Aluminum recycling currently occurs in a cascading fashion, where some alloys, used in a limited number of applications, absorb most of the end-of-life scrap. An expected increase in scrap supply in ...coming decades necessitates restructuring of the aluminum cycle to open up new recycling paths for alloys and avoid a potential scrap surplus. This paper explores various interventions in end-of-life management and recycling of automotive aluminum, using a dynamic substance flow analysis model of aluminum and its alloying elements with resolution on component and alloy level (vehicle-component-alloy-element model). It was found that increased component dismantling before vehicle shredding can be an effective, so far underestimated, intervention in the medium term, especially if combined with development of safety-relevant components such as wheels from secondary material. In the long term, automatic alloy sorting technologies are most likely required, but could at the same time reduce the need for magnesium removal in refining. Cooperation between the primary and secondary aluminum industries, the automotive industry, and end-of-life vehicle dismantlers is therefore essential to ensure continued recycling of automotive aluminum and its alloying elements.
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IJS, KILJ, NUK, PNG, UL, UM
Aluminum oxide (Al2O3) and Magnesium-Aluminum oxides (MgAl2O4) are well known refractory materials used in engineering industries. They are built to withstand high temperatures and possess low ...thermal conductivities for greater energy efficiency. Dross, a product/byproduct of slag generated in aluminum metal production process is normally comprised of these two oxides in addition to aluminum nitride (AlN). Worldwide, thousands of tons of aluminum dross are generated as industrial wastes and are disposed of in landfills causing serious environmental hazard. This paper explores the potential to synergize the characteristics of the favourable contents of aluminum dross and its availability (in tons) via synthesis of refractories and thereby develop a value added product useful for the modern industries. In this work, Al-dross as-received from an aluminum industry which comprised of predominantly Al2O3, MgAl2O4 and AlN, was used to develop the refractories. AlN possesses high thermal conductivity values and therefore was leached out of the dross to protect the performance of the developed refractory. The washed dross was calcined at 700° and 1000°C to facilitate gradual elimination of the undesired phases and finally sintered at 1500°C. The dross refractory pellets were subjected to thermo-physical and structural properties analysis: XRD (structural phase), SEM (Microstructure), EDS (chemical constituents) and thermal shock cycling test by dipping in molten aluminum and exposing to ambient (laboratory). The findings include the favourable prospects of using aluminum dross as refractories in metal casting industries.
In situ nitridation of pre-compacted aluminium flakes is shown to be a key to lightweight composites for many engineering applications such as more efficient and cost-effective construction vehicles. ...This new composite has the mechanical properties of high-strength streels while being ∼3.4 times lighter. This composite was produced by: (i) compaction of micrometric Al flakes into porous blanks, (ii) partial melting through rapid heating to 870 K in N2 and (iii) annealing of the pre-melted blanks at 750 K in N2, where different Al flake deoxidisers were used to control a sufficiently low level of H2O/O2 activating in situ nitridation. The nitrided composites contained stellar dendrites composed of Al, AlN and γ-Al2O3, in which the ceramic fraction increases over the nitridation stage. The traces of H2O in the N2 atmosphere were found to be beneficial for strengthening, due to oxidation and suppression of the composite dendrites from overgrowing and segregation.
•Activation of hindered in situ nitridation in pre-melted Al flakes.•Discovery and control of in situ growth of AlN stellar microdendrites in an Al matrix.•Novel lightweight (∼2.3 g cm-3) syntactic Al/AlN-Al2O3 foam with superior failure stress, 874 MPa and strain, 6.8%.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Maximum adsorption of fluoride on AlFu MOF occurred at 293K.•Maximum adsorption capacity for fluoride was 600mg/g at 293K.•The MOF exhibited adequate charge characteristic and high surface area ...(1156m2/g).•Second order reaction and intra particle diffusion (first 1.5h) was prevalent.•AlFu MOF exhibited high potential for fluoride removal from water.
Potential of aluminium fumarate metal organic framework (MOF) for fluoride removal from groundwater has been explored in this work. The laboratory produced MOF exhibited characteristics similar to the commercial version. MOF was found to be micro-porous with surface area of 1156m2/g and average pore size 17Å. Scanning electron micrograph of the AlFu MOF showed minute pores and texture was completely different from either of the parent materials. Change in the composition of AlFu MOF after fluoride adsorption was evident from powder X-ray diffraction analysis. Thermal stability of the AlFu MOF up to 700K was established by thermo-gravimetric analysis. Incorporation of fluoride phase after adsorption was confirmed by X-ray fluorescence analysis. As observed from FTIR study, hydroxyl ions in AlFu MOF were substituted by fluoride. 0.75g/l AlFu MOF was good enough for complete removal of 30mg/l fluoride concentration in feed solution. The maximum adsorption capacity for fluoride was 600, 550, 504 and 431mg/g, respectively, at 293, 303, 313 and 333K.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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•The microstructures of four NAB alloys are characterized by SEM and TEM.•The added Ni suppresses the formation of β' phase and increases the amount of κ phase.•The corrosion ...resistance and yield strength are improved via Ni addition.•The corrosion mechanism is analysed based on the EIS results and surface morphology.
