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3 Pre-aeration and gold cyanidation Cyanidation is typically conducted at a pH of over 10, with an O 2 ... facilities that treat gold ores containing low refractory gold ores.
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The leaching behaviour of a sulphide gold-silver ore was investigated in terms of a relationship between gold and silver extractions and cyanide consumption. 95.0% Au and 88.0% Ag extractions were obtained under the determined conditions as 24h leaching duration, -74 µm particle size, 40% solids ratio, 4 g/L NaCN concentration, and 450 rpm …
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Aeration curing, over a long duration in wetted stockpiles, shows promise as an affordable pretreatment method for oxidizing gold encapsulating sulfide minerals, and possibly organic matter, in low grade refractory ores. Following aeration pretreatment, the ore is reclaimed, neutralized, and cyanide leached by conventional practices. Large …
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Figure 1: Gold Recovery Tests for Carbonaceous Ore Figure 2: Gold Extraction Curve for Carbonaceous Ore with Kerosene Pre-treatment Gold Recovery - Carbonaceous Ore Standard Cyanide Leach Clean Mining Reagent Clean Mining + Kerosene Pre-treatment Clean Mining + Pre-aeration and RIL Gold Recovery (%) 100.0 90.0 80.0 70.0 60.0 …
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Cyanidation is the main process in gold leaching. There are several parameters that affect gold recovery and cyanide consumption. In this paper, the effect of the oxidative pretreatment and lead nitrate addition on the cyanidation of Zarshuran refractory gold ore containing 3.32 ppm Au, 1.09% As, and 0.5% sulfur were …
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The paper presents an overview of bio-oxidation of sulphidic refractory gold ores prior to gold cyanidation. This review discusses several factors, more importantly, oxygen requirements and oxygen ...
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The most common techniques include pre-aeration, roasting, high pressure oxidation and biological oxidation. ... Gold ores are catalogued as refractory if the extraction by direct cyanidation is less than 80%. With the cyanide bottle roll for the mineral concentrate, the gold recovery was only 23%, clearly indicating the refractoriness of this ...
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The gold dissolution for Test 2 (pre-aeration with oxygen, cyanidation with air) is similar to the dissolution with air used in both steps (Tests 1 and 3). TABLE 4 . ..., and the effect of using oxygen during the pre-aeration step. Measurements on the ore samples used in this study indicated that: ( 1 ) The oxygen consumption due to the ...
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Plant Location Ore Type Unit Process Issue Chapter; Consolidated Murchison mine: South Africa: Cyanidation under high oxygen pressure: Implemented with tube autoclaves 1.5: km long and 5 cm inner diameter.: Leaching at ambient temperature and 5 MPa oxygen pressure and 0.2–0.5% NaCN; 15 min residence time for 85% …
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including thiosulphate and ammoniacal cyanide, pre-aeration prior to ... leaching systems for pre-leaching of copper from gold ores. Pre-leaching by ammonia and sulfuric acid leaching 0 20 40 60 ...
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The oxidation roasting of carbon-bearing micro-fine gold can eliminate or weaken the robbing effect of carbonaceous materials and clay, and destroy the encapsulation of micro-fine gold. The micropores produced by gas escaping during the roasting process are conducive to the diffusion of leaching agents, thus enhancing the …
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Pre-aeration of the concentrate improved the gold and silver extractions by 4-14% and 23-44% at the subsequent cyanide leaching (1.5-3.5 g/L NaCN). ... These types of gold sulphidic ores may be ...
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Special pretreatment methods are used prior to the conventional cyanidation process to enhance gold recovery and to overcome the leaching resistance of refractory …
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Four iron-sulphide-containing gold ores from the White Mountain mine in the Jilin Province, China were studied to examine the benefits of using oxidative treatment prior to …
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Cyanide-refractory ores constitute 30 % of the world's gold mineral resource base. With the global decrease in the availability of high-grade and free-milling ores, low-quality ores, including ...
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The gold cyanidation process is the most important method ever developed for extracting gold from its ores. The reasons the widespread acceptance of cyanidation are economic as well as metallurgical. It usually obtains a higher recovery of gold than plate amalgamation and is easier to operate than the chlorine or bromine process. It …
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Pre-aeration of the concentrate improved the gold and silver extractions by 4-14% and 23-44% at the subsequent cyanide leaching (1.5-3.5 g/L NaCN). ... benefits and limitations of pre ...
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In gold ores containing carbonaceous material, the preg-robbing nature of carbonaceous material may impose challenges on gold extraction and cause gold losses. To extract gold from refractory sulfide ores, the ore needs to be finely ground and preoxidation is often required. Sulfide host minerals must first be oxidised to create a porous ...
