AA ATECH-2003 Aluminum Industry Technology Roadmap《铝业技术方针》.pdf

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1、 O O O O O O O O O O O Strong and lightweight Repeatedly recyclable for environmental sustainability Resistant to corrosion Good conductor of heat and electricity Tough and non-brittle, even at very low temperatures Easily worked and formed, can be rolled to very thin foil Safe for use in contact wi

2、th a wide range of foodstuffs Highly reflective of radiant heat Highly elastic and shock absorbent Receptive to coatings Attractive in appearance ALUMINUM INDUSTRY TECHNOLOGY ROADMAP 1 . Roadmap Background and Overview 1 2 . Primary Production 7 3 . Melting, Solidification, and Recycling 15 4 . Fabr

3、ication 27 5 . Alloy Development and Finished Products . 35 6 . Looking Forward: Implementation . 45 A . Acronyms 47 B . References . 49 C . Roadmap Contributors 51 o ALUMINUM INDUBTRY TECHMDLOQY ROADMAP I O0 ALUMINUM INDUSTRY TECHNClLOBY ROADMAP A filuminum is one of the most versatile and sustaina

4、ble materials for our dynamic global economy. The North American aluminurn industry charted a bold course for the future of this essentiai material in its 2001 publication Aluminum Industry Vlsion: Sustainable Solutionsfor a Dynamic World. In 2002, the industry created this updated Aluminum hdwq Tec

5、hnology Roadmap to define the specific research and development (R these activities are beyond the scope of this Roadmp. The aluminum industry has now defined a set of performance targets for assessing progress toward and achievement of each of the strategic long-term goals involving technical solut

6、ions: Products and Markets, Sustainablity, and Energy and Resources (Exhibit 1- 1). To achieve these targets, the industry must pursue an organized, strategic technology agenda. This Roadmap outlines that agenda, organized according to the major aluminum processes. It presents detailed, sector-speci

7、fic performance targets, technical barriers, research and development needs, and R these are also the R includes electricity losses at the plant). Hroult process is another priority for the industry. Even small efficiency gains in the energy-intensive smelting process can yield large cost savings, e

8、missions reductions, and other benefits. While the most advanced cells can achieve an energy intensity of just under 13 kWhikg, the industry average is near 15 kWh/kg. Before primary aluminum producers can achieve their performance targets, the industry must develop solutions to several technologica

9、l and institutional barriers. Exhibit 2-2 presents the technical barriers currently limiting primary aluminum smelting in four main categories: 0 Electrolytic Reduction Processes 0 Alternative Reduction Processes 0 Enabling Technologies 0 Institutional Barriers Technical limitations in existing redu

10、ction cells constrain improvements in their energy and production efficiencies, metal quality, and environmental performance. Enabling technologies such as sensors, controls, models, and materials can help to overcome these barriers; however, these enablers are also limited in their accuracy, applic

11、ability, or effectiveness. Additionally, the lack of commercially viable alternatives to the Bayer and Hall Hroult processes hinders primary aluminum producers in their efforts to achieve revolutionary advances in cost and efficiency. Less than optimal coordination among industry, government, and ac

12、ademia also limits or slows the rate of technology development. Optimizing these working relationships can help increase the effectiveness of collaborative research and development. 1) ALUMINUM INDUSTRY TECHNOLOGY ROADMAP ENA5LING TECHNOLOGIES e o Inadequate process tools, sensors, and controls for

13、reduction cells D inability to measure cell variables (other than resistance) in real time b lack of non-contact sensors o Lack of cost-effective metal-purification technologies o Inadequate process optimization models o Lack of materials (cathode, anode, and sensor tubes) that can withstand exposur

14、e to molten aluminum and cryolite 1 ONSTITUTOmNAL BARRPERS c l o Government role in research is unclear; collaboration between government, academia, and industry is not o Low researcher awareness of the state of the technology and of previous and ongoing research optimized; limited cross-institution

15、al communication 1 o Lack of regulatory cooperation (e.g., spent potliner) I Exhibit 2-2. Technical Barriers: Primary Production (priorities in bold) ELECTROLYTIC REDUCTION PRQCESSES o Lack of mathematical models to predict the performance of cell design concepts Q Lack of robust bath chemistry (con

16、strained by cryolite-based electrolyte) o Incomplete knowledge of how to raise thermal efficiency of reduction without negatively impacting the o Lack of economical method to retrofit older cells (including buswork) o Lack of economical technique to remove impurities from alumina in dry scrubbers o

