— Refractory gold ore is usually affected by the associated carbonaceous matter through the preg-robbing effect, which is eliminated by oxidation roasting, followed by leaching, to achieve a satisfactory gold leaching efficiency. Roasting–leaching experiments, pore structure measurements, scanning electron microscopy (SEM), and X …

 — Wu (Wu et al., 2019) and Rusalev (Rusalev et al., 2020) studied the effect of different factors on antimony in the sodium sulfide leaching process for treating high-grade antimony gold ore by electrochemical method. And it is found that the reduced iron powder could effectively decrease gold leaching in Na 2 S leaching solution.

 — As a refractory gold ore, a large proportion of finely disseminated gold is encapsulated in the sulfide matrix of arsenopyrite, resulting in inefficient gold recovery via the conventional leaching ...

 — But the proportion of gold production from refractory ore is just about 30% of the total gold production in the world. As the refractory gold resources have not been utilized well, countries around the world …

preparation techniques for the refractory ores. The major developments in the pressure hydrometallurgy of gold ores and concentrates began from the 1980s. The oxidative …

 — The process optimization and mechanism of microwave pyrolysis in a nitrogen atmosphere were studied to improve the gold leaching rate for high-arsenic-refractory gold sulfide resources, mainly containing minerals of elemental sulfur, dense pyrite, and arsenopyrite. The decomposability was evaluated using thermodynamic and …

 — 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 ...

 — Originally, biotechnology was applied as a bio-oxidation pretreatment for refractory gold ores and concentrates to make it more accessible in cyanidation. As a form of biotechnology that involves high efficiency, ... From an environmental perspective, microbial leaching is undoubtedly the most eco-friendly gold leaching process. Therefore ...

 — 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 …

 — The direct leaching of refractory gold ores in chloride solutions is a conceptual, unproven process, but it has been hypothesized to be able to provide a potential alternative to the costly and intensive pre-oxidation processes in the treatment of refractory gold ores.

be exposed. Mohammadi et al. investigated ammoniacal thiosulfate leaching of refractory oxide gold ore, and they obtained maximum gold extraction of 55% (Mohammadi et al., 2017). Shen et al. had researched the direct thiosulfate leaching of gold from refractory ore, and they achieved gold recovery of only 70% (Shen et al., 2013).

 — According to a recent article by global consulting firm McKinsey, approximately one-quarter of the gold in geological reserves and resources can be considered refractory, with gold production from refractory ores expected to grow 1.4 % in the next four years, versus 0.3 % for non-refractory ores.

Roasting: This traditional refractory gold pre-treatment option uses superheated air to fluidize the ore, thereby causing the sulphides to oxidize, separate from the gold, and volatilize into sulphur dioxide (SO 2). This method is sometimes referred to as a "Chemical Liberation" process and results in a calcine product that is amenable to ...

 — Optimization of the pretreatment process of gold refractory ore from Zarshuran gold mine was carried out using Taguchi method-orthogonal array optimization technique (OAOT). ... [21] Aazami M, Lapidus G and Azadeh A 2014 The effect of solution parameters on the thiosulfate leaching of Zarshouran refractory gold ore Int. J. Miner. …

 — Copper cyanide complexes in cyanide leach solutions deteriorate the recoveries of gold. Herein, five phosphonate-based [P204] − ionic liquids were synthesized, which were pioneered to apply to extraction of copper cyanide complex ions in cyanide leach solutions. In the extraction process, macroscopic layered solids rich in copper …

 — A novel pretreatment method for refractory gold ore using ultrasound-activated persulfate was developed to overcome the low extraction efficiency of gold in …

 — The current high gold price is increasing the focus on the development of refractory gold ores and concentrates. Outotec can deliver the three main oxidative processes for the treatment of refractory …

 — This paper presents the results obtained by processing a gold and silver telluride mineral concentrate from a mine in Colombia. An acid wash, also known as acidification, was carried out, followed by oxidation with nitric acid as a pretreatment. Cyanidations of the pretreatment residues were carried out and the results were …

 — Pretreatment using microwave-assisted roasting with NaClO 3 as an additive to the oxidizing agent is a new method of processing refractory gold ore. Oxidation was …

 — The Bacterial Oxidation (BIOX) process for the pre-treatment of refractory ores for gold recovery developed by Genmin, the mining division of Gencor, has been operating successfully at the ...

plying the pretreatment, standard leaching tests with thiosulfate solution were performed to quantify the effects of these three variables on the gold extraction. While only 23 and 29% gold ...

 — 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 …

The experimental results showed that under the conditions of liquid solid ratio 3:1, curing temperature 240 °C and the reaction time 1.5 h, the weight loss rate and iron removal …

 — 1. Introduction. At present, more than 35% of China's gold resources (with a total amount of more than 1,000 tons) are difficult to be exploited and smelted, and about 700 tons of gold ores with high arsenic, antimony or sulfur are difficult to be directly cyanide leached (Lei et al., 2016).However, as the gradual depletion of easy-to-treat gold ore …

This paper focuses on the research progress of the recovery of gold from non-cyanide leachates by ion exchange resins, summarizes the existing resin types and elution …

 — Gold telluride ores are important gold refractory ores due to the presence of sulfides and other gangue materials. The classification and main physical properties of gold telluride ores were described, and possible treatment methods including flotation, leaching, and oxidation were reviewed. The results show that flotation procedures are much …

Pre-treatment methods for ores, or concentrates. Pre-treatment method Phases in gold-bearing ore or concentrate Reference. Flotation Sulphides, silicates, carbonate Allan and Woodcock (2001), Yalcin and Kelebek (2011) Biological oxidation Silicates, sulphates, sulphides, oxides Asamoah, Skinner, and Addai-Mensah(2018) Gravity separation and ...

 — This research was carried out on Aghdareh gold ore. The Aghdareh mine and gold processing plant is located 32 km from Takab city in the western Azerbaijan province, Iran, at 46°58′30′′N and 36°39′29′′E. …

 — Effect of nitric acid pre-treatment on the extraction of silver from the ground ore (d 80 : 50 µm) in cyanide leaching (Cyanidation conditions: 1.5 g/L NaCN, pH 10.5, 25 3 C, flow rate of air: 1. ...

 — Under the conventional cyanide leaching system, the gold leaching rate is low, only about 75%. In order to search for a better recovery of gold from refractory gold concentrate containing arsenic after pretreatment and to improve the gold leaching effect, the process mineralogy and pretreatment of gold concentrate containing arsenic were …