Pressure oxidation is a hydrometallurgical technique that renders auriferous refractory materials, specially sulphides, amenable to cyanidation process. The effectiveness of the operation as a ...
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.
9 Citations. Metrics. Abstract. Pressure oxidation is a widely accepted method to treat refractory gold ores. Gold recovery is generally lower from alkaline than …
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 …
Refractory gold ore pretreatment Treatment of refractory gold ore (whole ore and flotation concentrates) has become more prominent since the 1980s, with many gold discoveries often including ores that are wholly or partially refractory. Refractory pre-treatment processes include pressure oxidation, biological oxidation and various forms of ...
Biological oxidation, chemical oxidation, pressure oxidation, and roasting oxidation are now using for the pretreatment of refractory gold concentrates (Li et al., 2009; Su et al., 2010; Wang et al., 2019), among which the pressure oxidation is the most promising (Zhang et al., 2016b). The other alternative is to search for non-cyanide lixiviants.
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.
Pressure oxidation refers to the oxidation of sulfides, such as pyrite [FeS 2] and marcasite [FeS 2], at elevated temperature and pressure. Oxidation releases …
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. …
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.
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 …
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.
The oxidation processes used for these pretreatments involve biological oxidation, high pressure oxidation, and roasting (Donato et al., 2007; Qin et al., 2021). With the development of the ...
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 ...
Although refractory high entropy alloys (RHEAs) have shown potentials to be developed as structural materials for elevated temperature applications, most of the reported oxidation behaviours of ...
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 ...
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, …
Many recent research activities on pressure oxidation of refractory gold ore focuse more on the control of the autoclave operation. There is a lack of a systematic study on the gold distribution in the solid discharge. ... High Temperature Pressure Oxidation of Ores and Ore Concentrates Containing Silver Using Contolled Precipitation of Sulfate ...
Concentrates with carbon content up to 1,5% must be overoxidized for 30–60 minutes, with content of 1,5–3,0% – for about 120 minutes at a temperature...
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 …
BCC HEAs based on refractory elements have shown interesting properties at elevated temperatures, such as outstanding high-temperature strength, high oxidation, and corrosion resistance, which ensure them promising materials for high-temperature applications [44, 96].
The high consumption of thiourea by the leaching system may be attributed to not only adsorption by mineral particles but also catalytic decomposition by some impurities in the ores, such as pyrite and soluble ferric oxide. ... S.J. Thorpe, and V.G. Papangelakis, Redox potential measurement during pressure oxidation (POX) of a refractory gold ...
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 …
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 …
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...
High-Temperature Eh-pH diagrams for the systems S-H20, Cu-S-H20 and Fe-S-H20, PhD Thesis, Imperial College, University of London. Mungoshi, J., 1989. The …
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 …
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 …
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, ...
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 ...