preg robbing gold in autoclave o idation

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PROCEDURE FOR CHARACTERIZATION OF CARBONACEOUS …

Autoclave pressure oxidation (AC POX) of refractory sulphide ores and subsequent cyanidation is ... or preg-rob gold from the cyanide leach solution. Carbonaceous matter present in the Carlin type carbonaceous sulphide ores has shown varying degree of preg-robbing activity [1-3]. In that regard it is important to develop technology and ...

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Speciation and quantification of surface gold in ...

Jan 19, 2011· Gold recovery can be adversely affected by preg‐robbing on inherent carbonaceous material during autoclave pressure oxidation of sulphide ores. The time of flight (TOF) SIMS (TOF‐SIMS) technique has been applied for direct determination of gold species on individual carbonaceous particulates from AC POX stream samples.

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Determining Gold Balance In Refractory Gold Ores | SRK ...

Trace amounts of gold with a mixture of illite/smectite clay, montmorillonite and free carbon were observed by Laser Ablation Inductively Coupled Plasma Mass Spectrometry, indicating potential for preg-robbing by clays and carbon. Preg-robbing is a process that prevents some of the gold from being recovered, making extraction less effective.

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Speciation and quantification of surface gold in ...

Jan 19, 2011· Gold recovery can be adversely affected by preg-robbing on inherent carbonaceous material during autoclave pressure oxidation of sulphide ores. The time of flight (TOF) SIMS (TOF-SIMS) technique has been applied for direct determination of gold species on individual carbonaceous particulates from AC POX stream samples.

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Pressure Oxidation Treatment - 911 Metallurgist

May 01, 2018· The ore also contains 0.4% carbon which is highly preg-robbing. Gold and silver are recovered by crushing and grinding the ore to 95% minus 200 mesh, followed by bulk sulfide flotation. A new round of in-house laboratory experimentation with pressure oxidation began in 1990.

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Practical Treatment Options for Carbonaceous Preg-Robbing ...

Jan 01, 2017· The Use of Mercury to Inhibit Autoclave Preg-Robbing of Gold Commercial Production of High Purity Nickel Cathode from Cop Geometallurgy – The Key to Improving Your Mine Value Chain Characterization of Solid Phases in the Iron-Sulfate-Water S The Technology of CO2 Sequestration by Mineral Carbonation:

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Patents Assigned to Barrick Gold Corporation - Justia ...

Dec 14, 2001· Abstract: A process for recovering gold in which an ore slurry of refractory sulfidic and refractory carbonaceous ore having preg-robbing characteristics due to the presence of organic carbon is subjected to pressure oxidation in an autoclave. The oxidized ore slurry is mixed with a thiosulfate salt lixiviant, which mixture is maintained at a ...

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Determination of Surface Gold Preg-Robbed on Carbonaceous ...

The CIL residue was analysed for possible losses due to preg-robbing of gold from the cyanide solution onto carbonaceous material present in the sample. Objectives: Detection ("speciation") of different forms of surface gold preg-robbed on carbonaceous matter: metallic gold Au° and gold compounds (Au(CN) 2 –, AuS(CN) 2 — …) by ToF-SIMS.

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Adsorption of aurocyanide complexes onto carbonaceous ...

test. In the preg-robbing test, a percent preg-robbing value %PR is obtained by measuring the change inŽ. solution of gold concentration after contacting a gold–cyanide solution with a known mass of ore in batch for 15 min 5,10 . The ability of the preg-rob-wx bing test to predict the preg-robbing …

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Process simulation and gate-to-gate life cycle assessment ...

An increasing amount of global gold production derives fromrefractory-typematerials.Thesematerialshavehighcon-centrations of sulfide minerals that encapsulate the gold, such as pyrite and arsenopyrite, and preg-robbing material such as carbonaceous minerals. They require pre-treatment methods such as roasting, pressure oxidation, or bioleaching ...

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Biological Oxidation Of Sulphides In Gold Ore

Thiocyanate oxidation as well as the decomposition of the preg-robbing component was evaluated.Pre-oxidation of the material with ozone in an acidic medium ph 12 resulted in the oxidation of sulphides and the liberation of gold.Partial destruction of the preg-robbing component was also observed.This resulted in increased gold recoveries.

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Pressure Oxidation Circuit

Jan 31, 2018· Partial oxidation has resulted in an autoclave plant that is able to achieve low operating unit costs. Process Description. The oxidation circuit consists of one autoclave, two stages of slurry heating, and two stages of flash cooling. The autoclave was designed to operate at 180°C (356°F) with a slurry residence time of 48 minutes.