17、High cost of reduction equipment o Large gap between theoretical and actual energy efficiency, and high associated power costs process ALTERNATIVE REDUCTION PROCESSES , Lack of feasible, economical electrolyte compositions that would require lower voltage without c1 Lack of systems approach to devel

18、oping overall alternative processes o Difficulties maximizing use of chemical versus electrical energy in alternative processes compromising product quality The industry can overcome the barriers to improved primary production through research, development, demonstration, and other activities aimed

19、at improving smelting technologies and processes. The R relative priority is shown by the arrows to the left of each R learn to cope with new anode materials (high sulfur, ash). (Ongoing) Develop advanced refractories for the cell. (Ongoing) Develop a cell capable of performing effectively with powe

20、r modulations (e.g,. off-peak power). Continue development of inert anodes (including materials development). (M-L) Refine method to extract impurities from alumina used in dry scrubbers. (N) Develop cost-effective, low-resistance, external conductors and connections for both the anode and cathode.

21、(M-L) Develop extended-life pot lining ( 5,000-day life). (L) Improve waste heat recovery (from exit gases and from the cathode). (L) Perfect the continuous, pre-bake anode. (M) Priority Level R+w Moddte Higi Low if only goal is to reduce voltage, moderate when considering lifetime of the cathode 20

22、03 2020 A I I I I I ihi I * I I I I Mid Term (3-10 years) ALUMINUM INDUBTRY TECHNOLOBY ROADMAP + Conduct scale-up acties on current * Develop metal purification techniques processes. (when starting with a metal with Develop the carbothermic reduction process on a commercial scale ROW I TECHNICAL RIS

23、K- , savings, but on-site carbon emissions will increase) mmm LHigh technical risk I Lm? rnWN0W m- RUR shape casting is considered in detail in the Metalcasting Industry Tecbnology Roadmap (see references). New, clean energy sources may enable the industry to meet its energy needs for melting, solid

24、ification, and recycling while further minimizing its impact on the environment. Identiing ways to apply advanced energy technologies to aluminum processes would help ensure rapid adoption. Aluminum companies seeking alternative sources of energy may benefit from a variety of technologies as they be

25、come available and cost-effective. Examples of such technologies include combined heat and power (CHI?), distributed generation (DG), hydrogen fuel, and induction melting using renewable electricity sources. The growing trend toward engineered material solutions implies that the scrap stream will co

26、ntain an increased share of aluminum-based composites and other materials with non- aluminum components. In the near term, all internai scrap generated during the processing and manufacture of these new, engineered materials must be captured and recycled. In the coming decades, when these materials

27、enter the post-consumer scrap stream at the end of their service life, they must also be recycled with no waste. By considering the entire life cycle of aluminum-based material solutions and designing them for easy and complete recycling, the aluminum industry can avoid creating products that are no

28、t fully recyclable. The original industry roadmap called for improvements in furnace designs for the future, and furnace improvements in pursuit of this need have been broad and numerous. Flame image analysis has been useful in improving understanding of combustion, optimizing ALU MI NUM I N DUBTRY

29、TECH N OLOOY ROAD MAP burner design, and improving temperature uniformity in furnaces. Improved burner designs, including low-NOx regenerative burners, oxy-fuel burners, and oxy-enriched burners have gained use throughout the industry, and pulsed and oscillating burners are being examined to further

30、 extend burner technology. Improved furnace sealing has helped to control the furnace atmosphere, minimize dross formation, and improve overall energy efficiency. Additionally, improved furnace designs, charging techniques, and molten metal pumps all help to increase melt rates and further improve e

31、fficiencies. New heating and melting techniques continue to be developed and demonstrated. The recent demonstration of reliable, high watt-density, immersion heaters that offer high energy efficiencies has pushed this promising technology closer to the market, while flotation, cupola-type melting an

32、d delacquering has been demonstrated at a prototype scale. Advances in filtration techniques and knowledge have gone part of the way to addressing this priority need from the industrys original roadmap. Specifically, a more complete understanding of the role of surface chemistry in inclusion capture

33、, unified depth capture based on computational fluid dynamics (CFD), and flow in reticulated foam media have all led to advances in filtration techniques. Inclusion sensor development has yielded several promising technologies. The proprietary liquid metal cleanliness analysis (LIMCATM) technology a

