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The aim of this study was to study the effect of temperature oxygen partial pressure and slurry density on pressure oxidation of pyrite arsenopyrite gold concentrate Batch oxidation tests in an autoclave were done using a factorial design Different responses were measured and analysed to study effect of the three factors and oxidation kinet ics Generally high slurry density required
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are driven by the gold recovery rate The pre treatment of refractory gold ore should increase the gold recovery rate in the cyanide leach process by 30 40 in order to be economical Large operations tend to choose roasting or pressure oxidation while smaller operations tend to select bacterial leaching says Dr Fleming Other Gold with 4 and 6 Oxidation States in AuF4 and AuF6 Aug 01 2024
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The high pressure nitric acid oxidation process is shown in Figure 1 LI D X Developments on the pretreatment of refractory gold minerals by nitric acid World Gold Conference 2024 The Southern African Institute of Mining and Metallurgy 2024 Developments in the pretreatment of refractory gold minerals by nitric acid D X LI
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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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high yield oxidation ore mineral processing equipment Developments in the pretreatment of refractory gold minerals by high pressure and high temperature equipment Bio oxidation processes processing refractory gold ores include the high pressure
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Microwave pre treatment of refractory gold ores Most of refractory gold occurs within sulphide minerals such as FeS 2 and FeAsS and are treated by roasting pressure leaching or bacterial leaching to render the gold amenable to recovery by subsequent treatment techniques Haque 1987
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The oxidation of refractory gold concentrates containing arsenopyrite and pyrite and the simultaneous dissolution of gold in aerated alkaline solutions at ambient temperatures and pressures without the addition of cyanide has been studied It involves the following aspects the chemistry of the oxidation of pure arsenopyrite and pyrite minerals in aerated alkaline solutions the kinetics of
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Pressure oxidation POX followed by thiosulfate gold leaching is applied to the double refractory gold ores containing sulfide and carbonaceous matter The POX process followed by thiosulfate gold leaching is expected to deliver high gold recovery through gold liberation from sulfides and elimination of preg robbing behavior of carbonaceous
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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 Normally gold is extracted from neutralized autoclave leach residue by cyanidation
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A refractory gold ore is an ore that has ultra fine gold particles disseminated throughout its gold occluded minerals These ores are naturally resistant to recovery by standard cyanidation and carbon adsorption processes These refractory ores require pre treatment in order for cyanidation to be effective in recovery of the gold A refractory ore generally contains sulfide minerals organic
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A FUNDAMENTAL STUDY OF THE ACIDIC PRESSURE OXIDATION OF ORPIMENT AND PYRITE AT HIGH ABSTRACT The acidic pressure oxidation of pyrite FeS 2 and orpiment As 2S 3 as a pretreatment of refractory gold ores has been studied by investigating the reaction chemistry and kinetics The effects of retention time temperature particle size oxygen
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The high pressure nitric acid oxidation process is shown in Figure 1 LI D X Developments on the pretreatment of refractory gold minerals by nitric acid World Gold Conference 2024 The Southern African Institute of Mining and Metallurgy 2024 Developments in the pretreatment of refractory gold minerals by nitric acid D X LI
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Gold recovery from refractory gold concentrates by pressure oxidation pre treatment and thiosulfate leaching Li Yu 1 gold pressure oxidation thiosulfate leaching RSM 1 Introduction Gold was an important rare and precious metal always coexists with sulphide minerals such as pyrite and arsenopyrite Azizi et al 2024 Nunan et al 2024 Due to the depletion of high grade gold ores
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How To Improve The Refractory Gold Leaching Process Aug 18 2024 The alkaline hotpressure oxidation is only suitable for refractory gold deposits with high carbonate content and low sulfide content 20 The acidic hotpressure oxidation means that the pyrite arsenopyrite and other sulfides react with the oxygen in an acidic medium under the high temperature and high pressure After the mineral
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Various pretreatment methods such as pressure oxidation and roasting have been used to liberate refractory gold However these methods are capital intensive and require high operational costs Biooxidation is another pretreatment method that is widely applied because it is less polluting of the environment and less demanding of energy and capital Biooxidation involves the use of iron and/or
