Jan 01, 1987· 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 a c t o r y gold …
2.1 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 …
Oxidation . ABSTRACT . The Leachox refractory gold process has to date been applied to the selectivetreatment of several refractory gold ores but on a relatively small scale. In this paper the successful implementation of the process, from initial testing through to commissioning at one of the world's largest refractory gold mines is described.
Examples of this include pressure oxidation (POX) of sulfide ores and concentrates, high-pressure acid leaching (HPAL) of nickel laterites, and wet-air oxidation of organics. Both batch and continuous reactors are available at Hazen for developing high-temperature processes. Hazen's engineers have assisted clients in developing POX processes for refractory gold …
Pyrite and arsenopyrite are known to be the most common gold-bearing sulfide minerals in refractory gold ores. Traditionally, these minerals have been first oxidized by roasting, acidic pressure ...
Pressure oxidation was developed for processing refractory ores where gold is occluded in the sulfide minerals typically pyrite or arsenopyrite Oxidation of the sulfides at elevated temperatures and pressures liberates the gold allowing it to be economically recovered by conventional circuits.
refractoriness is due to encapsulation of the gold particles inside the host mineral. To liberate gold for leaching the host mineral must be broken by mechanical or chemical means. 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.
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 associated with sulfides and is not amenable to conventional cyanidation. A brief review of the literature on pressure oxidation of refractory gold materials is presented. The chemistry of …
Refractory gold concentrates often contain sub-microscopic gold that is encapsulated within the crystal matrix of iron sulphide minerals such as pyrite, pyrrhotite and arsenopyrite. To recover the gold, the host mineral must generally be broken down chemically, by oxidative processes such as roasting, pressure oxidation or bacterial leaching, which expose the gold for subsequent …
Jan 01, 2009· An acidic pressure oxidation pre-treatment of refractory gold concentrates from the KweKwe roasting plant, Zimbabwe Minerals Engineering, 12 ( 8 ) ( 1999 ), pp. 863 - 875 Article Download PDF View Record in Scopus Google Scholar
pressure oxidation refractory gold minerals. Pressure oxidation - Wikipedia. Pressure Oxidation is a process for extracting gold from refractory ore.. The most common refractory ores are pyrite and arsenopyrite, which are sulfide ores that trap the gold within them.Refractory ores require pre-treatment before the gold can be adequately extracted.
Some ores require a high-temperature, high-pressure pretreatment process before leaching in order to improve metal recovery from the complex ore. ... The entire spectrum—or whatever elements are most appropriate to your operation—leads to successful pressure oxidation of refractory ores and sulfide concentrates. ... gold recovery from ...
2.3 Pretreatment of Refractory Sulfidic Gold Ores 15 2.3.1 Pressure Oxidation 18 2.4 Acidic Pressure Oxidation of Iron and Arsenic Sulfide Minerals 29 References 38 CHAPTER 3 FUNDAMENTALS OF OXIDATION 45 3.1 Thermodynamics 45 3.2 Kinetic Considerations 59 3.2.1 Kinetic Model 64 References 72 CHAPTER 4 EXPERIMENTAL PROGRAM 75 4.1 …
of pressure aqueous pre-oxidation of the sulphi de minerals. Pressure oxidation has been the most popular method for the treatment of refractory gold concentrates (see Table 1); This process utilizes oxygen or air at high pressures and temperatures to oxidize an aqueous
Telson Mining Corporation has reported encouraging historic leachox testing from its Campo Morado tailings material at the mine of the same name in the Guerrero State, Mexico.Maelgwyn Mineral Services of Wales, UK conducted preliminary testing of samples from the project in 2013 for Nystar, the project's former owner, of which Telson is now aware.
impervious sulphide mineral matrix, and is termed refractory. The most common refractory gold sulphide hosts are arsenopyrite and pyrite, and in order to achieve acceptable gold recoveries, it is generally necessary to break down the host mineral chemically. This is done by roasting, bacterial oxidation or pressure oxidation
"Pressure oxidation was selected as the most feasible processing technology for double refractory ores. It is able to achieve gold recoveries of 96% by utilising high temperatures, elevated pressure and oxygen to recover encapsulated gold, while conventional cyanidation methods would result in sub-optimal recovery rates of 20-40%.
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 2009,The Southern African Institute of Mining and Metallurgy, 2009. Developments in the pretreatment of refractory gold minerals by nitric acid D.-X. LI
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.
Challenges. Polymetal International Inc. is undertaking the Amursk POX Hub Expansion to recover gold from double-refractory (high carbon) sulphide concentrate from five of their mines in Siberia, Eastern Russia, and East Kazakhstan. The project will double Polymetal's concentrate treatment capacity to 250,000-300,000 t/a of refractory gold concentrate.
The present invention is directed to an improvement in a process for the recovery of gold from refractory sulfidic auriferous ores which comprises oxidizing a slurry of ore with oxygen gas under pressure in the presence of sulfuric acid, neutralizing the oxidized slurry, cyanidizing the neutralized slurry to leach gold therefrom, and recovering gold from the resultant leachate.
Aug 18, 2020· The alkaline hot-pressure oxidation is only suitable for refractory gold deposits with high carbonate content and low sulfide content (20%). The acidic hot-pressure 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 structure ...
The pressure oxidation approach that allows obtaining high gold recovery from double refractory materials was proposed. $/7$ : The chemical compositions of the concentrates
Following, pressure oxidation, the slurry can be subjected to cyanidation recovery of gold, and liquid from the tailings stream can be recycled upstream of the pressure oxidation step in a substantially untreated form. The process is useful for recovering gold contained as ultra-small masses in sulfide minerals.
Pressure oxidation (POX), high pressure oxidation (HiPOX) and ACTIVOX autoclave leaching are viable industry-standard technologies used to recover gold and other accessory metals. Read more The process is particularly well suited for treating refractory gold ores, which give low recovery when directly leached with cyanide.
Abstract: The use of alkaline pressure oxidation to pretreat refractory gold ore often results in insufficient gold recovery (<60%) in downstream thiosulfate leaching. To improve gold recovery, flotation was considered for the separation of carbonaceous matter (C-matter). In this study, the
The oxidation of refractory gold concentrates containing arsenopyrite and pyrite ... aerated alkaline solutions have been studied using high pressure ion chromatography ... an anodic oxidation of the mineral involving hydroxyl ions coupled to a cathodic process
The common definition of "refractory" gold ores, are those ores that do not ... Pressure oxidation: Utilizes oxygen and heat under pressure in a liquid medium, to effect oxidation of sulfur by way of a controlled chemical reaction. High pressure autoclaves are used for the reactors. Reactor operation is under
Keywords: pretreatment process, pressure oxidation, refractory gold ore and concentrate, leaching, modeling Investigation of high pressure pretreatment process for gold leaching is …
Aug 19, 2020· For the processing of free-milling ores to refractory gold ores, Outotec offers end-to-end process solutions including comminution, flotation, pressure oxidation, bio-oxidation (BIOX ...
Aug 11, 2018· 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.
High-pressure oxidation processes are difficult to carry out, because they require high high pressure oxidation of refractory gold minerals High Pressure O Idation Of Refractory Gold Minerals. pre v i o u s w o r k a n d s o u r c e s o f d a t a the blueschist pods consist of metamorphic minerals of high-pressure origin such as phengite mica ...
Iron sulfide minerals break down completely during pressure oxidation, and dissolve in the sulfuric acid solution that is generated from oxidation of the sulfides. This dissolution liberates the tiny gold particles that were originally trapped in the sulfide crystals, and gold recovery during subsequent cyanidation is usually very high (>95%).