Aluminum recovery from electronic scrap by High-Force® eddy-current separators

The amount of electronic scrap which contains a substantial portion of non-ferrous metals, primarily copper and aluminum, has been growing. The present study is directed toward aluminum recovery by a newly developed eddy current separator. The investigation on shredded personal computer and printed circuit board scrap demonstrates that the High-Force® eddy-current separator will be applicable for this purpose. It has been shown that, by a single pass of the materials on the High-Force® eddy-current separator, an aluminum concentrate out of personal computer scrap can be obtained with a purity of 85%, while maintaining a recovery in excess of 90%, with the feed rate being up to 0.3 kg/min.     

Historical evolution of anthropogenic aluminum stocks and flows in Italy

Dynamic stocks and flows analysis was applied to the anthropogenic aluminum cycle in Italy in order to detect and quantify metal flows and in-use stocks over the years 1947–2009. The model utilized a top-down approach, including data for production, consumption, loss, and trade flows of aluminum. Seven end-use markets were considered, namely buildings and construction, transportation, consumer durables, machinery and equipment, electrical engineering, containers and packaging, and miscellaneous appliance types. The results of this dynamic stocks and flows analysis model quantified the contemporary anthropogenic reservoirs (or in-use stocks) of aluminum at about 320 kg per capita, mainly embedded within the transportation and building and construction sectors. Cumulative in-use stock represents approximately 11 years of supply at current usage rates (about 20 Mt versus 1.7 Mt/year), implying significant potential for recycling in the future as this stock comes out of use. Flow analysis revealed that Italy imports mainly unwrought aluminum and exports final products, while the main material losses occur during alumina refining and collection of old scrap: specifically, containers and packaging have the highest old scrap generation rate, but for the lowest recovery rate (50%). Increasing support to collection of scrap and initiatives oriented to aluminum recovery specifically would allow Italy to increase its reliance on domestic material, and may also allow a decline of the country import-dependence on primary sources. The dynamic stocks and flows model created here provides a quantitative historical record of the aluminum required by Italian society during important periods of development and provides guidance for future decision-making around the use of domestic secondary resources.     

吉林油田稠油热采污水处理絮凝剂实验研究＊

在含油污水水质分析的基础上,采用烧杯实验和分光光度法研究絮凝剂的絮凝效果。筛选出以无机絮凝剂硫酸铝与两性高分子聚合物CE-3090的复配体系,同时研究了影响絮凝效果的因素并探究了其影响机理。结果表明:在温度为40℃,pH为7.72,170 r/min时高速搅拌1 min,然后50 r/min低速搅拌5 min,硫酸铝的加量为90 mg/L、CE-3090的加量为0.5 mg/L,絮凝沉降30 min后其絮凝效果较好。实验证明:该复配处理剂处理含油污水后,含油量和杂质含量都达到了SY/T 5329-94《碎屑岩油藏注水水质推荐指标及分析方法》油田污水回注的要求。     

Separation and recovery of carbon dioxide by a membrane flash process

A novel process for carbon dioxide (CO₂) separation, which was named a membrane flash process, was developed to realize an energy-saving technology and to substitute it for a conventional regenerator. The electric energy for CO₂ recovery in a membrane flash process using aluminum oxide and diethanolamine was lower than the thermal energy of the conventional chemical absorption process. Flashing at elevated temperature by the low temperature energy significantly reduced the electric energy and required much less membrane area. This process has potentiality of low cost capture of CO₂ when the low temperature energy, which is not available for other purposes, can be utilized to elevate flashing temperature.     

Metals recycling in the United States

Twenty-two metals for which secondary recovery is important, in terms of quantity and/or value, were compared and ranked for rate and efficiency of recycling, and availability of recycled metal. In general, their recycling rates trended upward over the period 1970–1993. Iron, aluminum, copper, gold, platinum, and lead accounted for most of the value of all secondary metal produced, while iron and steel dominated in terms of quantity produced and exported. The factors most influential on recycling rates are profitability, public support, organization of infrastructure, sortability, legislative support, and scrap purity. The share of supply accounted for by secondary metals is expected to surpass that of primary metals sometime in the next decade.     

