Autoclave Lining Construction with Dissimilar Materials
Pressure oxidation autoclaves for the recovery of gold, copper, and other metals operate at corrosive conditions that require specialized materials of construction. Typical autoclave construction consists of carbon steel pressure vessels lined with acid-resistant membrane and refractory systems.
Pressure Oxidation Overview
An overview of the pressure oxidation of refractory gold ores is provided in this chapter. ... Au: Whole ore: 1985: California, USA: 175: 2200: Au: Sulfide concentrate: 1986: São Bento, Brazil: 190: ... Most pressure oxidation autoclaves are protected by corrosion resistant, ...
Manipulating Iron Precipitation and Gold Deportment …
This can be achieved via three main routes: (i) roasting at high temperature (> 800 ˚C), an approach that has been phased out in Australia; (ii) BIo-OXidation (BIOX) …
(PDF) Pressure oxidation overview
The equation proposed for gold is: The pressure oxidation of pyrite involves ... highest extraction of Au were obtained with an oxygen pressure of 0.5 MPa, 6 g/L sodium cyanide, and a temperature ...
Pressure Oxidation Modelling for Design and Optimisation
A block flow diagram for a gold recovery flowsheet using POX to make the ... circuit is integrated with a copper heap leach that uses sulphuric acid generated from copper sulphate produced in the pressure oxidation autoclave. Fig. 2. Copper/gold POX flow diagram ... The former approach has historically been more common in Australia …
Autoclave Circuit & Gold
Sulfide sulfur oxidation through the autoclave is typically of the order of 90—92%. Residual S exiting the autoclave is targeted at less than 0.2%. Values greater than 0.25% S" typically result in poorer gold recoveries in the C1L circuit. Free-acid levels in the autoclave discharge are a function of S2 and CO2- in the autoclave feed, but ...
Pressure Oxidation Treatment
Gold recoveries of 97 to 98% were achieved in the second test with a temperature and pressure of 170°C (338°F) and 1.4 MPa (200 psig). The above results were obtained using 3 to 4 hours autoclave retention time and feed slurry densities of 30 to 35% solids. Autoclave discharges were highly oxidized as indicated by the acidity of 80 …
Pressure-oxidation autoclave as an analogue for …
Pressure-oxidation autoclaves are used to oxidise sulphide minerals so that fine-grained gold is released for cyanidation (Fig. 2a; LaBrooy et al. 1994; Johnstone et al. 2001).A slurry of crushed sulphide-bearing ore is heated under elevated oxygen pressure until the sulphides oxidise (Papangelakis and Demopoulos 1991; LaBrooy et …
Pressure Oxidation Leaching Process
Batch Autoclave Laboratory Procedures: The vessel used for the laboratory pressure oxidation process was a two-liter Parr titanium autoclave with dual impellers.It was heated and cooled externally and was pressurized with commercial-grade oxygen. A positive bleed of offgas was maintained in each test; the rate was measured in the …
SGS MINERALS SERVICES – T3 SGS 174 09-2013
the ore is termed "refractory". Gold encapsulated in a sulphide matrix can be readily recovered after a destructive oxidation treatment. After leaching and neutralization, cyanidation or CIL can recover the gold. Pressure leaching in autoclaves has been developed into a standard operating procedure and is being applied in many operating …
Influence of pressure oxidation autoclave conditions on gold …
Influence of pressure oxidation autoclave conditions on gold recovery (2015–2019) Grant type: NewCrest Mining Limited Researchers:
Electronic waste treatment: Part 1. Autoclave oxidation
A pressure oxidation process in an autoclave has been evaluated as an alternative. The process resulted in substantially higher gold recoveries (>90%) over shorter periods.
Effect of Chloride Concentration on Gold Recovery in …
The higher the Cl concentration, the lower the reduction potential (E) of AuCl. 4 -/Au. Oxidation of Auo is more favourable due to common ion effect, according to this reaction: AuCl -+ 3 e- Æ. 4 Auo + 4 Cl-. Study extended to effect of temperature, ferrous/ferric ratio and H2SO 4 concentration.
Under Pressure and Feeling the Heat: Autoclave Technology at …
Autoclaves are incorporated in the flowsheets for high-pressure acid leach (HPAL) and pressure oxidation (POX) processes. The process applied, either HPAL or POX, is directly related to the ore or ...
