Pressure oxidation (POX) is a well-established method for processing sulphide material containing refractory precious and base metals . POX typically takes place in a horizontal multi-compartment agitated pressure vessel at a temperature of 150–230 °C depending on the application. Sulphide minerals are broken down, reacting with oxygen …
The effect of elevated air pressure on the oxidation properties of the nickel-based superalloy, RR1000, at 650°C with different surface modifications October 2017 Materials at High Temperatures ...
The pressure oxidation of low-grade nickel sulfide concentrate with high iron sulfides content generates significant amounts of sulfuric acid that must be neutralized. This acid can be utilized to ...
Oxidation of atomically clean (110) nickel single crystals has been studied at room temperature and in pure oxygen or air at pressures from 1×10−9 torr to atmospheric. X-ray photoelectron (XPS) and Auger electron spectroscopic (AES) data indicate that the standard regimes of dissociative chemisorption, oxide nucleation, and oxide lateral …
The oxidation of nickel sulfide whose atomic fraction of sulfur,x s, is 0.40 to 0.44 was studied in a mixed O 2-N 2 gas stream at 923, 973, and 1023 K. The oxygen partial pressure was maintained at 2.0 x 10 4 Pa. In the oxidation of nickel sulfide ofx s = 0.40 and 0.41, a dense NiO layer was formed on the sulfide surface without the evolution of …
The oxidation of Mond nickel was studied between 1000° and 1200°C at oxygen pressures from . The oxidation rate was controlled by diffusion through the oxide and …
oxidation o f Fe +2 to Fe +3 was undertaken using 40 m l of 35 % ... This paper describes the experimental findings of the extraction of nickel and cobalt by high pressure acid leaching (HPAL) of ...
1400 °C. In addition it reports on in-house experimental data from investigations related to the. oxidation of high-purity Ni from 500 to 1300 °C in the oxygen pressure range 1 10 4–1 atm ...
1. Introduction. Nickel-based alloys have been widely used in coal-fired power plants owing to their superior oxidation resistance and good mechanical strength at high temperature [1], [2].Many attempts have been made to increase the temperature and pressure at which coal-fired power plants operate because these parameters are …
The oxidation of nickel and re-equilibration kinetics of nickel oxide have been studied thermogravimetrically as a function of temperature (1373–1673 K) and …
Undoped NiO. Nickel oxide (Ni 1− δ O) is a metal-deficient p-type semiconductor which is thermodynamically stable in a large temperature (T) and oxygen partial pressure (p O 2) range. 20 Nickel vacancies and …
Oxidation kinetics of high purity nickel, as well as the nonstoichiometry and chemical diffusion in nickel oxide have been studied as a function of temperature (1373–1673 K) and oxygen pressure (10–10 5 Pa) using microthermogravimetric techniques. In order to eliminate the possible participation of grain boundary diffusion in …
The aim of this thesis study was to investigate and find the most cost effective way of extracting nickel and cobalt into the pregnant leach solution (PLS) from Gördes lateritic nickel and cobalt ore by means of sulphuric acid leaching under high temperature and high pressure conditions.The high pressure acid leach (HPAL) experiments were conducted …
Further work was conducted to determine thermodynamics of nickel oxidation by measuring the fugacity of hydrogen using a palladium-silver thimble and estimations of the Henry's ... A pressure dependent equilibrium constant is suggested by Marshall 19 and is applied with success by Ziemniak 20 to model the solubility of CuO in …
Quinn, Turner and van der Muelen (Citation 2009) performed batch and pilot scale pressure oxidation studies on 70:30 nickel laterite:sulfide blends grading 1.24–1.63% Ni with a sulfide content of 3.2% under a variety of conditions (refer to Table 5). Nickel and cobalt extractions were 96.5% and 96.0%, respectively, after leaching the ore ...
Undoped NiO. Nickel oxide (Ni 1− δ O) is a metal-deficient p-type semiconductor which is thermodynamically stable in a large temperature (T) and oxygen partial pressure (p O 2) range. 20 Nickel vacancies and electron holes (h˙) are predominant defects, but the ionization degree of nickel vacancies (singly ionized: or doubly ionized: using the …
Pressure acid leaching of arid-region nickel laterite ores. Part III: Effect of process water on nickel losses in the residue. Hydrometallurgy (2005) ... Extraction of gold from typical Carlin gold concentrate by pressure oxidation pretreatment - Sodium jarosite decomposition and polysulfide leaching. Hydrometallurgy, Volume 208, 2022, Article ...
The demand for nickel and cobalt salts for lithium-ion battery manufacture is expected to continue to increase as electrification of the transportation sector …
The oxidation of Mond nickel was studied between 1000° and 1200°C at oxygen pressures from . The oxidation rate was controlled by diffusion through the oxide and had a gross activation energy of . Least squares straight line fitting over the entire pressure range indicated the rate was proportional to . However, the rates above 1 atm appeared ...