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Autoclave - an overview | ScienceDirect Topics

After the CCD wash circuit, the slurry is neutralized and forwarded to gold recovery by cyanidation. The Placer Dome (now Barrick) Campbell Mine facility was commissioned in July 1991 and represents one of the early autoclaves to treat an auriferous (Au: 213 g/t) sulfide concentrate with relatively high arsenic (10%) and sulfur (18%) contents.The first was São Bento in Brazil.

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ALTA Gold 2012 E-Doc

Refractory gold ores are those that do not yield high gold recoveries in conventional cyanide-leaching circuits, even when the ore is finely ground. The cause of low gold recoveries can be either through the presence of naturally occurring 'preg robbing' carbonaceous materials or gold physically 'locked' in sulphide minerals.

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Ammoniacal thiosulfate and sodium cyanide leaching of …

Apreg-robbingB wx2 . Preg-robbing occurs during ore processing when the ore sequesters gold from the pregnant cyanide solution during leaching. Carlin trend ores contain natural organic carbon that varies in preg-robbing behavior 3 . Since thewx preg-robbing nature of Carlin trend ore may prevent recovery of a significant fraction of gold ...

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The Metallurgy of Cyanide Gold Leaching – An Introduction ...

Oct 20, 2014· Preg-robbing material can be deactivated prior to leaching by the addition of kerosene or diesel or similar blinding agents. Cyanicides : Cyanide is an aggressive compound, and will react and be consumed by a number of mineral species other than gold – species known as cyanicides.

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The modes of gold loss in the calcium thiosulfate leaching ...

The processing of gold is becoming more complicated due to the increasingly complex nature of the remaining gold-bearing ore bodies. This worldwide phenomenon is the driving force for the development of alternative technologies for the leaching and recovery of gold from so-called double refractory ores. Barrick Gold recently commercialized a unique calcium thiosulfate leaching plant to treat ...

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preg-robbing Archives - International Mining

The project's base case post-tax net present value (10% discount) was measured at $112 million and factored in a $1,200/oz gold price, 65 RUB/$ exchange rate and a total of 4.3 Mt of concentrate containing 9.3 Moz of gold processed from Kyzyl, Nezhda, Mayskoye, and …

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US5536297A - Gold recovery from refractory carbonaceous ...

A process for recovering gold in which an ore slurry of refractory sulfidic and refractory carbonaceous ore having preg-robbing characteristics due to the presence of organic carbon is subjected to pressure oxidation in an autoclave. The oxidized ore slurry is mixed with a thiosulfate salt lixiviant, which mixture is maintained at a pH between 7 and 8.7 while the slurry is agitated in a ...

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Western University [email protected]

Study on the surface features of Preg-Robbing carbonaceous matter during oxidation treatment Mana Pourdasht The University of Western Ontario Supervisor Dr. Brian Hart The University of Western Ontario Graduate Program in Geology A thesis submitted in partial fulfillment of the requirements for the degree in Master of Science

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[PDF] PREG-ROBBING CARBONACEOUS MATTER: AN …

Gold losses related to carbonaceous matter (CM) during processing are a significant problem in the gold processing industry. Inherent CM in gold ores can behave similarly to activated carbon in its ability to adsorb gold cyanide. This phenomenon is termed preg-robbing as the surface adsorbed gold cannot, for the most part, be recovered.

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IN MINING & MINERAL PROCESSING - AFX Holdings

specifically developed for the processing of gold ores containing "preg-robbing" materials i.e. organic carbon. These materials reduce the gold yield by attracting the gold meant for the activated carbon. The employment of leaching and adsorption assists in minimising this problem.

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Preg-Robbing Carbonaceous Matter: An Evaluation of Surface ...

Jan 01, 2017· "Gold losses related to carbonaceous matter (CM) during processing are a significant problem in the gold processing industry. Inherent CM in gold ores can behave similarly to activated carbon in its ability to adsorb gold cyanide. This phenomenon is termed preg-robbing as the surface adsorbed gold cannot, for the most part, be recovered.

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Technical Report - i80Gold

Jan 22, 2021· indicating a preg-robbing mechanism. • Column leach tests on the CX Pit samples achieved gold recoveries of 82%. The testwork on the Ogee underground samples showed that: • Autoclave pre-treatment ahead of cyanide leach testwork demonstrated significant increases in gold recovery relative to baseline cyanide leach tests.

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Evaluation of preg-robbing potential of refractory gold ores

Preg-robbing TestsReagent grade sodium cyanide (NaCN) and sodium hydroxide (NaOH) were used in the study. All solutions were prepared using deionised-distilled water. A calibration standard solution of AuCl 4 - (1000 ppm) was used as a source of gold to prepare gold cyanide solutions. Preg-robbing tests were performed in 250-ml polypropylene ...

