Recovery of gold from refractory ore employing pressure oxidation …
The use of acidic pressure oxidation in refractory gold ore with a high carbonate content, ... (15% sulfides), followed by high-pressure acid oxidation and cyanidation. The POX stage occurs with continuous feeding of a flotation concentrate slurry in an autoclave at 225°C, an oxygen overpressure of 3.8 bar, and a residence time of 1 hour. ...
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Re-Processing Gold Tailings in South Africa
The pyrite concentrate will be treated by high temperature pressure oxidation (POX) in this flowsheet, to oxidize the sulphides to sulphates (mainly ferric sulphate and sulphuric acid) and liberate any gold and uranium locked in the pyrite. Uranium leaches under the oxidizing, acidic conditions prevailing in the autoclave, while gold remains in
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Pressure Oxidation Modelling for Design and Optimisation
Pressure oxidation (POX) is a well-established method for processing sulphide material containing refractory precious and base metals . POX typically takes place in a horizontal multi-compartment agitated pressure vessel at a temperature of 150–230 °C depending on the application. ... For example, high chloride concentrations could possibly ...
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Prediction of Core Electron Reactivity and High …
Recent first-principles calculations and crystal structure predictions revealed a striking phenomenon that the 5p core electrons of Cs can be activated and can form covalent bonds with F under high pressure, causing the formation of …
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Gold deportment and leaching study from a pressure oxidation …
In the hybrid leaching system, copper was stabilized by glycine and further utilized as a catalyst for gold leaching. To achieve higher gold extraction and lower lime consumption, a product with high sulfur oxidation degree and low iron sulfate content is preferable in pressure oxidation operation.
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ACID PRESSURE OXIDATION OF REFRACTORY GOLD …
ACID PRESSURE OXIDATION OF REFRACTORY GOLD MINERAL CARRIERS G.P. Demopoulos and V . G . Papangelakis Department of Mining and Metallurgical Engineering McGill U n i v e r s i t y, Montreal, Quebec, Canada H3A 2A7 ABSTRACT Acid pressure oxidation is c u r r e n t l y strongly advocated as the most e f f e c t i v e pre treatment method f o r r e f r …
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A FUNDAMENTAL INVESTIGATION OF THE HIGH …
pressure within a gold operation to reach the highest percent recovery, no matter what kind of ore is presented for treatment. For double refractory gold ores, the most crucial unit operation is performed by the roaster by creating a high temperature oxidation of the ore. An efficient roasting operation creates a
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Pressure Oxidation Pretreatment of Refractory Gold
Pressure oxidation of gold containing concentrates and ores is an effective pretreatment for liberating refractory gold. This is particularly true when an appreciable portion of the gold is …
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Gold deportment and leaching study from a pressure oxidation …
Pressure oxidation (POX) is an effective method for base metal extraction and a pretreatment of refractory gold ores. A residue from pressure leaching of chalcopyrite concentrate was collected and investigated for gold recovery and deportment of metals. A comprehensive mineralogical analysis and gold deportment study were conducted using techniques including …
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Oxidation of a refractory gold concentrate using pressure
*This is an abstract only. No full paper was prepared for this abstract. CITATION:Casingena, C, Czerny, C, Paterson, L and Carter, P, 2019. Oxidation of a refractory gold concentrate using pressure, atmospheric and bacterial oxidation processes, in Proceedings World Gold 2019, p 681 (The Australasian Institute of Mining and Metallurgy: Melbourne).
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Pressure oxidation overview
A similar comparison can be made between roasting and pressure oxidation of gold ores and concentrates. This is especially so for arsenopyrite-bearing gold, where arsenic and sulfide are fixed as ferric arsenate and sulfates, respectively, in pressure oxidation, whereas roasting produces toxic sulfur dioxide gas and arsenic xide fumes.
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A fundamental study of the alkaline sulfide leaching of gold
During the pressure oxidation of metal sulfides, the sulfide component can be either ... produce high grade, marketable sodium sulfate. The sodium sulfate is then be sold to and utilized in ... standard potentials for the oxidation of gold to gold thiosulfate and gold sulfide are 0.15V and –0.46V respectively (Hiskey and Atluri, 1986). ...
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Manipulating Iron Precipitation and Gold Deportment During Pressure
Pressure oxidation (POX) is the most utilized method for chemically liberating gold from sulfides. However, in the context of decreasing gold grades and increasingly complex mineralogy as well as variable qualities of process solutions, operations using POX can be challenged by high reagent consumption and in ensuring high gold recoveries.