34、nd subsequent refinements of molten metal analysis based on laser-induced breakdown spectroscopy (LIBS) are at or near commercialization, while ultrasonic inclusion sensors and neutron adsorption technologies are being investigated. Scrap identification and sorting technologies have enjoyed similar

35、success, with chemical, color, and LIBS-based sorting all achieving some degree of technical success. X-ray absorption-based scrap sorting and neutron activation-based scrap stream analysis are other areas of ongoing investigation. Finally, exploration of ways to use non-metallic products resulting

36、from aluminum melting in other applications has yielded some successes. Calcium aluminate, used for iron and steel fluxing, has been commercially produced from non-metallic products (NMP), and a range of other applications have been developed, including low-density concrete formulations with NMP add

37、itions, thermal insulation fiber, abrasives, and sand blasting grit. PERFOWMANEE TARGETS To guide R maximize the ability to deal with residual impurities in every step. To achieve its performance targets for secondary production and recycling, the aluminum industry must overcome a wide range of tech

38、nical barriers. Some of the key barriers are shown in Exhibit 3-2, with the highest-priority barriers displayed in bold text. These barriers have been organized into the following six process-related categories: 0 Melting and Recycling 0 Crosscutting Technologies 0 Metal Processing and Treatment 0 S

39、kim and Dross 0 Casting 0 Continuous Processes Achieving the performance targets in this area will require removal of the limitations on efficiency imposed by existing aluminum melting and recycling technologies and systems. Beyond melting and recycling technologies, however, the industry is lacking

40、 important crosscutting technologies that could eliminate wastes and improve the economics of recycling. Production and management of skim and dross create additional technical challenges for aluminum melters as the industry drives towards zero waste. Limited understanding of the solidification proc

41、ess and associated technologies hinders casting processes and limits the return secondary aluminum smelters can receive for their products. Additional barriers associated with the processing and treatment of metals center on fluxes, impurities, and fines. Finally, as the industry pushes productivity

42、 and efficiency higher, it will increasingly seek continuous operation, which is currently limited by control and processing technologies. ALUMINUM INDU6TRY TECHNOLOBY ROADMAP Exhibit 3-2. Technical Barriers: Melting, Solidification, and Recycling (priorities in bold) MELTING AND RECYCLING I o Sub-o

43、ptimal scrap melt rates o Low fuel efficiency in melting and holding furnaces; furnaces are not optimized for scrap heating and o Lack of methods to recycle new types of scrap that will result from new product mix (e.g., engineered o High contaminant levels in purchased scrap, including toxics; diff

44、iculties detecting non-metallic impurities in scrap o Lack of economic incentive to separate scrap by alloy o Inability to meet OSHA and other standards while using low-grade scrap o Some secondary specifications are based on scrap availabilities that no longer exist or are otherwise outdated o Temp

45、erature stratification and alloy segregation o Lack of economical alternatives to chlorine fluxes for magnesium and alkali removal waste heat recovery material solutions) CROS5CUTTiNG ECWNOLOGIESi o Inability to control quality and metallurgical structures in real time o Inability to predict metal q

46、uality and economics based on “first principles“ o Segmented, operation-specific thinking; too many non-value added, repetitive process steps (e.g., remelting, o Limited information and best-practice sharing to improve competitive position relative to other materials transportation, multiple cleanin

47、gs) METAL PROCESSING AND TREATMENT, o Lack of environmentally friendly reactive flux gases for metal treatment o Inadequate impurity removal methods o Generation and loss of fines during shredding and subsequent processing SKIM AND DRnSSi o Limited knowledge of, and lack of methods to prevent or con

48、trol molten aluminum-oxygen reactions to 0 Lack of applications for non-metallic products o Lack of methods to minimize oxidation of 5xxx alloys without using beryllium u Lack of alternative dross treatments; processes that require skimming are inherently limited create desired oxides CASTiNCi 0 Lac

49、k of closed-loop control for casting Poor water quality and uniformity around the mold 0 Poor metal quality in ingot head and tail during casting o Too many cavities and voids in the sows; inability to practically determine sow soundness 0 Inadequate means of detecting bleedouts in billet casting o Lack of understanding of cracking mechanisms as a function of alloy Q Incomplete control of surface quality for all types of casting Incomplete understanding of the conditions that trigger aluminum-water explosions and why certain coatings IJ Insuf