Effect of alkali doping on the preparation of calcium aluminate by aluminum dross calcification process

Xie, Mingzhuang; Lv, Han; An, Huilong; Liu, Fengqin; Zhao, Hongliang

doi:10.1016/j.eti.2023.103312

Cited by 5 publications

(2 citation statements)

References 25 publications

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“…After heat treatment at 1600 • C, a "core-shell" structure still appears around the CMA aggregate (Figure 13C). However, due to the overflow and reaction of the CA/CA 2 phase in the CMA aggregate with the matrix, resulting in the formation of CA 2 phase, and eventually transforming into CA 6 phase, 37 the 5-3 and 3-1 mm CMA aggregate form a structure consisting of MA-CA-CA 2 phases as the "core" and CA 2 -CA 6 phases as the "shell." On the other hand, the 1-0 mm CMA aggregate, with a large specific surface area, facilitates more CA and CA 2 phases overflowing into the matrix, leading to complete reaction with the matrix to form CA 6 phase.…”

Section: F I G U R E 1mentioning

confidence: 99%

Microstructural evolution and thermal shock resistance mechanism of calcium magnesium aluminate (CMA) aggregate in alumina castables

Chen,

Pan,

et al. 2024

Int J Applied Ceramic Tech

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The microstructural evolution and thermal shock resistance mechanism of calcium magnesium aluminate (CMA) aggregate after its introduction into alumina castables remain unclear. The hydration behavior of alumina castables containing CMA aggregates with various particle sizes under 25°C curing conditions is investigated. Additionally, the microstructural evolution and the interfacial properties of CMA‐containing castables with temperatures, as well as the recovery of castable strength of CMA‐containing aggregates after resintering, are comprehensively examined. The results indicate that CMA aggregate enhances early strength and promotes CAC hydration of castables, forming a “core–shell” structure with spinel–calcium aluminate (CA)–calcium dialuminate (CA2) as the “core” and hydration phase as the “shell.” Sintering at 1600°C causes different overflow behavior in CMA aggregates, affecting the castable strength. Following resintering at 1700°C, the recovery ratio of flexural strength of castables containing CMA aggregate exceeds 15%, attributed to the overflow of CA/CA2 in the CMA aggregate, which repairs microcracks and enhances thermal shock resistance.

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Section: F I G U R E 1mentioning

confidence: 99%

Microstructural evolution and thermal shock resistance mechanism of calcium magnesium aluminate (CMA) aggregate in alumina castables

Chen,

Pan,

et al. 2024

Int J Applied Ceramic Tech

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“…However, aluminum dross, which is composed of Al 2 O 3 , aluminum nitride (AlN), a small amount of aluminum (Al), and a small amount of aluminum carbide (Al 4 C 3 ), is listed as hazardous waste in the EU, and most of it goes directly to landfills without treatment [18,19]. Aluminum will react with water, resulting in ammonia (NH 3 ), flammable gases (hydrogen (H 2 ), and methane (CH 4 )) [20,21], thereby causing stinky burning and serious harm to groundwater and ecosystems [22][23][24]. According to the studies of C. Y. Lin, F. H. Lu, and Z. Su et al [25,26], the AlN in AD will transfer to Al 2 O 3 when the temperature is higher than 1000 • C. Hence, many studies have investigated sintered calcium aluminate from aluminum dross [26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Effects of Different CaO/Al2O3 Ratios on the Phase Composition and Desulfurization Ability of CaO-Based Desulfurizers in Hot Metal

Shen,

Lin,

Chang

et al. 2024

Metals

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In response to the development of low-carbon smelting technology, reducing the use of fluor-containing materials in desulfurizers is an important research topic. The development of new-generation KR (Kambara Reactor) desulfurizers is shifting towards a higher Al2O3 content rather than CaF2, yet there is currently an absence of thorough and comprehensive mechanisms for desulfurization. Consequently, this research provides an extensive comparison using a specially constructed small-scale KR desulfurization hot model test, alongside FactSage simulation and SEM analysis (of desulfurization process). The findings indicate that at 1400 °C, for the desulfurization of molten iron, the capacity for desulfurization initially increases and then diminishes as the Al2O3 content in the KR desulfurizer rises. With Al2O3 content in the desulfurizer below 22 wt.%, the phase composition predominantly consists of C3A, employing a solid(slag)–liquid(metal) diffusion method for desulfurization. The optimal desulfurization capacity (Ls: 64.1) is observed when the Al2O3 content is 15 wt.%, attributed to the simultaneous presence of CaO particle precipitation and C3A. However, as the Al2O3 content reaches 20 wt.%, all the oversaturated CaO integrates into C3A, leading to a reduction in Ls from 64.1 to 10.7, thereby diminishing the desulfurization capacity by approximately sixfold. When Al2O3 exceeds 22 wt.%, the phase composition transitions from the C3A to C12A7 phase, and the desulfurization approach shifts from solid(slag)–liquid(metal) to liquid(slag)–liquid(metal) diffusion, with Ls decreasing to 23.4. This reduction is due to C12A7’s lower sulfur capacity compared to C3A and the absence of saturated CaO particle precipitation. Therefore, for Al2O3 to effectively replace fluorite in KR desulfurizers, a higher presence of C3A phases and CaO particle precipitation are essential. The desulfurizer must contain over 65 wt.% CaO and maintain Al2O3 levels at 10~16.2 wt.%.

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Application of clean oxidation technology using H2O2 for simultaneous removal of sulfur and organic substances in the Bayer process

Li,

Liu,

Yan

et al. 2024

Hydrometallurgy

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Effect of alkali doping on the preparation of calcium aluminate by aluminum dross calcification process

Cited by 5 publications

References 25 publications

Microstructural evolution and thermal shock resistance mechanism of calcium magnesium aluminate (CMA) aggregate in alumina castables

Microstructural evolution and thermal shock resistance mechanism of calcium magnesium aluminate (CMA) aggregate in alumina castables

Effects of Different CaO/Al2O3 Ratios on the Phase Composition and Desulfurization Ability of CaO-Based Desulfurizers in Hot Metal

Application of clean oxidation technology using H2O2 for simultaneous removal of sulfur and organic substances in the Bayer process

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