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Base metal refineries in the platinum group metal business appear to operate pressure leaching at low acid concentration that may affect iron hydrolysis. Anderson et al. (2002) indicated that the Stillwater base metals refinery operate pressure leach process at acid concentration of 20–25 g/L and temperature of 130–135 °C. The principal ...
The typical processes that the autoclave is used for include pressure oxidation (POX), high-pressure acid leaching (HPAL), pressure alkaline leaching …
In late 2014, the increasing acid requirements in the Southwestern United States prompted a reevaluation of the Morenci concentrate leaching facilities. As a result, the pressure leaching circuit was restarted in high-temperature (200 °C) mode in May 2015 and has operated successfully for three years since recommissioning.
High-pressure acid leaching (HPAL) is being used for the recovery of nickel from nickel laterite ores, and increasingly atmospheric leaching is also being considered. As mentioned above, major reserves of nickel are …
A two-stage leaching process, namely, high-pressure acid leaching-atmospheric acid leaching, was used to treat laterite ores under mild conditions. The leaching ratio of Ni was low because of adsorption and incomplete leaching. In this work, surfactants were used as additives to boost the leaching ratio of Ni. The effect of …
The hydrometallurgical process included pressure leaching under slightly oxidising conditions in diluted sulphuric acid (at 80–105 °C and 140-350 kPa oxygen …
Provis et al. presented a semi-empirical mathematical model for the acid-oxygen pressure leaching of nickel–copper matte; the primary controlling factor in the leaching process is found to be galvanic inhibition of the more highly oxidized copper and nickel sulfide species by less oxidized species, particularly nickel alloy and nickel …
The nitric acid pressure leaching (NAPL) has several advantages. In order to solve the problems of environmental pollution and resource wastage caused by the NAPL residue, this work proposes a novel and green process for treating laterite residue to prepare high-purity iron phosphate.
The typical processes that the autoclave is used for include pressure oxidation (POX), high-pressure acid leaching (HPAL), pressure alkaline leaching (PAL), and pressurized precipitation. Hydrometallurgical pressure processes are used in a variety of different applications to extract different kinds of metals from refractory ore bodies …
Acid leaching is commonly performed by agitating an ore-leach mixture for 4 to as long as 48 hours at ambient temperature. Except in special circumstances, sulfuric acid is the leachant used; it is supplied in amounts sufficient to obtain a final leach liquor at about pH 1.5. ... Because the vapour pressure of magnesium metal is very high at ...
There are many different types of leaching processes, which are mainly categorized based on the reagents utilized, Such as Cyanide leaching (e.g. gold ore),Ammonia leaching (e.g. crushed ore),Alkali leaching (e.g. bauxite ore),Acid leaching (e.g. sulfide ore) The reagents needed are determined by the ores or pretreated material …
Pressure leaching and pressure oxidation are hydrometallurgical processes applied to the extraction of many metals.The processes occur above atmospheric boiling temperature, require a sealed reactor vessel, and often operate in highly corrosive and oxidizing environments. Pressure leaching and pressure oxidation have been applied …
The zinc pressure leach process depends upon the following simple reactions in which zinc sulfide, pyrrhotite, or iron in sphalerite, galena, and chalcopyrite react with sulfuric acid and oxygen to produce metal sulfates and elemental sulfur. ZnS + H 2 SO 4 + 0.5O 2 —> ZnSO 4 + H 2 O + S°. FeS + H 2 SO 4 + 0.5O 2 —> FeSO 4 + H 2 O + S°.
I. INTRODUCTION THE AMAX sulfuric acid leaching process involves countercurrent digestion of nickeliferous laterite ore at high pressure and at atmospheric conditions.t After solid/ liquid separation, the nickel and cobalt values are precipitated by hydrogen sulfide ~5 and refined into nickel and cobalt metal. 16Research at AMAX began in the early 1970's …
Laterite leach solutions were simplified to a ternary electrolyte system by lumping all divalent metal sulfates into one with the chemical and thermodynamic properties of MgSO4. The simplified leach solution was assumed to contain H2SO4, Al2(SO4)3, and pseudo-MgSO4. The ion-association-interaction approach, as developed previously, …
Pressure Oxidation (POX) is a process used to extract gold, copper, zinc, molybdenum, and uranium from refractory ore bodies. The POX process utilizes elevated temperatures (roughly 230 degrees Celsius), elevated …
Leaching is carried out by two main methods: simple leaching at ambient temperature and atmospheric pressure; and pressure leaching, in which pressure and temperature are increased ... Oxides are leached with a …
I. INTRODUCTION THE AMAX sulfuric acid leaching process involves countercurrent digestion of nickeliferous laterite ore at high pressure and at atmospheric conditions.t …
The leaching process has high Ni extraction ratio compared to that without microwave (82%) and conventional pretreatment (90.4%). Therefore, microwave pretreatment of limonitic laterite before nitric acid pressure leaching is an effective way to improve the selectivity and extraction of the leach.
The increase in complexity of newer polymetallic ore bodies, often containing deleterious elements (As, Hg) requires more sophisticated processing such as: Pressure Oxidation (POX) Pressure Oxidative Leach (POL) High Pressure Acid Leach (HPAL) HCl …
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 …
There are many different types of leaching processes, which are mainly categorized based on the reagents utilized, Such as Cyanide leaching (e.g. gold …
The acid pressure leaching process of laterites started in Moa Bay, Cuba, in 1959 [7]. The Moa Bay process includes the sulphuric acid leaching of nickel ores at about 250 °C, the phase separation and the nickel sulphide precipitation by hydrogen sulphide. The temperatures above 200 °C make possible
The pressure acid leach experiments conducted at different leaching durations showed that more nickel and cobalt could be extracted into the pregnant leach liquor at 255 °C by increasing the duration of leaching in the autoclave. However, as in the case of temperature, there was a limit to this increase, possibly due to the difficulty in ...
Based on test-work results, pressure leaching is operating at 220°C and 7 bar oxygen overpressure. Copper from is recovered by SX-EW. The client in this case has an existing heap leaching operation, and …
Phelps Dodge Copper Pressure Leaching Developments Phelps Dodge (& Placer Dome) have developed a suite of proprietary processes, including: High temperature process (HT) Converts essentially all sulfide sulfur to acid Maximizes acid production Suitable for locations where dilute acid can be used beneficially Medium temperature process (MT)
The acid pressure leach process works without a prior reduction roast and is applicable to low MgO ores. Screened and thickened ore slurry is pressure-leached at 250°C with concentrated sulfuric acid in autoclaves for one to two hours. Nickel and cobalt are precipitated by reacting the pregnant solution with hydrogen sulfide in horizontal ...
High pressure acid leaching (HPAL) is the primary method for extraction of nickel from limonitic laterite. The severe operating conditions, the complexity of facilities, …
There are a number of principal variables which affect the rate of leaching and the final extraction of the valuable metals from a given matte. In general, they apply to both ammonia and acid leaching. …
High pressure acid leaching (HPAL) is the primary method for extraction of nickel from limonitic laterite. The severe operating conditions, the complexity of facilities, and several technical ...
In essence, HPAL involves sulphuric acid leaching of lateritic ores at temperatures above 240ºC, which can only be achieved at high pressures. The HCE has a dedicated fully …