The Experts below are selected from a list of 11541 Experts worldwide ranked by ideXlab platform
Christoph A Heinrich - One of the best experts on this subject based on the ideXlab platform.
-
the relation between cu au ratio and formation depth of porphyry style cu au mo deposits
Mineralium Deposita, 2010Co-Authors: Hiroyasu Murakami, Jung Hun Seo, Christoph A HeinrichAbstract:Constraints on gold and copper ore grades in porphyry-style Cu–Au ± Mo deposits are re-examined, with particular emphasis on published fluid pressure and formation depth as indicated by fluid inclusion data and geological reconstruction. Defining an arbitrary subdivision at a molar Cu/Au ratio of 4.0 × 104, copper–gold deposits have a shallower average depth of formation (2.1 km) compared with the average depth of copper–molybdenum deposits (3.7 km), based on assumed lithostatic fluid pressure from microthermometry. The correlation of Cu/Au ratio with depth is primarily influenced by the variations of total Au grade. Despite local mineralogical controls within some ore deposits, the overall Cu/Au ratio of the deposits does not show a significant correlation with the predominant type of Cu–Fe sulfide, i.e., chalcopyrite or bornite. Primary magma source probably contributes to metal endowment on the province scale and in some individual deposits, but does not explain the broad correlation of metal ratios with the pressure of ore formation. By comparison with published experimental and fluid analytical data, the observed correlation of the Cu/Au ratio with fluid pressure can be explained by dominant transport of Cu and Au in a buoyant S-Rich Vapor, coexisting with minor brine in two-phase magmatic hydrothermal systems. At relatively shallow depth (approximately 3 km) and greater confining pressure is likely to precipitate copper ± molybdenum only, while sulfur-complexed gold remains dissolved in the relatively dense Vapor. Upon cooling, this Vapor may ultimately contract to a low-salinity epithermal liquid, which can contribute to the formation of epithermal gold deposits several kilometers above the Au-poor porphyry Cu–(Mo) deposit. These findings and interpretations imply that petrographic inspection of fluid inclusion density may be used as an exploration indicator. Low-pressure brine + Vapor systems are favorable for coprecipitation of both metals, leading to Au-Rich porphyry–copper–gold deposits. Epithermal gold deposits may be associated with such shallow systems, but are likely to derive their ore-forming components from a deeper source, which may include a deeply hidden porphyry–copper ± molybdenum deposit. Exposed high-pressure brine + Vapor systems, or stockwork veins containing a single type of intermediate-density inclusions, are more likely to be prospective for porphyry–copper ± molybdenum deposits.
-
100th anniversary special paper Vapor transport of metals and the formation of magmatic hydrothermal ore deposits
Economic Geology, 2005Co-Authors: Anthony E Williamsjones, Christoph A HeinrichAbstract:In most published hydrothermal ore deposit models, the main agent of metal transport is an aqueous liquid. However, there is increasing evidence from volcanic Vapors, geothermal systems (continental and submarine), Vapor-Rich fluid inclusions, and experimental studies that the Vapor phase may be an important and even dominant ore fluid in some hydrothermal systems. This paper reviews the evidence for the transport of metals by Vapor (which we define as an aqueous fluid of any composition with a density lower than its critical density), clarifies some of the thermodynamic controls that may make such transport possible, and suggests a model for the formation of porphyry and epithermal deposits that involves precipitation of the ores from Vapor or a Vapor-derived fluid. Analyses of Vapor (generally >90% water) released from volcanic fumaroles at temperatures from 500° to over 900°C and near-atmospheric pressure typically yield concentrations of ore metals in the parts per billion to parts per million range. These Vapors also commonly deposit appreciable quantities of ore minerals as sublimates. Much higher metal concentrations (from ppm to wt %) are observed in Vapor inclusions trapped at pressures of 200 to 1,000 bars in deeper veins at lower temperatures (400°–650°C). Moreover, concentrations of some metals, notably Cu and Au, are commonly higher in Vapor inclusions than they are in inclusions of coexisting hypersaline liquid (brine). Experiments designed to determine the concentration of Cu, Sn, Ag, and Au in HCl-bearing water Vapor at variable although relatively low pressures (up to 180 bars) partly explain this difference. These experiments show that metal solubility is orders of magnitude higher than predicted by volatility data for water-free systems, and furthermore that it increases sharply with increasing water fugacity and correlates positively with the fugacity of HCl. Thermodynamic analysis shows that metal solubility is greatly enhanced by reaction of the metal with HCl and by hydration, which results in the formation of species such as MeCl m . n H2O. Nonetheless, the