Environment-friendly technology for recovering nonferrous metals from e-waste: Eddy current separation

The current generation pattern of e-waste consisted of dead electronic and electrical equipments poses one of the world's greatest pollution problem due to the lack of appropriate recovery technology. Crude recovery methods of resource materials (aluminum, zinc, copper, lead, gold) from e-waste caused serious pollution in China in the past years. Thus, environment-friendly technologies have been the pressing demand in e-waste recovering. Eddy current separation (ECS) was advised as the preferable technology for recovering nonferrous metals from e-waste. However, just a few reports focused on the application of ECS in e-waste recovering. This paper introduced the information about ECS including the models of eddy current force and movement behavior of nonferrous metallic particle in the separation process. Meanwhile, the developing process of eddy current separator was summarized. New industrial applications of ECS in e-waste (waste toner cartridges and refrigerator cabinets) recovering were also presented. Finally, for improving separation rate of ECS in industrial application of e-waste recovering, some suggestions were proposed related to crushing process, separator design, and separator operation. The aim of this paper is to demonstrate the effectiveness of ECS technology as practical and available tool for recovering non-ferrous metals from e-waste which is now being ignored.     

The impact of monetary liquidity on Chinese aluminum prices

By expanding Frankel and Rose's (2009) theoretical model to consider the interaction of commodity prices with both money liquidity and expectation formation, this paper empirically studies the long-run relationship and short-term dynamics between aluminum prices and money liquidity via Vector autoregressive (VAR) and Impulse Response Function methodologies. Our results show that: (1) a cointegration relationship between money liquidity and Chinese aluminum prices exists, and monetary liquidity positively significantly influences the price over long periods; (2) a structural change has been found during the 2008 Financial Crisis and the change of Chinese monetary policies; and (3) the negative impact of production capacity mechanism on aluminum prices coexists with the positive impact of financial asset returns mechanism, to allow for varied market expectations on aluminum prices within and outside China.     

Deferoxamine pretreatment inhibits metal neurotoxicity in Caenorhabditis elegans

Neurodegenerative diseases are increasingly common in humans. Alzheimer's disease (AD) is a neurodegenerative disease characterized by the presence of extracellular plaques containing β‐amyloid peptides and neurofibrillary tangles in the brains. Researchers have focused on the elucidation of a correlation between high concentrations of aluminum or iron (in the organism with observed neuropathology). The objective of this study was to evaluate the effects of aluminum and iron on the behavioral parameters (pharyngeal pumping and defecation cycle) of the nematode Caenorhabditis elegans pretreated with deferoxamine (DFX). Acetylcholinesterase (AChE) activity was evaluated as well. DFX is a chelant that is widely used for the treatment of metal toxicity, and it has a high affinity for aluminum and iron. The worms were pretreated with DFX, and then exposed to aluminum and iron. In the absence of DFX, aluminum exposure decreased pharyngeal pumping compared with that in the control group. The defecation cycle of the control was significantly different from that of the worms exposed to aluminum. In contrast, an increased defecation cycle was observed in worms exposed to iron without DFX pretreatment. AChE activity increased in aluminum‐exposed groups that received DFX pretreatment compared with those that did not receive pretreatment. These results suggest that pretreatment with DFX is effective in reducing metal toxicity, particularly with reference to AChE activity, which did not decrease in groups that did not receive DFX pretreatment.     

The toxicological paradigms of aluminum and the etiology of Alzheimer's disease in the nematode Caenorhabditis elegans

This study examined behavioral and enzymatic changes of C. elegans from its exposure to aluminum, and the resulting relationship with Alzheimer's disease. After chronic and acute exposure to aluminum, the results indicated that it alters the cholinergic status and behavior parameters of the nematode, suggesting a relationship between exposure to aluminum and the etiology of AD.     

Environmental consequences of recycling aluminum old scrap in a global market

Nowadays, aluminum scrap is traded globally. This has increased the need to analyze the flows of aluminum scrap, as well as to determine the environmental consequences from aluminum recycling. The objective of this work is to determine the greenhouse gases (GHG) emissions of the old scrap collected and sorted for recycling, considering the market interactions. The study focused on Spain as a representative country for Europe. We integrate material flow analysis (MFA) with consequential life cycle assessment (CLCA) in order to determine the most likely destination for the old scrap and the most likely corresponding process affected. Based on this analysis, it is possible to project some scenarios and to quantify the GHG emissions (generated and avoided) associated with old scrap recycling within a global market. From the MFA results, we projected that the Spanish demand for aluminum products will be met mainly with an increase in primary aluminum imports, and the excess of old scrap not used in Spain will be exported in future years, mainly to Asia. Depending on the scenario and on the marginal source of primary aluminum considered, the GHG emission estimates varied between −18,140 kg of CO₂ eq. t⁻¹ and −8427 of CO₂ eq. t⁻¹ of old scrap collected. More GHG emissions are avoided with an increase in export flows, but the export of old scrap should be considered as the loss of a key resource, and in the long term, it will also affect the semifinished products industry. Mapping the flows of raw materials and waste, as well as quantifying the GHG impacts derived from recycling, has become an essential prerequisite to consistent development from a linear toward a circular economy (CE).     