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Assessment of the Possibility of Hydrometallurgical ...

highly preg-robbing with gold adsorbed within half an hour. The oxide minerals examined including kaolinite, goethite and hematite were significantly less preg-robbing under the same conditions. The presence of free thiosulfate can significantly reduce or eliminate preg-robbing of gold on mineral surfaces. Copper (I) was found to enhance

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Double-Refractory Carbonaceous Sulfidic Gold Ores ...

Jan 01, 2016· 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. Therefore, even if the sulfide oxidation is effective, the preg-robbing effect still causes issues with gold …

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Gold Process Mineralogy - SGS USA

usually recovered by pre-oxidation followed by cyanidation with or without prior concentration by flotation. Gold ... gold ores are pretreated by autoclave and roaster prior to cyanide leaching.4.5 In the JInya Carlin-type gold ... • Evaluate the preg-robbing potential of carbonaceous matter and gangue minerals • Determine the reasons(s ...

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Preg-robbing gold ores - ScienceDirect

Jan 01, 2005· Preg-robbing is an important phenomenon that inhibits gold recovery due to the presence of naturally occurring carbonaceous matter. In case of certain ores, gold recovery by cyanidation is limited by the presence of naturally occurring carbonaceous material that adsorbs gold from alkaline cyanide solution unless steps are taken to prevent this adsorption reaction from occurring.

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Gold mineral processing - Hatch Ltd

Gold recovery and refining. Companies need successful recovery methods that drive profits. Design teams with extensive experience in cyanide-in-leach (CIL), cyanide-in-pulp (CIP), carbon elution, carbon activation— in addition to newer thiosulfate leaching and regeneration processes—can enhance gold recovery and profitability.

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Recent Advances in the Development of an Alternative to ...

variable concentrations of preg-robbing graphitic carbon. These samples were representative of future Goldstrike reserves, and contrast the current feed material, which is generally sulphidic but not preg-robbing, and oxidized in autoclaves to achieve satisfactory gold recovery. In …

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Deportment of gold in an autoclave pressure oxidation (AC ...

The gold deportment data show that 37.5% of the gold losses in the CIL residue are related to sub-microscopic gold contained in the unoxidized pyrite mineral phase (Figure 1). The carbonaceous matter present in the ore exhibits strong preg-robbing capacity and contributes to 44.5% of the gold losses in the form of surface gold (Figure 1).

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Process simulation and gate-to-gate life cycle assessment ...

Dec 26, 2019· Sulfuric acid is generated in situ in the autoclave under operating conditions, Eqs. 1 and 2, see ESM S1.1 for the reaction mechanisms. It is beneficial to maintain excess sulfuric acid in the autoclave, in order to promote oxidation and prevent preg-robbing phenomena (Marchbank et al. 1996; Fleming et al. 2008). Cyanidation

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Use of ion-exchange resins to deal with the effect of preg ...

May 26, 2015· Use of ion-exchange resins to deal with the effect of preg-robbing of gold in the course of cyanide leaching Download PDF. Download PDF. Sorption and Ion Exchange Processes ... The suggested concept was used to diminish the loss of gold via partial oxidation of metallic gold in autoclave processing of pyrite- and arsenopyrite-containing ...

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Preg-Robbing Gold Ores - ScienceDirect

Jan 01, 2016· Thus, the preg-robbing value (or activity) of the sample can be characterized as: (49.9) Preg-robbing value = AuCN (ppm) + 3.4 ppm−AuPR where AuCN is the cyanide-leachable gold of an ore sample, AuPR is the final gold concentration after being preg-robbed and 3.4 ppm is the amount of gold spiked into the leach experiment (Wan et al., 1994).

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Chloride as an Alternative to Cyanide - Home | SGS

Application of the process to preg-robbing gold ores, and to silver ores, is also briefly discussed. Methods of recovering the gold from the PLATSOL ® liquors are examined. DEVELOPMENT OF THE PLATSOL ® PROCESS . Fundamentals Pressure oxidation has been used . commercially since 1985 to pretreat refractory gold ores prior to cyanidation [10].

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Minerals | Free Full-Text | CIL Gold Loss Characterization ...

A double refractory gold ore contains gold particles locked in sulphides, solid-solution in arsenopyrite, and preg-robbing material such as carbonaceous matter, and so on. The diagnostic leach test (DLT) and preg-robbing (PR) approaches are widely used to investigate the occurrence and the distribution of refractory gold. DLT serves to qualitatively evaluate the gold occurrences within the ore.

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