1、STD-AA b-ENGL L77Li W Ob04500 00LZdhb bL5 I Compatibility data on aluminum in the FOOD and CHEMICAL PROCESS INDUSTRIES SIXTH EDITION - The Aluminum Association Incorporated STD-AA bo-ENGL 1774 m Ob04500 00LZAb7 551 m I . ;AboutThe :Aluminum i Association ! : The member companies of The i : Aluminum
2、Association, Inc., i represent approximately 85 percent i : of domestic production of primary : : ingot and shipments of U.S. i aluminum mill products. Mill : products include sheet and plate; : : foil; extrusions; forgings and impact i i extrusions; electrical conductor and i : wire rod and bar. In
3、 addition to : producers of primary ingot and mill i i products, the associations : membership also includes : secondary smelters, foundries and : producers of master alloy and i additives. : The association is a primary i i source of statistics, standards and i i economic and technical information
4、i : on aluminum and the aluminum : : industry in the United States. i . GUIDELINES for the use of ALUMINUM with FOOD and CHEMICALS Compatibility Data on Aluminum in the FOOD and CHEMICAL PROCESS INDUSTRIES Sixth Edition April, 1994 The Incorporated Aluminum Association 900 19th Street, N.W., Washing
5、ton, D.C. 20006 STD*AA bo-ENGL 1994 Ob04500 00128b9 32q O 1994 The Aluminum Association STD-AA bo-ENGL 1774 Ob04500 O032870 04b NOTICE: The data and suggestions in this book are based on information believed to be reliable and are offered in good faith but without guarantee. Since much of the inform
6、ation contained herein is based on limited data and since the endless varieties of conditions and possible methods of use cannot be accurately predicted and adequately covered, the pro- spective user should determine the suitability of the materials for a particular application based upon the specif
7、ic conditions to be encountered in service. Accordingly, the Aluminum Association and its member companies assume no responsibility or liability for the use of these data and suggestions. No warranty express or implied, is made of this infor- mation by the Aluminum Association or by any of its membe
8、r companies. GUIDELINES for the use of ALUMINUM with FOOD and CHEMICALS FOREWORD: Paralleling the growth of our indus- trial society are mounting corrosion losses and costs of corrosion control systems. The soaring cost of maintenance labor, alone, demands increased atten- tion to low cost, corrosio
9、n resistant materials such as aluminum. There is equal incentive for the use of processing, handling and storage equipment basically compati- ble with sensitive products. Frequently, the materials engineer is faced with a choice of technically suitable, available materials for a given application. W
10、here aluminum is suitable, it usually offers the lowest total costs. This publication is intended to assist in determin- ing the suitability of aluminum alloys for specific ap- plications and in achieving their potential economy through proper specification and use. TYPICAL CORROSION-RESISTANT APPLI
11、CA- TIONS: Aluminum alloys can be readily fabricated and welded into storage tanks, tank trailers, tank cars, covered hopper cars, reaction vessels, heat ex- changers, process piping, distillation equipment and related process equipment. Distilled water, condensate and demineralized water have been
12、handled in laboratories, hospitals, chemical plants, paper plants, and power plants using aluminum alloy tanks and piping. Seawater and brine have been handled in aluminum alloy de- salination equipment. Seawater applications for alu- minum alloys include offshore drilling platforms, crude oil pipin
13、g, gas piping, barges, boats and sub- marines. Natural water supplies have been piped in aluminum alloy irrigation pipe. Nitrogen fertilizer solutions, ammonium nitrate, urea, ammonia and 98% nitric acid have been han- dled in aluminum alloy tanks, piping, heat exchang- ers, tank cars, covered hoppe
14、r cars, prilling towers, drums and containers. High concentration, high purity nitric acid has been processed in high purity aluminum equipment. Ammonium nitrate and urea prills have been stored in aluminum alloy warehouses and aluminum alloy bins. Sulfur, hydrogen sulfide and mercaptans have been p
15、rocessed and handled in aluminum alloy bins, piping and tanks. Sulfur dioxide in low concentra- tions and as dry gas refrigerant has been used in aluminum alloy food processing and refrigeration systems. Concentrated 95% sulfuric acid has been stored in aluminum alloy tanks in textile industries to
16、avoid iron contamination in the textile fiber. Amine scrubbers for the removal of sulfur dioxide and car- bon dioxide in petroleum refineries have often been made of aluminum alloys. Sulfite paper mills have used aluminum alloy conduit, drying machine rolls, hoods, vents and stacks. Tall oil has bee
17、n distilled in aluminum alloy columns, condensers and receivers. 3 STD=AA bO-ENGL L77Y = ObOY500 0012871 T82 W Paper and pulp niills have used aluminum alloy building materials. Organic chemicals such as alcohols, acetic and other organic acids, solvents, glycols, glycerin, as- pirin, rosin, turpent
