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Aluminum parts are used in the aviation industry because of the need for light. However, in addition to lightness, critical parts that must have high strength properties have also been developed. The corrosion resistance, resistance to high temperatures, and workability were investigated in this case. It becomes difficult to choose among many aluminum materials that can be alternatives to each other when these features are included. The developed approach, which considers many of the features listed above and ultimately recommends to the user the most suitable aluminum material for the relevant critical part, will be used in overcoming the difficulties in this process. A material selection model is proposed in this paper for this purpose, and the decision-making model is demonstrated with examples from the aviation industry. Therefore, the developed model, which will enable the selection of the most suitable materials among alternative materials, especially for critical parts in the aviation industry, will guide professionals working in this field. For this purpose, the fuzzy TOPSIS method is used in the study, and suitable alternatives are determined. Finally, a robustness analysis is proposed to determine the most suitable aluminum material for highly uncertain situations. We apply a stability evaluation study based on process control theory in the robustness analysis. [ABSTRACT FROM AUTHOR]

One of the most important parts used in various industries is the pipe, whose inner surface can be exposed to wear (especially sliding wear). In this study, increasing the wear resistance of the inner surface of the Al-15 Mg2Si composite tube, which is a suitable alternative to the most widely used aluminum alloy in the industry, (Al-Si alloy) has been investigated by optimizing the thermal parameters. In this study, the simultaneous effects of pouring temperature, solutionizing temperature, aging temperature, mold preheating temperature, wear force, and wear temperature on the sliding wear resistance of the inner surface of the above tube made by the centrifugal casting method was studied, and the results using Design Expert software were analyzed. The most effective parameter on the wear resistance of the above alloy was the dissolution temperature; the best temperature was 570 °C. The effect of aging temperature was found to be insignificant. The best pouring temperature was determined in the range of 750–700 °C, and the suitable temperature for preheating the mold was determined to be 300 °C. [ABSTRACT FROM AUTHOR]

An improved prediction algorithm of the hidden semi-markov model (HSMM) is proposed to predict the remaining useful life (RUL) of aluminum reduction cells (ARC). First, the degradation process of the ARC is analyzed, and the parameters that could characterize its degradation process are determined. Second, to facilitate the prediction of HSMM, exponential distribution, in which form the dwell time in the traditional HSMM is distributed, is replaced with the Erlang distribution based on the queuing theory. Third, an improved forward recursion algorithm that introduced dwell time has not only simplified the calculation of useful life predictions but also further facilitated HSMM in the prediction of the RUL. Finally, verification is carried out using the actual data of an aluminum electrolytic industry, and the results showed that the improved HSMM performed better in the prediction and is more accurate than the existing prediction method. [ABSTRACT FROM AUTHOR]

In this work, a collaborative strategy for the aluminum and iron industry based on red mud recycling through the hydrometallurgy method was proposed. In this method, Fe3+ and Al3+ were firstly separated from the red mud by using H2SO4 as a leaching agent, which was by-produced from the sintering process of an iron and steel industry. Multiple influence factors on the leaching process were investigated, with the H2SO4 addition amount showing the strongest influence on the leaching rates of Al and Fe. The main components of the filter residue were CaSO4, TiO2, and SiO2, which could be reused as additives in the building materials. Subsequently, the final Fe recovery product was obtained through the co-precipitation, Fe/Al separation, and Fe(OH)3 calcination. In the final product, the content of Fe2O3 reached 82.87%, and the iron grade was 58.01%, meeting the requirement being raw materials for sinter production. [ABSTRACT FROM AUTHOR]

With the development of the electrolytic aluminum industry, a large number of waste cathode carbons (WCC) of electrolytic aluminum remain, which are typical harmful solid wastes and cause serious harm to the environment. The harmless treatment of WCC is extremely important. Conventional heating and steaming is a good treatment method for WCC blocks. Fluoride has good selective heating characteristics, which promote the transformation of fluoride to escape in the form of gas, and realizes the separation of carbon and fluorine in the WCC of electrolytic aluminum. The characterization of WCC under steam high-temperature calcination was compared with that under traditional high-temperature calcination and chemical leaching. Tests show that, under the condition of water vapor, the carbon layer of WCC is larger, which is more conducive to the separation of carbon and fluorine. In this paper, the effects of different temperatures, heating times, and water flow rates on the defluorination rate were studied. The results showed that, when the WCC was heated at 950°C for 3 h, and the flow rate was 3.5 g/min, the defluorination effect of cathode carbon was the best, reaching 93%. [ABSTRACT FROM AUTHOR]

Metal casting has become increasingly significant in the manufacture of industrial components. Aluminium alloys have become a typical metal casting material due to their lightweight, excellent corrosion resistance, improved mechanical properties, and excellent electrical conductivity. Grain refinement is a preferred method for improving the strength and flexibility of metallic materials by modifying the size of the grain structure using various processes. As a result, aluminium grain refinement is regarded an essential method in the aluminium processing industry. Grain refinement involves severe plastic deformation, quick solidification, and the addition of an inoculant. This paper discusses semi-solid metal processing (SSMP) research that enhances material properties using the grain refinement technique. The effect of different grain refinement techniques to the microstructure formation is also highlighted. The importance of the fine equiaxed globular microstructure in SSMP areas is explained. This study is expected to help the researcher establish the most effective grain refining technique in SSMP. [ABSTRACT FROM AUTHOR]

