Wachstum von Kobalt und Nickel während der Reduktion von Kobalt(II)-oxid und Nickel(II)-oxid mit Wasserstoff

Pluschkell, Wolfgang; Sarma, B.

doi:10.1002/srin.197404583

Cited by 15 publications

(22 citation statements)

References 5 publications

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“…By maintaining this condition, a complete removal of oxygen in the NiO reduction process can be achieved. Arrhenius plots of the rates of NiO reduction of the present and previous results [16,24] at a hydrogen pressure of approximately 1 atm are shown in Figure 14. In the figure, the NiO reduction rates are presented as flux of oxygen removal.…”

Section: Discussionmentioning

confidence: 80%

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The Kinetics of Reduction of Dense Synthetic Nickel Oxide in H2-N2 and H2-H2O Atmospheres

Hidayat

Rhamdhani

Jak

et al. 2009

Metall Mater Trans B

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An investigation of the kinetics of reduction of dense synthetic nickel oxide has been carried out in H 2 -N 2 and H 2 -H 2 O mixtures between 500°C and 1000°C. The progress of the reduction was followed metallographically by the measurement of the advance of the nickel product layer. The influences of hydrogen partial pressure, hydrogen-steam ratio, and temperature were systematically investigated in both sets of the mixtures. Increasing hydrogen partial pressure under all conditions investigated results in an increase in the reduction rate. In H 2 -N 2 mixtures and H 2 -H 2 O mixtures with low steam content, the initial reduction rate was found to be first order with respect to hydrogen partial pressure. In both sets of mixtures, it was found that the progress of Ni thickness was not a monotonic function of temperature. A minimum rate of advancement of Ni product was observed between 600°C and 800°C, depending on the hydrogen partial pressures and reduction time. The change in reduction behavior is shown to be directly linked to changes in Ni product microstructure.

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Section: Discussionmentioning

confidence: 80%

“…In the figure, the NiO reduction rates are presented as flux of oxygen removal. The original data of Rashed and Rao [16] were presented in the form of oxygen flux, while the rates of the present study and Pluschkell and Sarma [24] need to be converted from linear Ni product growth rate (lmAEs À1 ).…”

Section: Discussionmentioning

confidence: 99%

The Kinetics of Reduction of Dense Synthetic Nickel Oxide in H2-N2 and H2-H2O Atmospheres

Hidayat

Rhamdhani

Jak

et al. 2009

Metall Mater Trans B

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“…Previous studies of the reduction of NiO with hydrogen gas [10][11][12][13][14][15][16] have shown that reduction to metallic nickel occurs readily with the formation of porous, nickel metal product. The porous product allows continuous access by gas-phase diffusion from the bulk gas to the NiO interface, at which a chemical reaction between gas and oxide occurs.…”

Section: Transformation Sequencementioning

confidence: 99%

“…Although reduction in hydrogen atmospheres was found by many investigators to occur readily, there are considerable differences in the reported kinetics of these processes due to the differing characteristics of the starting materials and the reaction geometries employed in these studies. [15][16][17][18][19][20][21] In relatively few studies, the reaction conditions have been well established, using either dense NiO sheets [16][17][18] or granules [20,21] to overcome gas-phase mass-transfer limitations. These studies show that the reaction rates increase with increasing temperatures up to 600°C, and then a slowdown between 600°C to 900°C, before increasing again above 950°C.…”

Section: Previous Studies On Bnc Decomposition and Nio Reductionmentioning

confidence: 99%

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Basic Nickel Carbonate: Part I. Microstructure and Phase Changes during Oxidation and Reduction Processes

Rhamdhani

Jak

Hayes

2008

Metall Mater Trans B

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A significant industrial problem associated with the production of nickel from basic nickel carbonate has been identified. Fundamental studies of the change of phase, product surface, and internal microstructures taking place during oxidation and reduction processes at temperatures between 110°C and 900°C have been carried out. The various elemental reactions and fundamental phenomena that contribute to the change of the physical and chemical characteristics of the samples during the processes taking place in Ni metal production through gas/solidreduction processes have been identified and thoroughly investigated. The following phenomena affecting the final-product microstructure were identified as follows: (1) chemical changes, i.e., decomposition, reduction reactions, and oxidation reactions; (2) NiO and Ni recrystallization and grain growth; (3) NiO and Ni sintering and densification; and (4) agglomeration of the NiO and Ni particles.

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Analysis of Product Morphologies and Reaction Mechanisms on Gaseous Reduction of Iron Oxides

Hayes

2011

steel research int.

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It is well established that in gaseous reduction processes solid iron oxides exhibit a wide range of reducibilities. Using the interface stability criteria developed to describe the decomposition of metal compounds in reactive gas atmospheres, together with microstructural evidence obtained under well characterised reaction conditions, the relationships between product structures, and the mechanisms and the kinetics of reduction of iron oxides have been examined. It is shown that the structures and reaction rates can be explained through the occurrence of four principal mechanisms; continuous gas pore formation, dense metal layer growth, discontinuous metal layer breakdown and continuous coupled growth of metal and pores. Through identification of the critical conditions for these different mechanisms, the maximum rates of reduction of a given starting material as a function of temperature, thermal history and gas conditions can be more clearly understood.

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Wachstum von Kobalt und Nickel während der Reduktion von Kobalt(II)-oxid und Nickel(II)-oxid mit Wasserstoff

Cited by 15 publications

References 5 publications

The Kinetics of Reduction of Dense Synthetic Nickel Oxide in H2-N2 and H2-H2O Atmospheres

The Kinetics of Reduction of Dense Synthetic Nickel Oxide in H2-N2 and H2-H2O Atmospheres

Basic Nickel Carbonate: Part I. Microstructure and Phase Changes during Oxidation and Reduction Processes

Analysis of Product Morphologies and Reaction Mechanisms on Gaseous Reduction of Iron Oxides

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