concentrations measured by these experiments are considerably lower than those measured in experiments involving aqueous liquids or determined for Vapor fluid inclusions. A possible explanation for this and for the apparent preference of metals such as Cu and Au for the Vapor over the coexisting brine in some natural settings is suggested by limited experimental studies of metal partitioning between Vapor and brine. These studies show that, whereas Cu, Fe, and Zn all partition strongly into the liquid in chloride-bearing sulfur-free systems, Cu partitions preferentially into the Vapor in the presence of significant concentrations of sulfur. We therefore infer that high concentrations of Cu and Au in Vapor inclusions reflect the strong preference of sulfur for the Vapor phase and the formation of sulfur-bearing metallic gas species. Phase stability relationships in the system NaCl-H2O indicate how Vapor transport of metals may occur in nature, by showing a range of possible Vapor evolution paths for the conditions of porphyry-epithermal systems. At the world-class Bingham Canyon porphyry Cu-Au deposit, evidence from fluid inclusions supports a model in which a single-phase fluid of intermediate to Vapor-like density ascends from a magma chamber. On cooling and decompression, this fluid condenses a small fraction of brine by intersecting the two-phase surface on the Vapor side of the critical curve, without significantly changing the composition of the expanding Vapor. Vapor and brine reach Cu-Fe sulfide saturation as both phases cool below 425°C. Vapor, which is the dominant fluid in terms of the total mass of H2O, Cu, and probably even Cl, is interpreted to be the main agent of metal transport. The evolution of fluids leading to high-grade epithermal gold mineralization is initiated by an H2S-, SO2-, Au-, and variably Cu- and As-Rich Vapor, which separates from an FeCl2-Rich brine in a subjacent porphyry environment. In the early stages of the hydrothermal system, Vapor expands rapidly and on reaching the epithermal environment, condenses, producing hypogene advanced argillic alteration and residual vuggy quartz and, in some cases, coeval high-sulfidation precious metal mineralization (e.g., Pascua). More commonly, the introduction of precious metals occurs somewhat later, after the site of magmatic fluid exsolution has receded to greater depth. Because of the relatively high pressure, the Vapor separating from brine at this stage cools along a pressure-temperature path above the critical curve of the system, causing it to contract to a liquid capable of transporting several parts per million Au to temperatures as low as 150°C.
Pingrang Hua - One of the best experts on this subject based on the ideXlab platform.
-
erasure of ferroelectric domain inversion in ti diffused linbo3 optical waveguide by li Rich Vapor transport equilibration
Journal of Alloys and Compounds, 2015Co-Authors: Pingrang Hua, Jiaji Dong, Kun Ren, Zhaoxi ChenAbstract:Abstract It is demonstrated that ferroelectric domain inversion layer in a LiNbO 3 plate caused by high-temperature Ti diffusion process as well as by heat treatment without diffusing Ti can be erased by Li-Rich Vapor-transport equilibration. It is figured out that the formation or erasing of inverted domain should be attributed to an internal electrical field, caused by the coupling of lithium, niobium or titanium diffusion rate based on ambipolar model. Moreover, specific domain-inversion mechanism is also discussed. A near-stoichiometric Ti-diffused LiNbO 3 waveguide was fabricated by indiffusion of Ti-strips into a congruent LiNbO 3 (i.e., standard Ti diffusion procedure) and Vapor-transport equilibration treatment in this paper. The resultant Ti-diffused LiNbO 3 waveguide supports a TM mode at 1553 nm with the aid of prism couplers. Different with the usual Ti-diffused LiNbO 3 waveguides fabricated on + Z face, no inverted domain was observed on the Ti-diffused region of this waveguide. This achievement can also be applied in ferroelectric domain engineering of single crystal lithium niobate.
-
li Rich Vapor transport equilibration temperature dependence of surface composition of initially congruent linbo3 crystal
Journal of the American Ceramic Society, 2012Co-Authors: Delong Zhang, Pingrang Hua, Zhen Wang, E Y B PunAbstract:The influence of Li-Rich Vapor transport equilibration (VTE) on surface Li2O-content of 1-mm-thick, congruent X-, and Z-cut LiNbO3 crystal plates was studied against the VTE temperature. The VTE-induced surface Li2O-content increase was evaluated from measured birefringence. The results show that the increase follows the traditional Arrhenius law with a surface Li2O-content alteration constant (614 ± 136)/(91 ± 10) mol% and an activation energy (0.76 ± 0.05)/(0.53 ± 0.03) eV for the X/Z-cut plate. An empirical expression that correlates the VTE-induced surface Li2O-content alteration with both the VTE temperature and duration is presented. The expression is useful for producing a near-stoichiometric LiNbO3 plate with the desired surface Li2O-content via balancing the VTE temperature and duration.
