Understanding of Interactions Between Pyrolysis Gases and Liquid Aluminum and Their Impact on Dross Formation

Dittrich, R.; Friedrich, Bernd; Rombach, G.; Steglich, Jan; Pichat, A.

doi:10.1007/978-3-319-51541-0_174

Cited by 3 publications

(1 citation statement)

References 9 publications

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“…In an incomplete combustion scenario with an oxygen-depleted atmosphere one can expect to find a mixture of all these molecules. [7] Increasing in the order CH4, CO, C4H10, CO2 have been shown to significantly increase oxidation of an aluminium melt compared to 5% O2 in Argon or pure Argon atmospheres [8]. Incomplete decoating where remnant pyrolysis products are left on aluminium samples have also been shown to reduce metal coalescence, increase dross formation and reduce yield compared to complete decoating process in which the coating and plastics are completely removed.…”

Section: Theorymentioning

confidence: 99%

Recycling of Aluminium from Mixed Household Waste

Eggen

Sandaunet

Kolbeinsen

et al. 2020

The Minerals, Metals &Amp; Materials Series

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Aluminium is used in packaging due to its density, strength and preservative capabilities. This paper outlines a methodology to evaluate the recyclability of aluminium waste, where parameters of scrap type, pre-treatment and remelting conditions are alternated in a factorial design, with measurements of yield and analysis of metal quality. In preliminary experiments three aluminium waste materials were evaluated for recyclability. The methodology was tested on one of the waste materials from mixed household waste, named Cans, and will be described in detail. Cans was decoated at 300 °C and 550 °C. The decoated material was then remelted, 4 separate additions of ∼ 2 kg per experiment, by submerging the sample material in molten aluminium. Porosity, oxide inclusion content and alloy composition were analysed to determine metal quality. The experimental results show that the yield of remelting, dross formation relative to melted sample material and the alloy composition of the remelted metal is dependent on decoating temperature. In conclusion: Cans is recyclable, with good quality and yield, when decoated before melting. Decoating at 550 °C improves metal yield and oxide inclusion content compared to decoating at 300 °C, however it also reduces magnesium content in the resulting alloy. Hopefully the methodology was useful for assessing the recyclability of an aluminiumrich waste and for evaluating the effects of various process parameters during recycling on metal yield and quality.

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Section: Theorymentioning

confidence: 99%

Recycling of Aluminium from Mixed Household Waste

Eggen

Sandaunet

Kolbeinsen

et al. 2020

The Minerals, Metals &Amp; Materials Series

View full text Add to dashboard Cite

show abstract

Thin-walled aluminium waste remelting in circulation circuit with magnetodynamic pump

Smirnov,

Fikssen,

Kukhar

et al. 2024

J Mater Sci

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Modern technologies for remelting thin-walled aluminium waste are considered, and a new method to implement such process is proposed. This made it possible to increase the yield of a suitable remelted product to 83% from the mass of the initial remelting portion. The main idea is to use indirect heating of the charge. This will allow to significantly reduce the irreversible loss of metal due to burning which can reach 60%. In the proposed process, solid waste is melted by overheated melt stream. The movement of such stream is provided by the action of electromagnetic field. For the practical implementation of the offered idea, there was used a magnetodynamic pump (MDP) designed in the Physico-Technological Institute of Metals and Alloys of National Academy of Sciences of Ukraine. The MDP has a significantly higher heat and power factor than electromagnetic pumps of travelling magnetic field which are often used in similar technologies. Mathematical model of the remelting process of aluminium thin-walled and fine charge due to convective heat transfer was developed. On the basis of this model, an engineering calculation of the specific process of remelting used aluminium cans in the liquid aluminium stream was also carried out. The obtained results were used at further conducting a full-scale experiment. There is designed and successfully practically tested the experimental two-chamber circulation circuit with MDP for remelting thin-walled aluminium waste. Recommendations for further development of the proposed process were formulated. Graphical abstract

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Effects of Compaction and Thermal Pre-treatments on Generation of Dross and Off-Gases in Aluminium Recycling

Vallejo-Olivares,

Gertjegerdes,

Høgåsen

et al. 2023

J. Sustain. Metall.

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Organic coatings are a challenge for aluminium packaging recycling since they tend to increase the re-melting metal losses. A solution is de-coating the scrap via a thermal pre-treatment to burn-off the organics before re-melting. Due to logistic benefits, the scrap is often pressed into bales. This study evaluates the influence of compaction on the de-coating efficiency and off-gas emissions, and its consequences for dross formation and recycling metal yield. Loose chips and two types of briquettes, one loosely compacted by uniaxial pressure and the other compacted by moderated-pressure-torsion to higher densities, were heated to 550 °C while analysing the off-gas emissions using FTIR. The briquettes were subsequently re-melted into a molten heel. Re-melting coated scrap multiplied the % wt of dross by a factor of 2 or 3, depending on the compaction pre-treatment, compared to re-melting uncoated aluminium. The densest briquettes emitted less than half the CO2 and CO gases during de-coating and formed significantly more dross. Compaction to the lower densities showed no tangible effects. The effect of de-coating compacted materials or not was small (± 2% wt dross), which was attributed to carbonaceous residues remaining after the thermal treatment. In conclusion, high compactions by torsion limit the de-coating reactions, which depend on factors such as temperature and gas transport. A complete removal of the organic residues is critical for a more sustainable recycling with less dross generated. Graphical Abstract

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Understanding of Interactions Between Pyrolysis Gases and Liquid Aluminum and Their Impact on Dross Formation

Cited by 3 publications

References 9 publications

Recycling of Aluminium from Mixed Household Waste

Recycling of Aluminium from Mixed Household Waste

Thin-walled aluminium waste remelting in circulation circuit with magnetodynamic pump

Effects of Compaction and Thermal Pre-treatments on Generation of Dross and Off-Gases in Aluminium Recycling

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