Processes | Free Full-Text | Combined Bacterial and Pressure Oxidation
Microbially assisted bio-oxidation of sulfide concentrates in stirred-tank reactors (stirred-tank reactor bio-oxidation (STRB)) and acid pressure oxidation (POX) are widely used to pretreat refractory sulfide concentrates and increase gold extraction via cyanidation. Continuous STRB requires a comparatively long residence time; however, in …
(PDF) Thermodynamic Behavior of Pyrite and Arsenopyrite
refractory gold ores. e advantages of pressure oxidation are that the reaction rate is fast, environmental pollution is low, decomposition of sul de minerals is perfect, mass re-
BASIC IRON SULPHATE – A POTENTIAL KILLER FOR PRESSURE OXIDATION …
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 generally be broken down chemically, by oxidative processes such as roasting, pressure oxidation or bacterial leaching, which …
Complete process and equipment solutions for refractory gold …
A typical pressure oxidization (POX) circuit for refractory ores consists of the following main process steps: comminution and flotation followed by carbonate removal, chloride removal, pressure oxidation, vent-gas scrubbing, conditioning, solid-liquid separation, and neutralization. Pressure oxidation technology is applied for both ores …
Basic iron sulfate — a potential killer in the processing of refractory …
Refractory gold concentrates often contain submicroscopic gold that is encapsulated within the crystal matrix of iron sulfide minerals, such as pyrite, pyrrhotite and arsenopyrite. To recover the gold, the host mineral must generally be broken down chemically by oxidative processes, such as roasting, pressure oxidation or bacterial …
Redox potential measurement during pressure oxidation (POX…
Pressure oxidation (POX) leaching has been commercially applied to refractory gold ores since the 1980s. In the process, sulphide material is oxidized and dissolved in order to release the gold ...
Gold deportment and leaching study from a pressure oxidation …
Many recent research activities on pressure oxidation of refractory gold ore focuse more on the control of the autoclave operation. There is a lack of a systematic study on the gold distribution in the solid discharge. Understanding the gold deportment in the residue will help develop a better prediction of the gold leaching behavior.
Pretreatment of refractory gold minerals by ozonation …
Pressure oxidation has been used successfully on an industrial scale in previous works. However, its capital and operating costs are significantly high [14]. 2.1.2. Grinding. The grinding method is an alternative for the liberation of refractory gold from sulphide minerals for further decrease in the sulphide particle size.
Gold recovery from refractory gold concentrates by …
Abstract: Naturally, refractory gold is enclosed by sulfide minerals such as pyrite and arsenopyrite and a higher content of organic carbon, which results in difficulty in …
Gold recovery from refractory gold concentrates by …
Pressure oxidation technology for the treatment of refractory gold concentrates has been deployed in some countries. Shuiyindong gold deposit is one of the Carlin-type deposits which is a typical difficult-to-treat gold deposit, located in Guizhou province in western China. It was the first application of acid pressure oxidation in China.
Pressure oxidation overview
The utilization of a pressure-oxidation circuit to treat refractory gold ores or concentrates is a complex decision, taking into consideration capital costs, operating costs, gold recovery, and environmental impacts. The payback and internal rate of return (IRR) has to be evaluated in the decision for selecting the process.
ACID PRESSURE OXIDATION OF REFRACTORY GOLD …
Pressure oxidation of these refractory gold mineral carriers is a very complex reaction system involving several oxidation and hydrolytic reactions which occur in series and/or parallel. Moreover these oxidation reactions are highly exothermic. Since the nature and composition of the reaction products can have a considerable impact on …
Oxidative pretreatment of refractory gold ore using …
The pretreatment of refractory gold ore is a complex chemical process. In addition to the oxidation of pyrite, some side reactions also occur. The phase changes of refractory gold ore before and after pretreatment are shown in Fig. 11. The main phases of refractory gold ore include quartz (SiO 2), pyrite (FeS 2), and dolomite (CaMg(CO 3) 2 ...
