Study on the Kinetics and Mechanism of Grain Growth during the Thermal Decomposition of Magnesite

Fu, Daxue; Niu, Feng; Wang, Yaowu

doi:10.5012/bkcs.2012.33.8.2483

Cited by 7 publications

(5 citation statements)

References 26 publications

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“…[12] in which the two low-lying isomers were found not to be C 1 and D 4h in sequence. The hybrid structure C s for (MgO) 5 has not been mentioned in Ref. [12].…”

Section: Resultsmentioning

confidence: 99%

“…For (MgO) 4 , stair-type fused rhombi (C 1 ) becomes easier to gather than octagonal rings structure D 4h . For (MgO) 5 , fused rhombi structure C 1 and hybrid structure C s become easier to assemble than ten-member ring structure D 5h . The lowest-energy structure of (MgO) 6 becomes the distorted cubic structure (D 2h ) instead of the stacked double ring structure (D 3d ).…”

Section: Growth Strategies Of (Mgo) N Clustersmentioning

confidence: 99%

“…Accurate control of the thermal decomposition of magnesite in industry is necessary to achieve a high reactivity [4]. Fu et al [5] observed the grain size of MgO during the thermal decomposition of magnesite by the X-ray line broadening technique. These experimental results reflect the information after product nucleation, but it is difficult to analyze the nucleation mechanism.…”

Section: Introductionmentioning

confidence: 99%

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Structure Stability and Growth Strategies of the (MgO)n (n=1-13) Clusters

Zhao¹,

Wang²,

Qi³

et al. 2016

Proceedings of the 2nd Annual International Conference on Advanced Material Engineering (AME 2016)

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Abstract. The thermal decomposition process of magnesite significantly affects the catalytic activity of MgO. The structure, stability and growth strategies of the (MgO) n (n = 1-13) clusters were investigated by density functional theory. From reaction energy it can be seen that the contributions of the small clusters to grow are larger at lower temperature. By analyzing the differences in Gibbs free energy between MgO crystal and (MgO) n clusters, it can be seen that at the initial decomposition temperature of magnesite (about 700K), the (MgO) n clusters with linear or distorted cubic structures become more stable than the hexagon ring structures, even the hybrid structures are more stable than the cage structures.

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“…[12] in which the two low-lying isomers were found not to be C 1 and D 4h in sequence. The hybrid structure C s for (MgO) 5 has not been mentioned in Ref. [12].…”

Section: Resultsmentioning

confidence: 99%

Section: Growth Strategies Of (Mgo) N Clustersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Structure Stability and Growth Strategies of the (MgO)n (n=1-13) Clusters

Zhao¹,

Wang²,

Qi³

et al. 2016

Proceedings of the 2nd Annual International Conference on Advanced Material Engineering (AME 2016)

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“…Similarly, Razouk et al 28 reported that water vapor accelerates sintering of magnesia. Fu et al 29 studied the surface structure of MgO and reported that steam results in growth of the MgO grains during calcination of magnesite. Therefore, it is logical to assume that the presence of steam during dolomite decomposition may sinter the produced MgO in the product layer and results in larger pores that facilitate the outward movement of produced CO 2 , resulting in lower partial pressure of CO 2 in the sample.…”

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 99%

Effect of Steam on Partial Decomposition of Dolomite

Zarghami

Ghadirian

Arastoopour

et al. 2015

Ind. Eng. Chem. Res.

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Partially decomposed dolomite is a promising base material for regenerable MgO-based sorbents to capture CO2 from precombustion syngas at high pressures and temperatures. An important characteristic of the sorbent affecting the economic viability of this class of sorbents is the reactivity and the capacity of the sorbent for CO2 capture. To improve the reactivity of the sorbent, the thermal behavior and the kinetics of partial decomposition of dolomite were studied in the temperature range of 520–610 °C in a dispersed-bed reactor. The microstructure and the nature of the solid products were found to be strongly dependent on the CO2 partial pressure near the reacting interface and on the decomposition temperature. A significant increase in the rate of the dolomite decomposition reaction was found in the presence of steam. Steam improves the kinetics of decomposition, modifies the radial distribution of the pores, and improves the connectivity of the pores inside the dolomite particles, which decreases the diffusion resistance of produced carbon dioxide inside the particle. A shrinking core model with variable product layer diffusivity was used to fit the experimental data and determine the kinetic parameters of the dolomite decomposition reaction. The results indicate that transport of CO2 across the reacting interface in the porous particle was the main limiting factor in the decomposition reaction at the experimental conditions investigated. The model is shown to provide an excellent fit to the experimental data on partial decomposition of dolomite in the temperature range studied.

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“…They obtained a result that the one-step Mg reduction production process can reduce reduction time and save energy [10][11][12][13]. Fu et al studied the thermodynamics and kinetics of the integration process of calcination and reduction and found that canceling the calcination process can greatly save energy [14][15][16][17][18]. These studies rely on reducing calcination to achieve continuous production of Mg. Other researchers used an inert gas to replace the vacuum state.…”

Section: Introductionmentioning

confidence: 99%

Nucleation and Condensation of Magnesium Vapor in Argon Carrier

Han

Guo

et al. 2020

Metals

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The nucleation and condensation of Magnesium (Mg) vapor carried by argon gas (Ar) were examined. The condensation of Mg vapor at a heat source temperature of 1273–1473 K and Ar flow rate of 0.1–0.4 m3/h was analyzed. The result indicated that the condensation temperature is affected by the heat source temperature and Ar flow rate, and the condensation temperature of Mg vapor was 1013.3 K at a heat source temperature of 1473 K and Ar flow rate of 0.2 m3/h. The effects of Mg vapor partial pressure and temperature of the condensation zone on the nucleation and condensation of Mg vapor carried by Ar were calculated and analyzed in terms of atomic collisions and critical nucleation radius. Increased vapor oversaturation and decreased condensation temperature were favorable for liquid nucleation growth. The Mg condensation products in Ar flow rate of 0.2 m3/h at a heat source temperature of 1473 K were analyzed by XRD, SEM, and EDS, which indicated that the condensed product was of high purity and not easily oxidized in Ar flow. In this paper, the quality of Mg vapor condensation was controlled, which provided the theoretical and experimental basis for a continuous Mg production process.

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Study on the Kinetics and Mechanism of Grain Growth during the Thermal Decomposition of Magnesite

Cited by 7 publications

References 26 publications

Structure Stability and Growth Strategies of the (MgO)n (n=1-13) Clusters

Structure Stability and Growth Strategies of the (MgO)n (n=1-13) Clusters

Effect of Steam on Partial Decomposition of Dolomite

Nucleation and Condensation of Magnesium Vapor in Argon Carrier

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