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The pressure oxidation of nickel sulfide concentrates and nick eliferous pyrrhotite concentrates has been extensively researched and processes have been both piloted and commer cially deployed which were described in the first part of this review Sulfuric acid pressure oxidation processes for the treat
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Ni s H 2 SO 4 aq Ni 2 aq SO 42− aq H 2 g The strongly oxidizing concentrated nitric acid HNO 3 reacts on the surface of iron and passivates the surface Reaction of nickel with air Nickel does not react with oxygen O 2 at room temperature under normal conditions Finely divided nickel can burn forming nickel II oxide NiO
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The utilization of ozone for the separation of cobalt from nickel sulfate was investigated by determining the oxidation rate for Co II and Ni II ions under various ozonation conditions at 60°C The oxidation reaction was observed to follow a first order rate with respect to the ozone partial pressure of the O3 O2 mixture gas and to be
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The effect of elevated air pressure on the oxidation properties of the nickel based superalloy RR1000 at 650°C with different surface modifications T D Reynolds M Taylor D Child H Evans Materials Science 2024 Abstract Samples of RR1000 with differing grain size and surface finish have been exposed to air at different pressures
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NiOOH formed on nickel anodes upon oxidation under alkaline conditions is a heterogeneous EPTM that has received relatively little attention during the past two decades Then the aqueous solution was acidified to ca pH = 4 with 3 M HCl The water was removed under reduced pressure the residue was suspended in EtOH and the solid KCl
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In addition the high pressure of deep magmatic degassing cooling as these gases rise and gas fluid rock interactions in local hydrothermal systems favor the more reduced sulfide over oxidized
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The invention relates to autoclaves for pressure oxidation POX of slurried ores and concentrates in particular to brickless POX autoclaves Autoclaves utilized in leaching operations of slurried ores and concentrates requiring elevated temperatures and pressures are subject to highly corrosive and erosive environment
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Oxidation of nickel and transport properties of nickel 2024 10 1 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
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A common method for nickel leaching from the matte is by using ammonia under high pressure producing a nickel bearing solution This solution is heated to remove copper and the use of hydrogen gas under high pressure precipitates nickel metal remaining nickel in the solution can be precipitated by adding hydrogen sulfide
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The electrochemical processes which occur on nickel electrodes in during a slow‐speed anodic potential sweep between −300 and 1500 mv were studied Tafel plots for hydrogen evolution were determined under different conditions and the impedance was measured at 100 cps as a function of potential
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a process for the pressure oxidation leaching of non ferrous metal sulphidic material comprising providing an autoclave assembly having a series of successive compartments with a
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NPI typically contains around 4 to 10 wt% nickel Its high amount of carbon >3 wt% silicon >3 wt% and manganese >1 wt% mean that its application in foundries is highly restricted In fact the main consumers of this product are stainless steel mills in China because of their capacity to reduce carbon and other undesired elements [5]
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The transient oxidation behaviour of a nickel base superalloy in different oxygen partial pressures studied using electron and ion microscopy showed that at high pO 2 a triple layered oxide developed outer nickel oxide then a complex aluminium chromium oxide and inner alumina layer
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Hastelloy N / UNS N10003 Hastelloy N rod has excellent oxidation resistance to hot fluoride salts in the temperature range of 704 to 871℃ It has good oxidation resistance in air It also has good fabricability and good resistance to aging and embrittlement ASTMB 573 ASTMB 434 ASTMB 906 ASTMB 366
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Gold and nickel are two of Canada s most valuable commodities by production value A key piece of equipment found on many of the flowsheets used to extract nickel and gold from ores is the autoclave Pressure Oxidation POX POX is a process that can be used in the extraction of various metals including gold copper zinc and nickel from
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The pressure oxidation of % w / w aged nickel concentrate at 250 °C as a function of time with 100 kPa O 2 overpressure and maximum oxygen flow rate of L/min was investigated several years after the initial tests
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The sulfates then are reduced to metalhc nickel and cobalt by heating with hydrogen at elevated temperatures under pressure The metals are obtained in their powder form Nickel peroxide an undefined black oxide of nickel is prepared from nickel sulfate hexahydrate by oxidation in alkaline medium with an ozone oxygen mixture [929] or with
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Abstract The oxidation behavior of solid solution nickel aluminum alloys was studied at four levels of oxygen pressure ranging from a partial pressure of 10−4 atmosphere to a total pressure of 10
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The gas phase partial oxidation of methane to methanol and formaldehyde at high pressure 20 100 bar and moderate temperature 350 500 °C has been known for over a century with significant experimental effort during the 1980s and 1990s typically with 2 10 vol % oxygen and a few seconds residence time in the reactor
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A low pressure nickel hydrogen battery using either a metal hydride or gaseous hydrogen for H 2 storage has been developed for use in implantable neuroprosthetic devices In this paper pressure variations inside the cell for the gaseous hydrogen version are analyzed and correlated with oxygen evolution side reaction at the end of charging the recombination of oxygen with hydrogen during
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Bioleaching is used today in commercial operations to process ores of copper nickel cobalt zinc and uranium whereas biooxidation is used in gold processing and coal desulfurization For most agitated reactors used for bio or pressure oxidation the following empirical equation describes the effects of the rate of addition of gas and
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The oxidation of nickel sulfide whose atomic fraction of sulfur x s is to was studied in a mixed O 2 N 2 gas stream at 923 973 and 1023 K The oxygen partial pressure was maintained at x 10 4 Pa In the oxidation of nickel sulfide ofx s = and a dense NiO layer was formed on the sulfide surface without the evolution of SO 2 gas because of the low sulfur activity
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of oxidation of Cu Ni alloys showed that nickel oxide was solely formed on the alloy surfaces [11 12] whereas at later stages both NiO and Cu20 are present with Cu2O as the outer layer [13 17] There are some studies of chemisorption of oxygen and hydrogen on different Ni Cu alloys [18 19] but not the transient stage of oxidation
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Electrode potentials for the metals Au Cu Fe and Zn against the potential V 2 for reduction of dissolved O2 at atmospheric pressure Oxidation of a metal can occur spontaneously if V 2 exceeds V metal It is seen that Zn Fe and Cu can oxidize at all pH values gold Au cannot oxidize
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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 significant amount of sulfuric acid
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Their findings were published in the journal Science and suggest that fracturing and erosion at the surface set the pace of oxidation which when it occurs slowly avoids runaway acidity
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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
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After the catalytic experiment the reactor was flushed with 50 cm 3 min −1 Ar for 1 h followed by a temperature programmed oxidation TPO For that purpose synthetic air with a flow rate of 10 cm 3 min −1 was led over the reactor at 1123 K for 2 h in order to remove all carbon depositions from the catalyst
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The substrate was fed at a rate of 6 mL/h normal conditions ρ = g/cm 3 by a high pressure pump HPP 5001 Commercial bicyclohexyl 99% Acros Organics Geel Belgium C 12 H 22 was used as a substrate Dehydrogenation was carried out at a temperature of 320 °C and atmospheric pressure for 4 h The content of nickel in various
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The oxidation behavior of solid solution nickel aluminum alloys was studied at four levels of oxygen pressure ranging from a partial pressure of 10 −4 atmosphere to a total pressure of 10 atmospheres Three such alloys containing and atomic percent a/o Al were oxidized at 1000 C for times of 25 and 100 hours Learn More
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