Bio-oxidation of Arsenopyritic and Pyritic Containing Gold ...
The bio-oxidation of arsenic-bearing gold ore from tianli gold mine was investigated by comparing the dissolution of the sample ore in four different media, in a mix bacterial medium, mix bacterial medium after centrifugation, acidic medium and in a pure sterile medium. The experimental results showed typical oxidation characteristics for the ...
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Synergistic extraction of gold from the refractory gold ...
A synergistic extraction method for gold from the refractory gold ores via ultrasound and chlorination-oxidation was developed. The effects of solid-liquid ratio, extraction time, ultrasound power, NaClO concentration and NaOH concentration on the extraction rate of gold from the refractory gold ore …
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Effect of Pretreatment of Sulfide Refractory Concentrate ...
more of it than gold in the ore. Oxidation of arsenopyrite is of practical and theoretical importance in processing gold ores and concentrates. However, the chemistry of arsenopyrite in relation to its dissolution, flotation, and electrochemistry has received little attention [6]. There- fore, in alkaline oxidizing conditions, arsenopyrite can be
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Atmospheric alkaline pre-oxidation of refractory sulphide ...
DOI: 10.14288/1.0366302 Corpus ID: 139611489. Atmospheric alkaline pre-oxidation of refractory sulphide gold ores @inproceedings{Rego2018AtmosphericAP, title={Atmospheric alkaline pre-oxidation of refractory sulphide gold ores}, author={Alan Joseph Rego}, year={2018} }
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Acid leaching decarbonization and following pressure ...
Carbonate decomposition of carbonic refractory gold ore and the following pressure oxidation were studied. In the carbonate decomposition procedure, the effects of liquid-to-solid ratio and reaction time on decomposition ratio of carbonate were investigated. The experimental result shows that the decomposition ratio of carbonate is 98.24% under the conditions of liquid-to-solid ratio of 5:1 ...
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(PDF) Refractory gold-bearing ores: a review of treatment ...
This means that even refractory ores and concentrates where gold is evenly distributed among pyrite may respond to selective bacterial oxidation [ 37 ]. Besides, bacterial attack of the sulphide appears to be preferential in gold-rich regions because gold acts like the cathode in the gold …
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Minerals | Free Full-Text | Gold in the Oxidized Ores of ...
Hypogene gold is commonly isolated but for supergene gold typically associated with ferric (hydr)oxides. New formation of gold occurred due to oxidation of sulfide ores and release of "invisible" gold, as well as dissolution, mobilization and re-deposition of metallic hypogene gold.
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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. The pressure oxidation process is used to prepare such ores for conventional gold extraction processes such as cyanidation.
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(PDF) Biooxidation of sulfidic refractory gold ores ...
As the scarcity of oxide gold ore deposits increases, the demand for more efficient ways to process refractory sulfidic gold ores increases as well. Most deposits in the USA are considered to be refractory sulfides. While, without the oxidation of the sulfidic coating, the gold …
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PRESSURE OXIDATION OF REFRACTORY GOLD ORES: THE …
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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Mineralogical factors affecting the extraction of gold in ...
For refractory gold ore processing, pre-treatment technologies such as fine-grinding, autoclaving, roasting and bio-oxidation will also be required. The reason for using different process flowsheets is mainly because gold often occurs in different forms and minerals, and each ore has to …
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Economic evaluation of biooxidation of gold ores ...
Biooxidation of gold ores or concentrates could be a very attractive alternative to pressure oxidation (POX) or roasting to liberate the gold grains from various sulfides. Crushed heap bioleaching was successful in US and many operations using tank bioleaching of gold concentrate are currently running around the world.
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US5071477A - Process for recovery of gold from refractory ...
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.
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Bio-Oxidation of a Double Refractory Gold Ore and ...
Carbonaceous sulfidic gold ores are commonly double refractory and thus require pretreatment before gold extraction. In this paper, the capacity of pre-bio-oxidation can simultaneously decompose sulfides or deactivate carbonaceous matters (CM) from a double refractory gold ore (DRGO) using pure cultures of A. ferrooxidans or L. ferrooxidans, and a mixed culture containing Acidithiobacillus ...
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Gold Sulphide Ore Oxidation by Alkaline Pressure
Oxidation of sulfides from a thermodynamic point of view is feasible over the entire pH range. Since 1985, acidic aqueous pressure oxidation has been used commercially (Berezowsky, 1984,1989). Acidic pressure oxidation of pyritic gold ore requires treatment temperatures between 160° to 210° C and pressures of up to 400 psig.