18、ine, nitro paraffins, phenols and aromatic compounds may be handled in aluminum alloy equipment. Pharmaceuticals, penicillin, cos- metics, drugs, latex, vitamins and related materials have been processed and shipped in aluminum alloy containers. The use of aluminum alloy containers avoids toxicity,
19、discoloration, rancidity and metal contamination. Hypodermic hubs have been made of aluminum alloys. Foods, vegetable oils, fatty acids, sugar solutions, corn syrup, sucrose, dextrose, candy, starch, confec- tions and many related products have been handled in aluminum alloys. Cookware and tableware
20、 have been made from aluminum alloys. Many aluminum alloy cans and containers have been used for such products as orange juice, beer, soft carbonated drinks, cheese, butter, frozen foods and bakery products. Beer and wine have been transported in aluminum alloy barrels or drums. Cryogenic liquids ha
21、ve been handled in aluminum alloy Dewar flasks and insulated double-wall tanks. Oxygen, nitrogen, argon, hydrogen, helium, meth- ane, natural gas, fluorine are some of the cryogenic liquids that have been handled in vessels and piping of aluminum alloys. Aluminum powder has been used as an infrared
22、radiation banier when added to powder insulation. Multilayer “Super Insulation” has used aluminum foil or aluminized mylar. Liquid methane tanks and liquid natura1 gas tanks in ships have been welded of aluminum alloys. Propane and butane are borderline cryogenic liquids which have used aluminum all
23、oy materials. Hydrogen peroxide in 3070, 50% and 90% con- centration has been handled in high purity alumi- num tanks and equipment. Rocket fuels such as hy- drazine compounds, nitrogen tetroxide and related materials have utilized aluminum alloy tanks and piping. Jet fuel, JP4, gasoline, kerosene a
24、nd lubri- cating oil have been handled in aluminum alloy pip- ing and tanks to reduce metallic contamination. Building materials of aluminum alloys have been successfully used in the paper and pulp, fertilizer, phosphate, potash, chlor-alkali, food, pharmaceuti- cal and electrical power generating i
25、ndustries. Tex- tile and plastic plants have been users of aluminum alloy siding, roofing and other building materials. Textiles such as nylon, polyethylene, dacron, cel- lulose acetate have been processed and handled in aluminum alloy equipment. The plastic pellets of polyethylene, polypropylene, c
26、ellulose acetate, poly- vinyl chloride, polyvinylidene chloride, nylon, poly- ester and polycarbonate have been transferred in aluminum alloy pneumatic lines, containers and covered railroad hopper cars. 4 Water desalination plants, sewage treatment plants and air pollution control equipment have be
27、en recent users of aluminum alloys. Aluminum alloy heat exchanger tubes and components have been used for seawater distillation units at a fraction of the cost for other materials. The use of aluminum al- loys in sewage tanks, settling basins, weirs, grating, ladders, aerators and piping has existed
28、 for a number of years. Air pollution control has required the use of alumina chemicals, aluminum alloy towers, duct- work, water washers and electrostatic precipitators. Swimming pools have been fabricated from alu- minum alloys coated for protection and appearance. The pools have been installed in
29、 concrete, sand, gravel or inside of such buildings as hotels, schools, and motels. Ladders and diving boards, likewise, have been made of aluminum alloys as have light poles, fixtures and chain link fence. Culvert pipe and drains have been other aluminum applications. USE OF THIS BOOK: This book pr
30、ovides a con- cise and up-to-date guide to the behavior of alumi- num alloys with a wide variety of foods and chemi- cals. Unless otherwise specified, the entries in this book describe the action of aluminum alloys in direct contact with the pure material in its normal state (solid, liquid, or gas);
31、 aqueous or other solutions are specified. In cases where specific laboratory test data are cited, the alloy tested has been listed. It must be rec- ognized that all aluminum alloys do not perform in the same manner when exposed to the same environ- ment, i.e. 2024 alloy will generally exhibit lower
32、 re- sistance to corrosion in a given environment than will alloy 3003. While the low and medium strength al- loys usually have similar resistance to corrosion in most environments, it is desirable to conduct tests prior to proceeding with the use of aluminum alloys for a specific application. It mu
33、st also be recognized that the conditions of use in a specific application may differ sufficiently from the ideal conditions of laboratory tests or from the conditions of previous service experience to change the performance of aluminum alloys in the anticipated application. Again, the need for test
