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 …

In unoxidized (refractory) ores, the micron-sized gold is associated with sulfide minerals and organic carbon such as kerogen and asphaltine. Oxidation of the Mercur deposit developed upwards progressively from the bottom of the deposit such that the upper portion of the deposit contains refractory ore.

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 …

carried out to recover gold from refractory sulfides in the. 1980s. Nowadays, iron- and sulfur-oxidizing bacteria are. widely used to oxidize sulfur-containing ores and. flotation concentrates. De ...

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.

The mineral composition analysis of the pyrite concentrate (Fig. 1 (a)) shows that it has the lowest content of gangue minerals and only the pyrite was (FeS 2) measured. ... Enhanced oxidation capacity of refractory sulfide gold ore3.2.1. Thermal activation pretreatment.

of sulfide minerals was provided via bio-oxidation using a microbial culture. The pH value was measured daily, maintained in a range of 1.0–1.2 by adding either concentrated

sure oxidation has been used to treat refractory gold or es or concentrates as pretreatment and subsequent cyanidation. Alkaline pressure oxidation is an effective pretreatment for

This study was undertaken to evaluate the nitric acid leaching as a potential pre-treatment. process prior to cyanidation of refractory gold/silver ores. The nitric acid pre -treatment ...

The mineral influence in the bio-oxidation process has been analysed, mainly the way the concentration of mineral substrate interferes in the bioleaching process. ... The refractory sulphide concentrate is constituted by pyrrhotite and arsenopyrite as the major ore minerals (around 27%) and pyrite as secondary. The gangue minerals are …

1. Introduction. The irregular discharge of wastewater has caused serious hazards to human production and life, such as the deterioration of water quality and the shortage of drinking water [1].Refractory organic contaminants in wastewater have the characteristics of strong obstinacy and high toxicity, which has become one of the most …

This review describes the historical development and current state of metals leaching and sulfide mineral biooxidation by the minerals industries. During the past 20 years commercial processes employing microorganisms for mineral recovery have progressed from rather uncontrolled copper dump leaching to mineral oxidation and …

Pyrite and arsenopyrite are prominent minerals in refractory sulfidic gold deposits and are readily bio-oxidized. The most commonly studied pyrite- oxidizing bacteria are mesophilic Thiobacillus fer- rooxidans, that oxidizes ferrous iron or reduced sulfur compounds, and Leptospirillum ferrooxi- dans that oxidizes ferrous iron but not sulfur [3].

Therefore investigating the effect of magnetic field on the bacterial oxidation of refractory gold sulphide ores is of high importance. ... The recovery of gold from refractory arsenopyrite concentrates by pyrolysis-oxidation. Minerals Engineering, 1997, 10, 919-928. Dunn, J.G., Ibrado, A.S. and Graham, J., Pyrolysis of arsenopyrite for gold ...

refractory gold sulphide hosts are arsenopyrite and pyrite, and in order to achieve acceptable gold recoveries, it is generally necessary to break down the host mineral chemically. This is done by roasting, bacterial oxidation or pressure oxidation . processes, in which the sulphide component of the host mineral is oxidized with oxygen to elemental

Refractory gold ores and arsenian sulfide ores host different proportions of free milling and refractory gold, as in the case of the sample M3. ... (0.41 V); to quantify and differentiate the response presented in the zone associated with mineral oxidation phenomenon, the values of the voltammogram slope, in the positive sweep (between 0.2 …

The use of acidic and neutral SOB together by performing oxidation in a 2-stage process utilizing acidophilic and neutrophilic bacteria consecutively has led to increased oxidation for refractory ...

The basic steps in heap/pool bio-oxidation of refractory gold ore include mining, crushing (pelletizing), heap construction, bio-oxidation, and metal recovery. The ore to be treated is crushed and evenly arranged on the hardened site. ... This is related to the inhomogeneity of sulfide minerals distribution as well as spraying liquid ...

@article{Zhang2022ColumnBO, title={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}, author={Shiqi Zhang and Hong-ying Yang and Pengcheng Ma and Zuochun Luan and Lin-lin Tong and Zhe-nan Jin and …

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 ...

the POX process and from insufficiently oxidized sulfide minerals [5]. Deficient oxidation rate caused by passivation can lead to the incomplete liberation of fine gold in sulfides [6]. In addition, in the alkaline POX discharge, unextractable gold was detected as the adsorbed ... Flotation of Carbonaceous Matter from a Double Refractory ...

This review presents developments and applications in bioleaching and mineral biooxidation since publication of a previous mini review in 2003 (Olson et al. Appl Microbiol Biotechnol 63:249–257, 2003). There have been discoveries of newly identified acidophilic microorganisms that have unique characteristics for effective bioleaching of …

Characterization indicated that pyrite was the main mineral. Simultaneous pressure oxidation and leaching experiments were conducted at a temperature range of 40–80 °C, oxygen pressure of 87.5 ...

Bio-oxidation of sulfide minerals, components of gold-bearing concentrates (arsenopyrite, pyrite), may be described by the following simplified overall reactions [6]: 2FeAsS + 7O 2 +H 2 SO 4 + 2H ...

Bacterial Oxidation "Bacterial oxidation is now considered to be a proven commercial technique for the treatment of refractory sulfide gold concentrates….testimony for the continuing emergence ...

Pyrite and arsenopyrite are known to be the most common gold-bearing sulfide minerals in refractory gold ores. Traditionally, these minerals have been first oxidized by roasting, acidic pressure ...

1. Introduction. Gold ores are considered refractory if gold extraction from a conventional cyanidation process is less than 80 % after fine grinding (Rusanen et al., 2013).Arsenopyrite, along with pyrite, is the principal refractory gold carrier (Chryssoulis and McMullen, 2016).Extraction of gold from sulphide minerals by hydrometallurgical …

Pressure oxidation is a hydrometallurgical oxidative pretreatment for refractory ores, such as sulfide ores. Here, simultaneous alkaline pressure oxidation and sodium cyanide leaching treatments were carried out on a pyritic ore from the Mulatos Mine located in Sahuaripa, Sonora, Mexico. Mineral characterization, agitation leaching, hot …

Results show that bio-oxidation pretreatment can greatly improve the gold recovery rate of high-sulfur refractory gold concentrate, and at the optimum pH 1.3 in this study, compared with the ...

The slurry from bioleaching is fed to a second reactor (P-8/FR-102), in which sulfur-oxidizing bacteria grow using a mix of carbon dioxide from the air and sodium bicarbonate as the carbon source ...