ALUMINUM ALLOYS HARRY W. FRITTS, Sales Development Division, Aluminum Co. of America, New Kensington, Pa. industry, the information should be helpful in evaluating and choosing particular alloys for use in corrosive e n v i r o n m e n t s . Several books (6, IS, 87, 39, 67) discuss the resistance t o corrosion and the applications of aluminum alloys and other metals in a number of industrial processes, both in the United States and Europe. A series of articles (49-44) covers a wide variety of applications of aluminum alloys id the European chemical industries. Aluminum storage tanks, containers for transportation of chomicals, and condenser tubes are widely used in the manufacture or refining of explosives, fertilizers, paints and varnishes, fatty acids and oils, hydrogen peroxide, inorganic and organic acids, aldehydes, salt solutions, alcohols, sulfur compounds, phenols, refrigerants, waters, and numerous other compounds. Similarly, Lawrence (88)has recounted applications of aluminum in the chemical, petroleum, and sewage disposal industries. Molecular distillation a t very low temperatures allows the separation of high molecular weight products such as fatty acids, vitamins, scents, plasticizers, and oils which cannot be separated by “conventional” distillation processes, even under high vacuum. Aluminum alloy equipment is used for this new technique (81). Juniere (S6) mentions several chemical industry applications for aluminum alloys in France. A 99.5% aluminum distillation tower, exchangers, trays, bubble caps, etc., were used in the distillation of beet sugar for one season and then later in an apple distillery. No corrosion was experienced in either service. In addition to these, he reports the use of aluminum in the recovery of pyroligneous acids and in the manufacture of hydrogen peroxide, urea , other organic chemicals, and petroleum products. Alcohols. Aluminum alloys have been used satisfactorily with most of the commercial alcohols up to the boiling point, providing a trace of moisture is present. Equipment consists of storage tanks, shipping containers, piping and fittings, stills, filters, heat exchangers, and condenser tubes (IO). Aspirin. A well-known pharmaceutical manufacturer has made considerable use of aluminum alloy equipment in a new aspirin plant. Storage tanka and measuring tanks are used t o handle acetic acid and anhydride. Other aluminum equipment consists of slurry tanks, hoppers, process piping, fittings, ventilators, and ducts (3). All-aluminum acetylator kettles are used to carry out the reaction of salicylic acid with acetic anhydride to form aspirin (6). By-product Coking. Where dephlegmators are used in conjunction with ammonia stills in by-product coking plants, they are generally made of aluminum alloys. Some corrosion has been experienced on the water side (shell side); however, life has been greatly extended by the use of zinc blocks fastened to the baffles for cathodic protection. Where water flows through the tubes, Alclad 3s heat exchanger tubes are a convenient solution to this problem. Aluminum alloy chutes, hoppers, and truck bodies have been used to handle coke that has been treated with calcium chloride dust preventatives. They are much longerlived than mild steel but should be designed to avoid crevices where coke breeze can accumulate (56). Fatty Acids. In an English solvent extraction plant for refining fatty acids, all parts in contact with fatty acids are either
Current expansions in aluminum production should ensure more aluminum for the “chemical industry requirements. Continued alloy and product development offer new fields for the use of aluminum in the process industries. This review points to a number of new applications in the chemical and petrochemical industries and gives additional information on the resistance to corrosion of aluminum alloys by a number of chemicals.
