·At high temperature pressure leaching conditions th e f ormation of sulphuric acid from sulphides in the ore is f avoured however at medium and low temperature conditions 150 165 o C and
·Arsenopyrite and pyrite are the most common mineral carriers 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
Box 16200 Aalto Espoo Finland Abstract Refractory gold ores have poor gold recoveries with direct cyanide leaching Typically the 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
Rose and Newman s very comprehensive book The Metallurgy of Gold does not even contain the term refractory in its latest fourth edition 1937 1 Dorr and Bosqui s Cyanidation and Concentration of Gold and Silver 2d edition 1950 has a brief chapter XIII on Cyanicides and Refractory Ores with only four pages devoted to
·Abstract This paper describes the experimental findings of the extraction of nickel and cobalt by high pressure acid leaching HPAL of a refractory limonitic nickel laterite ore from the Gordes region of Manisa in Turkey By optimizing the basic HPAL
·The principal gold minerals that affect the processing of gold ores are native gold electrum Au Ag tellurides aurostibite maldonite and auricupride
·A high pressure sampling mass spectrometer was used to detect the volatile species formed from SiO2 at temperatures between 1200C and 1400C in a flowing water vapor/oxygen gas mixture at 1 bar
·The extraction of gold from refractory gold ores RGOs without side reactions is an extremely promising endeavor However most RGOs contain large amounts of sulfide such as pyrite Thus investigation of the influence of sulfide on the gold leaching process is important to maximize the utilization of RGOs In this work the effects of pyrite on the stability of the
·This laboratory work presents a study of the effect of ultrafine grinding on the gold recovery of a highly refractory gold concentrate The particle size of the concentrate was P80 = 46 pm and the
·Arsenic is a common pollutant and impurity present in complex gold ores In the pressure oxidation POX of refractory gold bearing sulfides a major environmental challenge is the treatment of
Refractory gold ores have poor gold recoveries with direct cyanide leaching Typically the 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
·A more effective and economical strategy to recover gold from refractory ores involves the preliminary bacterial leaching of the refractory ore/concentrate to oxidize the sulfide minerals and
Refractory gold ores have poor gold recoveries with direct cyanide leaching Typically the 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
·The results show that gold is present in two forms native and/or refractory to a small extent in its native form and in its refractory form as association with sulfide minerals
·Gold a signicant precious metal has high corrosion resist ance excellent electrical and thermal conductivity [] In 1 the eld of gold extraction and smelting refractory gold ore is one of the most important gold resources at present [2] Approximately 30% of the world s gold production is derived from refractory gold ore and this proportion
·Pressure oxidation uses high pressure 4500 kPa and temperature ≥250 • C which pose safety risks as well as high capital expenditure for specialised equipment and operating costs
Pressure 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 A brief review of the literature on pressure oxidation of refractory gold materials is presented The chemistry of the
·Arsenic is a common pollutant and impurity present in complex gold ores In the pressure oxidation POX of refractory gold bearing sulfides a major environmental challenge is the treatment of
·For arsenic containing refractory gold concentrate gold recovery by leaching is extremely difficult due to the encapsulation of gold in arsenopyrite and pyrite In this work the pre oxidation of a high arsenic and high sulfur refractory gold concentrate in the acidic potassium permanganate or hydrogen peroxide solutions has been investigated The studied parameters
·Cyanide refractory ores constitute 30 % of the world s gold mineral resource base With the global decrease in the availability of high grade and free milling ores low quality ores including
Arsenopyrite is the main arsenic bearing mineral in refractory gold ore and pyrite and pyrrhotite are the main sulfide minerals In the process of oxidation the reaction of these three minerals is aerobic reaction Guo XY Zhang L Tian QH et al 2020 Gold leaching of high pressure acid leaching residue using a non cyanide system and its
·The process optimization and mechanism of microwave pyrolysis in a nitrogen atmosphere were studied to improve the gold leaching rate for high arsenic refractory gold sulfide resources mainly containing minerals of elemental sulfur dense pyrite and arsenopyrite The decomposability was evaluated using thermodynamic and thermogravimetric analyses Faster
Pressure oxidation POX is employed for gold recovery from refractory ores where gold particles are occluded by sulphide minerals mostly pyrite/arsenopyrite and standard cyanidation is not
·In the case of processing refractory gold ores and concentrates bioleaching makes it possible to recover gold through the destruction of gold bearing minerals pyrite arsenopyrite due to the
