Pressure Oxidation Pressure oxidation is employed to liberate gold and silver in refractory sulfide concentrates often and ores The main pressure oxidation products from iron sulfide minerals are sulfuric acid and metal sulfates and hematite Depending on the conditions within the autoclave acid containing iron compounds can be formed
Get Price
The results of an IR study on the interaction of CO/O 2 gas mixtures with planar Au/TiO 2 model catalysts at elevated pressures and at room temperature are presented The model catalysts were prepared by deposition of a flat titania film on a Ru 0 0 0 1 substrate and subsequent evaporation of gold on the titania film In the presence of the gas mixtures an IR band in the CO stretching region
Get PriceSun High Pressure Oxidation Of Refractory Gold Minerals Biooxidation Biooxidation uses sulfur consuming bacteria in a water solution to remove sulfur Pressure oxidation Utilizes oxygen and heat under pressure in a liquid medium to effect oxidation of sulfur by way of a controlled chemical reaction High pressure autoclaves
Get Price
High pressure study on the adso rption and oxidation of CO on gold/titania model catalysts Thomas Diemant Zhong Zhao Hubert Rauscher 1 Joachim Bansmann R Jürgen Behm
Get Price
Madix RJ Friend CM Liu X Anticipating catalytic oxidation reactions on gold at high pressure including liquid phase from ultrahigh vacuum studies J 2008
Get Price
pressure oxidation process gold bearing pyrite is subjected to high temperature high pressure oxidation in autoclaves to destroy pyrite lattice 12 13 This process has been practiced commercially since the early1980s 14 and is widely accepted by the gold mining industry all over the world for its high efficiency and low pollution
Get Price
The high pressure reaction that suggests this bridge is the aerobic aqueous oxidation of ethanol over gold 1 CH 3 CH 2 OH → CH 3 CHO → CH 3 COOH CH 3 CH 2 OOCCH 3 or more generally 2 ROH → R′CHO → R′COOH ROOCR′
Get Price
Uranium Nickel Gold Copper Cobalt Rare earths Zinc High Pressure Acid Leach HPAL and Pressure Oxidation POX testing services provide a unique opportunity to evaluate and optimise the most economically viable process routes for the recovery of most metals such as nickel from lateritic ores and gold from refractory ores
Get Price
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 capable of achieving the
Get Price
A thermogravimetric apparatus for operation in 1 and 70 atm steam hydrogen or steam helium mixtures was used to investigate the oxidation kinetics of sponge Zr containing 215 ppm Fe Weight gain rates reflecting both oxygen and hydrogen uptake were measured in the temperature range °C The specimens consisted of thin sponge Zr layers metallurgically bonded to a Zircaloy disk
Get Price
technology is not used to leach the gold but only to make the cyanide ions accessible to the gold in the host mineral 2 Extraction of gold and silver from the argentopyrite argentite ore 2 1 Pressure oxidation cyanidation chemistry The oxidation of gold and silver is a prerequi site for its dissolution in the alkaline cyanide lixiviant
Get Price
Alkaline pressure oxidation particularly in the presence of trona as additive can be used to oxidize high carbonate refractory gold ores as it prevents the formation of CO 2 in the autoclave However the presence of silica in the ore can lead to the encapsulation of
Get Price
Pressure oxidation POX high pressure oxidation HiPOX and ACTIVOX autoclave leaching are viable industry standard technologies used to recover gold and other accessory metals The process is particularly well suited for treating refractory gold ores which give low recovery when directly leached with cyanide
Get Price
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 enables better handling of environmentally sensitive impurities Normally gold is extracted from neutralized autoclave leach residue by cyanidation
Get Price
Keywords gold pressure oxidation thiosulfate leaching RSM 1 Introduction Gold was an important rare and precious metal always coexists with sulphide minerals such as pyrite and arsenopyrite Azizi et al 2010 Nunan et al 2017 Due to the depletion of high grade gold ores
Get Price
The reasons for gold bearing materials refractory nature and behaviour features of carbonaceous matter during pressure oxidation of concentrates were discussed The chemical processes that lead to
Get Price
Pressure oxidation was developed for processing refractory ores where gold is occluded in the sulfide minerals typically pyrite or arsenopyrite Oxidation of the sulfides at elevated temperatures and pressures liberates the gold allowing it to be economically recovered by conventional circuits