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Eliminating the gold preg-robbing effect of carbonaceous matter in carbonaceous gold ores is crucial for gold leaching. In this study, suspension oxidation …
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The leaching behaviour of a sulphide gold-silver ore was investigated in terms of a relationship between gold and silver extractions and cyanide consumption. Ninity five Au % and 88.0% Ag extractions were obtained under the determined conditions of
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and aeration could not provide a reduction in the cyanide consumption. Therefore, the effect of the pre-aeration followed by cyanidation was tested. Eventually, applying 4 h of pre-aeration before a shorter leaching duration of 12 h provided 92.0% Au and 90.5% Ag extractions with a lesser NaCN consumption of 2.44 g/dm3.
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The use of thiosulfate to extract gold from refractory ores is promising because of its non-toxicity and high selectivity. Sulfide minerals (i.e., pyrite, arsenopyrite, chalcopyrite), major gold carriers in refractory gold ores, however, hinder gold extraction due to the high consumption of a lixiviant. In this study, a new method to improve gold …
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The findings indicated that gold extraction from the refractory arsenopyritic gold ore improved up to 81% with the pretreatment, while with cyanide and thiosulfate …
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The technological processing flowsheet for gold-bearing ores varies widely. The choice of a particular technological flowsheet depends on several factors, including the nature of the gold in the ore, especially its size and chemical composition, the nature of the minerals associated with the gold, the presence of other valuable components in the …
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Keywords: Gold ore; Column flotation; Cyanidation; Refractory ore 1. INTRODUCTION Kolar Gold Fields owned by M/s. Bharat Gold Mines Limited (BGML) is well known for its gold reserves ... Effect of pre-aeration on gold dissolution (Solids: 50%, NaCN: 5kg/t, pH: 10.5) Pre-aeration conditions Feed g/t, Au Residue g/t, Au Pregnant liquor g/t, Au
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Introduction to Gold and Silver Leaching The cyanide leaching process is the most important method ever developed for extracting gold from its ores. The early development of the process is attributed to a Scotchman, John Stewart Mac Arthur, in collaboration with the Forrest brothers. The method was introduced into South Africa in …
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Sulfur containing anions such as thioantimonates (SbS 3 3−) and sulfides (S 2−) are known to be strong 'poisons' in the cyanidation of gold (Nicol et al., 1987), and Fink and Putnam (1950) have shown that dissolved sulfide levels of as low as 0.5 mg/L can have a significant deleterious effect on rates of gold dissolution.. In many cases where minor …
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Typically, gold is encapsulated or finely disseminated in refractory gold ores and the direct cyanidation is not effective for gold extraction from these ores, even after the ore is ground to exceeding small particles (Nazari, 2017, Corrans and Angove, 1991).Especially for sulfide refractory gold ores, in order to recover gold, many …
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These types of gold sulphidic ores may be pre-treated prior to cyanidation by means of an oxidation step, converting the sulphides into oxides or sulphates. This treatment leads to a reduction in the consumption of dissolved oxygen and of cyanide in the cyanidation step and to an improvement in the metallurgical recovery. In the current work we ...
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For Test 4 (oxygen in pre.aeration and cyanidation ) the final dissolution was 3.8% higher than the average ofTests I and 3 (air in pre-aeration and cyanidation ). The gold dissolution for Test 2 (pre-aeration with oxygen, cyanidation with air) is similar to the dissolution with air used in both steps (Tests 1 and 3).
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1. Introduction. Cyanidation has been the predominant leaching method for gold ores since 100 years ago [1].Despite the success of cyanidation, its applicability is limited by some gold mineralization [2].This method's main limitation is in dealing with refractory gold ores in which sulphide minerals surround gold particles [3].The major …
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It is believed that pre-aeration serves two purposes: (i) to oxidize and disintegrate sulphide minerals to expose encapsulated gold, and (ii) to passivate the sulphide
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nite were present in the Zarshuran refractory gold ore, as can be seen in Fig. 1. The result of the elemental analysis of the sample is shown in Table I, according to which the Zarshuran refrac-tory gold ore contains 3.32 ppm Au, 1.09% As, and 0.5% sulfur. This amount of sulfur indicates that the Zarshuran refractory gold ore is a low sulfide-
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This study investigates the alkaline oxidation pretreatment process of Zarshuran refractory gold ore. Taguchi method-orthogonal array design (OAD) is applied to evaluate and optimize the influence of five main factors including solution pH, aeration rate, agitation speed, temperature, and oxidation time.
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The pretreatment of gold ores before cyanidation is a challenging problem due to the world's annual huge waste of refractory gold minerals. Generally, the leaching of gold by cyanidation without any pre …
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The processing of low-grade gold ores is largely made possible through the use of the cyanide leaching process. The goal of any leaching process is to selectively bring a desired mineral into solution in order to efficiently separate it from the solid waste material. ... the dissolved oxygen (DO) levels is typically achieved through the ...
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