Minerals | Free Full-Text | Gold Extraction from a …
The low amount of gold extracted by conventional cyanidation (46%) occurs when the mineral has refractoriness properties due to occlusion by the pyrite matrix. When the pressure leaching and …
Pretreatment of refractory gold minerals by ozonation before the
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 any pre-oxidation causes an extraction lower than 90%. In recent decades, a variety of treatment and pretreatment methods have been used to …
Minerals | Free Full-Text | Specific Refractory Gold Flotation and …
Mechano-chemical activation of the refractory bio-oxidation product aided in overcoming the sulphate mineral-imposed refractoriness and improved gold recovery by about 1.8 times. Better monitoring of subtle process changes could help minimize process instabilities and maximize financial performance of mine operations.
Simultaneous Extraction of Gold and Vanadium From Vanadium …
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 gold ...
Bio-Oxidation and Biocyanidation of Refractory Mineral Ores for …
Bio-Oxidation and Biocyanidation of Refractory Mineral Ores for Gold Extraction: A Review. Bioleaching has emerged as a green technology with promising …
Improving the gold leaching process of refractory ores using the
Biological oxidation of refractory ores has become a more preferable pre-treatment method of sulphides and carbonaceous gold ores compared to roasting and pressure oxidation, which are costly and environmental unfriendly. Bio-oxidation involves the use of strains of bacterial to catalyze the decomposition of sulphide minerals.
Process for treating refractory gold ores by roasting under …
The common alternatives for the pretreatment of refractory ores are roasting, high or low-pressure oxidation, bacterial oxidation and chemical oxidation (Fernandez et al., 2000), but these ...
Comparative Study of Gold Extraction from Refractory Pyritic
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 …
Gold Extraction from Refractory Minerals Using Acid Oxidative
The refractory minerals with a high sulfide content require an oxidative pretreatment to increase the extraction of gold and silver in the cyanidation process [2, 5, 10]. The most common pretreatments at present are roasting [ 11, 12, 13 ], chemical oxidation [ 1, 2, 4, 5, 14 ], and biooxidation [ 15, 16, 17 ].
Bioprocessing of Refractory Gold Ores: The BIOX, MesoTHERM …
Refractory gold and base metal-bearing minerals typically present sulfur in oxidation states of −2 and −1 in sulfide minerals (Sand et al. 1995). It is improbable that the oxidation path of sulfide to sulfate (S oxidation state, +6) is simple and direct during biooxidation as the microbial facilitated kinetics is slow and biooxidation ...
Recent challenges in biological cyanidation and oxidation of
Gold is found in sulfide mineral phases such as pyrite, pyrrhotite, arsenopyrite, and chalcopyrite in refractory concentrates and these structures reduce the efficiency of …
Effect of grain size on the bacterial oxidation of a refractory gold
Bacterial oxidation was used to pre-treat a refractory gold sulfide concentrate obtained from the flotation of a gold ore from Madagascar. A mixed culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans was used to oxidize the sulfides. The major form of sulfide was pyrite, which represented approximately 24.8% of …
Simultaneous sulfide oxidation and gold dissolution by cyanide …
The advantage of chloride-bromide leaching is that the oxidation of refractory minerals can be conducted in atmospheric pressure. The kinetics of gold …
The Fate of the Arsenic Species in the Pressure Oxidation of Refractory
With the rising focus on the development of complex refractory ores, one of the major environmental challenges has been in the treatment and processing of arsenic-bearing minerals. An increasingly common approach is to immobilize arsenic as stable ferric arsenate phases during pressure oxidation, utilizing an existing process in the …
Column bio-oxidation of low-grade refractory gold ore containing …
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 sulfide …
