Aluminum Scrap Research Articles

Treatment of landfill leachate nanofiltration concentrate by a three-dimensional electrochemical technology with waste aluminum scraps as particle electrodes: Efficacy, mechanisms, and enhancement effect of subsequent electrocoagulation

Landfill leachate nanofiltration concentrate is a kind of wastewater containing high concentrations of color and refractory organics. Herein, we proposed a novel three-dimensional electrochemical technology (3DET) with waste aluminum scraps as particle electrodes for its treatment. The planar and particle electrodes were first optimized. Ti/RuO2 and graphite were used as anodes in the two-dimensional electrochemical technology (2DET). In the light of contaminant removal (color, UV254, COD, and TOC), chlorine reduction, and energy consumption, graphite was selected as planar anodes and cathodes. Moreover, 3DET with Al particle electrodes (Al 3DET) outperformed that with conventional granular activated carbon electrodes, 2DET, and Al particles. At 120 min, the removal efficiencies of color, UV254, COD, and TOC using Al 3DET were 98.94 %, 84.72 %, 51.93 %, and 67.46 %, respectively. UV–vis and EEM spectroscopy, and GC–MS analyses indicate that macromolecular organic matter such as humic-like substances could be effectively degraded and simultaneously removed. Reactive species identification tests including free radical quenching and EPR spectra were conducted. The results indicate that in addition to anodic direct oxidation, indirect oxidation by oxidative species (H2O2, •OH, and RCS) and flocculation by Al species also played a vital role in contaminant removal. Continuous-flow experiments show that Fe EC as a post-treatment step of Al 3DET could effectively provide a neutralization effect for the 3DET effluent and enhance the removal efficiency of contaminants. The total operating cost of combined process was 1.307 USD/m3. This study shows that the Al 3DET-Fe EC process is a promising technology for the treatment of nanofiltration concentrate.

OPTIMIZATION ROUGHNESS LEVEL OF TURNING FROM ALUMINUM SCRAP SMELTING RESULT USING SAND CASTING METHOD

The Production Machinery Workshop at the Sriwijaya State Polytechnic are producing a lot of aluminum scrap left over from turning, where this waste is still thrown away. This will cause pollution to the environment and will be detrimental to the Sriwijaya State Polytechnic workshop. Casting is one way to deal with aluminum scrap, scrap be melted and then reshaped into a practical material that can be reused. The use of sand as a printing medium in recycling scrolls is not recommended because it is less effective and efficient in terms of long-term use. After research has been carried out, the resulting aluminum shaving waste can be reused as practical material provided that the shavings must be separated from other waste such as iron and steel. In the optimization process, the best value is obtained at the spindle speed factor of 900 rpm (A1), then the feeding depth at 0.5 mm (B1), and the feeding speed at 0.08 mm/put.

Effect of Zinc (Zn) addition on Impact and Hardness Properties of Aluminium (Al) scrap

Effect of Zinc (Zn) addition on Impact and Hardness Properties of Aluminium (Al) scrap

Sustainable recycling of aerospace-grade ultra-clean 7050 aluminum alloy melts through argon refining without secondary aluminum dross generation

The refining of aluminum scraps commonly employs nitrogen-fluxes to eliminate impurities. However, the aluminum nitride (AlN) generated by the reaction between nitrogen and the aluminum melt, along with residual fluxes, contribute to low cleanliness of the recycled aluminum melt and pose difficulties for the disposal of secondary aluminum dross (SAD). Our innovative research has resulted in the recycling of aerospace-grade clean aluminum alloy melts. The results indicate that the argon bubble floating process adsorbs inclusions and hydrogen, achieving an aerospace-grade ultra-clean melt. The solid-liquid interface between the tube wall and the melt provides a diffusion channel for hydrogen atoms, and the bubbles rising up along the wall lead to a higher hydrogen content in the melt. The argon refining dross is primarily composed of Al and Al2O3, which can be recycled as a raw material for aluminum electrolysis. Argon refining can decrease the hydrogen content and the number of inclusions with particle size ≥40 μm in the recycled aluminum melt to the level of aerospace aluminum alloy melt. Nonetheless, the particle size ≥20 μm remains 1.5–2.5 times that of primary aluminum.