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Pretreatment of Refractory Sulfidic Gold Ores 15 Pressure Oxidation 18 Acidic Pressure Oxidation of Iron and Arsenic Sulfide Minerals 29 References 38 CHAPTER 3 FUNDAMENTALS OF OXIDATION 45 Thermodynamics 45 Kinetic Considerations 59 Kinetic Model 64 References 72 CHAPTER 4 EXPERIMENTAL PROGRAM 75 Materials 75
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1 Introduction Gold ores are considered refractory if gold extractions from a conventional cyanidation process are less than 80% even after fine grinding 1 Arsenic bearing refractory gold ore has stones extremely difficult to deal with In the stones gold is locked up in arsenic mineral matrix as the form of microscopic or submicroscopic lattice
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Generally these studies demonstrate that roasting pressure oxidation bacterial oxidation chemical oxidation alkaline oxidation and ultrafine grinding are as pretreatment methods prior to cyanide leaching to enhance gold recoveries from refractory ores In addition literature reveals that most of researches are focused on refractory sulphide ores with high content of pyrite pyrotite and
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The oxidation of refractory gold concentrates containing arsenopyrite and pyrite and the simultaneous dissolution of gold in aerated alkaline solutions at ambient temperatures and pressures without the addition of cyanide has been studied It involves the following aspects the chemistry of the oxidation of pure arsenopyrite and pyrite minerals in aerated alkaline solutions the kinetics of
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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 from refractory ores
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The oxidation of refractory gold concentrates containing arsenopyrite and pyrite and the simultaneous dissolution of gold in aerated alkaline solutions at ambient temperatures and pressures without the addition of cyanide has been studied It involves the following aspects the chemistry of the oxidation of pure arsenopyrite and pyrite minerals in aerated alkaline solutions the kinetics of
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Keywords pretreatment process pressure oxidation refractory gold ore and concentrate leaching modeling Investigation of high pressure pretreatment process for gold leaching is the objective of the present master s thesis The gold ores and concentrates which cannot be easily treated by leaching process are called refractory These types of ores or concentrates often have high content of
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Many refractory gold concentrates have high arsenic contents and there is an increasing demand for treating such concentrates using bio oxidation As the arsenic level increases in the concentrate beyond a certain level it can impair the rate of oxidation unless countermeasures are adopted Holder 2024
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Using Petropavlovsk s proposed pressure oxidation facility as an example the company said in 2024 it expected processing costs at its Pioneer mine of US$ per tonne for non refractory ore and US$ per tonne for refractory ore The company also budgeted US$500 million for the POX hub s development Not using special processing for the complex ore lodes also doesn t seem viable
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The effect of solid concentration % in bioleaching was investigated at pH and the temperature was kept at 32 °C The highest extractions of nickel cobalt zinc and iron at 5% and
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For the processing of free milling ores to refractory gold ores Metso Outotec offers end to end process solutions including comminution flotation pressure oxidation bio oxidation BIOX
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this is an abstract only no full paper was prepared for this abstract citation casingena c czerny c paterson l and carter p 2024 oxidation of a refractory gold concentrate using pressure atmospheric and bacterial oxidation processes in proceedings world gold 2024 p 681 the australasian institute of mining and metallurgy melbourne
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Pressure Oxidation Pressure oxidation is employed to liberate gold and silver in refractory sulfide concentrates often and ores The main pressure oxidation products from iron sulfide minerals are sulfuric acid and metal sulfates and hematite Depending on the conditions within the autoclave acid containing iron compounds can be formed
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PRESSURE OXIDATION OF REFRACTORY GOLD ORES THE 2024 10 1 Pressure Oxidation Pressure oxidation is employed to liberate gold and silver in refractory sulfi
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oxidation needs high pressure and high temperature to accelerate the oxidation process through the elimination of thin film sulfide and arsenide coatings from gold surfaces leading to easy cyanide access to gold However the strict requirements for equipment and the high operating cost are still big −25 Chemical oxidation can provide good results and chlorination roasting is
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