Spent cathode carbon (SCC) is hazardous waste from the electrolytic aluminum industry due to its high levels of soluble fluoride, while brick-fired kiln provides the clay and heating conditions needed to immobilize fluoride. However, SCC reusing is still understudied, meanwhile co-processing and resource utilization of SCC in brick-fired kiln were still not reported in the literatures in addition to a Chinese patent of the authors. Here, the effects of firing temperatures, firing time, clay doses and calcium doses on the fluoride-immobilized performance of SCC co-processing were explored in a simulated brick-firing kiln, and their mechanisms were analyzed by SEM and XRD. The results indicated that clay-added co-processing in brick-fired kiln was a preferred choice without required additional additives or operations. The leached fluoride met Chinese standards by clay-added co-processing at ≥ 800 °C/ ≥ 40 g clay/ ≥ 120 min. Clay and calcium-added co-processing in brick-fired kiln was another alternative choice with higher fluoride-immobilization rates. The leached fluoride met Chinese standard (GB5085.3–2007) by clay and calcium-added co-processing at ≥ 500 °C/ ≥ 30 min/ ≥ 5 g clay/ ≥ 0.5 g CaCO3. SEM and XRD indicated that SiO2 in clay reacted with sodium in SCC and formed vitreous analog (Na1.55Al1.55Si0.45O4) to prevent fluoride ion migration and the newly-formed k-Feldspar (K2O.Al2O3.6SiO2) may adsorb fluoride ions in clay-added co-processing. Soluble fluoride NaF in SCC were converted into water-insoluble cuspidine in clay and calcium-added co-processing, in addition to the crystalline phase conversion in clay-added co-processing. Therefore, the risks of finished bricks to human health and the environment were greatly reduced after clay-added or clay and calcium-added treatments. [ABSTRACT FROM AUTHOR]

Aluminum dross (AD) from aluminum alloy production is harmful for the environment, while it also contains valuable metal and oxides. Therefore, its comprehensive utilization in an environmental-friendly route is of great importance for the sustainable development of the aluminum industry. Therefore, a green route to comprehensively reuse AD was proposed in this paper. Effects of different processing conditions on extraction behaviors of aluminum, soluble salt and aluminum nitride (AlN) were studied. The extraction rate of aluminum can reach 96.5% with processing temperature of 750 °C, processing time of 40 min, and refining agent addition of 10 wt%. With the liquid–solid mass ratio of 10, the leaching time of 8 h, the leaching temperature of 90 °C and stirring speed of 300 rad/min, the maximum leaching rate of chlorine salt, fluorine salt and hydrolysis of AlN can reach 98.4%, 93.4% and 87.6%, respectively. The tailings after leaching treatment can be used in a variety of applications, such as the production of cement, ceramic and refractory which can be used in the chemical and metallurgical industry. [ABSTRACT FROM AUTHOR]

The energy transition into a modern power system requires energy flexibility. Demand Response (DR) is one promising option for providing this flexibility. With the highest share of final energy consumption, the industry has the potential to offer DR and contribute to the energy transition by adjusting its energy demand. This paper proposes a mathematical optimization model that uses a generic data model for flexibility description. The optimization model supports industrial companies to select when (i.e., at which time), where (i.e., in which market), and how (i.e., the schedule) they should market their flexibility potential to optimize profit. We evaluate the optimization model under several synthetic use cases developed upon the learnings over several workshops and bilateral discussions with industrial partners from the paper and aluminum industry. The results of the optimization model evaluation suggest the model can fulfill its purpose under different use cases even with complex use cases such as various loads and storages. However, the optimization model computation time grows as the complexity of use cases grows. [ABSTRACT FROM AUTHOR]

Red mud is a kind of strong alkaline hazardous slag discharged from aluminum metallurgy industry. In this study, the water immersion with high temperature and high pressure was developed for the selective dealkalization from red mud by adding Mg-based additives. The removal efficiency of alkali could reach 92% by using 12% MgCl2 with 9 mL/g at 250 °C for 60 min. The MgCl2 was the most effective leaching reagent to promote the decomposion of cancrinite lattice. The new minerals bearing Mg, i.e., chlorite (Mg5Al2Si3O10(OH)8) and pyrope (Mg3Al2Si3O12) could be formed, which was in favor of transforming the structural alkali into the free alkali by the analysis and validation of XRD and SEM-EDS. The dealkalization process was mainly controlled by chemical reactions according to the analysis of unreacted shrinking core model (USCM) of leaching kinetics. The leaching kinetics equation of 1 − (1 − x)1/3 = 32.2 × exp[4582.6 / T] × t was built and the apparent activation energy of 38.1 kJ/mol was obtained. This method may provide a new and cleaner way for the efficient dealkalization of red mud and a basis for the utilization of leaching residue as the soil amendment. [ABSTRACT FROM AUTHOR]

Red mud (RM) is a highly alkaline by-product produced by the aluminium industry. The total stockpile of RM in the world is evaluated to be close 4 billion tons, which caused serious soil and water pollution. The use of RM in masonry materials has proven to be a prospective strategy to alleviate the environmental problems caused by RM. During the past decades, various economical treatment methods have been developed for utilization of RM as a masonry material. There are two general categories of products using RM in masonry materials: sintered products and non-sintered products. In this review, the physicochemical properties of RM are introduced, and the different application scenarios for RM in masonry materials are summarized, which is valuable for solving the environmental problems caused by the accumulation of bauxite residue. Moreover, the potential environmental risks of utilizing RM are described. Finally, suggestions for solving the RM problem are proposed. [ABSTRACT FROM AUTHOR]

This paper presents an overview of the recent advances in optimization of die design through finite element analysis for aluminum alloys of 6xxx series. The die design and optimization play a crucial role in the production of 6xxx series alloys, in order to attain high quality's final products. Before the use of finite element analysis (FEA) in aluminum extrusion industry, many experiments and modifications are needed until an acceptable product becomes available. The use of finite element analysis acquires a key role in the direction of eliminating trials and defective extrudates and use is gaining more and more ground through most of the manufacturers. This review will show how various studies try to enhance the performance of the extrusion dies through simulations and how the majority of the most common defects could be prevented if the use of the suitable software and techniques are implemented. The main covered areas from the current review are material flow optimization, flow balance in extrusion of complex aluminum profiles, spread extrusion die design, optimization of porthole extrusion dies, front end and back end defects, die bearing geometry and surface defects, automatic die design optimization and liquid nitrogen die cooling. [ABSTRACT FROM AUTHOR]

