Applying microwaves with appropriate concentrations of additives and water resulted in high oxidation of sulfide minerals (>90%) and low sulfur emissions in roasting refractory gold ore with relatively low power, temperature, and time.
This insoluble layer restricts the access of the thiourea used to extract the gold from the mineral, causing low metal recuperation and/or high operational costs. The oxidation process enables the liberation of gold encapsulated in sulfide minerals, making the gold available for processing via traditional routes.
The complex mineralogy of the Porgera resource has a pronounced effect on process selection for the recovery of refractory gold and silver. Intimate association of gold with pyrite necessitates a high degree of sulphur preoxidation to achieve acceptable levels of gold recovery. Acid pressure oxidation has been demonstrated to be the only …
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 …
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. …
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 ...
Gold, a signicant precious metal, has high corrosion resist-ance, excellent electrical and thermal conductivity []. In 1 the eld of gold extraction and smelting, refractory gold ore is one of the most important gold resources at present [2]. Approximately 30% of the world's gold production is derived from refractory gold ore, and this proportion
During bio-oxidation refractory gold ores processes, mineral decomposition is believed to be mostly due to chemical attack by ferric iron, with the main role of the microorganisms being to reoxidize the resultant ferrous iron back to ferric iron (Rawlings, 2002). As a reference point, in this study experiments were generally conducted with ...
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, …
Abstract For arsenic-containing refractory gold concen-trate, gold recovery by leaching is extremely difficult due to the encapsulation of gold in arsenopyrite and pyrite. In this work, the pre-oxidation of a high-arsenic and high-sulfur refractory gold concentrate in the acidic potassium permanganate or hydrogen peroxide solutions has been
Based on rapid chlorine oxidation, vanadium and carbon-rich refractory gold minerals react with chlorine gas at high temperatures to form compounds (AuCl 3) that are highly volatile, [24,25,26] enabling the extraction of gold. An effective cyanide-free extraction method realized to extract gold from vanadium and carbon-rich refractory …
A "refractory" gold ore is an ore that has ultra-fine gold particles disseminated throughout its gold occluded minerals. These ores are naturally resistant to recovery by standard cyanidation and carbon adsorption processes. ... Miners could ship high-grade refractory ore or concentrate from several mines to centralized processing ...
Refractory gold concentrates often contain sub-microscopic gold that is encapsulated within the crystal matrix of iron sulphide minerals such as pyrite, pyrrhotite and arsenopyrite. To recover the gold, the host mineral must
In this study, A novel method for gold recovery from refractory gold ore was proposed with the purpose of improving recovery efficiency of gold and reducing environmental pollution.
Gold Metallurgy in South Africa, edited by R. J. Adamson and published by the Chamber of Mines of South Africa (1952), contains about six pages with meaningful contents on …
The best type of oxidation for double refractory ore, especially due to dealing with the carbon component, is high temperature oxidation, or roasting. Figure 1.1 shows where …
Small particles of gold, a metal of higher interest, are mostly found in a matrix of sulfide-based minerals and not affordably recovered with conventional approaches encompassing cyanidation, pyrometallurgy, extreme heating (roasting), oxidation of …
Semantic Scholar extracted view of "Bio-oxidation of a high-sulfur refractory gold concentrate with a two-stage chemical-biological approach" by Guohua Wang et al.
The research on alternative oxidation roasting pretreatment of refractory gold ore has been ongoing for many years. However, it has yet to replace its role in industrial production of refractory gold ore. In this study, SR-AOPs …
In a certain region (Fig. 8), a high concentration of hydrochloric acid is a concern to a high oxidation leaching ratio of As-and Sb-bearing minerals of the refractory gold ore, as well as a high Au-extraction ratio of the oxidation residue. Coupled with the electrochemical analysis, high acidity is related to a better dissolution of As-Sb ...
of refractory gold minerals and locking of submicroscopic gold in sulfide mineral structure etc. Gold process mineralogy helps address issues and problems related to gold ore processing. It provides useful information on process selection, flowsheet development, recovery improvement and reagent consumption optimization.
The eect of bio-oxidation and neutral atmospheric oxidation pre-treatment of refractory gold concentrates on gold and silver extraction during cyanidation was investigated. A series of pre-treatment experiments was conducted on three high sulfur (>9%) refractory concentrates with 0.92–1.25 g/t gold and 64–90 g/t silver.
The oxidation of refractory gold concentrates containing arsenopyrite and pyrite and the simultaneous dissolution of gold in aerated alkaline solutions at ambient temperatures and pressures without the addition of cyanide has been studied. It involves the following aspects: the chemistry of the oxidation of pure arsenopyrite and pyrite minerals in …
Double refractory gold ore, meaning significant gold is locked in sulfides and being "preg-robbed" by carbonaceous material, presented a new challenge in which pretreatment by oxidation was a necessary step.
Combined Bacterial and Pressure Oxidation for Processing High-Sulfur Refractory Gold Concentrate. October 2023 ... it cannot effectively oxidize some sulfide minerals. POX enables oxidation in a ...
Currently, there is a lack of research on column bio-oxidation for low-grade refractory gold ore with high arsenic and sulfur content. Therefore, it is essential and significative to investigate column bio-oxidation for this type of gold ore.
The presence of gold telluride minerals may render an ore refractory, the extent of this depends on the telluride mineral present and the mineralogical association [3]. Gold, silver, and gold/silver-telluride minerals in ores dissolve more slowly than native gold in cyanide solutions, which results in less efficient gold extraction [4].
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 …
In this study, a two-stage chemical-biological oxidation approach was utilized to intensify the oxidation process of a high sulfur refractory gold concentrate. It was found that the oxidation efficiency and recovery rate of gold were elevated significantly with a two-stage approach.
Semantic Scholar extracted view of "Column bio-oxidation of low-grade refractory gold ore containing high-arsenic and high-sulfur: Insight on change in microbial community structure and sulfide surface corrosion" by Shiqi Zhang et al.