Life cycle energy impacts of automotive liftgate inner

This paper compares the life cycle energy use of a cast-aluminum, rear liftgate inner and a conventional, stamped steel liftgate inner used in a minivan. Using the best available aggregate life cycle inventory data and a simple spreadsheet-level analysis, energy comparisons were made at both the single-vehicle and vehicle-fleet levels. Since the product manufacture and use are distributed over long periods of time that, in a fleet, are not simple linear combinations of single product life cycles. Thus, it is all the products in use over a period of time, rather than a single product, that are more appropriate for the life cycle analysis. Using a set of consistent data, analyses also examine sensitivity to the level of analysis and the assumptions to determine the most favorable materials with respect to life cycle energy benefits.As expected, life cycle energy impacts of aluminum are lower than steel at a single-vehicle level – energy savings are determined to be 1.8 GJ/vehicle. Most energy savings occur at the vehicle operation phase due to improved fuel economy from lightweighting. The energy benefits are realized only very close to the average vehicle life of 14 years. With the incremental growth of the vehicle fleet, it takes longer – about 21 years – for aluminum to achieve life cycle equivalence with steel. The number of years aluminum needs to achieve equivalence with steel was found to be quite sensitive to aluminum manufacturing energy and fuel economy. As the steel industry races to compete with other materials for automotive lightweighting, a systems approach, instead of part-to-part comparison, is more appropriate in the determination of viability of aluminum substitution from an energy perspective.     

氧化铝行业水污染控制措施探讨

根据氧化铝行业生产用水及排污特点,结合某氧化铝生产企业生产废水的处理实践,推荐采用逆向洗涤赤泥和氢氧化铝,节约用水量;综合利用赤泥洗液和含碱废水;对生产用水设置循环水系统和二次利用水系统;设置生产废水处理站,氧化铝系统和热电厂的生产系统排水、循环水系统的排污水,以及化验等废水全部排入生产废水处理站处理,废水经处理后作为二次利用供水返回生产系统使用,通过综合利用生产废水,可以实现厂区废水的零排放,节约资源的同时,提高清洁生产水平,避免对环境造成污染。     

Evaluation of an acid ammonium oxalate extraction to determine fluoride resident concentrations in soils

Fluoride depositions near aluminum smelters and other fluoride-emitting plants can lead to fluoride accumulation in soils, which constitutes a risk for ground water contamination. This study was conducted to investigate the capacity of a 0.2 M acid ammonium oxalate solution to selectively and quantitatively extract fluoride accumulated in soils. The recovery of fluoride added to three soils was evaluated following 7- to 28-d incubations. Oxalate extraction was also compared with a total fluoride extraction method, using oxalate-extractable fluoride (Fox) and total fluoride (Ftot) accumulation profiles derived from column percolation experiments. To determine low-level fluoride concentrations without interference from high Al and Fe concentrations, an adapted ion chromatography method was used. Following soil incubations, oxalate extracted 42 to 86% of added fluoride. Recovery varied between soils and, in one soil, increased with added fluoride concentration. Recovery was unaffected by incubation time. Maximum recovery was obtained in a soil high in amorphous Fe and Al, low in clay, and free of carbonate. Lower recoveries were obtained in soils with higher clay or carbonate contents. Only 4 to 8% of Ftot was extracted in untreated samples using Fox, which suggests a high selectivity of this method for added fluoride. In percolation experiments, the use of Fox reduced considerably the background noise associated with Ftot for the evaluation of fluoride accumulation profiles. Because of its high selectivity and despite incomplete fluoride recovery, the use of Fox to determine fluoride resident concentrations in soils may improve environmental monitoring of fluoride accumulation and movement in contaminated soils.     

含油浮渣的资源化综合利用研究初探

针对铝盐系无机混凝剂（如硫酸铝、聚合铝）用于含油废水脱油净化处理而产生的含油浮渣，提出了一种使含油浮渣资源化综合利用的无机酸直接酸化处理的工艺方法。本处理工艺的特点在于：①可以充分回收原油；②循环使用铝盐混凝剂；③免除对含油浮渣饼的焚烧处理过程。铝盐混凝剂经５次循环使用，仍保持很好的除油效果。     