Contrary to the ionic conductivity, the electronic conductivity of cryolitic melts, which can be up to 30 pct of the total conductivity in industrial electrolysis cells, remains largely unknown as very few experimental data are reported in the literature. The aim of this work is to fill this gap by providing reliable estimations of the electronic conductivity as a function of both cryolitic ratio and temperature in the range of interest for the aluminum production industry. [ABSTRACT FROM AUTHOR]

The use of aluminum waste sludge as a raw material in the ceramic industry was studied due to its economical, energy, and environmental advantages. This study focused on preparation and characterization of alumina crucibles made from aluminum industrial waste for the purpose of glass melting. The main objective of this project was to reduce or replace both alumina powder and alumina crucibles imported from abroad. The trial formulas were composed mainly of calcined aluminum waste (CAW) from aluminum factory. Additionally, sodium silicate and sodium salts of polycarboxylic acid were used as deflocculants while polysaccharide was used as a binder. The crucibles were shaped by the slip casting method and then sintered at 1600 and 1700 °C. The water absorption, bulk density, apparent porosity, and 3-point bending strength were investigated. After sintering at 1600 and 1700 °C, the crucible with 75 wt% of aluminum waste (75AC formula) showed 0.18 and 0.06% water absorption, 3.41 and 3.36 g/cm3 bulk density, 0.61 and 0.20% apparent porosity, and 139.11 and 159.84 MPa bending strength, respectively. The coefficient of thermal expansion between 25 and 1000 °C of 75AC composition was 6.9807 × 10−6/°C and the crucibles passed three cycles of 20–200 °C thermal shock resistance testing. The resulting crucibles were successful in the trial for glass melting between 1450 and 1500 °C without either breaking or affecting the glass component. Calculation of the production costs for these lab-scale trials revealed that the crucible made from aluminum waste was about 70% cheaper than that made from commercial alumina. As a result, this study indicated that the alumina crucible made from aluminum industrial waste performed comparably with the commercial crucible being used for glass melting purposes. [ABSTRACT FROM AUTHOR]

The global warming potential of perfluorocarbons (PFCs) is much higher than that of CO2 in the aluminum reduction industry; hence, the release of PFCs is becoming increasingly regulated. Mitigation of PFC release by reducing anode effects (AEs) occurring during aluminum reduction is challenging. In this study, online anode current measurements were conducted at the anode beam of 400-kA cells, following which a simple local AE detection model was developed for AE prediction. A satisfactory AE true positive prediction rate of 80.3% was obtained in an industrial test. An independently controlled feeder strategy was then developed and applied to cells integrated with the local AE detection and prevention. The results show that the process provides an improved current efficiency with low direct current power consumption. Finally, the immense potential to reduce AE is confirmed with twinkling AEs and normal AEs, and daily AE duration decreased by 42.8%, 60%, and 56.9%, respectively. [ABSTRACT FROM AUTHOR]

Spent pot liner (SPL) is a toxic solid waste generated in the aluminum mining and processing industry. SPL is considered as an environmental pollution agent when is dumped on environment. Thus, it is important to access its toxicological risk for the exposed organisms. The comet assay and micronucleus test are efficient tests to detect genotoxic/mutagenic compounds by DNA damage observation. Therefore, in the present study, the genotoxic potential of SPL was evaluated through the micronucleus and comet assay on human leukocytes. After ethics committee approval (COEP—UFLA n°. CAAE 11355312.8.0000.5060), blood aliquots collected from healthy volunteers were exposed to increasing concentrations of SPL (from 0.1 to 80 g L−1). All SPL treatments, including the lowest concentration applied (0.1 g L−1), significantly increased the micronucleus frequency. The frequency of DNA damage was determined by visual scores (from 0 to 4) and the results were expressed on percentage of damage and arbitrary units (AU). CaCl2 (0.01 M) was applied as negative control (NC) and doxorubicin (10 μg mL−1) as positive control (PC). It was observed a dose-dependency between SPL treatments: as SPL concentration for cell incubation increases, the frequency of damage on DNA also increases. Cells incubated on the NC presented nucleoids class 0 to 2, while those exposed to SPL presents nucleoids class 0 to 4. SPL-incubated cells increasing significantly the frequency of nucleoids class 4. For the PC, the UA of damage was 267.74, which is lower than the one observed for the treatments with high doses of SPL (40–287.40 g L−1 and 80–315.30 g L−1). Thus, it was demonstrated that the SPL is a genotoxic agent that induces DNA damage on exposed organisms. [ABSTRACT FROM AUTHOR]

The Hall–Herault process is the only methodology applied in the industrial production of aluminum. Energy saving has long been the focus of the aluminum industry since its invention. Nowadays, the pursuit of high productivity, low DC energy consumption and large-scale cell adds new urgency to energy saving, among which the improvement of magnetic-hydro-dynamic (MHD) stability in aluminum electrolysis cells plays a very important role. This article reviewed the developments and applications of the measures in improving MHD stability in terms of structure, effectiveness, simulation, pilot and industrial results. Also some studies were conducted on a TiB2 wettable cathode. At the end, some suggestions on further reduction of energy consumption in the future are proposed. [ABSTRACT FROM AUTHOR]