Refractory Gold Pressure Oxidation Technology at …
The Campbell Mine pressure oxidation plant uses the following pro - cess steps: • Pretreatment of concentrate with recycled acidic slurry • Oxidation of sulphides in the autoclave • Flashing of autoclave discharge slurry •ashing of oxidation residue to remove acid and cyanicides W Gold recovery by conventional cyanidation
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 ...
Optimisation of Circuits for Gold Pressure Oxidation
Refractory ores need to be pretreated prior to cyanide leaching for acceptable gold recovery. Pressure oxidation is one method of rendering the ores more suitable for cyanidation. The focus of this work is optimisation of autoclave configuration for pressure oxidation. An autoclave for the pressure oxidation of a feed containing pyrite and …
Pressure oxidation of pyrite-arsenopyrite refractory gold concentrate
Oxidation kinetics at 225 degrees C temperature, with 1050 kPa oxygen partial pressure and 15% slurry density was found to be fastest resulting in complete conversion of sulfides in 30 minutes. At ...
Pressure Oxidation Leaching Process
Batch Autoclave Laboratory Procedures: The vessel used for the laboratory pressure oxidation process was a two-liter Parr titanium autoclave with dual impellers. It was heated and cooled externally and was pressurized with commercial-grade oxygen. A positive bleed of offgas was maintained in each test; the rate was measured in the offgas after the …
Refractory gold reserves: Challenges and …
Refractory gold reserves, which require more sophisticated treatment methods in order to achieve oxide-ore recovery rates, correspond to 24 percent of current gold reserves and 22 percent of gold resources …
Refractory Gold Technology
an autoclave circuit, on arsenopyrite-pyrite concentrates, starting in ... process, the sulphide and arsenide minerals are completely oxidized by pressure oxidation, thereby liberating the gold. Subsequent treatment by conventional techniques yields typical gold recoveries ... of Refractory Gold Feeds TECHNOLOGY Au V1.FEB25.2019.
ALTA 2013 Gold eProceedings
Gold Conference Melbourne, Australia PROCEEDINGS 4th Annual Gold Event Sponsored by. PROCEEDINGS OF ALTA 2013 GOLD SESSIONS 30-31 …
Alkaline Pressure Oxidation of a Gold- Bearing
Alkaline pressure oxidation at 160°C, 2413 kPa O2and 2 M NaOH resulted in about 98% sulfur oxidation and 86% arsenic dissolution. Cyanidation of the leach residue resulted in 82% Au extraction ...
Cyanide-free recovery of metals from polymetallic and refractory gold
Pressure oxidation conditions are similar to those used in conventional refractory gold autoclaves. Atmospheric leaching of POX residue is one patented Kell innovation that is useful for ore types with other HCl-soluble components, while the heat treatment innovation is useful for ore types with components deleterious to chlorination …
(PDF) AUTOCLAVE TECHNOLOGY OF REFRACTORY GOLD …
As a result of the pilot test it was shown that the additional autoclave oxidation of bioleaching products can significantly improve gold recovery to 96% and reduce cyanide consumption from 50 kg ...
Gold Recovery from Electronic Waste by Pressure Oxidation …
Gold recovery by pressure oxidation Recovery of gold was reached oxidizing the metal substrate (Fe, Ni, and Cu) where gold was superficially associated as coating. Substrate oxidation was performed using different concentration (0.66-1.31 M) of ammonium persulfate (≥98% (NH4)2S2O8) with a liquid solid rate variation between 15-25 mL/g.
REDOX POTENTIAL MEASUREMENT DURING PRESSURE …
Pressure oxidation (POX) is employed for gold recovery from refractory ores where gold particles ... The autoclave was first heated to a set point 0 to 10 °C below the target temperature, to ...
sbm/sbm autoclave pressure oxidation gold au c grinding …
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Pressure-oxidation autoclave as an analogue for …
Pressure oxidation of refractory gold ores containing pyrite (FeS2) and arsenopyrite (FeAsS) in an autoclave is viewed as analogous to the natural acid-sulfate alteration of andesite rocks during ...
Pressure-oxidation autoclave as an analogue for …
Pressure-oxidation autoclaves are used to oxidise sulphide minerals so that fine-grained gold is released for cyanidation (Fig. 2a; LaBrooy et al. 1994; Johnstone et al. 2001). A slurry of crushed sulphide-bearing ore is heated under elevated oxygen pressure until the sulphides oxidise (Papangelakis and Demopoulos 1991; LaBrooy et al. 1994).