Arsenious and sulphur-bearing micro-disseminated gold ore is a kind of typical refractory Carlin-Type. The gold in Carlin-Type gold ore grains is distributed finely, existing as invisible or submicroscopic gold, encapsulated in arsenopyrite and pyrite. The technical difficulty of treatment Carlin-Type gold ore lies in how to release the fine gold …

Gold extraction by cyanidation is reduced to less than 30% as the copper content in the ore is higher than 0.3% Cu. Thiosulphate leaching process could overcome this problem. The effect of the variables on the gold extraction have been investigated. Under the optimun leaching conditions: 0.4 M thiosulphate, 0.2 M ammonia, 0.03 M …

1. Introduction. Due to the rapid depletion of free-milling types of gold ores, it is accepted worldwide that there is an increasing trend in the treatment of refractory gold ores, which often requires oxidation, such as roasting, as a pre-treatment process prior to cyanidation (Adams, 2016, Zhou and Fleming, 2007).Via oxidizing/roasting, pyrite (the …

Abstract Electronic waste is a dominant global issue with over 50 million tons generated annually. Still, as an amalgamation of precious and rare raw materials, electronic waste is a considerable economic resource with the most valuable components located on the printed circuit boards. Gold is widely used in electronics in numerous applications, …

The gold content was 24.7 g/t and iron, sulfur, total and organic carbon were found to be 1.79%, 0.65%, 5.38% and 0.18% respectively. ... Thiosulfate ions can gradually dissociate with additional sulfur-bearing ... Nie Y, Xiang P (2014) The copper–ethanediamine–thiosulphate leaching of gold ore containing limonite with …

Laboratory testing on mixed-sulfide gold-bearing ores showed that the flotation recovery of iron sulfides was highest at +50 mV, and the recovery began to decrease at higher potentials (Hintikka and Leppinen, 1995). For copper-activated pyrite, the optimum Eh at a pH value of 9 was +35 mV (Shuhua et al., 2004).

Using iron or copper ions as oxidants, a low concentration of chloride ions (0.3 M) can yield a gold leaching rate of 64%, providing a theoretical basis for the leaching of copper-bearing refractory gold ores with seawater (Ahtiainen and Lundstrom, 2019).

By Aalto University October 13, 2021. A research team has effectively replaced cyanide in a crucial step of gold extraction from ore. Credit: Robert von Bonsdorff/Aalto University. Study shows new chloride-based process recovers 84% of gold compared to the 64% recovered with traditional methods. Gold is one of the world's most popular metals.

The leaching tests of gold ore in the copper-citrate-thiosulfate solutions are performed under various ... A fundamental study of the reductive leaching of chalcopyrite using metallic iron part I: kinetic analysis. ... Yen, W.T., 2011. Process for extracting gold from gold-bearing ore. U.S. Patent 7985277 B2. Google Scholar. Xu et al., 2019a ...

This thesis's assigned topic is "New possibilities in leaching of gold ores". Gold is a very desirable raw material, and the demand for it increases in proportion to the development of new technologies. This demand calls for research in the field of financially efficient mining and treatment of gold-bearing ores. This work focuses precisely on the

Trans. Nonferrous Met. Soc. China 25(2015) 1286í1297 Characterization of an iron oxy/hydroxide (gossan type) bearing refractory gold and silver ore by diagnostic leaching Oktay CELEP, Vedat SERBEST Hydromet B&PM Group, Division of Mineral & Coal Processing, Department of Mining Engineering, Karadeniz Technical University, …

was assessed using leaching conditions of 24 g/L thiourea, 0.6% iron (III), pH of 1.00 at 25 °C for a period of two hours. They reported that samples of < 149 µm resulted in around. 90% gold ...

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 ...

According to the electron microprobe analysis, gold occurs mainly as native gold, with minor amounts of calaverite and petzite. Hessite only contains trace amount of gold and an unknown gold-bearing mineral (possible gold-bearing goldfieldite) was also observed as shown in Table 4. The liberated gold grains range from 2 to 133 µm and …

ammonium bromide was applied for a gold bearing or e containing high limonite, in which the gold leaching percentage reached up to 94.3% whilst thiosu lfate consumption was as low as 1.12 kg/t ...

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 …

The resultant gold-bearing ore is then sieved t hrough a dry screen to separate the particles into size clas ses, as shown in Table 5. The size range n ormally used for leaching is ≤75

DOI: 10.1039/B406148A Corpus ID: 97618536 'Green' leaching: recyclable and selective leaching of gold-bearing ore in an ionic liquid @article{Whitehead2004GreenLR, title={'Green' leaching: recyclable and selective leaching of gold-bearing ore in an ionic liquid}, author={Jacqueline A. Whitehead and …

The leach conditions used were:- 1.Stage 1: Leaching in dilute cyanide (0.1%) at pH 9.5 for 24 hours to dissolve native gold but not gold ± silver tellurides.2.Stage 2: leaching the residue from ...

Barrick Gold Corp. Barrick Gold has been granted a patent for a gold recovery process that uses activated carbon to accelerate thiosulfate leaching of gold from a gold-bearing material. The process involves contacting the precious metal-bearing material with activated carbon, thiosulfate, an anion exchange resin, and an oxidant to …

A pyrite ore containing 3.2 g/ton of gold finely disseminated in the sulphide matrix was leached to recover this precious metal. The leaching was carried out in columns containing 200 kg of ore ...

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 ...

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. In a relatively simple system of this type the gold dissolves readily. The only requirements are that the gold be free and clean, that the cyanide solution …

Publisher Summary. Gold tellurides are treated commercially in a small number. The leaching of telluride ores has always been problematical with a perceived mismatch of findings between the researchers and the operators as to the recoverability of gold by cyanide leaching of gold-telluride ores without some form of oxidative pre …

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 …

The generated thiosulfate from sulfide gold ore can still be applied to leaching oxide gold ore, gold calcine and other exposed gold-bearing raw materials. More research is needed to investigate the process mechanism and gold extraction effect of refractory sulfide gold ore generating thiosulfate to obtain a satisfactory gold …

A combined process of flotation-cyanide leaching is used in this ore, realizing total gold recovery rate of this ore is 93.30% when a combined process of flotation-cyanide leaching is used, and 89 ...

Bio-leaching is a cost effective, efficient, safe, and. environmentally friendly way to treat refractory gold concentrates and ores. Compared. to roasting, bio-leaching can generally reduce ...

Gold production in South Africa is projected to continue its decline in future, and prospects for discovery of new high-grade deposits are limited. Many of the mining companies have resorted to mining and processing low-grade and complex gold ores. Such ores are technically challenging to process, which results in low recovery rates, excessive …

2.1 Cyanide leaching. Cyanide is a cheap but highly toxic reagent that is very effective in leaching gold from low-grade minerals and mining wastes. Therefore, cyanidation is the most widely used method for the extraction of gold from mining wastes.