We conducted immunological examination of men 40–69 years of age working in the aluminum industry with occupational bronchopulmonary conditions of various etiologies (chronic non-obstructive bronchitis (CNB) and chronic obstructive pulmonary disease (COPD)). Persistent polyclonal immunosuppression was observed in both CNB (95% of cases) and COPD (85%). We recorded differences in the production of antibodies (ABs) depending on the form of bronchopulmonary conditions. We detected an increase in the levels of ABs against the S100, β1-AdrR, GFAP, AdrM proteins in CNB. We found a decrease in ABs against LuS and β2-GP I combined with an increase in ABs against GFAP in COPD. These changes in the content of visceral ABs are more likely to reflect destructive and inflammatory processes in the corresponding tissue structures and, consequently, different mechanisms of disease. Using discriminant analysis, we determined the most sensitive indicators in the CNB diagnosis: ABs against membrane antigens of lung tissue (LuM), ABs against the S100 protein, which is a regulator of cellular functions, and ABs against cytoplasmic antigens of neutrophils (ANCA). The data can help to improve the quality of diagnosis of occupational bronchopulmonary conditions in aluminum industry workers and provide the most optimal treatment options. [ABSTRACT FROM AUTHOR]

The reshaping of the planet by people is having significant consequences for the environment and for human communities. Even though the degradation is visible and pervasive, much of the harm inflicted by humans remains outside the realm of and is not addressed by our criminal justice systems. Such harms tend not to be criminalized and while they may be regulated, such regulation has not led to the overall preservation of the environment or to non-humans. Furthermore, weak and uneven environmental regulations across the globe often have not led to local communities enjoying the economic prosperity from which corporations have benefited greatly. We will demonstrate this complex relationship between the economy and the environment by revisiting the closure of Rio Tinto Alcan's Lynemouth aluminum plant in North East England. Through a literature review and document analysis, we present the past and current socio-economic and environmental contexts of a deprived community entangled in global efforts to protect and improve the environment. Our research reveals a discourse from corporations promoting their social and environmental responsibility in a community that faces socio-economic marginalization and environmental challenges. [ABSTRACT FROM AUTHOR]

This paper examines how expected excess capacity fosters impediments to entry and incentives to exit. To examine this phenomenon, we apply the switching regime methods of Goldfeld and Quandt to a logit model using data from the U.S. aluminum industry over the period 1954 through 2010. The results show that both entry and exit decisions are statistically significantly affected by excess capacity. However, the correlation of entry and exit with capacity is more significant than with production. The evidence implies that excess capacity in the aluminum industry rises to be a substantial threat to entry only when the company produces ahead of demand growth. Excess capacity is also an impetus to exit during the later stage after primary aluminum production reverts to a declining trend. [ABSTRACT FROM AUTHOR]

Aluminum manufacturing has been reported as one of the largest industries and wastewater produced from the aluminum industry may cause significant environmental problems due to variable pH, high heavy metal concentration, conductivity, and organic load. The management of this wastewater with a high pollution load is of great importance for practitioners in the aluminum sector. There are hardly any studies available on membrane treatment of wastewater originated from anodic oxidation. The aim of this study is to evaluate the best treatment and reuse alternative for aluminum industry wastewater using membrane filtration. Additionally, the performance of chemical precipitation, which is the existing treatment used in the aluminum facility, was also compared with membrane filtration. Wastewater originated from anodic oxidation coating process of an aluminum profile manufacturing facility in Kayseri (Turkey) was used in the experiments. The characterization of raw wastewater was in very low pH (e.g., 3) with high aluminum concentration and conductivity values. Membrane experiments were carried out with ultrafiltration (PTUF), nanofiltration (NF270), and reverse osmosis (SW30) membranes with MWCO 5000, 200-400, and 100 Da, respectively. For the chemical precipitation experiments, FeCl3 and FeSO4 chemicals presented lower removal performances for aluminum and chromium, which were below 35% at ambient wastewater pH ~ 3. The membrane filtration experimental results show that, both NF and RO membranes tested could effectively remove aluminum, total chromium and nickel (>90%) from the aluminum production wastewater. The RO (SW30) membrane showed a slightly higher performance at 20 bar operating pressure in terms of conductivity removal values (90%) than the NF 270 membrane (87%). Although similar removal performances were observed for heavy metals and conductivity by NF270 and SW30, significantly higher fluxes were obtained in NF270 membrane filtration at any pressure that there were more than three times the flux values in SW30 membrane filtration. Due to the lower heavy metal (<65%) and conductivity (<30%) removal performances of UF membrane, it could be evaluated as pretreatment followed by NF filtration to protect and extend NF membrane life. The water treated by both NF and RO could be recycled back into the process to be reused with economic and environmental benefits. [ABSTRACT FROM AUTHOR]

The article discusses the 2018 Light Metals Keynote Session held at the 2018 Minerals, Metals & Materials Society (TMS) meeting. Topics include the talk titled ""Climate and Energy Efficient Aluminum Production,"Sustainability in the Aluminum Industry, and "cost-driven, performance-driven, and corrosion-driven development of new magnesium alloys; and decreased energy consumption through a combination of technology and management attention.

This paper has two research objectives: first, it derives and analyses energy intensity trends for seven energy intensive manufacturing industries and the aggregate manufacturing sector in India for the period 1973-1974 to 2011-2012 and compares the same with best practice benchmarks. Second, based on Index Decomposition Analysis, it studies the extent to which the energy efficiency has contributed in the decoupling of industrial activity growth from growth in energy use. The study finds faster decline in energy intensity in all the seven industries during the recent years (1998-1999 to 2011-2012). Aluminium, cement and fertilizer industries are found to operate close to the global best-practice energy intensities with transformational changes in process technology. Iron and steel and pulp and paper are found to be lagging behind with only incremental transformation in technology in place. The decomposition results show that activity growth is the major driver of growth in energy demand with marginal impact coming from structural change. However, declining energy intensity has been able to neutralize a major portion of the growing energy demand resulting in decoupling trends, especially in recent years, with more energy efficiency-related voluntary and mandatory policies in place). [ABSTRACT FROM AUTHOR]

