Drawing on recent experimental and commercial developments, this review reappraises potential substitute leach reagents for cyanide in the gold mining sector. In …
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Furthermore, the interaction between various factors for Na 2 S + NaOH leaching of the low-grade antimony-bearing gold ore are also determined through response surface model using Design-Expect 8.0.6 software. The expected results can provide a reference for the pre-removal of antimony in low-grade antimony-bearing gold …
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Ammonium thiosulfate is an alternative lixiviant for the hydrometallurgical treatment of sulfide gold ores. The present study is primarily focused on ammonium thiosulfate leaching of gold (Au) and silver (Ag) from the sulfide ore (Sunshin mine in Korea). The main chemical composition of the concentrate was Au (84 ppm), Ag (852 …
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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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Heap or vat leaching is a process that has been extensively used for the recovery of valuable metals like copper, gold (Au) and silver. The ore is prepared for vat leaching by either crushing or...
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In the direct alkaline leaching process, with the NaOH dosage of 8 g/L, the tellurium leaching rate was 40.99%, and the Te grade in the leach residue was 95 g/t, while in the oxidative roasting-alkali leaching process, with the NaOH dosage of 7 g/L, the tellurium leaching rate was 59.51%, and the Te grade in the leach residue was 81.6 g/t.
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The results of large-scale tests on intensive cyanidation of gravity concentrates Parameters Gravity concentrates obtained during the concentration of the ores from the deposits I II IV in the concentrate 260 212 120 in the cyanidation tailings 5.74 42.5 6.5 The length of leaching, h 10 9.5 17 Gold recovery, % 323 172.6 140 The consumption of ...
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Firstly, the refractory ore was pretreated with sodium hydroxide under ultrasound. Secondly, the pretreated ore was leached under ultrasound. The leaching ratio of gold decreased …
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Heap leaching, a process used to extract copper, uranium, and some precious metals from their ores. Another process in which copper and uranium are recovered via a process called In-Situ Leaching. Tank Leaching and Vat Leaching are processes wherein the ores are placed in large tanks (or vats) which contain leaching solutions. They can be used ...
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The application of pressure oxidation (POX) followed by thiosulfate gold leaching is an efficient method used to extract gold from double refractory gold ores containing both sulfide and carbonaceous matter. This process is expected to result in high gold recovery rates, as it liberates gold from sulfides and eliminates the preg-robbing …
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Ultrasound increased also the leaching rate of refractory gold ores during electro-chlorination because it reduced the diffusion resistance of HClO and ... (Na 2 S + NaOH) and 70 g of gold ore were added to the beaker. After the mixture was heated for 60 min with stirring, the solid residues were separated by filtration and were used to analyze ...
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Treatment of gold-bearing ore with hydrogen peroxide during heap leaching of gold increases gold recovery by 1.2% and amounts to 55.89%, without treatment - 54.69%. This increases the consumption ...
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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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technique in pretreatment and leaching for the refractory gold ores. KEY WORDS: gold ore; intensified leaching; ultrasound. 1. Introduction Cyanide leaching has been applied to separate gold from ore for over 120 years. Gold ores can be classified as free milling, complex, or refractory based on gold recovery achievable by direct cyanidation.
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Leaching and washing may require from two to ten days depending on the ore. Gold Leaching Flowsheet C1. This flowsheet is for a medium grade ore where a high recovery is made by the Mineral Jig in the grinding circuit and where a large percentage of the fine gold is dissolved during grinding. The solution is then sufficiently high grade to ...
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During leaching with Ferric ion a critical balance between Fe 2 + and Fe 3 + ions in the leach solution is essential to maintain efficiency of leaching and subsequent electrolysis. The ferric ion is also …
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In this work, the feasibility of using alkaline cyanide solutions for leaching copper, gold, and silver from Cu/Au/Ag ores is analysed and compared with acid leaching.
