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Sulfides and carbonaceous matter in double refractory gold ore (DRGO) were bio-treated sequentially using an iron-oxidizing archaeon Acidianus brierleyi followed by lignin peroxidase-dominating crude enzymes released from the white-rot fungus Phanerochaete chrysosporium to significantly improve gold recovery from 24% to 92%. …
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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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Many gold deposits contain finely disseminated gold particles in iron sulfide minerals such as pyrite. These minerals are called refractory gold ores because of the presence of gold, which occurs either as disseminated fine gold particles—typically <1 µm [] or as fine particles of gold encapsulated in the ore host [2,3].In certain ores, extraction …
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The refractory gold ore is used for single-factor experiments and the pure pyrite crystal is used for mechanism study. The pyrite powder and pyrite slice are prepared by pure pyrite crystal which was obtained from Guangxi Province. The pyrite powder was crushed to −200 mesh.
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The gold recovery of the ore was improved from 57% to 80% during CIL, after the ore was treated with 4.48 mM naphthalene sulfonate at pH 11.3 adjusted by 4.36 mM Ca(OH) 2. The main factor, that was likely responsible for the improved gold recovery, was the passivation of the adsorption sites on the carbonaceous matter in the ore.
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A brief analysis of the existing and developed methods for processing refractory- and double-refractory gold raw materials showed the futility of focusing on the existing modern technological schemes, which, despite being considered effective, in many cases are fundamentally incapable of providing efficient processing of such ores …
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The effect of different parameters on leaching of a refractory gold ore, containing high amount of orpiment, was investigated in ammonia/EDTA thiosulfate solutions. The results showed that gold recovery is very low in the absence of EDTA and ammonia. The introduction of a small amount of EDTA in the thiosulfate system lowered …
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The refractory gold ore with high arsenic and sulfur used in this study was obtained from Yuantong Mining Company, Inner Mongolia, China. The chemical composition of the raw gold ore is presented in Table 1. Fig. 1 (a) gives the X-ray diffraction diagram of the raw gold ore. The data showed that pyrite and arsenopyrite are the main …
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S and As are common impurities in refractory gold ores and must be removed before gold extraction. Thermodynamic analyses show that it is possible to simultaneously remove S and As by an O 2-enriched single-stage roasting, which is confirmed with experimental results from roasting of a gold refractory ore.The range of …
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As a pre-treatment method of refractory gold ore, carbonaceous matter (C-matter) flotation was investigated with multi-stage flotation by rougher, scavenger, and cleaner stages. Different …
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Pressure oxidation is a widely accepted method to treat refractory gold ores. Gold recovery is generally lower from alkaline than acidic pressure oxidation discharge due to passivation and incomplete oxidation of mineral. Gold ore from Goldstrike, NV, is a typical refractory gold ore containing sulfide and carbonaceous matter. …
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At the plant of the Consolidated Murchison Co. in the Transvaal, South Africa, where a refractory high-antimony gold ore is being treated, flotation and cyanidation of the flotation concentrates and tailings are being practiced. The association of the antimony and gold is very intimate, and during 1946, while the antimony recovery amounted to ...
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The problems during the leaching of gold show the necessity for ore pretreatment to minimize the gold entrapment with refractory minerals and solve the gold low recovery challenge from surrounding …
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The refractoriness of gold is a consequence of ore mineralogy. Refractory gold ores have the following characteristics: (1) gold in intimate association with and locked in sulphide minerals and siliceous gangue, (2) gold associated with active carbonaceous matter and (3) gold in solid-solution with other minerals.
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The use of alkaline pressure oxidation to pretreat refractory gold ore often results in insufficient gold recovery (<60%) in downstream thiosulfate leaching. To improve gold recovery, flotation was considered …
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Persulfate is a suitable oxidant for extracting gold from ore in iodide solution. • Under neutral conditions, the gold extraction rate from refractory ore reaches 80%. • The S 2 O 8 2− − I − − H 2 O system provides a green and economical gold leaching method. • Activated carbon adsorbs the gold iodide complex, which facilitates ...
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The present pre-processing of the As-and-Sb-bearing refractory gold ore has some flaws in the tediously flow, low treatment, and metal extraction efficiency. Based on these considerations, a whole wet gold extraction way combined Mn-oxide hydrochloric acid oxidation with acidic chlorination leaching for the As-and-Sb-bearing refractory …
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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. …
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Gold recovery from arsenopyrite carbon-containing concentrates obtained by ore flotation concentration has been studied. The breakdown of concentrates was carried out with HNO 3 (1·5–3 mol/l) at 80–85°C. Thiosulphate leaching (0·5 M Na 2 S 2 O 3 + 0·5 M NH 3) of …
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The refractory gold ore, obtained from Yunnan Province, was crushed to −200 mesh. The main gangue of refractory gold ore is pyrite, quartz, and dolomite. The gold content was 27.5 g/t, and it was chiefly encased in sulfide gangue (96.16 %, mainly pyrite) based on diagnosis leaching and MLA analysis. All the chemicals (PDS, sulfuric …
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The gold particles of ALRG gold ore are almost wrapped by pyrite and arsenopyrite, and the direct gold leaching extent is less than 40 %, making it an extremely refractory gold ore. The ore sample in this study has an extremely low gold content of 0.85 g·t −1, iron content of 3.21 %, sulfur content of 2.27 %, and arsenic content of 0.19 …
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refractory carbonaceous sulfide ore is at Barrick's Goldstrike Mine where gold occurs in pyrite in refractory sulfide ore and double-refractory sulfidic/ carbonaceous ore. These ores are pretreated by autoclave and roaster prior to cyanide leaching (Thomas et al., 2000; Wickens et al., 2003). In the Jinya Carlin-type gold deposit in China, gold
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A comprehensive mineralogical and physico-chemical examination of two refractory gold ores and concentrates from the Ghanaian gold province was conducted …
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Luckily, the gold contained in refractory ores is not unsalvageable. Gold's resistance to oxidation is a critical point of most refining and extraction methods, and the …
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Refractory is generally defined as the ore thatyields <80 wt.% Au after standard physicochemical leaching conditions [11].Au-refractory ores, in most cases, contain elevated concentrations of arsenic, mainly with the form of arsenian pyrite (FeS 2), arsenopyrite (FeAsS), realgar (As 4 S 4), and orpiment (As 2 S 3).The entire …
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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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A detailed characterization of an iron oxy/hydroxide (gossan type) bearing refractory gold/silver ore was performed with a new diagnostic approach for the development of a pretreatment process ...
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Additionally, refractory sulfide gold ore constitutes a significant portion of refractory gold ores, with gold mainly encapsulated by arsenopyrite and pyrite (FeAsS and FeS 2) in microscopic or sub-microscopic form (Wang et al., 2020). The dense microstructure of sulfide inclusions causes difficulty to expose the encapsulated gold by …
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2.1 Microwave pre- treatment of refractory gold ores . Most of refractory gold occurs within sulphide minerals such as FeS 2 and FeAsS and are treated by roasting, pressure leaching or bacterial leaching to render the gold amenable to recovery by subsequent treatment techniques (Haque, 1987).
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In sulfidic refractory gold ores, fine gold particles may be highly disseminated and locked up in sulfide minerals such as pyrite and arsenopyrite. All the largely …
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