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Is smelting an oxidation process? - Quora
Answer (1 of 2): Smelting is a process used to extract pure metals from their ores. The metals in the mineral ore are already oxidized as metal ions such as Fe2+ or Fe3+. So to convert them back to their metallic form they must be reduced (gain electrons). Reducing agents, often charcoal or coke...
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Microbial oxidation of gold ores and gold bioleaching ...
Abstract Much recent work in the field of biohydrometallurgy has been directed to the study of bio‐oxidation of gold ores by acidophilic iron and sulfur oxidizing microorganisms. This work has been done worldwide and has resulted in several pilot plant and commercial scale operations for gold ore bio‐oxidation.
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Lowering the Threshold for Refractory Gold Deposits with N.
sulfide encapsulation of the gold. These refractory ores must be oxidized before extraction of the gold, and for many years roasting was the only economical means to process sulfidic ores. More recently, pressure oxidation in autoclaves has been used successfully, and in the past 10 years, biooxidation has been gaining acceptance as an ...
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Bio-oxidation of refractory gold ores containing stibnite ...
Arsenic and antimony are environmental pollutants associated with several diseases, including skin cancer. One of the main sources of both elements is the oxidation of sulphide minerals, particularly arsenopyrite and therefore any of both elements is a concern in gold mining operations because arsenic- and antimony-bearing sulphides may contain significant gold contents.
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Leaching refractory gold ores – Gold Metallurgy
For some ores liberation is no problem and direct cyanidation works well if the pyrite is finely ground. But traditionally, these ores are simply roasted to oxidise the iron and arsenic and liberate the finely dispersed gold for cyanidation. However, the oxidation roast may not liberate the gold fully, or give unexpectedly low gold recoveries.
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ALTA Gold 2012 E-Doc - Home | Albion Process
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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Ore deposits formed by oxidation and supergene enrichment
Ore Deposits Formed by Oxidation and Supergene Enrichment · When ore deposits are exposed to the oxidation zone they are weathered and altered with the country rocks. · The surface waters oxidize many ore minerals and yield solvents that dissolve other minerals. · An orebody thus becomes oxidized and generally leached of many of its valuable materials down to the groundwater table, or to ...
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oxidation of gold ores
Gold Sulphide Ore Oxidation by Alkaline Pressure. Pressure oxidation of gold ores is therefore a pretreatment leaching step to enhance gold recovery. Although pressure oxidation of gold ores and concentrates does not directly recover gold in a strict sense of the above definition, it is an essential step to enable the gold to be recovered. Get More
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Technical Resource Document: Extraction and Beneficiation ...
ORES AND MINERALS VOLUME 2 GOLD August 1994 U.S. Environmental Protection Agency Office of Solid Waste Special Waste Branch 401 M Street, SW Washington, DC 20460. Technical Resource Document: Gold DISCLAIMER AND ACKNOWLEDGEMENTS This document was prepared by the U.S. Environmental Protection Agency
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Environmentally Benign, Rapid, and Selective Extraction of ...
The extraction of gold from ores and electronic waste is an important topic worldwide, as this precious metal has immense value in a variety of fields. However, serious environmental pollution and high energy consumption due to the use of toxic oxidation reagents and harsh reaction conditions is a well-known problem in the gold industry.
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TECHNOLOGY FOR PROCESSING OF REFRACTORY GOLD …
Gold, atmospheric oxidation, refractory concentrate, leaching . INTRODUCTION The considerable part of the world Au-bearing reserves is present by refractory ores with finely disseminated gold. Gold in such ores is often associated with sulphide minerals and locked in so called
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Gold Sulphide Ore Oxidation by Alkaline Pressure
sulfide ores and was used commercially for treating a cobalt-nickel arsenic ore (14). Alkaline pressure oxidation was also used to treat high-acid-consuming mercury gold ore (15). Alkaline pressure oxidation yields a residue composed primarily of iron oxide, which is environmentally safe and compatible with the cyanidation process.
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Understanding the heap biooxidation of sulfidic refractory ...
An investigation has been conducted into the nature and rates of the physical, chemical, biological, and thermal processes involved in the heap biooxidation of pyrite from refractory gold ores. A heap-scale model of the ideal process was developed, aided by a systematic experimental approach, which accounts for the following phenomena. Grain-Scale Kinetics - The thermal and chemical ...
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PRESSURE LEACHING - RPMGlobal
A major revolution in gold processing was the pressure oxidation of refractory, pyritic ores. In these ores, gold is chemically entrained in sulfides which require oxidation prior to standard cyanidation techniques. Many of these plants were built in the western United States in …
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(PDF) Bio-Oxidation and Biocyanidation of Refractory ...
Bio-Oxidation and Biocyanidation of Refractory Mineral Ores for Gold Extraction: A Review October 2014 Critical Reviews in Environmental Science and Technology 45(15)
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