high pressure oxidation refractory
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- high pressure oxidation refractory
Pressure oxidation of the refractory sulfide/carbonaceous ores has gained world-wide acceptance. Compared with roasting, pressure oxidation yields higher gold extractions from ores or concentrates and enables better handling of environmentally sensitive impurities. ... At high Fe/As ratios, ferric arsenic species precipitate [11] as ferric ...
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9 Citations. Metrics. Abstract. Pressure oxidation is a widely accepted method to treat refractory gold ores. Gold recovery is generally lower from alkaline than …
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A refractory ReTaWNbMo high-entropy alloy (HEA) with an equal atomic ratio prepared by rapid solidification displays a BCC crystal structure. After annealing the as-quenched samples at 673, 873, 1073, and 1273 K for 12 h, respectively, the crystalline phase still keeps its BCC structure, but the crystalline morphology transforms from …
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1.. IntroductionHigh temperature (200–230 °C) acid pressure oxidation leaching of metal sulfides was first commercialized in the 1950's. However, the more recent commercial success of medium temperature pressure oxidation of zinc sulfide concentrates and high temperature pressure oxidation of refractory gold ores and …
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scope of high temperature and pressure. And the problem of nitric acid regeneration hasn't been solved. The superiority of technology hasn't yet been confirmed by the practices of industrialized production.21,22) 3.5. Pressure Oxidation Pressure oxidation process is more mature. It oxidizes and decomposes gold bearing sulfide to make gold ...
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The specific goal of Phase 1 was to find treatment conditions and methods that would consistently yield greater than 80% CM oxidation in the ore within 20 min. …
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For a silica scale forming on SiC, the total vapor pressure beneath SiO 2 rapidly approaches 1 atm as temperature is increased; for C rich SiC, ... in the study of the oxidation of some alloys and high-temperature refractory materials, care must be used in interpreting weight-change data because of the formation of volatile oxides ...
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The effect of bio-oxidation and neutral atmospheric oxidation pre-treatment of refractory gold concentrates on gold and silver extraction during cyanidation was investigated. A series of pre-treatment experiments was conducted on three high sulfur (> 9%) refractory concentrates with 0.92–1.25 g/t gold and 64–90 g/t silver. Cyanidation of …
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Moreover, the silver recovery is yielded between the range of 92.5–95% recovery at high-pressure media. Most notably, this study represents a higher possible recovery of silver from fully oxidized refractory ore through both pressure oxidation and chemical oxidation with NaOCl agent.
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At extremely high temperatures (2000 K) we observe the removal of oxygen atoms with the manipulation of the oxygen pressure. Even at 10 −9 bar, there is still 0.333 ML oxygen coverage on the ...
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Alkaline pressure oxidation is an effective pretreatment for releasing refractory gold from pyrite and arsenical concentrates before cyanidation [11,14]. Simultaneous pressure leaching oxidation involves the oxidation of pyrite and Au cyanidation in alkaline media, where oxidation liberates or exposes gold particles that …
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Refractory metal samples were oxidized in ambient air or in a system capable of achieving a base pressure of <10 −7 Pa (5×10 −9 Torr) after bakeout. For the low pressure exposures, the system was evacuated to a low pressure and brought to the desired temperature before oxygen was introduced via a micrometering valve.
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The nitric acid pre-treatment experiments for refractory silver ore and gold/silver concentrate were performed for 2.5 hours at 5M HNO 3 and 80 o C. Before and after nitric acid pretreatment ...
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Pressure oxidation, roasting, CIL: 50% of gold in refractory carbonaceous sulfides. Sulfuric acid to remove carbonates before autoclave. Whole-ore acidic leach: 21: Mercur: USA: Fine gold with sulfides and organic carbon, carbonates: Pressure oxidation, CIL: Whole-ore alkaline leach owing to high carbonates: 21: Campbell: Ontario: High As …
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Pressure oxidation is a hydrometallurgical oxidative pretreatment for refractory ores, such as sulfide ores. Here, simultaneous alkaline pressure oxidation and sodium cyanide leaching treatments were carried out on a pyritic ore from the Mulatos Mine located in Sahuaripa, Sonora, Mexico. Mineral characterization, agitation leaching, hot …
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These results mean that high oxygen pressure can effectively accelerate the oxidation reaction rate and ... S. et al. Wet oxidation of refractory organic compounds in industrial aqueous wastes via ...