-
postgrown li Rich Vapor transport equilibration induced mg diffusion within mgo linbo3 crystal
Journal of Materials Research, 2010Co-Authors: Delong Zhang, Hui Zheng, Pingrang Hua, E Y B PunAbstract:A number of congruent LiNbO3 crystals homogeneously doped with 5 mol% Mg in growth melt were subjected to Li-Rich Vapor transport equilibration (VTE) treatments at 1100 °C for different durations. Secondary ion mass spectrometry study shows that the VTE induces the Mg diffusion within the crystal and an inhomogeneous Mg depth profile. The surface Mg concentration, determined from measured ordinary refractive index, shows a strong VTE duration dependence. Neutron activation analysis shows that the amount of MgO diffusing out of the crystal is ignorable, allowing to conclude that the Mg ions counter diffuse to the crystal surface at the early stage of VTE and then come back toward equilibrium as the Li concentration comes to equilibrium. The VTE-induced Li2O content increase in crystal was determined by the gravimetric method. The crystalline phase, crystal composition, and site occupation of Mg and Li are discussed.
Delong Zhang - One of the best experts on this subject based on the ideXlab platform.
-
li Rich Vapor transport equilibration temperature dependence of surface composition of initially congruent linbo3 crystal
Journal of the American Ceramic Society, 2012Co-Authors: Delong Zhang, Pingrang Hua, Zhen Wang, E Y B PunAbstract:The influence of Li-Rich Vapor transport equilibration (VTE) on surface Li2O-content of 1-mm-thick, congruent X-, and Z-cut LiNbO3 crystal plates was studied against the VTE temperature. The VTE-induced surface Li2O-content increase was evaluated from measured birefringence. The results show that the increase follows the traditional Arrhenius law with a surface Li2O-content alteration constant (614 ± 136)/(91 ± 10) mol% and an activation energy (0.76 ± 0.05)/(0.53 ± 0.03) eV for the X/Z-cut plate. An empirical expression that correlates the VTE-induced surface Li2O-content alteration with both the VTE temperature and duration is presented. The expression is useful for producing a near-stoichiometric LiNbO3 plate with the desired surface Li2O-content via balancing the VTE temperature and duration.
-
postgrown li Rich Vapor transport equilibration induced mg diffusion within mgo linbo3 crystal
Journal of Materials Research, 2010Co-Authors: Delong Zhang, Hui Zheng, Pingrang Hua, E Y B PunAbstract:A number of congruent LiNbO3 crystals homogeneously doped with 5 mol% Mg in growth melt were subjected to Li-Rich Vapor transport equilibration (VTE) treatments at 1100 °C for different durations. Secondary ion mass spectrometry study shows that the VTE induces the Mg diffusion within the crystal and an inhomogeneous Mg depth profile. The surface Mg concentration, determined from measured ordinary refractive index, shows a strong VTE duration dependence. Neutron activation analysis shows that the amount of MgO diffusing out of the crystal is ignorable, allowing to conclude that the Mg ions counter diffuse to the crystal surface at the early stage of VTE and then come back toward equilibrium as the Li concentration comes to equilibrium. The VTE-induced Li2O content increase in crystal was determined by the gravimetric method. The crystalline phase, crystal composition, and site occupation of Mg and Li are discussed.
Woo Seung Kim - One of the best experts on this subject based on the ideXlab platform.
-
analysis of a Rich Vapor compression method for an ammonia based co2 capture process and freshwater production using membrane distillation technology
Chemical Engineering Research & Design, 2019Co-Authors: Asad Ullah, Mujeeb Iqbal Soomro, Woo Seung KimAbstract:Abstract Post-combustion capturing of CO2 through chemical solvent absorption is a promising technique for reducing the CO2 emissions from fossil fuel power plants. However, the energy penalty associated with the absorbent regeneration continues to be a critical challenge in the chemical solvent absorption process. In this study, the operating parameters of ammonia-based CO2 capture were optimized to reduce the energy penalty. This optimized process was considered a base process to which process modifications were added, with the goal of further reducing the energy consumption. These process modifications included absorber inter-cooling and Rich Vapor compression (RVC) combined with cold solvent split (CSS) processes. The combined RVC and CSS process was compared with the base process and advanced NH3-based CO2 capture processes, such as the Rich split process and the inter-heating process. Compared to the base process, the combined process reduced the energy requirements by 20.2%, which was higher than the 11.6% and 8.26% energy reductions obtained via the Rich split and inter-heating processes, respectively. The combined process was also compared with MEA-based process modifications. The energy savings from the combined process were higher than those of the MEA-based process modifications. To estimate the trade-offs between the energy savings resulting from the combined process vs. the capital cost of the additional equipment required, the Aspen Capital Cost Estimator (ACCE) was used. The results showed that the combined process saved $0.707 million per year. Furthermore, a membrane distillation (MD) technology was integrated with the CO2 capture unit to produce freshwater. This additional process produced freshwater at a rate of 719.240 m3/day at a feed stream temperature to the MD unit of 35.66 ℃.
