oxidation abstract the leachox refractory gold process has to date been applied to the selectivetreatment of several refractory gold ores but on a relatively small scale. In this paper the successful implementation of the process, from initial testing through to commissioning at one of the worlds largest refractory gold mines is described.significant advances have taken place in the treatment of refractory gold ores and concentrates during the past decade. In sulfide ores, pyrite is the most common host mineral for gold. studies by gasparrini showed that gold occurs in pyrite as native gold or electrum in all sizes and forms. arsenopyrite is probably the second most common host for gold and forms similar associations
options for refractory gold ores: roasting; pressure oxidation; bio-oxidation; and ultra-fine grinding. In roasting, pressure oxidation and bio-oxidation, the iron sulphide minerals are oxidised to create sulphur dioxide gas in the case of roasting, or sulphate ions in pressure oxidation and bio-oxidation. the iron component isdisseminated 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 gt. the concentrate size was 80% -80 um. mineral composition of the concentrate comprises 17% of rock-forming minerals, 59% of pyrite and 24%
jun 01, 2020 additionally, conventional thiourea leaching cannot extract gold efficiently from refractory gold concentrate calcine samples, due to the complicated chemical composition of gold minerals part of gold is still encapsulated in the iron oxides and quartz minerals even if the gold concentrate with high-sulfur and high jan 01, 1991 minerals engineering, vol. nos pp. 055, 1991 87591 $3.00 000 printed in great britain 1991 pergamon press plc treatment OF carbonaceous refractory gold ores p.m. afenya dept. of mining engineering, lae, papua new guinea abstract gold ores can be categorized into two types free milling and refractory.
gold mainly occurr ed in the form of enclosing gold, fracture gold, and intergranular gold in pyrite, arsenopyrite, sphalerite, jamesonite, and gangues. minerals 2019 406 offor extraction of gold from refractory ores or concen- trate, in which gold is surrounded or covered by iron sul- fide minerals, mainly arsenopyrite and pyrite, mineral oxidative pretreatment is essential to oxidize sulfides and to expose gold to the leaching solution. pyrometallurgi- cal oxidation by roasting is under environmental restric-
sep 28, 2016 both have experience in mining refractory ore: polyus at its massive olimpiada mine, which uses proprietary bio-oxidation techniques to process concentrate, while polymetal deals with refractory ore at two producing mines and one mine in development. for bigger companies willing to deal with tricky minerals, russia has some rich pickings it seems.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.
gold recoveries increased by as a result of bio-leaching.if the gold grade is high enough, an autoclave leaching process can be effectively used to oxidize the sulphide minerals and exposing gold for cyanide leaching.challenges. polymetal international inc. is undertaking the amursk pox hub expansion to recover gold from double-refractory sulphide concentrate from five of their mines in siberia, eastern russia, and east kazakhstan. the project will double polymetals concentrate treatment capacity to 250,00,000 ta of refractory gold concentrate.
bio-oxidation is an effective technology for treatment of refractory gold concentrates. however, the unsatisfactory oxidation rate and long residence time, which cause a lower cyanide leaching rate and gold recovery, are key factors that restrict the application of traditional bio-oxidation technology.refractory gold ores, has been studied by investigating the reaction chemistry and kinetics. the effects of retention time, temperature, particle size, oxygen partial pressure, pulp density, sulfuric acid concentration, and cupric ions were evaluated for both minerals. the effect of ferric ions on the oxidation rate of As to As was also
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 leaching 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.
of refractory gold. statistics show that, in the world, about gold resource belongs to the difficult processing ores, and about total output of world gold is produced from refractory gold. this proportion will further increase in future. therefore, pre-treatment of arsenic-bearing refractory gold has an extreme-ly important significance.aug 19, 2020 metso outotec, a frontrunner in minerals and metals processing, has recently launched the outotec mesotherm biox process for the treatment of refractory gold
extraction of refractory gold can only be achieved by employing a pre-oxidation process prior to cyanide leaching. antimony, bismuth sulfide, and telluride gold ores are often somewhat refractory due to the presence of slow-dissolving gold minerals such as aurostibite maldonite and gold tellurides. carbonaceous sulfide oresthe gold leaching rate of much refractory gold concentrate is as high as 98% after the hot-pressure leaching. biological oxidation. the basic principle of the biological oxidation is that the metal sulfide minerals are resolved through the action of biological enzymes, so the gold ores are dissociated.
low-grade, finely disseminated refractory sulfide gold ores associated with high arsenic are ubiquitous resources all over the world. since heap bio-oxidation is an economic and promising biotechnology to recover gold, low grade, high organic carbon and arsenic bearing gold ores from zhesang mines in china were chosen for this purpose to study the key factors that would affect biooxidation.csiro, australia, has developed a thiosulfate-based reagent system for gold leaching that has excellent stability and shown broad applicability in the laboratory compared to the thiosulfate system commercially implemented by barrick to treat double refractory gold ore following pressure oxidation at its goldstrike mine in nevada, usa.
currently, a greater percentage of gold is extracted from low grade, refractory gold ores, following depletion of most high grade deposits increasing complexity of these refractory ores warrants improvement in our fundamental and applied knowledge un-derpinning sustainable, cost-effective, commercial gold extraction process and commod-chloridehypochlorite oxidation and leaching of refractory sulfide gold concentrate fig. the pourbaix diagram of fes at Fe and fig.
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 aerated alkaline solutions; the kinetics of arsenopyrite is a common gold carrier in many refractory gold concentrates. arsenopyrite is typically oxidised under the neutral leaching conditions. the resultant product is ferric arsenate ferric arsensate is a stable and environmentally inert arsenic mineral.
gold. the oxidation of refractory arsenical gold concentrates in aerated alkaline solutions results in the formation of thiosulfate, arsenate and sulfate as well as the dissolution of gold, copper and iron. It appears that the dissolution of gold is due to the complex reactions of gold with thiosulfate ions promoted by the catalytic effect ofTo compare process routes and recoveries, pressure oxidation can completely breakdown the sulphides and then achieve high gold recoveries, maybe greater than 95%. where as with the leachox process and the partial oxidation, depending on the nature of the mineralogy, recoveries in the range 80% to 90% can be expected.
fundamental investigation of the high temperature oxidation of gold ores that contain sulfides and carbonaceous materials titlea fundamental investigation of the high temperature oxidation of gold ores that contain sulfides and carbonaceous materials, authorwill friesinger, yea for gold recovery, a chinese refractory, high-sulfur gold concentrate was subjected to biooxidation with high pulp density in a single stirred-tank reactor. the flotation concentrate contained 36.9 percent sulfur and 33.9 percent iron different experimental regimes for biooxidation were applied. with a mixed culture and by controlling the amount of addition of the gold ores and the
gold extracted during the next four stages indicates minerals that the gold occurs with and suggests process options, such as pressure oxidation, biooxidation or roasting that could lead to improved recovery of the refractory gold values. gold remaining in the stage leach residue is most likely locked or encapsulated and probably not