Effects of alum and aluminum chloride on phosphorus runoff from swine manure

Phosphorus (P) runoff from fields fertilized with swine (Sus scrofa domesticus) manure may contribute to eutrophication. The objective of this study was to evaluate the effect of aluminum sulfate (alum) and aluminum chloride applications to swine manure on P runoff from small plots cropped to tall fescue (Festuca arundinacea Shreb.). There were six treatments in this study: (i) unfertilized control plots, (ii) untreated manure, (iii) manure with alum at 215 mg Al L(-1), (iv) manure with aluminum chloride at 215 mg Al L(-1), (v) manure with alum at 430 mg Al L(-1), and (vi) manure with aluminum chloride at 430 mg Al L(-1). Manure application rates were equivalent to approximately 125 kg N ha(-1). Alum and aluminum chloride additions lowered soluble reactive phosphorus (SRP) levels from about 130 mg P L(-1) to approximately 30 mg P L(-1) at low rates. At high rates, SRP levels in swine manure were around 1 mg P L(-1). Soluble reactive P concentrations in runoff were 5.50, 3.66, 3.00, 0.87, 0.87, and 0.55 mg P L(-1), for normal manure, low alum, low aluminum chloride, high alum, high aluminum chloride, and unfertilized control plots, respectively. Hence, high alum and aluminum chloride reduced SRP concentrations in runoff by 84% and were not statistically different from SRP concentrations in runoff from unfertilized control plots. These data indicate that treating swine manure with alum or aluminum chloride could result in significant reductions in nonpoint-source P runoff.     

Effect of long‐term exposure to aluminum and high‐fat diet on NTPDase and 5′‐nucleotidase activities in lymphocytes and platelets of rats

Aluminum is one of the most abundant metals in the earth's crust. Although it shows no known biological function, it is recognized as an adjuvant in vaccines for human and veterinary uses. This study aims to evaluate the role of lifestyle and environment in the promotion of chronic disease. In it, we associated two factors: chronic exposure to aluminum and high‐fat diets. Thus, we aimed to determine whether the association of long‐term exposure to aluminum and high‐fat diets affects the NTPDase and 5′‐nucleotidase activities in the blood platelets and lymphocytes obtained from the mesenteric lymph nodes of young rats. In fact, the ectonucleotidase activities were shown to be upregulated upon exposure to aluminum plus high‐fat diets. As a result, we can suggest that the progressive upregulation of ectonucleotidase activities that we observed could be controlling the extent of inflammation and immune response.     

基于腐蚀损伤表征参数的铝合金预腐蚀疲劳裂纹扩展修正模型

服役环境中的腐蚀介质会在铝合金表面形成以腐蚀坑为代表的典型点蚀形貌。在疲劳载荷作用下,这些腐蚀坑会有助于裂纹的萌生,加速并影响其扩展行为,威胁结构安全。考虑腐蚀坑的影响,建立了一个基于腐蚀损伤表征参数的线弹性裂纹扩展表征模型。利用航空结构中常见承力构件所采用的LD2铝合金进行验证性实验。结果表明,所建立的模型能够反映出腐蚀损伤对于裂纹扩展行为的影响,对于铝合金构件的腐蚀疲劳寿命预测和损伤容限评估具有参考价值。     

A common pattern in long-term metals production

A common pattern equation for the production of metals over their entire life is proposed. The equation is tested for five metals namely: copper, aluminum, lead, molybdenum and tungsten which have distinctly different historical spans. Various stages of early and take-off growth are identified and labeled stages I–IV. The very early stage of growth leading to a diminishing in activity appears to be decoupled from the later high growth stages. An approximately 12 year perturbation life cycle is noted in stage III for most metals. Copper and aluminum are not yet in stage IV, nor show any signs of entering this stage in the next 50 years. The pattern equation appears to have generality. A strict interpretation of the various parameters in the pattern equation is not attempted in this article.     

对电解铝厂周边氟污染的环境影响评价

通过测定广西某电解铝厂周边大气、土壤和农作物中氟化物含量,对该厂周边的氟化物污染进行了评价,结果表明：电解铝厂周围大气氟污染与采样点的方位成显著相关关系;农作物玉米叶片氟污染主要来自于电解铝厂无组织排放的氟化物,而土壤中总氟含量除受大气中氟化物的影响外,还与当地的地质构造、土壤类型等因素有关,与主导风向无明显的相关关系,土壤中水溶氟含量与采样点到电解铝厂距离呈负相关。     

Air Pollution from Secondary Aluminum Production: Determining the Applicability of MACT Requirements

EPA's Maximum Achievable Control Technology rule for secondary aluminum production is intended to substantially reduce emissions of hazardous air pollutants. It may also impose significant costs on affected facilities. © 2001 John Wiley & Sons, Inc.