanism. In such cases, a starting mineral is dissolved into a fluid and this dissolution is coupled with the precipitation of a replacement phase across the reaction front. In cases where there are close relationships between the crystal structures of the parent and newly formed minerals, the replacement can be topotactic (interface-coupled dissolution and reprecipitation). The kinetics and chemistry of the CDR route are fundamentally different from solid-state diffusion and can be exploited i) for the synthesis of materials that are often difficult to synthesise via traditional methods and ii) to obtain materials with unique properties. This review highlights recent research into the use of CDR for such synthetic challenges. Emphasis has been given to i) the use of CDR to synthesise compounds with relatively low thermal stability such as the thiospinel mineral violarite ((Ni,Fe) 3 S 4 ), ii) preliminary work into use of CDR for the production of roquesite (CuInS 2 ), a potentially important photovoltaic component and, iii) examples where the textures resulting from CDR reactions are controlled by the nature and texture of the parent phase and the reaction conditions; these being the formation of micro-porous gold and three-dimensional ordered arrays of nanozeolite of uniform size and crystallographic orientation.

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“…15 This simplifies the data interpretation because hydrothermal reactions are usually complex and a significant change of fluid composition during the course of the reaction can change the mechanism drastically. 3,16,17 To achieve a higher working temperature and pressure, and a larger fluid volume, we have previously constructed a thermosyphon driven flow-through cell and commissioned on Wombat, Australian's new high intensity powder diffractometer at the OPAL research reactor, run by Nuclear Science and Technology Organization ͑ANSTO͒. 18 The cell worked smoothly but the thermosyphon is sensitive to local temperature and air flow variations in the neutron guide hall.…”

Section: Introductionmentioning

confidence: 99%

“…In nature, the transformation may occur during cooling of the magma, under which condition the temperature can be as high as a few hundreds of Celsius, or after the host rock has solidified, under which condition the temperature can be as low as room temperature. 21 Also considering the proportional relationship between specific surface area and the reaction rate for hydrothermal mineral transformations, 3,17 the extrapolations estimate that in the presence of salt water ͑ca. 0.6M Na + ͒ it takes around 7600 years at 25°C ͑after solidification of host rock͒ or only 8 h at 300°C ͑cooling from magma͒ to completely transform a 0.5 mm ͑typical size͒ leucite crystal to analcime.…”

mentioning

confidence: 99%

A large volume cell for in situ neutron diffraction studies of hydrothermal crystallizations

Xia

Qian

Brugger

et al. 2010

Review of Scientific Instruments

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The mechanism of nickel sulfide induced rapid crystallization of highly textured tungsten disulfide ( W S 2 ) thin films: An in situ real-time diffraction study J. Appl. Phys. 103, 063501 (2008) A hydrothermal cell with 320 ml internal volume has been designed and constructed for in situ neutron diffraction studies of hydrothermal crystallizations. The cell design adopts a dumbbell configuration assembled with standard commercial stainless steel components and a zero-scattering Ti-Zr alloy sample compartment. The fluid movement and heat transfer are simply driven by natural convection due to the natural temperature gradient along the fluid path, so that the temperature at the sample compartment can be stably sustained by heating the fluid in the bottom fluid reservoir. The cell can operate at temperatures up to 300°C and pressures up to 90 bars and is suitable for studying reactions requiring a large volume of hydrothermal fluid to damp out the negative effect from the change of fluid composition during the course of the reactions. The capability of the cell was demonstrated by a hydrothermal phase transformation investigation from leucite ͑KAlSi 2 O 6 ͒ to analcime ͑NaAlSi 2 O 6 ·H 2 O͒ at 210°C on the high intensity powder diffractometer Wombat in ANSTO. The kinetics of the transformation has been resolved by collecting diffraction patterns every 10 min followed by Rietveld quantitative phase analysis. The classical Avrami/Arrhenius analysis gives an activation energy of 82.3Ϯ 1.1 kJ mol −1 . Estimations of the reaction rate under natural environments by extrapolations agree well with petrological observations.

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Mechanism and kinetics of a mineral transformation under hydrothermal conditions: Calaverite to metallic gold

Cited by 67 publications

References 51 publications

Textural and compositional complexities resulting from coupled dissolution–reprecipitation reactions in geomaterials

Textural and compositional complexities resulting from coupled dissolution–reprecipitation reactions in geomaterials

A Novel Route for the Synthesis of Mesoporous and Low-Thermal Stability Materials by Coupled Dissolution-Reprecipitation Reactions: Mimicking Hydrothermal Mineral Formation

A large volume cell for in situ neutron diffraction studies of hydrothermal crystallizations

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