The chemical-technological features of using fluorine compounds in aluminum production have been studied. The modes and parameters of technological processes that significantly decrease the emissions of hazardous substances have been specified by the method of computer modeling. The methods for obtaining fluorides and optimizing their chemical and granulometric composition have been updated. The measures for improving the electrolysis technology that reduce losses of valuable components are developed. [ABSTRACT FROM AUTHOR]

White aluminum (Al) dross is the waste or by-product generated from the smelting of Al. Improper disposal of this waste will affect the sustainability of the environment. This study was aimed at investigating the feasibility of Al dross as a thermoplastic filler. Various content of Al dross (10-40 wt.%) was blended with polypropylene (PP) using an extruder. An improvement in thermal and flame resistance properties was evident, which was associated with the presence of aluminum hydroxide elements in Al dross as revealed from x-ray diffraction analysis. It was shown that the higher Al dross content in PP did cause the composites to possess high stiffness and low crystallinity. An advantage in wear properties further showed that the Al dross can be used as a filler for thermoplastics. [ABSTRACT FROM AUTHOR]

During aluminum production by self-fi ring anode technology, complete combustion of anode gas components (carbon monoxide, resin substances) is accomplished in electrolyzer burner units. With the aim of reducing combustion product temperature entering the gas conduit network of the electrolyzer body, air is fed into a burner unit in excess (α = 6). This amount considerably exceeds that recommended for burning gaseous fuel. As a result of the excessive air intake, excess air the temperature in the combustion zone may be reduced to 300°C. Unburned resin substance is carried with this into the gas exhaust system that is cooled, condensed, and together with dust particles contained in transported anode gases, is deposited on the walls of gas conduits reducing their useful cross section. An improvement in anode gas fuel component complete combustion by optimizing excess air within the limits of α = 1.5-1.2 provides a temperature within the combustion zone within the limits of 1270-1330°C. However, in the process the temperature of combustion products entering from a burner into the gas circuit increases to 1000°C and above, and this is connected with the risk of irreversible deformation of steel gas conduits and melting of gas cleaning unit (GCU) bag filters whose permissible operating temperature is in the range 140-160°C. Engineering solutions are proposed in this article aimed at providing safe operation of gas conduit circuits and electrolysis housing GCU with increased efficiency for burning resin substances in electrolyzer burner units. [ABSTRACT FROM AUTHOR]

Industrial enterprises constitute a major portion of the world's economy, as well as a large proportion of a country's businesses and total employment. In Turkey, industrial enterprises are underdeveloped in terms of knowledge, skill, capital, and particularly accessing and benefiting from the advantages provided by modern information and communication technologies. Aluminum manufacturing has been reported to be the largest industry in Turkey with respect to production volumes and application fields. However, aluminum production is known to be an important contributor to environmental pollution, and the relative contribution of other related enterprises to the total industrial environmental impact is unknown. Environmental pollution sources can typically be classified into three categories: gaseous emissions, solid wastes, and wastewaters. The types of wastes produced by aluminum production vary based on the process line used, the variety of target products produced, and the production capacity of a given plant. As the capacities of facilities grow, the type and amount of waste become more variable. Therefore, the primary objective of this study is to determine the priority of each waste type in aluminum manufacturing industries. This study was conducted in the Industrial Zone of Kayseri in Turkey. Three different facilities that range in size from large to small based on their production volume, plant capacity, and variety of production are selected for this study. The priority of waste types was determined by combining the AHP and PROMETHEE II multicriteria decision methods. While wastewater was categorized as having the highest priority in large facilities, solid waste was determined to be the highest priority in medium and small facilities. [ABSTRACT FROM AUTHOR]

Purpose: The International Aluminium Institute's (IAI) aim was to publish life cycle inventory (LCI) data for use by life cycle assessment (LCA) practitioners through professional databases. The need to provide robust data stems from the increasing application of LCA as a tool for making material and design choices and the importance for representative, up-to-date information to underpin such studies. In addition to this, the institute aimed to evaluate the significance of potential environmental impacts, based on the LCI results, against a defined set of impact categories which can be tracked over time. Methods: Key environmental data collected as part of the IAI's long-running industry surveys provided the foundation for the life cycle inventory. In order to evaluate the environmental impact, direct input and output data for primary aluminium production were supplemented with background data for indirect processes available in GaBi version 6 (PE International, 2013b). A cradle-to-gate model was constructed with two distinct datasets, global (GLO) and global minus China (rest of world (RoW)). A partial life cycle impact assessment (LCIA) was completed using the models, and the following six CML (2001-Nov 2010) midpoint environmental impact categories were reported: acidification potential, depletion of fossil energy resources, eutrophication potential, global warming potential, ozone depletion potential and photo-oxidant creation potential. Water scarcity footprint of primary aluminium (Buxmann et al. in this issue) was also included. Results and discussion: The results indicated that the largest greenhouse gas contributions were attributed to the alumina refining and electrolysis unit processes in both datasets, with electricity and thermal energy, being the major contributing factors to these higher values. The energy intensive nature of primary aluminium production means energy supply can significantly influence the overall environmental impact. Electricity production was found to contribute between 25 % and 80 % to all impact category indicator results, with higher values in the global dataset, a result of the inclusion of Chinese energy data and the increased share of coal-based electricity consumption that it represents. Conclusions: The global aluminium industry remains dedicated to transparent reporting of its environmental impacts and ensuring that up-to-date, representative LCI data is available. Development of suitable methodologies for new indicators will be required to ensure that the industry continues to report accurately all its relevant impacts. Additionally, with the increased importance of Chinese aluminium production, inclusion of foreground data from Chinese production would further enhance the dataset from which the global impacts of aluminium production are assessed from cradle to gate. [ABSTRACT FROM AUTHOR]

