A new approach to recover the valuable elements in black aluminum dross

Zuo, Zhiyuan; Lv, Han; Li, Rongbin; Liu, Fengqin; Zhao, Hongliang

doi:10.1016/j.resconrec.2021.105768

Cited by 42 publications

(10 citation statements)

References 26 publications

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“…The surface of α-Al 2 O 3 was mainly smooth and round, and γ-Al 2 O 3 was mainly rod or column shaped with a large specific surface area. 36,37 The fine particles of AlN less than 1 μm were uniformly distributed in the raw material. Figure 8b shows that AlN in denitrified EAD was completely converted into Al(OH) 3 , forming a rough folded bayerite aggregate on the particle surface.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

A Denitrification-Phase Transition and Protection Rings (DPP) Process for Recycling Electrolytic Aluminum Dross

Liu

Zuo

et al. 2021

ACS Sustainable Chem. Eng.

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The continuous growth of the aluminum electrolysis industry has produced large amounts of electrolytic aluminum dross (EAD) as a waste product, which lacks proper recycling methods and poses serious environmental pollution risks. A short and clean process for recycling EAD is proposed involving the preparation of anode protection rings, which can effectively reduce the corrosion of anode steel stubs, improve the quality of molten aluminum, and return to aluminum reduction cells for recycling alumina and fluoride after being broken. The phase transition path of Al(OH) 3 in denitrified EAD by thermal decomposition was bayerite → boehmite → γ-Al 2 O 3 → α-Al 2 O 3 . The calcination temperature should be controlled at 600−800 °C for 2 h to obtain a higher content of activated γ-Al 2 O 3 . The average dissolution rate of denitrified EAD in the aluminum electrolyte was 7.33 times higher than that before denitrification treatment. After using EAD anode protection rings, the corrosion rate of anode steel stubs decreased by 67.7% on average. Furthermore, the iron and silicon contents in the molten aluminum were reduced by 18.57% and 6.25%, respectively. The alumina consumption for producing primary aluminum was reduced by 8.14 kg•t −1 . The experimental results suggest that the proposed process is economical and promising for EAD recycling.

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Section: ■ Results and Discussionmentioning

confidence: 99%

A Denitrification-Phase Transition and Protection Rings (DPP) Process for Recycling Electrolytic Aluminum Dross

Liu

Zuo

et al. 2021

ACS Sustainable Chem. Eng.

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“…9 porous ceramics, 10 glass-ceramics, 11 and other products. 12,13 Generally, the aluminum dross is subjected to pretreatment methods such as acid leaching, purification and calcination, and finally sintered to obtain alumina powder, which involves many steps and strict requirements during processing, limiting applications for industrial production. Shen et al used the AlN in SAD as a reducing agent to reduce heavy metals and prepared glassceramics, 11 and the utilization rate of SAD is relatively low of 23%-27%.…”

Section: Introductionmentioning

confidence: 99%

Hydrolysis‐induced simultaneous foaming and coagulation casting of secondary aluminum dross aqueous suspension

Zhang

Shen

et al. 2023

J Am Ceram Soc.

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The reactive AlN, heavy metal ions, and salts in secondary aluminum dross make them harmful to the environment and difficult to handle, and therefore categorized as hazardous solid waste. A novel, simple, and versatile technique has been proposed here to prepare hierarchically porous ceramics using secondary aluminum dross as the sole raw material, namely, the hydrolysis-induced simultaneous foaming and coagulation casting method. As the main component, Al and AlN could be hydrolyzed to generate aluminum hydroxide sol, which can form three-dimensional network and lead to the outstanding compressive strength of green body (7.03 MPa). Gas release during hydrolysis, high-temperature oxidation of AlN, and metallic Al based on Kirkendall effect could account for the final multilevel pores. The utilization of harmful components in secondary aluminum dross, supplys an alternative colloidal forming way for porous green body with complex shape when combined with other ceramic powders or inorganic solid waste. Low sintering shrinkage of 1.38%-3.60% for hierarchically porous ceramics offers this highly effective and low-cost method to be easily promoted for industrial production.

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“…SAD is the dross produced after reclaiming valuable aluminum metal in the secondary aluminum industry, which commonly includes metallic Al, Al 2 O 3 , aluminum nitride (AlN), spinel (MgAl 2 O 4 ), periclase (MgO), quartz (SiO 2 ), chlorides, fluorides, and salt solvent 4–7 . With continuous expansion of aluminum industry's production scale and increase of aluminum output, the secondary aluminum of China output has reached about 7.15 million tons in 2019, which generated SAD of 804.375 million kg to 1.216 billion kg 8 . At present, most production enterprises only recycle and reuse primary aluminum dross with high metal aluminum content, and the remaining aluminum (aluminum is mainly present in the form of aluminum oxide) is mostly in the form of waste dross.…”

Section: Introductionmentioning

confidence: 99%

“…[4][5][6][7] With continuous expansion of aluminum industry's production scale and increase of aluminum output, the secondary aluminum of China output has reached about 7.15 million tons in 2019, which generated SAD of 804.375 million kg to 1.216 billion kg. 8 At present, most production enterprises only recycle and reuse primary aluminum dross with high metal aluminum content, and the remaining aluminum (aluminum is mainly present in the form of aluminum oxide) is mostly in the form of waste dross. Currently, the treatment and disposal of aluminum dross mainly include stockpiling/accumulation, landfilling, and recycling.…”

Section: Introductionmentioning

confidence: 99%

Porous ceramics with near‐zero shrinkage and low thermal conductivity from hazardous secondary aluminum dross

Zhang

Shen

et al. 2022

J Am Ceram Soc

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Herein, a simple, versatile, and low-cost approach has been proposed to realize the green utilization of secondary aluminum dross, the hazardous solid waste, namely directly sintering dry-pressed green bodies from secondary aluminum dross to fabricate porous ceramics according to high-temperature foaming process spontaneously without adding spare foaming agents. Aluminum nitride (AlN) in secondary aluminum dross was employed to realize high-temperature foaming due to its oxidation, which makes traditional AlN and salts removal process needless. Moreover, near-zero shrinkage or even expansion during sintering of porous ceramics have occurred because in-situ foaming process together with the oxidation of Al particles well offset the sintering shrinkage. After sintering at 1400 • C for 2 h, porous ceramics composed of α-Al 2 O 3 and spinel phases with open porosity of 37.91%, sintering expansion rate of 1.13%, flexural strength of 45.67 MPa, and thermal conductivity of 0.97 W/(m⋅K) have been prepared. Cenospheres as pore-forming agents have been added to further improve the porosity, and alumina-based porous ceramics with open porosity of 28.39%-43.20% and flexural strength of 15.80-52.48 MPa have been obtained. This effective solution for recycling secondary aluminum dross could supply high-performance porous ceramics, which is expected to be applied in the fields of light-weight structural components and thermal insulations.

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A new approach to recover the valuable elements in black aluminum dross

Cited by 42 publications

References 26 publications

A Denitrification-Phase Transition and Protection Rings (DPP) Process for Recycling Electrolytic Aluminum Dross

A Denitrification-Phase Transition and Protection Rings (DPP) Process for Recycling Electrolytic Aluminum Dross

Hydrolysis‐induced simultaneous foaming and coagulation casting of secondary aluminum dross aqueous suspension

Porous ceramics with near‐zero shrinkage and low thermal conductivity from hazardous secondary aluminum dross

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