Reduction of Nickel and Iron from Low-Grade Nickel Laterite Ore via a Solid-State Deoxidization Method Using Methane

Li, Bo; Zhang, Ding; Wei, Yonggang; Zhou, Shiwei; Wang, Hua

doi:10.2320/matertrans.m2017351

Cited by 17 publications

(8 citation statements)

References 20 publications

(19 reference statements)

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“…Despite extensive investigations ,,,,,, of NiO reduction by methane, many questions remain about its kinetics and molecular and structural transformation mechanisms. The carbon deposition, however, limits the kinetic measurement of NiO reaction with CH 4 . , Nonisothermal experiments with low heating rates (25 K/min) showed that reduction starts at ∼625 K and the full conversion can be achieved at ∼1000 K, while further heating results in pyrolytic carbon deposition .…”

Section: Introductionmentioning

confidence: 99%

“…19−21 In chemical looping combustion, cyclic oxidation and reduction of Ni-based oxygen carriers are essential for clean power generation with simultaneous separation of CO 2 . 22−30 Despite extensive investigations 5,7,11,27,28,31,32 of NiO reduction by methane, many questions remain about its kinetics and molecular and structural transformation mechanisms. The carbon deposition, however, limits the kinetic measurement of NiO reaction with CH 4 .…”

Section: Introductionmentioning

confidence: 99%

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Kinetics and Mechanism of Nickel Oxide Reduction by Methane

2019

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Nickel oxide reduction by methane is of particular importance in catalysis, extractive metallurgy, and clean power generation technologies. Despite extensive investigations of the NiO + CH 4 reaction, many questions remain about its kinetics and molecular and structural transformation mechanisms. This work reports the reduction kinetics of bulk polycrystalline NiO by CH 4 using a new calorimetric method. The method permits rapid, controllable heating of the NiO/Ni wires and continuous data (electrical power, the electrical resistivity of the wire, and temperature) acquisition with a frequency of 10 kHz. The method also allows arresting and preservation of the structure of the sample by programmed termination of electric power in thin specimens. This approach, coupled with ex situ electron microscopy, allows determination of the reaction rate and tracking of the ongoing structural transformations. The mechanism of NiO reduction by methane is suggested based on direct correlations between reaction kinetics and the observed microstructure transformations. The kinetic data treatment revealed that the nucleation−growth model describes the reaction kinetics. Ex situ microscopy observations of reacted specimens showed that the first nuclei rapidly accelerate the process. Pore formation occurs at the nucleation sites, and the porous structure then quickly grows into the bulk NiO. The second type of reduced Ni microstructure, compact layer, can be observed only on the outer surface of the wire. Based on kinetic data and microstructural observations, a mechanism of reduction was suggested according to which porous microstructure forms predominantly by NiO reduction with carbon. The compact layer observed on the outer surface of the wire forms through the diffusion-controlled hydrogen reduction.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Kinetics and Mechanism of Nickel Oxide Reduction by Methane

2019

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“…Extensive research has been conducted on the reduction of NiO using CH 4 . ,,,,− These works show that pyrolytic carbon forms and deposits on the reduced nickel, creating kinetic limitations. , For example, in nonisothermal conditions, at 350–750 °C, the reduction proceeds without forming pyrolytic carbon, while at 750–1020 °C, rapid decomposition of CH 4 results in significant carbon buildup . The reduction kinetics at these distinctive temperature ranges follow geometrical contraction and nucleation–growth models with calculated activation energies of 103 and 111 kJ/mol, respectively.…”

Section: Introductionmentioning

confidence: 99%

Initial Stages of Hydrogen-Enhanced Methane Reduction of Nickel Oxide

Vardanyan,

Kharatyan,

Olshin

et al. 2024

Ind. Eng. Chem. Res.

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This study investigates the initial stages of hydrogen-enhanced methane (CH4) reduction of nickel oxide (NiO) under reduced gas pressure (below 15 kPa) at 1050 °C. An experimental setup to investigate the reduction process enabled rapid (10–100 ms) reaction termination and quenching of samples to probe these early stages. The effects of hydrogen (H2) pretreatment on NiO and the reduction with H2 + CH4 mixtures with a low H2 content are investigated at nearly zero degrees of conversion. The results are compared to reductions by H2 or CH4 under similar conditions. Even brief H2 pretreatment or low H2 content in the H2 + CH4 mixture significantly alters the nucleation and kinetics of CH4 reduction. In the absence of H2, during CH4 reduction, Ni nuclei appear in selected areas on NiO and grow into the NiO bulk, forming a porous structure. High-resolution electron microscopy investigations suggest that H2 facilitates rapid Ni nucleation on the entire surface of NiO crystals, while it does not change the growth mechanism. Continuous reduction leads to significant morphological evolution of Ni, creating nanoscale grains and porous structures. CH4 decomposition on nanoscale Ni accumulates carbon on the pore walls, and high carbon solubility in the newly reduced Ni lattice accelerates the overall reduction reaction. This finding is crucial for understanding the dynamics of NiO reduction in industrial applications, offering insights into optimizing the process for enhanced efficiency.

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“…It has a wide range of applications in the fields of national defense and military industry, chemical industry, metallurgy, aerospace, transportation and new materials. 1,2) According to the statistics of all nickel reserves, 30% exists as sulfide ores with the balance comprised of oxide ores. In nickel production, about 60% of the metal nickel was produced from sulfide ores, and laterite nickel ore only accounts for 40%.…”

Section: Introductionmentioning

confidence: 99%

Extraction of Ferronickel Concentrate by Reduction Roasting-Magnetic Separation from Low Grade Laterite Nickel Ore under the Action of Compound Additives

Wang

Zhi

et al. 2022

Mater. Trans.

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Nickel is an important strategic metal in the world. As the sulfide ore containing high-grade nickel is increasingly depleted, the laterite nickel ore, which is rich in resources, has attracted people's attention. In this paper, the reduction roasting-magnetic separation process is used to study the method of preparing ferronickel concentrates from low-grade laterite nickel ore under the action of composite additives (Na 2 CO 3 and CaF 2 ). The research results showed that when the ratio of additives Na 2 CO 3 and CaF 2 was 1:7, reduction temperature was 1250°C, reduction time was 60 min, magnetic field strength was 150 mT, and wet grinding time was 12 min, the nickel grade and recovery extent were 8.39 wt.% and 98.54%, iron grade and recovery extent were 67.70 wt.% and 71.73%.

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Reduction of Nickel and Iron from Low-Grade Nickel Laterite Ore via a Solid-State Deoxidization Method Using Methane

Cited by 17 publications

References 20 publications

Kinetics and Mechanism of Nickel Oxide Reduction by Methane

Kinetics and Mechanism of Nickel Oxide Reduction by Methane

Initial Stages of Hydrogen-Enhanced Methane Reduction of Nickel Oxide

Extraction of Ferronickel Concentrate by Reduction Roasting-Magnetic Separation from Low Grade Laterite Nickel Ore under the Action of Compound Additives

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