The pyrite contains 43.36% Fe and 41.26% S. The occurrence of gold in the different phases of the sulfide refractory gold ore is shown in Fig. 2, which indicates that 93.94% Au is encapsulated, especially, sulfide-encapsulated gold up to 80.85%. The X-ray diffraction …
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 extraction from sulfide bearing gold ores is proposed based on the model experiments using a mixture of gold powder and ...
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 ...
Bio-oxidation of refractory sulfidic gold minerals has been applied at the commercial scale as a pre-treatment to improve gold yields and reduce chemical consumption during gold cyanidation. In this study, the effect of initial cell concentration on the oxidation of pyritic gold ore was evaluated with four aerated bioreactors at 30 °C with 10% ...
pressure within a gold operation to reach the highest percent recovery, no matter what kind of ore is presented for treatment. For double refractory gold ores, the most crucial unit operation is performed by the roaster by creating a high temperature oxidation of the ore. An efficient roasting operation creates a
called low refractory gold ores, while the ores that cannot get higher gold leaching rate by increasing the dosage of chemicals are divided into medium refractory gold ores or high refractory gold ores. [9-10] Table 1 Classification of refractory gold ores Gold leaching rate <50% 50%~80% 80%~90% 90%~ Sorting difficulty High difficulty in ha
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 commercially proven process …
Typical refractory ores have a high sulphide content, such as those found in the Barberton greenstone belt. ... A.C. 1997. The recovery of gold from refractory arsenopyrite concentrates by pyrolysis-oxidation. Minerals Engineering, ...
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 …
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 ...
Bacterial oxidation is now considered to be a proven commercial technique for the treatment of refractory sulfide gold concentrates. Since 1986 the technique has been applied successfully on a commercial scale for the removal of arsenopyrite and pyrite to give high gold extractions on cyanidation (Van Aswegen et al., 1989).A chronology of gold projects, …
A more effective and economical strategy to recover gold from refractory ores involves the preliminary bacterial leaching of the refractory ore/concentrate to oxidize the sulfide minerals and ...
disseminated gold from the flotation concentrate resulted from processing of a refractory ore of one of Russian gold deposits. Concentrate description Gold grade of the head flotation concentrate was 29.6 g/t. The concentrate size was 80% -80 um. Mineral composition of the concentrate comprises 17% of rock-forming minerals, 59% of pyrite and 24%
Refractory gold ore pretreatment Treatment of refractory gold ore (whole ore and flotation concentrates) has become more prominent since the 1980s, with many gold discoveries often including ores that are wholly or partially refractory. Refractory pre-treatment processes include pressure oxidation, biological oxidation and various forms of ...
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 attach great importance to the exploitation and utilization of refractory gold ore and the research on refractory gold extraction process.
Pressure oxidation (POX) is employed for gold recovery from refractory ores where gold particles are occluded by sulphide minerals, mostly pyrite/arsenopyrite, and standard cyanidation is not ...
These methods not only enhance reaction efficiency but also create local "hot spots" and cavitation free radicals through ultrasound, further promoting oxidation efficiency, breaking down pyrite structures, and exposing encapsulated gold. The research on alternative oxidation roasting pretreatment of refractory gold ore has been ongoing for ...
The pressure oxidation of both the concentrate and STRB residues increased Ss oxidation by 97–99% and gold recovery by 96–97%. For 2 days, STRB decreased the Ss content and increased the ...
The resources of high-sulphur and high-arsenic refractory gold concentrate (HGC) are abundant and can be found in many areas in China, such as Guizhou, Guangxi, Jiangxi and Yunnan provinces. Because air and water was introduced into the stratum, HGC was oxidized spontaneously and released acids and many heavy metals such as As, Pb, Zn and so …
refractoriness is due to encapsulation of the gold particles inside the host mineral. To liberate gold for leaching the host mineral must be broken by mechanical or chemical means. The aim of this study was to study the effect of temperature, oxygen partial pressure and slurry density on pressure oxidation of pyrite-arsenopyrite gold concentrate.
The temperature has often peaked at values as high as 53 °C for short periods. Although oxidation rates were still acceptable, a definite loss in bacteria activity was noticed. The time period at the high temperature was nevertheless too small to assess the effect on the oxidation rates. BIOX Process Improvements
The cyaniding gold extraction method adopts specific arsenic-resistant bacteria which are prepared by mixing Thiobacillus ferrooxidans, Thiobacillus thiooxidans and Leptospirillum ferrooxidans, and conducts oxidation pretreatment of high-arsenic complex refractory gold ore. The high-arsenic complex gold ore containing 8 to 20 percent of arsenic ...
Arsenical ores vary from highly refractory to free-milling. Arsenopyrite in highly refractory ores is finer grained, As-deficient (27–32.5 at.% As), contains high average concentrations of submicroscopic gold (60–270 ppm), but does not contain inclusions of particulate gold.
Typical refractory ores have a high sulphide content, such as those found in the Barberton greenstone belt. ... A.C. 1997. The recovery of gold from refractory arsenopyrite concentrates by pyrolysis-oxidation. Minerals Engineering, ... F.D. 1989. Mineralogical characteristics and treatment of refractory gold ores. Minerals Engineering, ...
gold resources. One such example is double refractory gold ores. Double refractory gold ores are known as ores from which gold extraction is poor due to the presence of sulphide minerals and carbonaceous matter (CM) in the ore which preg-rob dissolved gold. In this study, a double refractory flotation concentrate from a mine in Barberton was ...
The results show that gold is present in two forms (native and/or refractory): to a small extent in its native form and in its refractory form as association with sulfide minerals (i.e ...
The biooxidation portion of the incremental operating and capital costs when using this technology have been estimated for a pyritic refractory deposit at processing rates of 2,500 and 10,000 …
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), …
The ozonation of refractory minerals can improve gold extraction through direct treatment or indirect oxidation. It minimizes gold entrapping with refractory minerals by creating desired oxidizing ...
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. ... using microwave-assisted roasting with NaClO3 as an additive to the oxidizing agent is a new method of ...
Common refractory gold bearing minerals include arsenopyrite, pyrite and copper sulphides, which are highly resistant to extraction by standard cyanidation and usually require pre-treatment for cyanidation to be effective. ... High Pressure Oxidation (HPOx): Refractory ores where gold is contained within sulphides, such as pyrite or ...
Gold resources are explored and mined widely in the world. But with the increasing depletion of free-milling gold ores, the mining and utilization of refractory gold ores have …