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POx applications in gold mines
Oxygen injection processes utilize high-pressure pumps that facilitate oxygen into the autoclave, ensuring optimal conditions for the oxidation of sulfide minerals and subsequent gold extraction. During slurry circulation, …
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Pretreatment of refractory gold minerals by ozonation before the
Gold can be liberated from refractory ores by roasting, high or low-pressure oxidation, bacterial oxidation and chemical oxidation [12], but these processes often imply environmental problems, excessive capital requirements, high operating and maintenance costs, or the need of highly trained operating personnel.The ozonation process has been …
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Pressure oxidation of double refractory gold concentrates
The pressure oxidation approach that allows obtaining high gold recovery from double refractory materials was proposed. $/7$ : The chemical compositions of the concentrates
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ALTA Gold 2012 E-Doc
leaching to the aggressive conditions found in pressure oxidation. The gold and sulphur (sulphides and elemental sulphur) grades relate directly to the economics of the process. Much has been written about the suitability of particular pretreatment processes, such as pressure oxidation, bio oxidation and roasting, for specific ores bodies (1-4 ...
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Gold recovery from refractory gold concentrates by pressure …
Abstract: Naturally, refractory gold is enclosed by sulfide minerals such as pyrite and arsenopyrite and a higher content of organic carbon, which results in difficulty in the recovery of gold. In this …
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Pressure Oxidation Overview
Pressure oxidation of gold ores is therefore a pretreatment leaching step to enhance gold recovery. ... To achieve higher gold extraction and lower lime consumption, a product with high sulfur oxidation degree and low iron sulfate content is preferable in pressure oxidation operation. Hematite is a stable product and does not impair gold leaching.
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Sulfur speciation matters
At the lowest oxidation states studied, represented by values of ΔNNO of 0.0 to –1.0, H 2 S and HS – were predominant, and these correlated with the highest solubilities of gold, strongly ...
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Gold Sulphide Ore Oxidation by Alkaline Pressure
Acidic pressure oxidation of pyritic gold ore requires treatment temperatures between 160° to 210° C and pressures of up to 400 psig. The resulting residue requires …
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Enhanced Gold Recovery from Alkaline Pressure Oxidized Refractory Gold
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 pressure oxidation …
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Pressure Oxidation Overview
Pressure oxidation refers to the oxidation of sulfides, such as pyrite [FeS 2] and marcasite [FeS 2], at elevated temperature and pressure. Oxidation releases encapsulated gold grains from the sulfides and makes the oxidation residue of the ore or concentrate more amenable for gold recovery by cyanidation in a subsequent leaching step. Pressure ...
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Pressure Oxidation
Pressure Oxidation (POX) is a process used to extract gold, copper, zinc, molybdenum, and uranium from refractory ore bodies. The POX process utilizes elevated temperatures (roughly 230 degrees Celsius), elevated pressures (roughly 35 bar or 510 psi), and oxygen to liberate the minerals …
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MODELING OF HIGH PRESSURE PRETREATMENT …
6 LIST OF SYMBOLS KH Henry's constant, L Pa/mol O2 k oxygen mass transfer coefficient, 1/min n1 reaction order for pyrite conversion n2 reaction order for concentration of dissolved oxygen n3 reaction order for pyrite conversion n4 reaction order for concentration of ferric ions O2 P partial pressure of oxygen in the gas phase, Pa R gas constant, R=0.008314 kJ/mol K
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Recovery of gold from refractory ore employing pressure …
With the global depletion of ores containing high gold content and low arsenic levels, pressure oxidation (POX) under acidic conditions becomes the preferred option for pre-treating …
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High Pressure Metallurgy | Autoclave Technology
Every pressure hydrometallurgical circuit is a custom design. With the right innovative and proprietary equipment designs, your pressure oxidation or pressure leaching needs will be effectively met, from pilot-scale unit operations and demonstration plants to commercial facilities. Our services are tailored to the requirements of your project.
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Pressure Oxidation Leaching Process
Batch Autoclave Laboratory Procedures: The vessel used for the laboratory pressure oxidation process was a two-liter Parr titanium autoclave with dual impellers.It was heated and cooled externally and was pressurized with commercial-grade oxygen. A positive bleed of offgas was maintained in each test; the rate was measured in the offgas after the …
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Pressure oxidation overview
Pressure oxidation refers to the oxidation of sulfides, such as pyrite [FeS 2] and marcasite [FeS 2], at elevated temperature and pressure. Oxidation releases encapsulated …
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Pressure Oxidation Circuit
Gold Pressure Oxidation Plant Control System. FirstMiss Gold installed a supervisory control system based on Pavilion Technology's Process Insights neural network software and Oil System's PI data historian. The primary goal of the system was to control the acid preconditioning circuit. However, our first successful control loop was on the ...
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