Phase composition and pore evolution of porous periclase-spinel ceramics prepared from magnesite and Al(OH)3

Lin, Xiaodong; Yan, Wen; Li, Nan

doi:10.2298/sos1602147l

Cited by 28 publications

(17 citation statements)

References 9 publications

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“…Using porous spinel aggregates as raw materials is a good way to prepare high-efficiency and energy-saving spinel containing refractory lining [14][15][16][17][18]. These porous spinel aggregates could be obtained by crushing the porous spinel ceramics [19,20].…”

Section: Introductionmentioning

confidence: 99%

Effect of Al(Oh)3 particle size on microstructures and strengths of porous MgAl2O4 ceramics

Zhi¹,

Chen²,

Yan³

et al. 2020

PAC

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Porous MgAl 2 O 4 ceramics were prepared via in-situ decomposition pore-forming (ISDP) technique using Al(OH) 3 and magnesite as raw materials. The influence of Al(OH) 3 particle size (0-44 µm, 44-88 µm, 88-100 µm, 100-150 µm) on the microstructures and strengths of porous spinel ceramics were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The bimodal distributions were observed among all the pore size distributions of the porous spinel ceramics. The small pores existed inside the particles and the big pores existed between the particles. When the Al(OH) 3 particle size decreased from 100-150 µm to 0-44 µm, the peak of large pores shifted towards left while intensity of the peak of small pores decreased. Simultaneously, the neck-bonds formed between particles grew significantly, which resulted in the increase of compressive strength from 1.4 to 10.8 MPa. The optimized product is the sample with the Al(OH) 3 particle size of 0-44 µm, which has a high apparent porosity (55.2%), a high compressive strength (10.8 MPa) and a relatively homogeneous pore size distribution.

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Section: Introductionmentioning

confidence: 99%

Effect of Al(Oh)3 particle size on microstructures and strengths of porous MgAl2O4 ceramics

Zhi¹,

Chen²,

Yan³

et al. 2020

PAC

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“…11a). When the heating temperature increased to 300-800 °C, CaCO 3 and Al(OH) 3 decomposed to CaOand Al 2 O 3 , and then the CaCO 3 pseudomorphs and Al 2 O 3 with micro-sized pores were formed [22,23] (Fig. 11b).…”

Section: Tab III the Special Surface Of Cao Granules (×10mentioning

confidence: 99%

Effect of Al(OH)3 and La2O3 on the sintering behavior of CaO granules via CaCo3 decomposition

Wei

et al. 2020

Sci Sintering

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Hydration resistance of CaO aggregates is the key to the successful application of lime-based refractories. Granulation technology on limestone with additives and one step calcination method was used in this study to investigate the effects of Al(OH)3 and La2O3 on the sintering behavior and the hydration resistance of CaO granules. The result showed that the hydration resistance of CaO granules was improved significantly by adding Al(OH)3 and La2O3. The shell of sintered CaO granules was relatively dense after calcination and the specific surface area of CaO granules decreased from 7.5?10-2 m2/g to 1.2?10-2 m2/g. The average pore size of CaO granular was decreased from 3.54 ?m to 0.83 ?m due to the liquid phase sintering when Al(OH)3 additive was used. La2O3 promoted the densification of CaO compact by the ion substitution and solution with CaO. La3+ approached into CaO lattices, which enlarged the vacancy concentration of Ca2+ and accelerated the diffusion of Ca2+.

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“…[1][2][3] The fabrication of magnesia aggregates also plays a crucial role in the preparation of magnesia-based refractories. Since magnesia aggregates have several shortcomings, such as low sinterability, [4] high thermal conductivity, [5] poor penetration resistance, and poor thermal shock resistance, [6] various additives such as oxides and some halides are frequently used to improve their performance. [7][8][9] Meanwhile, CaZrO 3 is widely utilized in magnesia-based refractories as a second phase for improving their mechanical strength and resistance against basic phases and alkali attack.…”

Section: Introductionmentioning

confidence: 99%

Formation Mechanism of In Situ Intergranular CaZrO3 Phases in Sintered Magnesia Refractories

Zou

Huang

et al. 2020

Metall Mater Trans A

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Sintered magnesia refractories combined by in situ intergranular CaZrO 3 phases were synthesized using natural MgO-containing natural minerals with CaO and SiO 2 impurities and nano-sized ZrO 2 additive. A homogenous distribution of intergranular CaZrO 3 , independent from the intergranular CaO-MgO-SiO 2 phases, was formed in situ within the sintered magnesia aggregates by introducing 0.75 wt pct nano-sized ZrO 2 into the magnesite. The formation mechanism of the in situ intergranular CaZrO 3 phases was determined. The nano-sized ZrO 2 was introduced and uniformly distributed at grain boundaries of the magnesia due to the micron-nano-sized particles composite system and wetting grinding process. Then the CaO in impurities were prior to SiO 2 to react with the ZrO 2 for generating CaZrO 3 at the grain boundaries by increasing sintering temperature. Nevertheless, the nano-sized ZrO 2 particles were encapsulated in the MgO crystallites with similar particle size decomposed from brucite and prevented from reacting with CaO impurities in magnesite. The mixing homogeneity of magnesite particles and ZrO 2 particles and the direct contact between ZrO 2 and CaO impurities in magnesite has a crucial effect on the formation of intergranular CaZrO 3 phases. Furthermore, the intergranular CaZrO 3 phases could enhance the bonding of magnesia grains and have great potential for improving the service performance of magnesia.

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Phase composition and pore evolution of porous periclase-spinel ceramics prepared from magnesite and Al(OH)3

Cited by 28 publications

References 9 publications

Effect of Al(Oh)3 particle size on microstructures and strengths of porous MgAl2O4 ceramics

Effect of Al(Oh)3 particle size on microstructures and strengths of porous MgAl2O4 ceramics

Effect of Al(OH)3 and La2O3 on the sintering behavior of CaO granules via CaCo3 decomposition

Formation Mechanism of In Situ Intergranular CaZrO3 Phases in Sintered Magnesia Refractories

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