Improvement of aluminium alloy properties with aids of elements generated from cow horn additive

The researchers in the area of material science have employed various agricultural wastes to improve the properties of aluminium alloys. They took advantage of various elements present in these wastes to enhance the properties of aluminium alloy. The choice of materials should always depend on their capability in term of elements present in them. Inability to choose a material wisely may result into total failure of the components. Materials possess various properties ranging from mechanical properties such as tensile strength and impact strength to electrical properties such as thermal conductivity. Also, some materials have been identified to be deficient in certain areas such as low thermal conductivity, high wear rate, poor ductility, poor machinability, and weak strength, due to some elements present in them. In the present study, aluminium scraps (secondary aluminium) was used as base material and reinforced with locally available inexpensive cow horn particulate (agricultural wastes) of 3, 6, 9 and 12% by weight of aluminium to develop an improved material taking the advantage of the elements present in the reinforcing material. The spectrographic analysis was conducted to determine the chemical compositions of all the specimens, which shows various elements present in control sample and CHp reinforced aluminium alloy. Aluminium is in the range 91.3 - 93.0%, followed by silicon with 4.36 - 5.01%, other elements present include iron, copper, magnesium, manganese, chromium, nickel, zinc, titanium, lead and others. The elements present in each sample were studied and application areas of each sample were suggested.

Hydrogen from industrial aluminium scraps: Hydrolysis under various conditions, modelling of pH behaviour and analysis of reaction by-product

The study explores the feasibility of utilizing aluminium scrap waste from the construction industry for hydrogen production via hydrolysis. Specifically, the study involves a primary analysis of aluminium scrap waste and the impact of various reaction parameters, such as NaOH molarity, reaction temperature, amount of Al scrap, solvent quantity, and the reaction vessel insulation, and their effects on the reaction rate, H2 yield, and by-product formation. The pH of the reaction solution was continuously monitored to determine the reaction mechanism, while the structure of the by-product was analysed at two stages: after removal and drying, and after removal and washing. Our findings indicate that increasing the reaction temperature has the most significant influence on the reaction kinetics. Insulating the reaction vessel ensured self-promoted hydrogen production due to the heat generated from the exothermic reaction inside the vessel, resulting in an approximate temperature increase of 5 °C for all tested reaction solution molarities compared to non-insulated conditions. The pH measurements were conducted in two different ways. The first one involved immersing a pH probe directly into an open reaction container. The second approach utilized a closed reaction container under isothermal conditions, where both the pH and H2 yield were measured simultaneously. In addition, the obtained data was compared between the measured pH values and the predictions generated by models utilizing the measured H2 evolution in order to forecast the pH behaviour. The modelling results recognize and suggest the existence of separate reaction phases or zones, each characterized by distinct influences on the pH level.

Classification of Shredded Aluminium Scrap Metal Using Magnetic Induction Spectroscopy.

Recycling aluminium is essential for a circular economy, reducing the energy required and greenhouse gas emissions compared to extraction from virgin ore. A 'Twitch' waste stream is a mix of shredded wrought and cast aluminium. Wrought must be separated before recycling to prevent contamination from the impurities present in the cast. In this paper, we demonstrate magnetic induction spectroscopy (MIS) to classify wrought from cast aluminium. MIS measures the scattering of an oscillating magnetic field to characterise a material. The conductivity difference between cast and wrought makes it a promising choice for MIS. We first show how wrought can be classified on a laboratory system with 89.66% recovery and 94.96% purity. We then implement the first industrial MIS material recovery solution for sorting Twitch, combining our sensors with a commercial-scale separator system. The industrial system did not reflect the laboratory results. The analysis found three areas of reduced performance: (1) metal pieces correctly classified by one sensor were misclassified by adjacent sensors that only captured part of the metal; (2) the metal surface facing the sensor can produce different classification results; and (3) the choice of machine learning algorithm is significant with artificial neural networks producing the best results on unseen data.

Tolerance of Al–Mg–Si Wrought Alloys for High Fe Contents: The Role of Effective Si

Aluminum scrap is often contaminated with steel parts, leading to accumulation of Fe in recycled Al alloys. Consequently, low limits for Fe in Al wrought alloys are difficult to meet by recycling without dilution with primary Al. Wrought alloys with a higher tolerance for Fe could help overcome this problem and improve the sustainability of Al wrought products. Here we study the effects of increasing the Fe content in EN AW-6060, 6005A, and 6082 from 0.2 to 0.7 wt pct. The microstructure and mechanical properties of the alloys after extrusion and artificial ageing are compared to the standard alloys. We found that 6082 is more tolerant to above-standard Fe contents than 6005A, which in turn is more tolerant than 6060: the strength of the 6082-based alloy with increased Fe content is comparable to that of standard 6082 and the elongation at break is increased. In contrast, the artificial ageing potential of the 6060-based alloy with more Fe is drastically reduced compared to 6060. This data and literature values show that the effective Si content is a good overall predictor of alloy strength. Effective Si is not bound in AlFeSi-type phases and is available for precipitation hardening. Additional effects of increased Fe levels are discussed.