Purpose: The cradle-to-gate water scarcity footprint (WSFP) of primary aluminium has been determined for global aluminium including China (GLO) and global aluminium excluding China (RoW). It consists of the following: Methods: The calculation of the direct WSFP follows the requirement of ISO 14046 to aggregate data of sites at locations with different water scarcity after multiplication with the local water scarcity index. For the indirect WSFP, regional averages of the water consumption and water scarcity index were used for an initial screening study to determine fields for further investigation. Results of this study demonstrate that data on evaporation of water from reservoirs of hydropower plants has an extremely high contribution to the indirect WSFP of primary aluminium (79 % of the GLO value and 92 % of the RoW value). Therefore, a plant-by-plant approach was applied for hydropower which considers the net freshwater consumption of the hydropower reservoirs and uses the local water scarcity index of each power station, individually, for the calculation of the generic WSFP of the country or region. A special treatment has been given to some multipurpose reservoirs which typically have a beneficial effect on water scarcity, i.e. they have a negative WSFP if seasonal water scarcity indices are used. Results and discussion: With this approach, the WSFP of primary aluminium has been calculated as follows: Conclusions: In order to avoid distorted results of water footprint studies, in depth analysis of identified hotspots in water consumption is necessary, in this case the plant-by plant approach, in accordance with ISO 14046. Data providers are encouraged to facilitate such analysis by improving the accessibility of such detailed data. [ABSTRACT FROM AUTHOR]

The objective of this work is to understand the different mechanisms of crack formation in dense anodes used in the aluminum industry. The first approach used is based on the qualitative characterization of the surface cracks and the depth of these cracks. The second approach, which constitutes a quantitative characterization, is carried out by determining the distribution of the crack width along its length as well as the percentage of the surface containing cracks. A qualitative analysis of crack formation was also carried out using 3D tomography. It was observed that mixing and forming conditions have a significant effect on crack formation in green anodes. The devolatilization of pitch during baking causes the formation and propagation of cracks in baked anodes in which large particles control the direction of crack propagation. [ABSTRACT FROM AUTHOR]

The growth of the modern aluminum industry is characterized by a search for methods of increasing the capacity of electrolyzers, reducing emissions into the environment, and reducing energy consumption. In the production of aluminum, the specific electricity consumption can be reduced and current efficiency increased by decreasing the distance between the anode and cathode and at the same time reducing the horizontal currents in the molten aluminum. The horizontal component of the current density can be reduced by placing electrical insulation between the cathode carbon block and the bloom on the section 'crust boundary - projection of the anode periphery on the bottom block'. Heatproof materials with the following properties are technologically most effective and economical for use as electrical insulation: good adhesion to steel, chemical resistance to cryolite-alumina melt, and quite low ultimate strength in compression. Low strength and stiffness are needed because during thermal expansion of the materials in the bottom block during the period of heating the tank to the working temperature with high resistance to compression there is a risk of the load increasing on the carbon cathode block and cracks forming in it. Moreover, such properties of the material will make it possible to decrease the risk of fracture of the cathode carbon block if the volume of the electric-insulation insert increases as a result of the electrolyte penetrating into it. The results of the investigations of the mechanical properties of some heatproof materials for use as electrical insulation of blooms in aluminum electrolyzers at high temperatures are presented in order to optimize the composition. [ABSTRACT FROM AUTHOR]

The warm reverse deep drawing process is proposed to form cylindrical cups with greater drawing depths. Experimental and numerical investigations were conducted to analyze the effect of the temperature field on the drawing depth limit and the stress distribution during the warm reverse deep drawing process of a 5A06 aluminum plate. The effects of the punch temperature and initial flange temperature on the temperature gradient in the blank are discussed. The drawing depth limits for the different temperature gradients in the blank were determined. In addition, the effect of the temperature field on the radial stress distribution was analyzed. A 180°C temperature gradient occurs when the punch temperature is room temperature. When the temperature field generated in the blank is uniform, a fracture occurs, and the drawing depth limit (72 mm) is only 20% of the desired depth. When the temperature gradient is 100°C, the drawing depth limit increases by 400%. Fracture occurs for a uniform temperature field because the radial stresses at the inside corner are larger than those at the punch corner. As the temperature gradient increases, the radial stress at the inside corner is lower than that at the punch corner, which prevents fracture. A deep cup with a 375-mm drawing depth was produced when the temperature gradient exceeded 100°C. [ABSTRACT FROM AUTHOR]

The disposal of red mud, which is a solid waste that is generated during the extraction of alumina from bauxite, is one of major problems faced by the aluminum industry. Alkali in red mud seeping under the soil may pollute land and water. The Northeastern University, China, has proposed a calcification-carbonation method to deal with low-grade bauxite or red mud. Its main purpose is to change the equilibrium phase of red mud to 2CaO·SiO and CaCO hydrometallurgically, so that recomposed alkali-free red mud can be widely used. We conducted calcification transformation experiments using diasporic bauxite sampled from Wenshan, and investigated the effects of parameters such as diasporic bauxite grain size, temperature and treatment time on the calcification transformation digestion rate, which is also termed the calcification transformation rate (CTR). The main phase in the calcification transformation slag (CTS) is hydrogarnet with different grain sizes. The CTR increases with decrease in diasporic bauxite grain size, or increase in temperature or reaction time. The CTR reaches a maximum of 87% after 120 min reaction at 240°C. The NaO/AlO ratio decreases with increase in temperature and reaches 1.5. The sodium content in the CTS decreases with increasing reaction time and is lower than that in the red mud treated using the Bayer process (4-12%). [ABSTRACT FROM AUTHOR]