34、ing and/or supplemental corrosion protection should be considered. The information contained herein applies to mas- sive aluminum surfaces as exist in typical processing equipment, such as storage tanks, heat exchangers, pressure vessels, piping and valves, etc. The infor- mation may not be applicab
35、le to finely divided alu- minum such as powder. The term “handling” refers to the use of piping, drums, tanks, tank cars and the like for transporta- tion and storage of a product. The phrases such as “have been used for,” or “have been handled in” indicate known applications of aluminum with the su
36、bstance. However, the com- plete history and longevity of the applications are not known, The terms “elevated temperature” and “low tem- perature” refer to any temperature above or below ambient encountered in normal production or use of the chemical product. TYPES OF CORROSION: Corrosion is defined
37、 as the deterioration of a metal by chemical or electro- chemical reaction with its environment. This deteri- oration takes place in different ways, depending upon the corrosive media, temperature, presence of other metals, and other factors. Uniform Corrosion: Uniform corrosion is the term applied
38、when the metal surface corrodes evenly over the entire area. Pitting: Pitting is a localized form of corrosion that usually occurs randomly in the form of small pits or craters, roughly hemispherical in shape. Pits usually become covered with a mound or nodule of corrosion product which tends to sti
39、fle further corrosion. As a result, the rate of penetration of a pit tends to dimin- ish with time. Some pitting usually can be tolerated if the wall thickness is adequate. Galvanic Corrosion: Galvanic or dissimilar metal corrosion is the corrosion that takes place when dif- ferent metals or alloys
40、are coupled together electri- cally in the presence of an electrolyte. The severity of corrosion depends upon several factors, one being the position of the dissimilar metals in the galvanic series in the table below. Galvanic Series magnesium alloys zinc aluminum-zinc alloys aluminum-magnesium allo
41、ys aluminum, 1100, 3003, Al-Mg-Si alloys Cadmium Aluminum-copper alloys mild steel, cast and wrought iron chromium lead-tin solders lead tin brasses copper bronzes monel nickel stainless steels In this series, any material tends to be corroded by contact with any other metal beneath it. The extent o
42、f corrosion also depends upon the conductivity of the electrolyte; it can become negligible in solutions of low conductivity such as high purity water. Despite its low position in the series, stainless steel can be safely coupled to aluminum in many environments because the steel is highly polarized
43、. In high chloride environments, stainless steel can cause substantial corrosion of contacting aluminum. Deposition Corrosion: Deposition corrosion is a form of corrosion in which ions of heavy metals, such as copper, lead, mercury, tin, nickel and cobalt are electroplated onto aluminum; the resulti
44、ng couple of dissimilar metals leads to further corrosion. Copper is the heavy metal most commonly encountered in practice because of the use of copper equipment. Mercury ions are less common, but even more detri- men tal. Poultice Corrosion: Poultice corrosion is a form of corrosion that takes plac
45、e when moisture is absorbed by porous materials, such as insulation, wood, cloth, cork and paper in contact with aluminum. The cor- rosion reaction is the result of differences in oxygen concentration in the electrolyte in adjacent regions of the material. These differences lead to a concen- tration
46、 cell and the region on the aluminum which is oxygen-starved corrodes. CORROSION RATE UNITS: The most commonly accepted unit for expressing the rate of corrosion of a metal is mils per year, abbreviated mpy. One mil is equal to 0.001 “. In this book, the following terminol- ogy is used to indicate c
47、orrosion rates. Resistant = less than 1 mpy attack Mild action = 1-5 mpy attack Moderate action = 5-20 mpy attack Corrosive or corroded by = greater than 20 mpy It must be recognized that these ranges of corro- sion rates may provide insufficient information for a particular application. However, th
48、ey should provide at least general information on the compatibility of the food or chemical with aluminum alloys. In some cases the actual value for corrosion rate as well as the range has been included for the readers assistance. In any case, advice and/or testing are desirable be- fore proceeding
49、to use aluminum alloys in any appli- cation. ALUMINUM ALLOYS: Systems of four digit nu- merical designations are used to identify wrought and cast aluminum alloys. 5 STD-AA bo-ENGL L77Li D ObClLi500 0032873 855 = Designations for Wrought Aiioy Groups Alloy No. lxxx Aluminum-99.00% minimum and greater. . Major Alloying Element Copper,. . 2xxx Aluminum Manganese 3xxx Silicon 4xxx grouped Magnesium . 5xxx by major Magnesium and Silicon . 6xxx alloying Zinc 7xxx elements Other Element. 8xxx I Unused Series . 9xxx alloys The first digit of the designation as shown in the table serves to indica