Get Price
kPa All plants achieve high gold extractions generally exceeding 90 High temperature oxidation is critical in these designs to minimize elemental sulfur formation and limit cyanide consumption A general flowsheet demonstrating the unit operations of pressure oxidation of The most recent sulfide pressure
Get Price
Pressure oxidationrefers to the oxidation of sulfides such as pyrite FeS2 and marcasite FeS2 at elevated temperature and pressure Oxidation releases encapsulated gold grains from the sulfides and makes the oxidation residue of the ore or concentrate more amenable for gold recovery by cyanidation in a subsequent leaching step
Get PricePressure oxidation of gold containing concentrates and ores is an effective pretreatment for liberating refractory gold This is particularly true when an appreciable portion of the gold is associated with sulfides and is not amenable to conventional cyanidation
Get Price
Pressure oxidation was selected as the most feasible processing technology for double refractory ores It is able to achieve gold recoveries of 96 by utilising high temperatures elevated pressure and oxygen to recover encapsulated gold while conventional cyanidation methods would result in sub optimal recovery rates of 20 40
Get Price
These gold nanosheets exhibit high catalytic activity and stability in the solvent free selective oxidation of carbon–hydrogen bonds with molecular oxygen There is interest in the study of two
Get Price
Outotec can provide a complete pressure oxidation plant including all auxiliary processes for refractory gold sulfide oxidation Gold is efficiently released from the sulfide matrix for the subsequent leaching process whether cyanidation or chloride leaching The Outotec pressure oxidation main process steps Carbonate and chloride removal
Get Price
Alkaline pressure oxidation particularly in the presence of trona as additive can be used to oxidize high carbonate refractory gold ores as it prevents the formation of CO 2 in the autoclave However the presence of silica in the ore can lead to the encapsulation of
Get Price
The oxidation of the pyrite present in gold and uranium ores is often desirable to either liberate the gold present in the pyrite or to generate iron III and acid for uranium extraction The current study aimed to define a rate equation to describe the pressure oxidation POX kinetics of a Witwatersrand pyrite concentrate
Get Price
Keywords pretreatment process pressure oxidation refractory gold ore and concentrate leaching modeling Investigation of high pressure pretreatment process for gold
Get Price
Gold nanorods Au NRs nanospheres and other nanoparticles display numerous superior physicochemical properties such as resistance to oxidation and aggressive agents strong enhancement of local electric field and a high absorption coefficient in
Get Price
arsenopyrite gold concentrate Batch oxidation tests in an autoclave were done using a factorial design Different responses were measured and analysed to study effect of the three factors and oxidation kinet ics Generally high slurry density required high temperature and oxygen partial pressure to reach com plete oxidation Oxidation
Get Price
The first gold pressure oxidation plant commissioned was at the Homestake McLaughlin operation CA USA in 1985 and served as the pioneering installation for whole ore acidic treatment The largest by tonnes of ore treated is Barrick Goldstrike which is described below Thomas and Williams 2000 3 1 Geology and mining
Get Price
ENGLISH ABSTRACT The oxidation of the pyrite present in gold and uranium ores is often desirable to either liberate the gold present in the pyrite or to generate iron III and acid for uranium extraction The current study aimed to define a rate equation to describe the pressure oxidation POX kinetics of a Witwatersrand pyrite concentrate
Get Price
Roasting is the only commercialised process in Zimbabwe for the pre treatment of refractory gold feedstocks for the subsequent cyanidation leaching This process results in only about 75 gold recovery and is characterised by high gold values in the residue A pressure oxidation process in an autoclave has been evaluated as an alternative The process resulted in substantially higher gold
Get Price
Caldera Engineering has extensive experience providing solutions for High Pressure Acid Leach HPAL and Pressure Oxidation POX mineral processing plants Ph 801 356 2862
Get Price