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In the process of high temperature, high pressure, and rich oxygen pretreatment by acid, jarosite is easily formed, and part of the bare gold is secondary encapsulated. ... Basic iron sulphate-A potential killer for pressure oxidation processing of refractory gold concentrates if not handled appropriately. SGS Miner. Serv. (2009), pp. 1 …
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Refractory multi-principal-element alloys (RMPEA) are promising alloys for high-temperature (HT) applications 7 if stability, strength, and oxidation resistance in harsh-service conditions can be ...
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Strongly oxidizing conditions of POX (high temperature, oxidation-reduction potential or ORP, and acidity) favor formation of gold-halide (mostly, gold-chloride) complexes, which tend to...
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pressure within residence time of 30 min. Hydrogen peroxide con-sumption to make peroxyacetic acid corresponds to half of the total operating cost. After the oxidation step, sulfone separation was con-ducted through liquid/liquid extraction to raffinate fraction with lower sulfur amount and extract fraction with high sulfur concentration.
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Despite offering a higher grade, these ores can only be processed using specific pretreatment methods such as ultrafine grinding, bio oxidation, roasting, or …
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A study was carried out to process a sulfide mineral concentrate from Norwest of Mexico containing 97 g/t Au, 0.15% Cu, and 15% Fe. An oxidative acid pretreatment was investigated using ferric sulfate as oxidant, followed by leaching of gold with sodium cyanide. Scanning electron microscopy, SEM-EDS, and X-ray diffraction, …
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High sulfide conversion, up to 99%, can be achieved during the roasting process (see Chapter 23). 2.2. Pressure Oxidation. Pressure oxidation (POX) methods that are used to treat sulfidic ores, under either acidic or alkaline conditions, usually do not significantly change the nature of the noncarbonate carbon in the ore.
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Abstract: This paper reviews the raw materials, additives, general properties, oxidation and corrosion of MgO–C refractories, which are irreplaceable in the steelmaking process. ecause it is a b ... refractories are shaped at high pressure and are tempered or cured but not fired. The main properties of MgO–C refractories are as fol- ...
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This work uses both analytical and computational thermodynamic approaches to investigate and quantify the effects of this large variation and the resulting …
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For high-arsenic and high-sulfur refractory gold concentrate, fine-grained gold is always encapsulated by sulfide minerals, such as arsenopyrite and pyrite, which inhibits gold extraction during the leaching process [9, 10]. Roasting, pressure oxidation, chemical pre-oxidation, ...
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Pressure oxidation can cause high efficiency in refractory gold extraction. Zhang et al. [23] achieved up to 90.2% gold leaching efficiency by pressure oxidation under the optimum condition. In a study by Xu et al. [24], the gold extraction from ore after the oxygen pressure alkaline leaching reached 78%.
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Pressure oxidation (POX) leaching has been commercially applied to refractory gold ores since the 1980s. In the process, sulphide material is oxidized and dissolved in order to release the...
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The principal limitation of this type of refractory is related to oxidation of carbon. Oxidation resistance depends on temperature, oxygen partial pressure and quality of carbon. Usage of anti-oxidizing agents such as SiC, Al metal powder, Si–metal powder is extremely important as it protects carbon from oxidation and reduces porosity ...
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Pressure oxidation is a widely accepted method to treat refractory gold ores. Gold recovery is generally lower from alkaline than acidic pressure oxidation discharge due to passivation and incomplete oxidation of mineral. Gold ore from Goldstrike, NV, is a typical refractory gold ore containing sulfide and carbonaceous matter. Alkaline …
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