Aluminum Waste Research Articles

Spark plasma sintering of dense alumina ceramics from industrial waste scraps

The implementation of environmentally-friendly manufacturing, which include the reuse and recycling of materials is nowadays crucial in order to meet the circular economy approach. The present study shows the possibility of recycling waste alumina scraps obtained after the green machining step during the manufacturing process of alumina ceramics as a broken ware, which contained small amounts (≤5 ​wt.% in total) of sintering additives in the form of organic binders and MgO. Dense alumina samples containing various amounts of waste alumina powder (0–100 ​wt.%) were produced by spark plasma sintering (SPS) at sintering temperature of 1450 ​°C, dwell time of 5 ​min ​at a 50 ​MPa of uniaxial pressure. The influence of waste alumina content on microstructure, hardness, and fracture toughness was investigated to determine the possibility of recycling broken ware.

Advanced fabrication and multi-properties of aluminium hydroxide aerogels from aluminium wastes

Over 60 million tons of aluminium are produced annually, requiring sustainable and eco-friendly recycling methods of aluminium waste. In this work, aluminium metal waste is utilized in the fabrication of aluminium hydroxide aerogels using a cost-effective and environmental-friendly process. The developed aerogels with varying contents of aluminium and poly(vinyl alcohol) as a binder exhibit a low density (0.060–0.108 g/cm3), a high porosity (92.3–95.5%) and a low electrical conductivity ([1.8–5.2] × 10–8 S/m). The results indicated that aluminium hydroxide aerogels have an ultra-low thermal conductivity of 0.028–0.032 W/m K and are able to withstand high temperature of 800 °C with less than 50% decomposition. It is suggested that the synthesized aerogels can be a promising candidate for high-value engineering applications such as thermal insulation of pipes and buildings to expand the usage of recycled aluminium.

Subtle early-warning indicators of landfill subsurface thermal events

It is generally accepted that landfills undergo at least four phases of decomposition, 1) an initial aerobic phase, 2) an anaerobic acid phase, 3) an initial methanogenic phase, and 4) a stable methanogenic phase. While landfill fires are common, recently anoxic subsurface heating events (ASHEs) have been recognized, potentially catalyzed by aluminum waste. This paper reviews two such events to forensically examine if there are predictable early warning signs in the gas record prior to the onset of an ASHE that could facilitate early action. At the Countywide Recycling and Disposal Facility in East Sparta, Ohio, decreasing methane (CH4) in landfill gas was identified in a post-mortem analysis as an early indicator parameter (IP) of an abnormal landfill condition because the ASHE inhibited methane-producing microorganisms. Here the CH4:CO2 ratios also decreased to < 0.8 at least one year prior to onset of the full-fledged ASHE in some gas wells. Landfill A was a municipal solid waste landfill that operated through December 2004. The landfill gas and temperature profiles appeared normal after closure until 2009, when landfill gas characteristics in several wells started to evolve toward an upset condition, with decreasing methane (CH4 <43%), increasing carbon monoxide (CO > 500 ppm), increasing balance gas (>20%) and a CH4/CO2 ratio decreasing below 0.8. The evolution in sequencing of ASHE IPs was, 1) declining CH4, followed by, 2) increasing CO2 and % balance gas and, then 3) CO before onset of the ASHE. Subsequently, 4) leachate volumes increased as did, 5) the BOD/COD ratios and benzene in leachate, and finally 6) release of landfill contaminants to groundwater. These multiple lines of evidence suggest that operators should carefully evaluate data trends as indicators of potential upset conditions. The gas profiles in many Landfill A gas wells were similar to those at Countywide and appear to be predictable by a Landfill Fire Index (LFI) based on temperature, CO2 and CH4 patterns. While there were sporadic exceedances of the NSPS temperature (131 °F), and above the Higher Operating Value (140 °F) in some wells, the change in landfill gas IP signature and the LFI appears to have pre-dated the major thermal event by between ½ to 3 years, depending on the well.

Deactivation Influence of HF on the V2O5–WO3–TiO2 SCR Catalyst

The electrolytic aluminum waste contains harmful components, such as fluorides. Sending it to coal-fired boilers seems to be a prospective scheme to achieve the harmless treatment of waste. However, the negative influence of F on the SCR catalyst should be examined. In this study, a fixed-bed reactor system is built up to study the deactivation of the V2O5–WO3–TiO2 SCR catalyst by HF when the electrolytic aluminum waste is co-fired with coal in boilers. The activity of the catalyst is evaluated by the NH3-SCR reaction. The deactivation mechanism is investigated through tests of NH3 temperature-programmed desorption, H2 temperature-programmed reduction, X-ray diffraction, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller (BET), in situ diffuse reflectance infrared Fourier transform spectroscopy, and Raman spectroscopy. The results show that for deactivated catalyst samples, the SCR catalytic activity drops obviously, especially when they work at lower temperatures. Although HF could enhance Brønsted acid sites, increase the Oα (adsorbed oxygen) concentration, and facilitate the Lewis acid site formation, it would not compensate for decreases of V5+ on the catalyst surface and BET surface area, which results in an activity reduction of the catalyst sample.