Optimizing the alkaline oxidation pretreatment of a refractory gold …
Generally, these studies demonstrate that roasting, pressure oxidation, bacterial oxidation, chemical oxidation, alkaline oxidation and ultrafine grinding are as pretreatment methods prior to cyanide leaching to enhance gold recoveries from refractory ores. ... Muravyov M I and Kondrat'eva T F 2010 Two-stage bacterial–chemical …
TECHNOLOGY FOR PROCESSING OF REFRACTORY …
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 …
Enhanced Gold Recovery from Alkaline Pressure Oxidized …
Pressure oxidation is a widely accepted method to treat refractory gold ores. Gold recovery is generally lower from alkaline than acidic pressure oxidation …
Pre concentration and pressure oxidation of Porgera refractory gold …
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 …
Pressure Oxidation of a Refractory Sulfide …
Pressure oxidation of the refractory sulfide/carbonaceous ores has gained world-wide acceptance. Compared with roasting, pressure oxidation yields higher gold extractions from ores or concentrates and …
Gold Extraction from Refractory Minerals Using Acid …
Gold extraction was improved to 98% using pressure leaching, at 0.62 MPa, a temperature of 70 °C, a particle size of 26.5 μm, and a contact time of 120 min. Apparently, the oxidation in the acidic medium caused a greater porosity in the mineral, which provided a suitable environment that improved conditions in the cyanidation stage …
The Fate of the Arsenic Species in the Pressure Oxidation of …
The Fate of the Arsenic Species in the Pressure Oxidation of Refractory Gold Ores: Practical and Modelling Aspects. Wei Sung Ng., Yanhua Liu., Qiankun …
Oxidation of a refractory gold concentrate using pressure …
*This is an abstract only. No full paper was prepared for this abstract. CITATION:Casingena, C, Czerny, C, Paterson, L and Carter, P, 2019. Oxidation of a refractory gold concentrate using pressure, atmospheric and bacterial oxidation processes, in Proceedings World Gold 2019, p 681 (The Australasian Institute of Mining …
Refractory Gold Pressure Oxidation Technology at …
of ore at the Lihir gold mine in Papua New Guinea (commissioned in 1997). In addition, Sherritt had conducted process development studies for Homestake's McLaughlin Mine operation in California, which had come on stream in 1985, for the treatment of refactory gold ore. Refractory Gold Pressure Oxidation . Technology at Campbell Mine ...
Research on chlorination leaching of pressure-oxidized refractory gold
The optimum conditions for leaching the gold in the refractory gold concentrates pretreated with the pressure oxidation are as follows: 4 of pH, above 1.0 V of the redox potential, 75 g/L of the NaCl concentration, and 40 °C of the leaching temperature, 3:1 of the liquid-solid ratio, and 2 h of the reaction time.
Gold deportment and leaching study from a pressure oxidation …
Pressure oxidation (POX) is an effective method for base metal extraction and a pretreatment of refractory gold ores. A residue from pressure leaching of chalcopyrite concentrate was collected and investigated for gold recovery and deportment of metals. A comprehensive mineralogical analysis and gold deportment study were …
Pretreatment of refractory gold ore by curing with …
Different from traditional high-temperature roasting, concentrated sulfuric acid was used as both an oxidant and leaching agent in a sulfide-encapsulated …
Refractory gold reserves: Challenges and opportunities for a …
High-grade refractory gold reserves offer the potential for lower costs per ounce despite higher capital and operational costs. A focus on three action …
Treatment of Refractory Gold Ores | SpringerLink
Abstract. Problem ores that yield low (say less than 80%) gold recovery by cyanidation when "normally ground" are defined as refractory. The term, as well as the technical methods used to treat such ores, are relatively new. Rose and Newman's very comprehensive book, The Metallurgy of Gold, does not even contain the term refractory …
Basic iron sulfate
In the pressure oxidation (POX) of refractory gold-bearing sulfides, a major environmental challenge is the treatment of the hazardous waste released from arsenic-bearing minerals during processing.
Pressure oxidation of double refractory gold concentrates
Santa Fe Pacific Gold Corp. conducted pressure-oxidation pilot plant studies on refractory carbonaceous gold ores from the Twin Creeks Mine in Nevada. The tests were conducted at Hazen Research ...
Pressure Oxidation Pretreatment of Refractory Gold
Abstract. Pressure oxidation of gold containing concentrates and ores is an effective pretreatment for liberating refractory gold. This is particularly true when …