Aluminium reference data sheet

ТЕЕ Reference Data Sheet for Alurтinum August 1996 Reference Data Sheet for AI umi num POTENTIAL PROBLEM AREAS • lndustrial accidents in'vOI\Ang production of aluminum powders and paste • Labeling, wamings, and markings 1 • Transportation of aluminum powders and pastes 2 • Waste disposal of aluminum powders and pastes 3 • Storage and handling of aluminum powders and pastes 4 • Dusts generated in processing and finishing aluminum and its alloys 5 • Employee hazard communication 6 • Work practices • Facility design 7• 8 INTRODUCTION Aluminum is the most abundant metal in the earth's crust, and the third most abundant element; howewr, elemental aluminum does not occur in nature. Bauxite оге is the principal source of aluminum. Aluminum is а silwry-white, light metal with а specific gra\Aty of 2. 70 and а melting point of 660 °С (1220 °F). Pure aluminum is soft and lacks strength, but сап easily Ье formed, machined, ог cast; has а high thermal conducti\Aty; and has excellent corrosion resistance due to а protectiw coating of aluminum oxide formed оп the surface (this coating is at times deliberately thickened in the process of "anodizing"). lt is nonmagnetic and non-sparking, stands second among metals in the scale of malleabllity, and sixth in ductility.9 lndustrial forms of aluminum include commercially pure metal and alloys with other metals such as chromium, соррег, iron, magnesium, manganese, nickel, titanium and zinc. Aluminum alloys may contain as much as fifteen percent of the alloying metals. ln powder form, aluminum and its alloys аге combustiЫe in air and present а potential explosion hazard. ln sheet ог Ыосk forms, aluminum will not normally propagate ог sustain combustion.10 REACTIONS AND INCOMPATIBILITIES Hydrogen Generating Reactions Aluminum is а wry reactiw metal, and the greatest industrial hazards associated with aluminum аге chemical reactions. Aluminum is an excellent reducing agent, and should react with water readily to liberate hydrogen. Howewr, the protectiw aluminum oxide coating protects it from reaction with moisture ог oxygen. lf the protectiw coating is broken, for example, Ьу scratching ог Ьу amalgamation (the process of coating with а film of mercury in which the metallic aluminum dissolws; the aluminum oxide coating does not adhere to the amalgamated surface), rapid reaction with moisture and/or oxygen сап occur. Тhе significance of this reaction is dependent upon the quantity of aluminum availaЫe to react. Aluminum is also oxidized Ьу heat at а temperature dependent rate. Aluminum metal is amphoteric (exhiblts both acidic and basic characteristics). Therefore, aluminum will react with acids ог bases; both reactions liberate hydrogen, а flammaЫe gas. However, aluminum does not react with concentrated nitric acid because the oxidizing potential of the acid contributes to the formation of the protective aluminum oxide coating.11 Thermite Reactions Aluminum readily extracts oxygen from other metal oxides to form aluminum oxide with the simultaneous release of large amounts of heat (enough heat to melt the products of the reaction). For example, the reaction of aluminum with ferric oxide to produce liquid aluminum oxide and liquid iron produces temperatures approaching ЗООО 0 С (5400 ° F). This reaction, referred to as the "thermite reaction," has Ьееп used to weld large masses of iron and steel; when enclosed in а metal cylinder and ignited Ьу а ribbon of magnesium has Ьееп used in incendiary bombs; and, with ammonium perchlorate added as ап oxidizer, has pro\Jided the thrust for the space shuttle booster rockets.1 2 Dust Explosions А dust explosion is а complex phenomenon in\01\Jing simultaneous momentum, energy, and mass transport in а reactive multi-phase system.13 Aluminum particles, when in dust, powder, ог flake forms from operations such as manufacturing powder, grinding, finishing, and processing, may Ье suspended as а dust cloud in air and consequently may ignite and cause serious damage. lf the dust cloud is unconfined, the effect is simply опе of flash fire. lf, however, the ignited dust cloud is at least partially confined, the heat of combustion may result in rapidly increasing pressure and produce explosion effects such as rupturing of the confining structure. Aluminum dust is not always easily ignitaЫe, and, therefore, the hazard of dust explosions is often ignored.1 4,15 Minimum explosive concentrations of aluminum dust have Ьееп reported upwards from about 40 grams рег cublc meter (0.04 ounces рег cublc foot) of аiг.16 IMPL/CA T/ONS Lack of avvareness of the potential hazards and reactivities associated wth aluminum роvюег тау exist because: • Aluminum роvюег is naturally protected wth а barrier of aluminum oxide which тау prevent reactions at times; • Thermite reactions usually require а strong ignition source and therefore do not often оссиг in unplanned