Research of process factors increasing metal yield during aluminum waste remelting

The article presents the results of research determining the most effective technologies for increasing metal yield in the processing of aluminum-containing waste. In particular, peculiarities of the processes of melting aluminum alloys were analyzed using complex methods of furnace and off-furnace processing of charge material containing an increased amount of shovelling scrap and swarf. Studies on the impact of charge preparation and aluminum remelting technology were carried out in SAT-0,16 and IAT-0,4 furnaces on the АК12М2 alloy. Experiments proved that batchwise loading 20 kg of swarf briquette preheated to 300–400 °C into the SAT-0,16 furnace with the addition of flux (composition: NaCl – 50 %; KCl –35 %, Na3AlF6 – 15 %) in the amount of 3 % of total metal mass is the most efficient technology. This technology makes it possible to achieve a metal yield of about 94 %. The study of the remelting technology influence on IAT-0,4 furnace metal yield showed that the greatest effect can be obtained in case of furnace charge (95 kg swarf briquette) by batches of 2 kg into the 7 kg liquid bath with modifier flux (composition: NaCl – 62 %; KCl – 13 %, NaF – 25 %) added in the amount of 2 % from the total metal mass. This technology provides up to 93.5 % of metal yield. Data from 10 series of 5–9 melts were also analyzed with the comparison of metal yield results depending on the mass of briquetted swarf charged into the furnace. A histogram of the change in the porosity of AK12M2 and AK9 samples depending on the content of swarf in the charge (from 0 to 45 %) during remelting. It was found that an increase in the content of swarf in the charge, all other things being equal, leads to an increase in the average porosity score, which indicates the need for additional refining of such melts.

Low-Calcination Temperature to Synthesize A-Alumina From Aluminium Waste Can Using Sol-Gel Method

Many countries around the world are facing issues in managing solid waste materials; most of these wastes such as aluminium can are deposited to the landfills, leading to environmental pollution. Recycling is considered as an effective technique to manage the aluminium can waste since it can provide benefits in terms of energy savings, reduce volumes of waste and cost-effectiveness. In this article, it was desired to turn the aluminium can waste into α-Alumina using sol-gel method. Alumina exists in many crystalline structures which degenerate to the most stable hexagonal α-phase at high temperatures. α-Alumina (a-Al2O3) is the most stable crystalline structure widely used and studied as electronic packaging, corrosion resistance ceramics, high-temperature structural material, and translucent ceramics. FTIR, XRD, SEM-EDX, TGA, and BET were employed to investigate the properties of a-alumina. The experimental results obtained from this study demonstrates the possibility of producing alumina from an aluminium can waste with the exact surface area of 5.2105 m2/g, crystallite size at 132.50 nm and total weight loss of 2.71% at 900 °C calcination temperature.

Design of crashworthy attenuator structures as a part of vehicle safety against impact: Application of waste aluminum can-based material

The impact attenuator is an essential system in both race cars and urban vehicles. The structure of an impact attenuator serves as a safety barrier between the impacted surface and the driver in an accident. Attenuator materials tend to have a high price; thus, alternative materials were explored in the current work, i.e., used cans from food and beverage containers. The study deployed a nonlinear finite element algorithm to calculate a series of impacts on the attenuator structures. The thickness of the cans and velocity of the impact were considered as the main parameters. Analysis results concluded that the attenuator's average energy was 16000 J for a can thickness of 1 mm. This value is more than two times the 0.5 mm thick used cans. The attenuator's new design was then matched with an attenuator regulation, and the results surpassed the standard value of 7350 J.