Contamination by any substance takes place through air, water or soil and causes serious effects on flora and fauna of the regions. Air-transmitted pollutants spread in a faraway place from emission points of the pollutant source via wind (speed and direction as causing factors). Fluoride is one the pollutant generated in aluminium industries which is harmful to human and plants in excess concentration. This study focuses on the use of spatial interpolation methods for assessment of fluoride concentration around aluminium industries. The samples were collected from different test sites in the study area to investigate the fluoride concentration level. The test sites include several locations such as industrial unit, river site, residential and distant villages. Then, the collected samples were used to predict the overall fluoride concentration in the entire study area. The aim of the study was to evaluate the spatial variation and presence of fluoride concentration in the surroundings of the aluminium industries. Geostatistical interpolation modelling was applied to assess the prediction of fluoride contamination for other non-sampling points using the direction and distance method of empirical Bayesian kriging (EBK) modelling. Thus, geospatial modelling was used to predict the contamination of fluoride around the study area to create environmental awareness. In particular, this study assesses the fluoride pollutant concentration which might become dangerous with slowly increasing concentration against its standard concentration, which will severely impact the human health. In overall, EBK can provide valuable information regarding the fluoride concentration on possible level of fluoride in concern to public health. [ABSTRACT FROM AUTHOR]

The quality requirements of the metals produced and the articles manufactured from them increases as non-ferrous metallurgy advances. In the course of aluminum production it is necessary to remove impurities present in the melt. The types of impurities present in aluminum melt and methods for removing them by filtering the melt are briefly reviewed. The existing ceramic filters and methods of manufacturing them are examined. [ABSTRACT FROM AUTHOR]

Better technology and process improvements are needed to improve energy efficiency, throughput, and melt loss within the secondary aluminum industry. One of the first steps is to understand our current state to provide a basis to know where work is needed. This article provides a review of current aluminum melting and holding furnaces with several benchmarks. Suggestions for potential improvements and topics for further study will be provided. [ABSTRACT FROM AUTHOR]

Primary aluminium production is a highly energy-intensive and greenhouse gas (GHG)-emitting process responsible for about 1 % of global GHG emissions. In 2009, the two most energy-intensive processes in primary aluminium production, alumina refining and aluminium smelting consumed 3.1 EJ, of which 2 EJ was electricity for aluminium smelting, about 8 % of the electricity use in the global industrial sector. The demand for aluminium is expected to increase significantly over the next decades, continuing the upward trend in energy use and GHGs. The wide implementation of energy efficiency measures can cut down GHG emissions and assist in the transition towards a more sustainable primary aluminium industry. In this study, 22 currently available energy efficiency measures are assessed, and cost-supply curves are constructed to determine the technical and the cost-effective energy and GHG savings potentials. The implementation of all measures was estimated to reduce the 2050 primary energy use by 31 % in alumina refining and by 9 % in primary aluminium production (excluding alumina refining) when compared to a 'frozen efficiency' scenario. When compared to a 'business-as-usual' (BAU) scenario, the identified energy savings potentials are lower, 12 and 0.9 % for alumina refining and primary aluminium production (excluding alumina refining), respectively. Currently available technologies have the potential to significantly reduce the energy use for alumina refining while in the case of aluminium smelting, if no new technologies become available in the future, the energy and GHG savings potentials will be limited. [ABSTRACT FROM AUTHOR]

In the present work, combustion of aluminum dust cloud has been studied in media with spatially discrete sources by means of numerical approach. A thermal model has been generated to estimate the flame propagation speed in various oxidizer concentrations. The model is based on conduction and radiation heat transfer mechanisms and using the heat point source method. First combustion of single-particle is studied and the solution is presented. Then the dust combustion is investigated using the superposition principle to include the effects of particles. Oxygen and Nitrogen have been considered as the main oxidizer and the inert gas, respectively. Flame speed as a function of particle diameter has been studied and the effects of radiation heat transfer have been taken to account. Furthermore, Minimum ignition energy as a function of dust concentration for different particle diameters has been investigated. Reasonable agreement between the results of numerical solution of aluminum dust cloud combustion and experimental data is obtained in terms of flame propagation speed and minimum ignition energy. [ABSTRACT FROM AUTHOR]

The development of new filters for the aluminum industry requires investigations on the wettability of aluminum and its alloys on novel filter materials. The requested filter effects require not only an adequate wetting but also information about the interaction between the filter material and the metal. In the present work the wettability of an AlSi5Mg alloy on spodumene (LiAl[SiO]) containing substrates is investigated using the sessile drop technique. These measurements were carried out at 1223 K (950 °C) under vacuum. The spodumene-based substrates showed a completely different wetting behavior compared with an alumina substrate. The contact angel reduced more quickly and leveled out at a lower value (75 ± 2 deg) than in case of a pure alumina substrate (90 ± 1 deg). The reason for this behavior is a reaction between the LiAl(SiO) and the alloy droplet which supported deoxidation and formed a silica-rich reaction layer at the droplet/substrate interface. [ABSTRACT FROM AUTHOR]

This study explores the dependence of the spectral emissivity on the temperature ranging from 800 K to 910 K for an oxidizing surface of aluminum 3A21. In this experiment, the infrared radiation stemming from the specimen is received by an InGaAs photodiode detector, which operates at the wavelength of 1.5 $$\upmu $$ m with a bandwidth of about 20 nm. The temperature of the specimen surface is determined by averaging the two R-type platinum-rhodium thermocouples, which are tightly welded on the specimen surface. The spectral emissivity is reported before the first measurement over the temperature range from 800 K to 910 K. The variation of the spectral emissivity with the heating time is evaluated at a given temperature. The variation of the spectral emissivity with temperature is discussed for a given heating time. Oscillations of the spectral emissivity have been observed, which are affirmed to be connected with the thickness of the oxidization layer on the specimen surface, and formed by the interference effect between the radiation coming from the oxidization layer and the radiation stemming from the substrate. The effect of surface oxidization on the spectral emissivity of aluminum 3A21 is evaluated, and compared with that of SPHC steel. Analytical expressions of the spectral emissivity of aluminum 3A21 versus the temperature are derived at some given heating times. A conclusion is obtained that the experimental results obtained at a given heating time from 800 K to 910 K abide by the same functional form. [ABSTRACT FROM AUTHOR]