The mechanical properties and corrosion behaviour in 3.5 wt.% NaCl solution of as-cast nickel-aluminium bronze (NAB) alloys with four Ni contents were investigated. The increase in Ni content leads to more precipitated κ phases, therefore improving the yield strength and hardness of the NAB alloys. Ni addition was found to significantly suppress the formation of corrodible β' phase and increase the Ni concentration in α solid solution. The electrochemical impedance spectroscopic and static immersion tests showed that the increase in Ni content (4.5–10 wt.%) improved the corrosion resistance of the NAB alloys in 3.5 wt.% NaCl solution.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•In-situ and ex-situ confocal Raman measurements revealed chemical states of vanadium compounds.•The inhibition effect is mostly provided by a polymerized film with mixed V(V) and V(IV) ...species.•Intermetallic particles in the alloy have a strong influence on the vanadate inhibition process.•Deposition of polymerized vanadate compounds is mainly connected with micrometer-sized IMPs.•The inhibition mechanism involves first reduction and then re-oxidation of the vanadium species.
Chemical interactions between aqueous vanadium species and aluminium alloy AA6063-T5 were investigated in vanadate-containing NaCl solutions. Confocal Raman and X-ray photoelectron spectroscopy experiments were utilised to gain insight into the mechanism of corrosion inhibition by vanadates. A greenish-grey coloured surface layer, consisting of V+4 and V+5 polymerized species, was seen to form on the alloy surface, especially on top of cathodic micrometre-sized IMPs, whereby suppressing oxygen reduction kinetics. The results suggest a two-step mechanism of corrosion inhibition in which V+5 species are first reduced to V+4 or V+3 species above cathodic IMPs, and then oxidized to mixed-valence V+5/V+4 polymerized compounds.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Implementation of cheap and efficient electrocatalysts towards oxygen reduction reaction (ORR) falls in the central focus on fulfilling cost-affordable and high-performance fuel cells and metal-air ...batteries. In this study, N and S dual-doped porous carbon was prepared by a facile strategy for using tribute chrysanthemum as precursor and zinc chloride as activating agent. The catalyst prepared at 800°C (NSC800) depicts multiscale porous with large specific surface area (810m2g−1) and abundant exposed intrinsic dopants. The electrochemical characterizations exhibit that its onset potential is 0.0966V versus Hg/HgO electrode, much higher than that of the other reported N, S co-doped carbons, and it also shows the better methanol tolerance, carbon monoxide (CO) poisoning and stability than commercial Pt/C. Consequently, NSC800 catalyst shows attractive properties when used as the air cathode of a home-made primary aluminum-air battery, e.g., an open-circuit potential of ca. 1.64V, a discharge specific capacity of 288mAhg−1, and a peak power density of 46mWcm−2. Such attractive performances could be mainly attributed to the synergistic effect of exposed intrinsic N and S active sites and increased specific surface area with multiscale porous. Our idea on developing such doped carbons by utilizing extensive intrinsic components of biomass would be a promising strategy to cathode electrocatalyst for fuel cells and metal-air batteries.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Ionic liquids are of great importance for electrodeposition of metals, which can't be deposited from aqueous electrolytes due to their negative standard potentials. In this paper non-woven polymers ...were coated with aluminium by electrodeposition from 1-ethyl-3-methyl-imidazolium chloride and subsequently established as 3D current collectors for lithium-ion batteries. We investigated the long-term stability of the ionic liquid (IL) for electrodeposition of aluminium under process-oriented conditions. The degradation products were analysed by headspace gas chromatography-mass spectrometry, pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) and super(1)H/ super(13)C nuclear magnetic resonance spectroscopy (NMR). The main decomposition products derived from thermal degradation, especially from cleavage of an alkyl chain and were identified as chloromethane, dichloromethane, methylimidazole, ethylimidazole and deprotonated 1-ethyl-3-methylimidazole.
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IJS, KILJ, NUK, UL, UM, UPUK
The mechanism underlying the considerable refinement of primary Al3Ti intermetallic particles induced by ultrasonic treatment (UST) in an Al-0.4 wt% Ti alloy in the fully liquid state was ...investigated. Scanning electron microscopy, energy dispersive X-ray spectroscopy, focused ion beam 3D tomography and transmission electron microscopy were used to clearly identify that α-Al2O3 particles were located at or near the centres of primary Al3Ti particles in the samples solidified with and without UST. Crystallographic evaluation using the edge-to-edge matching model and experimental determination of orientation relationships between the α-Al2O3 and primary Al3Ti particles using the convergent beam Kikuchi line diffraction patterns confirmed the high potency of α-Al2O3 particles as nucleation sites for the Al3Ti phase. Based on the experimental results, the refining mechanism is discussed in terms of proposed hypotheses in the literature. It is suggested that the significant refinement of primary Al3Ti particles upon UST is due to the cavitation-induced deagglomeration and distribution of the α-Al2O3 particles and the cavitation-enhanced wetting of the α-Al2O3 particles by liquid aluminium.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Aluminium adjuvants are commonly used in vaccines to boost the effects of vaccination. Here, we assessed the benefits and harms of different aluminium adjuvants vs. other aluminium adjuvants or vs. ...the same aluminium adjuvant at other concentrations, administered a different number of doses, or at different particle sizes used in vaccines or vaccine excipients. We conducted a systematic review with meta-analysis and Trial Sequential Analysis to assess the certainty of evidence with Grading of Recommendations Assessment, Development and Evaluation (GRADE). We obtained data from major medical databases until 20 January 2023 and included 10 randomized clinical trials of healthy volunteers. The comparisons assessed higher vs. lower aluminium adjuvant concentrations; higher vs. lower number of doses of aluminium adjuvant; and aluminium phosphate adjuvant vs. aluminium hydroxide adjuvant. For all three comparisons, meta-analyses showed no evidence of a difference on all-cause mortality, serious adverse events, and adverse events considered non-serious. The certainty of evidence was low to very low. None of the included trials reported on quality of life or proportion of participants who developed the disease being vaccinated against. The benefits and harms of different types of aluminium adjuvants, different aluminium concentrations, different number of doses, or different particle sizes, therefore, remain uncertain.
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