Evaluating recycling potential of waste alumina powder for ceramics production using response surface methodology

The generated process losses such as broken ware from shaping, if not recycled internally, are considered as waste. Furthermore, the collected process losses are provided to external recycling companies or waste disposal facilities. This study investigated the recycling potential of waste alumina powder, which was accumulated during industrial machining of the ceramic green body. The samples containing up to 20 dwb. % (dwb – weight amounts based on dry matter) of powdered waste alumina were prepared by slip casting method and conventionally sintered at various sintering conditions according to Box-Behnken design. Sintered samples were characterized for density, microstructure, hardness, and indentation fracture toughness and compared with samples made of pure commercial alumina. The study shows that the addition of waste alumina up to 20 dwb. % sintered at higher sintering temperature with dwell time 1–3 h did not negatively affect the hardness, nor the indentation fracture toughness of the sintered samples. The enabled recycling potential of waste alumina powder can have direct positive environmental impact, although economic benefits cannot be ignored.

Investigating the effects of calcination time on Α-alumina synthesis from aluminum waste can

Several countries around the world are confronted solid waste management most especially from aluminum beverage containers. The recycling process is seen as an effective approach since it is energy saving, cost effective and reduced emission. In this study, the Sol-gel method was used to process the aluminum wastes and to consequently synthesize them into aluminum oxide (α-Al2O3) and presented in several crystalline structures. The result from this study indicated that the synthesized α-alumina at lower calcination time exhibited a lower FTIR peak intensity which indicated a more crystallinity. However, the synthesized α-alumina exhibited higher and sharper FTIR bands at higher calcination time. Moreover, the morphological characteristic shows that exhibited almost similar features with a non-spherical heterogeneous particle sizes. The results of the elemental analysis suggest a direct proportionality between the calcination time, and atomic percentage of aluminum among the samples. Conclusively, this study shows that the waste aluminum can be converted into economical value-added products.

The mechanical properties of green mortar contained aluminum wastes as substitution of sand

In this investigation, the natural sand replaced up to 30% by aluminum wastes (AW) to produce green cement mortar for different construction applications. The dry density and the compressive strength of all specimens at ages (7, 14, and 28) days were measured. To examine the microstructure of the specimens at 28 days, the scanning electron microscopy (SEM) was done. The compressive strength decreased sharply by incorporating AW in cement mortar and the reduction ratio ranged between 63% and 95% for mixes contained 5% and 30% of AW respectively. The decrease in dry density was less and varied between 8% and 46% for 5% and 30% of AW in mixes respectively. The AW had the effect of retarding develop the strength. The SEM images showed that there an increase in the number and size of voids and a decrease in hydration products when AW was utilized in mortar. The mortar contained up to 5% of AW can be used for structural application. The AW ratio in the range of (15–30) % can be suitable for lightweight mortar for nonstructural applications.

Microhydrogen production with water splitting from daily used waste aluminum

a bstract In this study, different types of waste aluminum produced in daily life and their pure equivalents were evaluated and compared in terms of their hydrogen generation performance through the water-splitting reaction. An experimental system was designed for the production process that consisted of electrodes, DC power supply, alkaline solution, and various waste aluminum products. The hydrogen generation rate of the aluminum source was then measured to determine the optimum conditions for hydrogen production with different types of pure and waste aluminum, normality of the aqueous solution, and applied DC voltage. The best results for micro-hydrogen generation were obtained using pure powder Aluminum, which was attributed to the increased active surface area for the reaction. For beverage can waste (and its powder form), the maximum hydrogen generation rate (cm 3 /g.min) was achieved using the powder form of the waste aluminum at 2 N alkaline solution. However, the total amount of hydrogen generation (cm 3 /g) yielded different results compared to the maximum hydrogen generation rate where, when the amount of hydrogen generation volume per mass was considered, the beverage can pieces achieved the best result under constant voltage. This result was attributed to a longer total reaction time. • Hydrogen production from waste Al drink cans are studied. • Parametric study is applied with voltage, concentration and forms of Al. • Micro-production of hydrogen is a good candidates for a sustainable energy system.

Refractory Ceramics of Clay and Alumina Waste

Abstract Refractory ceramics were produced from clays and alumina waste. Specimens were shaped by uniaxial pressing, subjected to thermal analysis by dilatometry and heat-treated in a conventional furnace at 1300 and 1400oC, applying a heating rate of 5oC/min and a dwell time of 2 and 3 hours at the maximum temperature. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and physicomechanical properties. The dilatometric analysis before heat treatment indicated that the formulation containing the largest amount of fluxing oxides presented the highest linear shrinkage. The XRD analysis revealed that mullite was the major phase and needle shaped crystals typical of mullite obtained from clay minerals were observed by SEM. The increase in firing temperature and dwell time at the maximum temperature improved the physicomechanical properties of the specimens. The thermal expansion coefficient (TEC) in the range of 25 to 1000oC varied from 6.2 to 6.9 x 10-6°C-1.