Recovery of gold from sulfide refractory gold ore: Oxidation …
In addition, SiO 2 and FeAsS are also the major minerals for the sulfide refractory gold ore. Table 2. Chemical composition of the sulfide refractory gold ore and pyrite (mass percent, %). Empty Cell ... Redox potential measurement during pressure oxidation (POX) of a refractory gold ore. Canadian Metallurgical Quarterly, 57 (4) …
Thermodynamic Behavior of Pyrite and Arsenopyrite in
Recently, preoxidation is an effective pretreatment method of refractory gold ore, which has been widely used due to the high desulfurization, arsenic removal, low environmental pollution, and rapid reaction rate. In this paper, we describe the thermodynamic considerations of preoxidation of pyrite and arsenopyrite, the main …
Biooxidation-thiosulfate leaching of refractory gold concentrate
A process of biooxidation followed by thiosulfate leaching of gold from refractory gold concentrate was investigated. Mineralogical studies on the concentrate showed that very fine gold grains (<10 µm) were encapsulated in pyrite and arsenopyrite, while the proportion of monomer gold was only 21%. The gold-bearing sample was …
(PDF) A Preliminary Study on Nitric Acid Pre-treatment of Refractory
The nitric acid pre-treatment experiments for refractory silver ore and gold/silver concentrate were performed for 2.5 hours at 5M HNO 3 and 80 o C. Before and after nitric acid pretreatment ...
Bio-Oxidation and Biocyanidation of Refractory …
Process flow of bio-oxidation and biocyanidation of Au bearing refractory mineral ores. Bio-leaching mechanism (a) contact leaching by A. ferrooxidans or L. ferrooxidans ; (b) noncontact...
Gold Extraction from Refractory Minerals Using Acid Oxidative
Gold Extraction from Refractory Minerals Using Acid Oxidative Pretreatment at Low Pressure Published: 23 January 2022 Volume 39, pages 721–731, ( 2022 ) Cite …
Refractory gold evaluation
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 ...
Minerals | Free Full-Text | Mineral Phase Evolution during Oxidation
Oxidation roasting pretreatment is the most common pretreatment approach to treatment refractory gold ores [13,14,15,16,17]. To achieve good recoveries in subsequent leaching, the majority of the sulfur and organic carbon has to be oxidized to SO 2 and CO 2 ; the arsenic of ore has to be transformed to the volatile trivalent compound.
The BIOX™ Process for the Treatment of Refractory Gold
In: Proceedings of the colloquium bacterial oxidation for the recovery of metals, Johannesburg, pp 1–12. Google Scholar Fraser GM, Kubera PM, Schutte MD, Weetman RJ (1993) Process/mechanical design aspects for Lightnin A315 agitators in mineral oxidation. In: Proceedings Randol 1993, Beaver Creek, pp 247–253.
Processing of refractory gold ores
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 conditions for sulphides destruction. Therefore, it is a suitable substitution for conventional pretreatment techniques.
Oxidation of sulfide mineral and metal extraction analysis in the
Applying microwaves with appropriate concentrations of additives and water resulted in high oxidation of sulfide minerals (>90%) and low sulfur emissions in …
ACID PRESSURE OXIDATION OF REFRACTORY GOLD …
Acid pressure oxidation is currently strongly advocated as the most effective pretreatment method for refractory gold ores and concentrates. Arsenopyrite and pyrite …
Two-step processing of refractory gold-containing sulfidic
Pyrite is the mineral most refractory to ferric leaching and is passivated by layers of chemical reaction products, such as jarosite and elemental sulfur ... Muravyov MI, Bulaev AG (2013) Two-step oxidation of a refractory gold-bearing sulfidic concentrate and the effect of organic nutrients on its biooxidation. Miner Eng 45:108–114.
Pretreatment of refractory gold minerals by ozonation before the
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 conditions for sulphides destruction.
The BIOX™ Process for the Treatment of Refractory Gold
Sulfide mineral oxidation is an ... Results revealed that culture media containing ca. 4.5 and ca. 0.9 g/L thiosulfate favored biological oxidation of the refractory sulfidic ore using T ...