situations, although optimum conditions could allow these reactions to оссиг; • Aluminum dust is not alvvays easily ignitaЬ/e due to dependency ироп particle size, air distribution, and other factors; and, • А false sense of security тау exist due to hazard reduction when dealing wth coated aluminum povюers and pastes. Although organic coatings ог pastes тау generally offer some protection against dust generation, should dust formation ог а fire ensue, the organic compounds тау act as additional fuel. То alleviate this lack of avvareness, етр/оуее hazard communication, labels, vvamings, and markings should adequately address the hazards associated wth aluminum; storage and handling parameters should Ье based ироп consideration of the physical and chemical properties of aluminum; and, adequate precautions for incidents which тау involve transportation of aluminum povюers and pastes should Ье assessed. INDUSTRIAL PROCESSES/POLLUTION/WASTE Aluminum is produced Ьу the electrolysis of alumina which is usually oЫained from bauxite оге. This production, referred to as the primary aluminum smelting industry, in\Olves several operations, with each ha\Jing associated solid wastes, sludges, effluents, and/or air emissions. ln addition, molten aluminum may represent а special hazard due to thermal and quality control factors.17, 18 Emissions of сопсегп in the aluminum industry include hydrocarЬons, total particulates, fluoride particulates, and gaseous fluorides. Typical emission control de\Jices include spray towers, floating-bed scrubbers, venturi scrubbers, quench towers, electrostatic precipitators, multiple cyclones, and baghouses.19 Wastewater pretreatment controls include conditioning, thickening, dewatering, conversion, and drying processes which should Ье designed with the consideration of the parameters of the sludge/effiuent. 20 The United States En\Jironmental Protection Agency has promulgated standards concerning air, water, and land pollution. ln addition to the primary aluminum smelting industry, these standards may Ье applicaЫe and/or relevant to other industries using aluminum, for example, aluminum die casting operations.21 The secondary aluminum smelting industry is essentially composed of industries in\Olved in the remelting/recycling of aluminum (such as aluminum pigs, foundry retums and scrap). The process encompasses fluxing, alloying, degassing and demagging. Paint, dirt, oil, grease, degassing fluxes, and magnesium-reducing fluxes (such as chlorine) may additionally contribute to potential sources of en\Aronmental pollution and additional hazards. Controls selected are generally similar to those found in the primary aluminum smelting industry.22 IMPL/CA T/ONS lndustries involved in producing ог using aluminum тау require specific facility design criteria, wth consideration of the process, environmental pollution, and the hazards of using a/uminum. For ехатр/е, a/uminum dust col/ection is desiraЬ/e to reduce particulate emissions; however, the collected dust from а process тау present the physical and chemical hazards of aluminum. lnerting potentially f/аттаЫе atmospheres, such as those found in processes involving mixing of po'Мiers, тау Ье appropriate. Processes involving wet verses dгу methods (such as pollution control, milling, etc.) should also have design considerations conceming the properties of aluminum dust. Work practices for employees shou/d encompass emergency procedures, general housekeeping, waste disposa/ procedures, and апу special precautions required in the particular июгk setting. HEALТН EFFECTS Aluminum particles deposited in the еуе may cause local tissue destruction. Aluminum salts may cause eczema, conjuncti\Atis, dermatoses, and irritation of the upper respiratory system \Аа hydrolysis-liberated acid.23 Aluminum is not generally regarded as an industrial poison, although inhalation of finely di\Aded aluminum powder has been reported as а cause of pneumoconiosis. 24 ln most investigative cases, however, it was found that exposure was not solely to aluminum, but to а mixture of aluminum, silica, iron dusts, and other materials.25 Aluminum in aerosols has been referenced in studies in\0I\Ang Alzheimer's disease.26 Most exposures to aluminum occur in smelting and refining processes. Because aluminum may Ье alloyed with various metals, each metal (e.g., copper, zinc, magnesium, manganese, nickel, chromium, lead, etc.) may possiЫy present its own health hazards.27 The American Council of Governmental lndustrial Hygienists (ACGIH) recommends the need for five separate Threshold Limit Values (ТLVs) for aluminum, depending оп its form (aluminum metal dust, aluminum руга powders, aluminum welding fumes, aluminum soluЫe salts, and aluminum alkyls).28 The Occupational Safety and Health Administration (OSHA) has also estaЫished PermissiЫe Exposure Limits (PELs) for aluminum.29 IMPL/CA T/ONS Aluminum dust is strongly fibrogenic. Мetallic aluminum dust тау cause nodular lung fibrosis, interstitial lung fibrosis, and emphysema as indicated in animal experimentation, and effects арреаг to Ье coп-elated to particle size of the dust30; however, и,hеп exposure to aluminum dusts have Ьееп studied in тап, most exposures have Ьееп found to Ье to other chemicals as we/1 as aluminum. REFERENCES 1. 