This article presents the historical development of the AP Technology (Aluval, Voreppe, France) pot series starting with the AP13 in the 1960s, followed by the AP18 and the AP30 in the 1980s and 1990s. For most of the modern-era technology, from the late 1970s on, development has been based on a three-stage pattern, the first one being the pot modeling, followed by the pot prototype stage, and then the industrial stage, which fully validated the technology. This development pattern has proven to be successful since it has led to the very robust AP Technology pot design generation and a large number of greenfield smelters built in the 1990-2010 selected the AP Technology design. AP60 is the latest of this series: The development at the prototype level was initiated in the 1990s and is presented in the article. It is now followed by the first industrial realization at Jonquière with the startup in late 2013 and the full validation of the technology in mid-2014. The development of APXe, which aims at very low energy consumption, uses many common elements pertaining to the AP60 design and is presented in the article. AP Technology has also addressed the need for continuous and fast improvement of pot performances adapted to each existing client or site specifics; for this purpose, a new development methodology has recently emerged thanks to the very high modeling capabilities. This methodology, based on the validation of 'technology bricks' and their integration in the final design following a strict process, is presented in the last section of this article. [ABSTRACT FROM AUTHOR]

The potentiometric determination of fluoride with the use of an ЭKOM-F ion-selective electrode in red muds (waste of aluminum production) is described. The accuracy of ionometric determination of fluorine is estimated. The results are supported by the 'added-found' method and the method of varying the sample weight, as well as by a comparison with the results obtained by an independent procedure. [ABSTRACT FROM AUTHOR]

Over the past decade, both labor and multifactor productivity have fallen in copper, iron ore, coal, and many other mining operations, causing production costs to rise. This decline, following years of rising productivity, has led many to conclude that new technology can no longer offset the adverse effects of resource depletion. As a result, real mineral commodity prices will be permanently higher in the future. This article questions this hypothesis. It first provides a conceptual analysis that shows that much or perhaps even all of the recent drop in productivity could be due to the unanticipated growth in market demand and the sharp jump in prices it provoked. It then surveys a number of the available empirical studies of productivity trends. For copper, iron ore, and coal, it finds substantial support for the view that much of the recent drop in productivity can be attributed to higher prices. Aluminum on the other hand did not experience the same jump in real price over the 2000s nor did it suffer a significant drop in productivity. These findings have important implications. In particular, they suggest that new technology may well continue to offset most or all of the cost-increasing effects of resource depletion. If so, real commodity prices will be lower over the long run than many now assume. This possibility has important consequences for mineral-producing firms making large investments in future capacity, for mineral-producing countries dependent on revenues from mining, and for society as a whole in terms of the long-run availability of nonrenewable commodities and the future threat of mineral depletion. [ABSTRACT FROM AUTHOR]

The origins of High purity aluminum production are likely to have a strong impact on future production in conventional reduction cells. Many of the key elements that are necessary to produce Very High purity ingot were in place at the very beginning of the 20th century. In this article, the author examines some of the history of the industry. He also comments on aspects of aluminum smelter design that will continue to serve purity markets into the 21st century. [ABSTRACT FROM AUTHOR]

Fine particulate matter (PM2.5) in air pollution, primarily from combustion sources, is recognized as an important risk factor for cardiovascular events but studies of workplace PM2.5 exposure are rare. We conducted a prospective study of exposure to PM2.5 and incidence of ischemic heart disease (IHD) in a cohort of 11,966 US aluminum workers. Incident IHD was identified from medical claims data from 1998 to 2008. Quantitative metrics were developed for recent exposure (within the last year) and cumulative exposure; however, we emphasize recent exposure in the absence of interpretable work histories before follow-up. IHD was modestly associated with recent PM2.5 overall. In analysis restricted to recent exposures estimated with the highest confidence, the hazard ratio (HR) increased to 1.78 (95% CI: 1.02, 3.11) in the second quartile and remained elevated. When the analysis was stratified by work process, the HR rose monotonically to 1.5 in both smelter and fabrication facilities, though exposure was almost an order of magnitude higher in smelters. The differential exposure-response may be due to differences in exposure composition or healthy worker survivor effect. These results are consistent with the air pollution and cigarette smoke literature; recent exposure to PM2.5 in the workplace appears to increase the risk of IHD incidence. [ABSTRACT FROM AUTHOR]

Increasing evidence indicates that exposure to particulate matter (PM) at environmental concentrations increases the risk of cardiovascular disease, particularly PM with an aerodynamic diameter of less than 2.5 μm (PM2.5). Despite this, the health impacts of higher occupational exposures to PM2.5 have rarely been evaluated. In part, this research gap derives from the absence of information on PM2.5 exposures in the workplace. To address this gap, we have developed a job-exposure matrix (JEM) to estimate exposure to two size fractions of PM in the aluminum industry. Measurements of total PM (TPM) and PM2.5 were used to develop exposure metrics for an epidemiologic study. TPM exposures for distinct exposure groups (DEGs) in the JEM were calculated using 8385 personal TPM samples collected at 11 facilities (1980-2011). For eight of these facilities, simultaneous PM2.5 and TPM personal monitoring was conducted from 2010 to 2011 to determine the percent of TPM that is composed of PM2.5 (%PM2.5) in each DEG. The mean TPM from the JEM was then multiplied by %PM2.5 to calculate PM2.5 exposure concentrations in each DEG. Exposures in the smelters were substantially higher than in fabrication units; mean TPM concentrations in smelters and fabrication facilities were 3.86 and 0.76 mg/m3, and the corresponding mean PM2.5 concentrations were 2.03 and 0.40 mg/m3. Observed occupational exposures in this study generally exceeded environmental PM2.5 concentrations by an order of magnitude. [ABSTRACT FROM AUTHOR]