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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 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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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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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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A novel method for gold recovery from sulfide refractory gold ore is proposed with two stages of roasting and thiourea leaching. The method improves gold recovery …
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Effect of pre-aeration on gold leach recovery. In the paper "Treatment of Gold Ore containing Pyrrhotite at Sub-Nagel, Limited" the authors describe investigations carried out to determine the cause of high residues at the aforesaid property and the measures taken to correct the difficulty. The following treatment was evolved:
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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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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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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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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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Pre-aeration and Ore Washing. In some ores, particularly partially sulfidized ores, aeration (prior to the introduction of cyanide) of the ore in water at high pH can render elements such as iron and sulfur less reactive to cyanide, and therefore the gold cyanidation process more efficient.
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So, the aim of the present work is to study a pretreatment with nitric acid as an alternative to improve the recovery of gold from ores associated with gold and gold …
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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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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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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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A refractory gold ore is defined as an ore with low gold recovery (less than 80%) when treated by conventional cyanidation. ... cyanidation at high pH or pre-aeration, and leaching using chlorination. Nitric acid has been used successfully in the pretreatment of gold ores associated with sulfides such as pyrite and arsenopyrite.
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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 conventional cyanidation to leach gold. ... Gold extraction was seen to rise in most cases after an increased rate of aeration during pre-treatment. Finally, the iron ...
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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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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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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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The global approach toward growth and development of industries is driving the increase in demand for precious metals such as gold (Street et al. 2015; Qin et al. 2023).Furthermore, the global gold reserves of ore types that can be processed more facilely are becoming exhausted (Oktay et al. 2016)plex ore deposits or …
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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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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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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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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 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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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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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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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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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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