Recyclability of aluminium piston alloy

One of the most recycled and recyclable materials now in use is aluminium. Frequently, aluminium cans, automobile components, and window frames are recycled back into itself. A vital component of the contemporary aluminium industry is recycling. Recycled aluminium production uses only around 5% of the energy required to produce new aluminium, resulting in lower carbon emissions and cost savings for both corporations and end users. As a result, today's use of roughly 75% of all aluminum created throughout history. Recycling rates for aluminium exceed 90% in the majority of industrial sectors, including the construction and automobile industries. Every year, the United States saves more than 90 million barrels of oil equivalent through industry recycling. Capability to re-melting aluminium alloys scrap without losing its alloying elements and finding optimum pouring temperature are the purpose of this paper, and the results will determine the possibility of reusing piston alloy to make components similar to those they were recycled from. Automotive cast aluminium scrap obtained from pistons were used as experimental specimens, which were melted via an electrical furnace then poured at four different temperatures, namely 680, 720, 760, and 800 °C into a strip fluidity steel mould. The chemical composition of the four specimens were examined using spark emission spectrometer and the length of melted metal that flowed through the mould strips was measured as well to determine fluidity. Also, an optical microscope was used to detect microstructure defects. The chemical composition ratios of alloying elements before and after recycling showed that the resulting alloys could be closely equivalent to the commercial alloy that was originally used to make the components. In addition, the higher the pouring temperature the greater the casting fluidity. Generally, the consumed aluminium piston alloy can be re-melted and used to produce many parts.

Recovery of Pure Lead-Tin Alloy from Recycling Spent Lead-Acid Batteries.

Spent lead-acid batteries have become the primary raw material for global lead production. In the current lead refining process, the tin oxidizes to slag, making its recovery problematic and expensive. This paper aims to present an innovative method for the fire refining of lead, which enables the retention of tin contained in lead from recycled lead-acid batteries. The proposed method uses aluminium scrap to remove impurities from the lead, virtually leaving all of the tin in it. The results of the conducted experiments indicate the high efficiency of the proposed method, which obtained a pure Pb-Sn alloy. This alloy is an ideal base material for the production of battery grids. This research was carried out on an industrial scale, which confirms the possibility of facile implementation of the method in almost every lead-acid battery recycling plant in the world.

Recycling of aluminium scrap into phase change materials for high-temperature storage applications: Thermophysical properties and microstructural characterisation

Metal scrap is often generated during conventional production processes and at the end-of-life of metallic components finding use as a recycled metal source. However, the impurities introduced in the recycling process can deteriorate the mechanical properties of the final product leading to down-cycling from structural applications or requiring great effort to make the material viable again.Metallic phase change materials (mPCMs) are promising materials due to their high energy storage density and high thermal conductivity relative to common inorganic and organic thermal storage materials. Metals used for thermal applications, such as mPCMs do not have strict mechanical requirements, and could potentially be made from recycled sources unsuitable for structural significant applications. Thermal storage offers an alternative use for scrap sources, especially aluminium alloys which according to the International Energy Agency are among the metals with the highest recovery rates.AlSi cast alloys are widely used in different applications, especially the automotive industry. In this work, the eutectic composition Al-12.6 wt% Si has been proposed as thermal storage material due to the great potential and excellent storage properties in the temperature range 500–600 °C. Thermophysical properties including melting temperature, heat of fusion, heat capacity and thermal diffusivity were experimentally determined via Differential Scanning Calorimetry (DSC) and Light Flash Analysis (LFA) in order quantify the impact of impurities typically present in commercial aluminium alloys such the 2000 and 3000 series.Four different AlSi alloys with different impurity levels from scrap-equivalent compositions were investigated as candidate materials for latent heat storage applications and their potential contribution in the circular economy.