2. 3. 4. 5. 6. American National Standard for Hazardous lndustrial Chemicals - Precautionary Labeling, ANS/ Z129.11988, American National Standards lnstitute, lncorporated, New York, 1988. Code of Federal Regulations, 1itle 49, Part 172 - Hazardous Materials ТаЫеs, Hazardous Materials Communications Requirements, and Emergency Response Requirements, United States Department of Transportation. Code of Federal Regulations, 1itle 40, Part 261, Subpart С - Characteristics of Hazardous Waste, United States En\Aronmental Protection Agency. Recommendations for Storage and Handling of Aluminum Powders and Paste, Brochure Number ТR-2, The Aluminum Association, 900 19th Street, N.W., Washington. Guidelines for Handling Aluminum Fines Generated During Various Aluminum Fabricating Operations, Brochure F-1, The Aluminum Association, 900 19th Street, N.W., Washington. Code of Federal Regulations, 1itle 29, Part 1910, Subpart Z, Section 1910.1200 - Hazard Communication, 11 11 11 11 1 1 11 7. 8. 9. 10. 11. 12. 13. 14. United States Occupatianal Safety and Health Administratian. Standard far the Manufacture af Aluminum and Magnesium Pawder, 1987. NFPA 651, Quincy, МА: Natianal Fire Protectian Assaciatian. Standard far the Processing and Finishing af Aluminum, NFPA 65, Natianal Fire Protectian Assaciatian, 1987. Weast, Rabert, Editar, CRC Handbook of Chemistry and Physics, 63rd Editian, CRC Press, lncarparated, Васа Ratan, Flarida, 1982, р. В-5. Metals and Allays, Lass Pre\entian Data 7-85, Factary Mutual Engineering Carparatian, 1976. Brady, James Е. and Humistan, Gerard Е., General Chemistry: Principles and Structure, Third Editian, Jahn Wiley and Sans, New Yark, 1982, р. 580. lbld., рр. 580-581. Ogle, R. А., Beddaw, J. К., Chen, L. D., and Butler, Р. В., An ln\estigatian af Aluminum Dust Explasians, Combust. Sci. and Tech., 1988, Valume 61, рр. 75-99. Martin, R., Dust-Explasian Risk with Metal Pawders and Dusts, Р/М Group Annual Meeting 1975: Handling Metal Pawders, Sessian 1: Health and Safety in Pawder Handling, Po'Мier Мetallurgy, No. 2, рр.70-73. Мау, David С., and Berard, David L., Fires and Explasians Assaciated with Aluminum Dust fram Finishing Operatians, Joumal of Hazardous Materials, 17 (1987): 81-88. Standard far the Processing and Finishing af Aluminum, NFPA 65, Natianal Fire Protectian Assaciatian, 1987. Buanicare, А. J. and Davis, W. Т., Editars, Air Pollution Engineering Мапиа/, Van Nostrand Reinhald, New Yark, 1992, рр. 590-605. Weber, Jr., W. J., Physicochemical Processes for Water Quality Control, Wiley-lnterscience, New Yark, 1972, рр. 533-588. Buanicare, et al, рр. 590-605. Weber, et al, рр. 533-588. Bell, J. М., Editar, Proceedings of the 43rd lndustrial Waste Conference, Мау 10, 11, 12, 1988: Purdue University, West Lafayette lndiana, Lewis PuЫishers, lncarparated, Chelsea, Michigan, 1989, рр. 587-592. Danielsan, J. А., Editar, Air Pollution Engineering Мапиа/, Secand Editian, Environmental Pratectian Agency, Research Triangle Park, North Carolina, 1973, рр. 283-292. Кеу, Marcus М., Henschel, Austin F., Butler, Jack, Liga, Rabert N., and Tabershaw, lrving R., Editars, Occupational Diseases-A Guide to Their Recognition, Revised Editian, (U.S.) Department af Health, Educatian, and Welfare, Washingtan, 1977, рр. 323-325. Sax, N. lrving, and Lewis, Sr., Richard J., Dangerous Properties of lndustrial Materials, Se\enth Editian, Van Nostrand Reinhald Сатрапу, New Yark, 1989, Valume 11, рр. 134-135. Кеу, et al., Occupational Diseases-A Guide to Their Recognition, Revised Editian, рр. 323-325. Sax, et al., Dangerous Properties of lndustrial Materials, Valume 11, рр. 134-135. Кеу, et al., Occupational Diseases-A Guide to Their Recognition, Revised Editian, рр. 323-325. Documentation of the Threshold Limit Values and Biological Exposure lndices, Sixth Editian, American Canference af Ga\emmental lndustrial Hygienists, lncarparated, Cincinnati, Ohia, 1991, рр. 46-47. Code af Federal Regulatians, Тltle 29, Part 1910, Subpart Z, Sectian 1910.1000 - Air Cantaminants, United States Occupatianal Safety and Health Administratian. Chen, Zhau, and Hangchuang, Chen, The Fibrosis and Other Marphalagic Changes af the Rat Lung Caused Ьу lntracheal lnjectian af Different Sizes af Metallic Aluminum Dusts, Proceedings of the Vllth lntemational Pneumoconioses Conference, Part 11, U.S. Department af Health and Human Services, Washingtan, 1990, рр. 1167-1171. 11 11 11 11 11 11 11 11 11 11 11 15. 11 11 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 11 11 11 11