A study of age effect through NDT and crushing strength of concrete with different industrial wastes under loading and unloading conditions

The strength of concrete is affected by several factors, such as water to binder ratio, quality and the ratio of coarse to fine aggregates, ambient temperature, method of curing, and curing age. This research work aims to study the impact of curing age on NDT and crushing strength of concrete with different industrial wastes under loaded and unloaded conditions. Three different types of wastes were utilized in high-strength concrete, grade M60. In the first mix, the fine aggregate was substituted by the crushed waste glass with various percentages of 0, 10, 20, 30, and 40 by weight. In the second mix, the cement was substituted by aluminum waste with different percentages of 0, 2, 4, 7, and 12%, and LDPE was added by weight of cement with 3.5, 7, 12.5, and 21%. To study the role and effect of LDPE waste only on strength of concrete and NDT results, the third mix LDPE with varying percentages of 0, 3.5, 7, 12.5, and 21 was added by cement weight. A precise experimental program was conducted to investigate the response of specimens by applying ultrasonic pulse velocity and surface hardness under unloaded conditions and loading conditions with 25% of the ultimate crushing strength. The findings of unloaded and loaded conditions for UPV and surface hardness found from concrete specimens of various waste at stipulated ages have been associated with their compressive strength. Increased surface hardness and pulse velocity test results of the concrete with varying substitution levels of the wastes after 210 and 270 days of curing are discussed. It was found that the industrial wastes used in this study with different substitution levels reduce the ultrasonic pulse velocity under unloading conditions at the age of 28, 210, and 270 days. The findings related to UPV and surface hardness for all type of wastes under loaded conditions are found lower than that of unloading conditions.

Development of metal matrix composites using recycled secondary raw materials from aluminium wastes

Metal matrix composites have proven to be a class of materials with high potential to replace a large number of materials used in the automotive, aerospace, electronics, defence and manufacturing industries, where the requirement for light and high-strength parts is increasing. The possibility of combining different materials (metal–ceramic–nonmetal) provides the opportunity to change the properties of metal matrix composites, which are mainly determined by the properties of the component materials. Therefore, there is the question of finding recycling technologies, replacing new materials with recycled materials in order to minimise the amount of waste, which does not involve too much expenditure with their implementation and at the same time does not raise particular problems when applying them in industrial practice. The purpose of this study is to highlight the most efficient methods of recycling aluminium alloys in order to be applied in the practice of composites. This research concerns the liquid mixing (Vortex method) processing of composite materials with metal matrix of aluminium alloys, reinforced with ceramic particles. This technology uses common and cheap raw materials, matrix alloys in the moulded state, from recycling. This process has general economic and technological advantages, consisting of a small number of operations, with low durations and low energy consumption. Also, liquid mixing can be obtained by composite materials with a homogeneous distribution of ceramic reinforcement particles in the metal matrix. This study was carried out using laboratory installations designed and carried out within the Department of Engineering and Management of the Faculty of Engineering Hunedoara, University Politehnica Timisoara, within a doctoral program.

Investigation of lightweight structural materials produced using aluminum scraps with cement mortar

A lot of environmental concerns are increasing day after day result in the raise of solid waste in large quantities in the world resulting from the demolition of buildings and various industrial and commercial activities. This research provides the possibility of reusing one of these wastes solid aluminum scrap (Als) by using it to produce a modified type of cement mortar. The research focuses on the mechanical behavior of the new cement mortar type obtained by adding aluminum scrap by different percentages (1%, 2%, 3%, 4%, and 5%) as a replacement ratio from the weight of sand mixed with Ordinary Portland Cement (OPC). The findings of this research indicated the possibility of using aluminum waste material in certain limits where the compressive strength significantly reduced by increasing the percentage of als. The most interesting observation was to increase the volume of the mixture by increasing the ratio of als. According to the results, it is possible to use this type of cement mortar to produce lightweight structural members such as slabs, bricks, etc. Finally, the general formulation was proposed based on the regression analysis and experimental measurements to give a capture of the compressive strength of mortar under any variables alter (age of specimen and/or quantity of aluminum replacement).

Utilization of aluminium dross for the development of valuable product – A review

Abstract Today a lot of literature is available to separate the Aluminium from the waste metallic aluminium dross produced in various manufacturing industries. The waste aluminium dross chemically consists of Al2O3, SiO2, Fe2O3, MgO, SO3, CaO, TiO2, and Na2O. The waste aluminium dross is very hazards to groundwater, ozone layers, agriculture and eco-system. The greater part of the nations is making expected alterations to decrease ozone harming substance discharges and to expand the utilization of efficient power vitality arrangements. Under this development, the significance of utilizing recyclable materials has picked up force in the course of the most recent decade. In this way, aluminium, with its novel property of 100% recyclability has changed the elements of the manufacturing industries. The pioneering offering of this review article provides systematic approaches and methodology to current researcher and industrial persons to obtain a suitable method and approach to recycle the waste aluminium dross.