-
ammonia based co2 capture parameters optimization and analysis of lean and Rich Vapor compression processes
Separation and Purification Technology, 2019Co-Authors: Asad Ullah, Mujeeb Iqbal Soomro, Woo Seung KimAbstract:Abstract Carbon dioxide (CO2) capture through chemical solvent absorption process is the most favourable and well-proven technique to reduce CO2 emission. However, in this technique, the energy penalty correlated with absorbent regeneration is a critical challenge. To reduce energy consumption, the operating parameters in NH3-based CO2 capture process were optimized. Then flowsheet modifications including Rich Vapor compression (RVC) and lean Vapor compression (LVC) were proposed for the first time in the NH3-based CO2 capture process. Both the LVC and RVC schemes were combined with cold solvent split (CSS) process to further reduce the energy requirements. Moreover, the LVC and RVC processes of this study were also compared with the advanced NH3-based and MEA-based LVC and RVC processes with respect to energy reduction. The optimized process was considered as a base process and it was compared with the modified processes. The RVC and LVC combined with CSS process reduced the reboiler duty by 26.7% and 19%, respectively. These energy savings are much higher than that of 11.6% and 8.26% energy savings of the advanced NH3-based Rich split and inter-heating processes, respectively. The total equivalent energy savings of LVC, RVC, LVC with CSS, and RVC with CSS processes in this study were about 6.4%, 18.1%, 3.4%, and 15%, respectively, which are higher than 3.4% and 8.5% energy savings of MEA-based LVC with CSS and RVC with CSS processes, respectively. Furthermore, these combined processes can also avoid the use of a condenser.
Hiroyasu Murakami - One of the best experts on this subject based on the ideXlab platform.
-
the relation between cu au ratio and formation depth of porphyry style cu au mo deposits
Mineralium Deposita, 2010Co-Authors: Hiroyasu Murakami, Jung Hun Seo, Christoph A HeinrichAbstract:Constraints on gold and copper ore grades in porphyry-style Cu–Au ± Mo deposits are re-examined, with particular emphasis on published fluid pressure and formation depth as indicated by fluid inclusion data and geological reconstruction. Defining an arbitrary subdivision at a molar Cu/Au ratio of 4.0 × 104, copper–gold deposits have a shallower average depth of formation (2.1 km) compared with the average depth of copper–molybdenum deposits (3.7 km), based on assumed lithostatic fluid pressure from microthermometry. The correlation of Cu/Au ratio with depth is primarily influenced by the variations of total Au grade. Despite local mineralogical controls within some ore deposits, the overall Cu/Au ratio of the deposits does not show a significant correlation with the predominant type of Cu–Fe sulfide, i.e., chalcopyrite or bornite. Primary magma source probably contributes to metal endowment on the province scale and in some individual deposits, but does not explain the broad correlation of metal ratios with the pressure of ore formation. By comparison with published experimental and fluid analytical data, the observed correlation of the Cu/Au ratio with fluid pressure can be explained by dominant transport of Cu and Au in a buoyant S-Rich Vapor, coexisting with minor brine in two-phase magmatic hydrothermal systems. At relatively shallow depth (approximately 3 km) and greater confining pressure is likely to precipitate copper ± molybdenum only, while sulfur-complexed gold remains dissolved in the relatively dense Vapor. Upon cooling, this Vapor may ultimately contract to a low-salinity epithermal liquid, which can contribute to the formation of epithermal gold deposits several kilometers above the Au-poor porphyry Cu–(Mo) deposit. These findings and interpretations imply that petrographic inspection of fluid inclusion density may be used as an exploration indicator. Low-pressure brine + Vapor systems are favorable for coprecipitation of both metals, leading to Au-Rich porphyry–copper–gold deposits. Epithermal gold deposits may be associated with such shallow systems, but are likely to derive their ore-forming components from a deeper source, which may include a deeply hidden porphyry–copper ± molybdenum deposit. Exposed high-pressure brine + Vapor systems, or stockwork veins containing a single type of intermediate-density inclusions, are more likely to be prospective for porphyry–copper ± molybdenum deposits.