Evolutionary mechanism of the precipitation behavior and organization of iron-containing intermetallic phase during solidification of recycled high-Fe Al-Zn-Mg-Cu melts

The remelting of aluminum scraps can result in the accumulation of impurities, with iron being the most prevalent among them. The presence of such impurities can cause downgrading and hindered utilization of the material. Despite this, the evolution mechanism of the Iron-containing Intermetallic Phase (IIP) in recycled high-Fe and low-Si aluminum melt has received limited attention and requires further investigation. This study investigates the evolution mechanism underlying the precipitation behavior and organization of the IIP during the solidification process of recycled high-Fe Al-Zn-Mg-Cu melts, utilizing a combination of simulation and experiment. Our findings indicate that the precipitation behavior of the high-temperature precipitation phase (HPP) in the melt is influenced by the Mn and Si, which subsequently determines the organization of the IIP. Specifically, the predominant forms of IIP in the recycled high-Fe Al-Zn-Mg-Cu alloys are lamellar and hollow rod-like phases with anisotropic, as well as skeletal phases with isotropic organization. Moreover, the synergistic addition of Mn and Si can increase the precipitation temperature (PT) and precipitation temperature interval (PTI) of the Al15(Fe,Mn)4Si2 phase in the melt, leading to the transformation of the IIP into a skeletal organization that can be easily removed and has less impact on the material properties. These findings provide insights into alloy design strategies aimed at minimizing the impact of iron accumulation on the cycle life of aluminum scraps and the performance of recycled aluminum.

Direct Regeneration of NCM Cathode Material with Aluminum Scraps.

Hydrothermal-based direct regeneration of spent Li-ion battery (LIB) cathodes has garnered tremendous attention for its simplicity and scalability. However, it is heavily reliant on manual disassembly to ensure the high purity of degraded cathode powders, and the quality of regenerated materials. In reality, degraded cathodes often contain residual components of the battery, such as binders, current collectors, and graphite particles. Thorough investigation is thus required to understand the effects of these impurities on hydrothermal-based direct regeneration. In this study, we focus on isolating the effects of aluminum (Al) scraps on the direct regeneration process. We found that Al metal can be dissolved during the hydrothermal relithiation process. Even when the cathode material contains up to 15 wt.% Al scraps, no detrimental effects were observed on the recovered structure, chemical composition, and electrochemical performance of the regenerated cathode material. The regenerated NCM cathode can achieve a capacity of 163.68 mAh/g at 0.1 C and exhibited a high-capacity retention of 85.58 % after cycling for 200 cycles at 0.5 C. Therefore, the hydrothermal-based regeneration method is effective in revitalizing degraded cathode materials, even in the presence of notable Al impurity content, showing great potential for industrial applications.

An Investigation on Inclusions Forming During Remelting of Aluminum and Magnesium Scraps Under a Salt Flux

An Investigation on Inclusions Forming During Remelting of Aluminum and Magnesium Scraps Under a Salt Flux

Efficacious degradation of ethylene glycol in baffled ozonation reactor in the presence of waste-derived MIL-53(Al/Fe)-metal-organic framework derived Al2O3/Fe3O4

Ethylene glycol (EG) has been widely used to produce polyethylene terephthalate (PET) bottles, antifreezes, and de-icing fluid. However, EG possesses toxic detrimental effects on human and aquatic creatures. The degradation of EG in catalytic ozonation based advanced oxidation processes was rarely reported before. In this regard, a novel porous catalyst, magnetic MIL-53(Al/Fe)-metal-organic framework (MOF) derived Al2O3/Fe3O4 (wAl-Fe@MOF) was synthesized for the first-time using PET, iron, and aluminum scraps for efficacious catalytic ozonation system (COS) of EG. A maximal EG degradation and mineralization of 97.03 ± 2.79% and 57.75 ± 2.60% were obtained in wAl-Fe-based COS, which was higher than sole O3 (70.76 ± 3.90%; 22.65 ± 2.20%) and O3/H2O2 (74.51 ± 2.58%; 36.57 ± 3.10%). The wAl-Fe@MOF displayed only about 18% drop in deterioration efficiency after 5th cycle of reusability, demonstrating outstanding stability and recyclability. The electron paramagnetic resonance and radical scavenging tests confirmed that surface adsorbed ˙OHads were majorly accountable for EG degradation. Phytotoxicity revealed that COS effectively reduced the toxicity of EG towards Vigna radiata. The energy consumption and operating cost were found to be 0.863 kWh m−3 order−1 and 0.086 $ m−3 order−1, indicating wAl-Fe@MOF based COS could be highly appropriate for wastewater purification in real field applications.