Utilizing Faujasite-type zeolites prepared from waste aluminum foil for competitive ion-exchange to remove heavy metals from simulated wastewater

Utilizing Faujasite-type zeolites prepared from waste aluminum foil for competitive ion-exchange to remove heavy metals from simulated wastewater

Insight into Tar Formation Mechanism during Catalytic Pyrolysis of Biomass over Waste Aluminum Dross

Tar is one of major products from biomass pyrolysis. Its formation mechanism in a catalytic pyrolysis system comprising pine sawdust and waste aluminum dross (AD) is investigated with the aid of analytical methods including thermogravimetric analysis (TG), Nuclear Magnetic Resonance (NMR), electron paramagnetic resonance (EPR), and gas chromatography coupling with mass spectrometry (GC-MS). The results show that AD plays a vital role in cleavage of C-O bonds to enhance selective formation of furans, ketones, and phenols. The catalytic pyrolysis is initiated by active C-O-M intermediate formation that accelerates C-O bond cleavage and generates great amounts of free radicals to 1020 spins/g at 300–500 °C. Compared with pure pine pyrolysis, the percentage of glucosidic bonds from cellulose decreases from 14.00% to 9.66% at 500 °C; the etherified guaiacyl is more actively ruptured and disappears at 700 °C. Furans and ketones increase from 17.45% to 22.23% and 6.71% to 10.80% at 500 °C, respectively. Phenols increase from 66.75% to 71.57%. The preferential production of higher value-added products via catalytic pyrolysis between biomass and industrial wastes may bring new insight to the simultaneous valorization of agricultural, municipal, and industrial waste.

Strength, Load-deflection Behavior And Impact Resistance of Two-way Slab for Concrete Incorporating Waste Aluminum Fibers

This research investigated about the effectiveness of waste aluminum results from waste cans of gassy drink, as fibers in concrete. strengths, load-deflection behavior under flexural load and impact resistance under low velocity repeated impact load were investigated. Two length of fibers were examined 40 mm and 20 mm for 0%, 0.5%, 0.75% and 1% fibers content. Results showed that compressive strength has inconsiderable affected by adding fibers while splitting tensile strength, modulus of rupture and impact resistance for concrete incorporating aluminum fibers especially for 0.75% and 4-mm fibers have clear improvement. Compared to experimental results, ACI equation underestimated the tensile strength of fiber concrete. Load –deflection of beam with fibers showed a more ductile behavior at failure under flexural load compared to reference one. Bond strength improved by adding aluminum fibers. Slabs that incorporating aluminum fibers showed a higher energy absorbed, less deflection and smaller cracks width at failure than the one without fibers under impact loads. From results, one can see that mixes with 0.75% fibers showed a best performance compared with other mixes. Finally, the 40 mm fiber was more effective in improvement in concrete resistance than 20 mm fiber length.

Towards recycling: Understanding the modern approach to recover waste aluminium dross

With a growing concern of the modern recycling engineers, the industrial wastes pose a challenge that the world faces. Aluminium dross is one of the many industrial wastes that are generated in aluminium smelter plants all around the world. Utilizing these industrial wastes for the generation of valuable products is one of the major areas of current research. The primary target of the recyclers has been to recover the metallic content of aluminium dross. The modern Salt-Free Technologies (SFT) has been able to achieve this target. The cost of operation, however, is greater than the conventional rotary salt furnaces (RSF).The hydrometallurgical routes involve the leaching of the dross. This process leads to the extraction of metallic aluminium into the liquor and this liquor is utilized to synthesize various valuable products like alums and sulfates, etc. With the leaching, the liberation of various gases (H2, CH4 and NH3) takes place. These gases may be captured and used in their respective applications. The residual solid obtained post-leaching is utilized for the production of alumina, which further finds its applications in the generation of composites. The dross has also been directly used as a raw material for the production of refractories, composites, cement clinkers, etc.Therefore, an industrial waste, aluminium dross is employed with good resultant products. Not only is the metallic content of the dross valued, the modern trend implies the complete utilization of the waste. With minimum waste generation and reduced environmental burden, the modern approaches of recycling achieve the recovery of aluminium dross. The present work focuses on these modern technologies and the recent research trends.