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Modeling the cyanide heap leaching of cupriferous gold ores Part 1: Introduction and interpretation of laboratory column leaching data. Hydrometallurgy 52 (2), 151–175. Costello, M.C., Ritchie, I.C., Lunt, …
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The role pH has in affecting gold leaching rates by cyanide and the functions of calcium hydroxide in cyanidation are as follow:. 1. For safety and to prevent loss of cyanide by hydrolysis. 2. To prevent loss of cyanide by the action of carbon dioxide in the air. 3. To decompose bicarbonates in mill water before using it in cyanidation.
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The ongoing depletion of gold and silver-containing ore deposits demands a shift towards the processing of more complex sources. Leaching of gold or silver from these sources, which are named refractory and are typically low-grade, can be complicated due to one or more of the following effects: (1) kinetic or thermodynamic impediments on …
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The leaching kinetics were carried out with a duration of five hours, and based on volume sampling at certain time intervals from three samples, with the characteristic NaOH concentration, the leaching …
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Tin species were studied from Makundju ores in DRCongo. The identification of tin species released in aqueous solution during leaching of solids from the alkaline smelting (NaOH-KOH) was done to prepare added-value mining products on tin ores mined in the eastern DR Congo. Prior to alkaline...
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Gold recovery and % difference normalized as a function of Au grade (A and B) and Ctot content (C and D), respectively. The % difference = 1 -(recovery with activated carbon/recovery without ...
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(1) Halides act as both oxidants and ligands during leaching, which is the main reason for
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Metallurgy - Leaching, Extraction, Refining: Oxides are leached with a sulfuric acid or sodium carbonate solvent, while sulfates can be leached with water or sulfuric acid. Ammonium hydroxide is used for …
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This article will focus on the alkaline leaching of gold-bearing tetrahedrite concentrate in a solution containing sodium sulfide and sodium hydroxide. This selective leaching is followed by the leaching of heavy and waste metals into the solution, which may influence the physical properties and quality of the desired product, possibly …
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Treatment of gold-bearing ore with hydrogen peroxide during heap leaching of gold increases gold recovery by 1.2% and amounts to 55.89%, without treatment - 54.69%. This increases the consumption ...
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This thesis aims to show the methodology of new leaching processes, point out possible alternatives in the market for processing raw materials and approach the research …
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The reactions that take place during the dissolution of gold in cyanide solutions under normal conditions have been fairly definitely established. Most agree that the overall cyanide equation for leaching and cyanidation of gold is as follows: 4 Au + 8 NaCN + O2 + 2 H20 = 4 NaAu(CN)2 + 4 NaOH . Cyanide Leaching Chemistry
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-16μm) and chemical (alkaline, NaOH) pre-treatment and microwave roasting and microwave-assisted cyanide leaching were investigated to increase gold recoveries. Ultrafine . grinding was the most effective, producing recoveries of 66.5%. NaOH pre-leaching of ultrafine milled material increased recovery to 71.5%.
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takes place in a series of agitated leach reactors or pachucas. Before leaching the pH of the pulp is normally adjusted to a value of around 9.5–11 to ensure minimum loss of cyanide as hydrogen cyanide. The leaching of gold can be conveniently represented by the Elsener equation: [1] Although air agitated leach tanks were commonly used in
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As the leaching solution is sprinkled in the air, it is enriched in oxygen, which is indispensable for dissolving gold with cyanide. In some pilot heap tests, addition of …
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The hydrometallurgical leaching of native gold from gold-bearing ores or the dissolution of gold metal during the recycling of electronic and precious metal scrap is …
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Leaching Low-Grade Gold Ores A dilute cyanide solution is an efficient solvent of gold. However, as in ... Ore reserves plotted as a function of ore grade. 0.25 0.2 ~ 0.15 ai ~ Ol
Leaching of Sb 2 S 3 ore in an alkaline system involves the combination of sodium sulphide (Na 2 S) and sodium hydroxide (NaOH) to form a solution of sodium thioantimonite as shown in reactions 1 ...
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