Nickel, Cobalt, and Copper Technologies. Ammonia Pressure Leaching . Sherritt, Canada (1993, 1954) Western Mining Corporation Ltd., Australia (1969) Hydrogen Reduction. ... Refractory Gold Pressure Oxidation. The Application of Pressure Oxidation at the Campbell Red Lake Mine;
The invention discloses a pressure oxidation leaching method of nickel-cobalt oxide ore, which comprises the process flows of grinding nickel-cobalt oxide ore pulp, adding sulfur powder pulp or sulfide ore concentrate pulp, carrying out high-pressure kettle oxidation reaction, self-evaporating a flash tank, adding a coagulant, carrying out 7-stage …
Since oxidation of Pt-modified nickel aluminides promotes the formation of metastable polymorphic alumina phases (γ-and θ-Al 2 O 3 ) during the first stages of oxidation at 800-1100°C with ...
Oxidation of nickel at low O 2 partial pressure and room temperature can be considered as a three stage process [20], [21]: (i) dissociative chemisorption of oxygen on various surface sites according to the orientation of Ni substrate [22], (ii) epitaxial NiO island formation, and (iii) lateral growth of NiO island till a film of NiO of about 3 ...
Pressure Oxidation of Nickel Concentrates to Prepare Mixed Hydroxide Precipitate: An Alternate Battery Supply Chain Feed Source ... The NiCo Sulphide is leached under pressure oxidation (POX) conditions in a continuously operating, five compartment autoclave. The autoclave retention time is approximately 2.5 h and …
Low pressure oxidation studies of Ni-18%Cr alloy were carried out at temperatures of 500–600°C for very brief periods. Detailed XPS, AES, SEM, and TEM studies identified four stages in the initial oxidation. These are: (1) formation of a mixed nickel-chromium oxide overlayer; (2) growth of submicron-sized oxide nodules; (3) development of dark "hole …
Overview. High Pressure Acid Leach (HPAL) is a process used to extract nickel and cobalt from laterite ore bodies. The HPAL process utilizes elevated temperatures (roughly 255 degrees Celsius), elevated pressures (roughly 50 bar or 725 psi), and sulfuric acid to separate nickel and cobalt from the laterite ore.
High temperature pressure oxidation of a low-grade nickel concentrate was examined to demonstrate the potential benefits and shortcomings of this approach. The high iron sulfide content ensured that acid generation was much greater than for higher grade concentrates. This results in the formation of basic iron sulfate phases and a …
EDS analysis showed that there were no other elements in the NiO layer. Hence, the lower oxidation rate was due to the lower oxygen partial pressure in this case. The oxygen partial pressure (7 ppm in this study) of the post-treatment was higher than the equilibrium oxygen partial pressure (1.7 × 10 −10 atm) of Ni/NiO at 1000 °C.
The Ni(III) oxidation state is relatively rare and is usually prepared by chemical or electrochemical oxidation of Ni(II) precursors (Schröder, 1994).Gelemser, referenced by Besenhard and McBreen (1999), describes a method to produce β-NiOOH by mixing a solution of Ni(NO 3) 2 and KOH with Br 2.The structural determination of the …
The transformation of Ni nanoparticles (NPs) of different sizes (average diameters of 9, 26, and 96 nm) during oxidation to hollow (single void) or porous (multiple voids) NiO through the nanoscale Kirkendall effect was observed by transmission electron microscopy. Samples treated for 1−4 h at 200−500 °C show that the structures of the …
The isothermal oxidation behaviour of IN740H alloy was studied by conducting experiments in a thermogravimetric analyser in the presence of air and synthetic flue gas in the temperature range of 760–900 °C. SEM/XRD/EPMA/Raman spectroscopy was used for analysing surfaces/cross sections of oxidized/corroded specimens. The …
A chemical kinetic model for high-pressure methane oxidation was established, with particular emphasis on the peroxide chemistry. The thermodynamic properties of CH 3 OO and CH 3 OOH, as well as the rate constants for the abstraction reactions CH 3 OOH + CH 3 = CH 3 OO + CH 4 and CH 3 OH + CH 3 = CH 3 O + CH 4, …
Nickel concentrate · Pressure oxidation · Mixed hydroxide precipitate 1 Introduction 1.1 Background Nickel sulfide minerals found in nature can be concentrated using conventional mineral processing methods. Nickel concentrates often contain iron sulfide minerals such as pyrrhotite or pyrite, and copper sulfide minerals such as chalcopyrite
The successful commercialization of a pressure oxidation (POX) process for recovering metal values, including gold, copper, zinc, nickel and molybdenum, is the result of a carefully planned development program. The initial task involves developing one or more conceptual flowsheets, including the POX autoclave and downstream purification …
Regulating the electronic structure of nickel phosphides via interface engineering and molybdenum doping boosts benzyl alcohol oxidation coupled with hydrogen production ... [11]. Among these, benzyl alcohol oxidation reaction (BAOR) is thermodynamically favorable (0.48 V vs. RHE) [12] and can be coupled with HER, …