Aluminium scrap becomes carrier for hydrogen energy

Aluminium scrap becomes carrier for hydrogen energy

Performance studies on hybrid nano-metal matrix composites for wear and surface quality

Abstract Aluminium-based hybrid nano-metal matrix composites are right materials, finding application in the aerospace and automotive industry. The present research focused on the effects of sliding load, sliding velocity, and temperature on wear behaviour of a novel hybrid metal matrix nano-composite .Stir-squeeze casting setup is used to produce the composites. The base metal is scrap aluminium alloy wheel (SAAW) reinforced with 1, 2, wt.% and 5.5, 7 wt.% of micro-sized alumina (Al2O3)m and nano-sized alumina (Al2O3)n particle respectively. An orthogonal array L9 (OA) has been used for designing the experiments. Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) is applied to find the optimal condition for Coefficient of Friction(COF),wear, surface roughness. Analysis of Variance (ANOVA) results show that the reinforcement contributes 19.40% and most influencing factor is sliding load with 62.33%. The samples tested were examined and analyzed using a Field Emission Scanning Electron Microscope (FESEM) and an energy-dispersive X-ray spectrometry (EDX). Additionally, a profilometer was used to measure the surface roughness of the worn-out specimen.

The positive effect of designing a gas fired reverberatory furnace in recycling aluminum scraps in our environment

A furnace is a device for high furnace heating, through (fuel or gas combustion, co-generation, electric or induction). A gas fired reverberator furnace was designed,a reverberator furnace is mainly used for the extraction of tin, copper, aluminum and nickel metals as well as in the production of certain concretes and cements. It is a metallurgical or process furnace that isolates the materials being processed from contact with fuel, but not from contact with combustion gases.The furnace was fired with liquefied petroleum gas (butane) at a constant temperature of 660.3 degrees was maintained in order to melt metals efficiently. The reverberator furnace side walls were lined with refractory bricks and glass fibers to reduce heat loss to the amount. The device was observed to use only one-third(1/3) of the time used by the conventional bituminous coal charged. Addition of oxygen enhances the combustion rate, thereby reducing the time in melting. An efficiency of about 76% was obtained from design analysis as melted scraps were used in the production of simple tools.

Sustainability Study of a New Solid-State Aluminum Chips Recycling Process: A Life Cycle Assessment Approach

Nowadays, reducing greenhouse gas emissions in all human activities has become crucial. This article presents a life cycle assessment (LCA) investigation conducted to evaluate the environmental benefits of a newly developed solid-state recycling process for aluminum chips, involving two steps: direct rolling and accumulative roll bonding. A comparison was made between this process and two current industrial methods of recycling aluminum scraps to obtain wrought products, which involve melting, casting, and subsequent rolling. The LCA analysis considered a scenario where 50% of the total electric requirement was met by photovoltaic energy. The results of the study indicate that in all examined impact categories, direct rolling has a lower environmental footprint compared to both traditional recycling and twin-roll cast technology. These results suggest that this new solid-state recycling procedure has significant potential to replace environmentally harmful melting processes.

Studies on Water–Aluminum Scrap Reaction Kinetics in Two Steps and the Efficiency of Green Hydrogen Production

This work aims to explain aluminum hydrolysis reaction kinetics based on a properly chosen theoretical model with machined aluminum waste chips as well as alkali solutions up to 1M as a promoter and to estimate the overall reaction profit. The purpose of this work is to assess the optimal alkali concentration in the production of small- and medium-scale green hydrogen. To obtain results with better accuracy, we worked with flat Al waste chips, because a flat surface is preferable to maximally increase the time for the created hydrogen bubbles to reach the critical gas pressure. Describing the reaction kinetics, a flat shape allows for the use of a planar one-dimensional shrinking core model instead of a much more complicated polydisperse spheric shrinking core model. We analyzed the surface chemical reaction and mass transfer rate steps to obtain the first-order rate constant for the surface reaction and the diffusion coefficient of the aqueous reactant in the byproduct layer, respectively. We noted that measurements of the diffusion coefficient in the byproduct layer performed and discussed in this paper are rare to find in publications at alkali concentrations below 1M. With our reactor, we achieved a H2 yield of 1145 mL per 1 g of Al with 1M NaOH, which is 92% of the theoretical maximum. In the estimation of profit, the authors’ novelty is in paying great attention to the loss in alkali and finding a crucial dependence on its price. Nevertheless, in terms of consumed and originated materials for sale, the conversion of aluminum waste material into green hydrogen with properly chosen reaction parameters has positive profit even when consuming an alkali of a chemical grade.