L
AST year a$ this time, aluminum alloys were in short supply
because of national defense requirements (SO). This shortage has continued up to the present time, although prospects for increased supplies are bright. The leveling off of defense requirements and the increased capacity of the aluminum producers should ensure more aluminum for the chemical industry requirements. Aluminum capacity of the United States a t the start of the Korean war was about 1,500,000,000 pounds annually. Expansions, many of which will be completed by the end of 1952, will just about double the U. S.aluminum capacity (I6,29). NEW PRODUCTS
Of particular interest to the chemical industry is the introduction of a new high-strength nonheat-treatable sheet and plate alloy, designated XA54S. The good mechanical properties of welded XA.548,together with its good resistance t o corrosion, will permit a substantial reduction in the thickness of welded sections used in pressure vessels as compared with 35 alloy. This new alloy is currently being evaluated for tank cars, tank trucks, storage vessels, and other applications (6). A new general-purpose aluminum alloy coiled tube was introduced late last year. Made from alloy B50S-0, the new tubing costs substantially less per foot than copper. Available in 1000foot lengths, it possesses high fatigue stren@;th, good flaring, forming, and bending characteristics, and high resistance to corrosion in industrial and marine atmospheres. It is reported t o work-harden less than annealed copper under repeated bending (17, $0). This tubing is suitable for use in instrument air, vacuum, and hydraulic lines and for handling fuel oils, gasoline, lubricating oils, cutting oils, and refrigerants except methyl chloride. An all-aluminum brazed heat exchanger is available commercially, which offers substantially greater heat-transfer surface per unit volume than conventional shell and tube exchangers, The brazed units can be used from below -300’ F. to as high as 500‘ F. and can be designed for counterflow or C~OSBflow circulation (16,36,48). A recent article by Hoglund (33)discusses welding of aluminum alloys and includes properties, procedures, inspection, design, and applications, Hartmann and Plummer (38)have given design suggestions and typical applications for the use of aluminum alloys in constructing storage tanks and tank roofs. Arnold (8)describes a procedure used in welding several large aluminum alloy tanks for ammonium nitrate solutions and acetic acid. CHEMICAL APPLICATIONS
General. The effect of impurities and alloying on the corrosion resistance of both wrought and cast aluminum ia discussed in several articles by Lees (40) and Whitaker (67-76). Although these articles do not cover specific applications in the chemical
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INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 44, No. 10
aluminum or stainless steel (19) Aluminum alloys are known to possess excellent resistance to corrosion by these acids and do not discolor or catalyze breakdonn of the finished products. The Dutch (45) recently installed two large 99.6% aluminum fatty acid storage tanks a t the chemical works in Gouda. Numerous other installations have been made both in the United States and abroad ( 5 , 3 6 ) . Formaldehyde. The presence of formic acid in formaldehyde aolutions is believed to cause the initial corrosion of some alumi-
Peppermint Oil. An 85-gallon portable pilot plant for peppermint oil distillation was constructed of aluminum alloys, because they are more resistant than most metals to the corrosion by mint oil and cause no deterioration of the oil ( 1 ) . Phenol. Aluminum drums have been approved by the Inteistate Commerce Commission for shipping solid phenol. Aluminum storage tanks have given corrosion-free service for over 20 year.. of handling phenol solutions. Other aluminum equipment has been used in the production of phenolic resins ( I d ) .
num alloys used for taiiks and piping. This initial pitting attack self-limiting. Apparently, the depth of attack after 5 years is no greater than that observed after 6 months in equipment handling formaldehyde u p to 160” F. (60). Hydrocarbon Solvents. Aluminum alloys are virtually unaffected by most hydrocarbons encountered in the chemical, petrochemical, and petroleum industries. Aluminum has been used for tanks, shipping containers, heat exchangers, stills, piping, and similar equipment handling a xide variety of hydrocarbon chemicals (22). Hydrogen Peroxide. The passivation of aluminum storage and handling equipment and the inhibition of hydrogen peroxide t o prevent corrosion of aluminum has been discussed in several articles (36, 58). Aluminum of 99.6% purity is commonly used for storage tanks and shipping drums where contact with hydrogen peroxide is over an extended period of time. For pipes, fittings, and tank cars where contact with the peroxide is for short periods, commercially pure aluminum is acceptable. Mineral Acids. Binger ( 1 1 ) has covered briefly the applications of aluminum alloys with nitric acid. Especially important is the suitability of aluminum alloy drums for handling nitric acid above 82% (by weight), including red fuming nitric acid, a t ambient temperatures. A new style of aluminum drum is being manufactured in Italy especially for the transport of nitric acid (2). Shepard (62) states that aluminum is serviceable x i t h very dilute sulfuric acid and quite concentrated sulfuric acid. It has been used successfully in fume ducts handling sulfur dioxide and sulfur trioxide mists a t atmospheric temperatures. It also has been used to a limited extent in handling concrntrated sulfuric acid and oleum at moderate temperatures. Nitro P a r a f i s . Aluminum alloy storage tanks ale unaffected by nitro paraffins such as nitromethane, nitroethane, l-nitropropane, and 2-nitropropane. These compounds are stored under essentially anhydrous conditions to increase stability (18). Oxygen. Conway ($33)describes the construction of aluminum alloy fractionation and condensing equipment for a tonnage oxygen plant. The fractionators, bubble caps, trays, piping, and beat exchangers are made of alloy 35.
Sulfur. Sulfur in liquid 01 vapor form dow riot attack aluniinum. Molten sulfur has been handled successfully in aluminum pipes and tanks. Aluminum alloy freight cars are used to transport sulfur and sulfur-bearing ores and coals without appreciable corrosion. Ordinary steel cars arc seriously corioded by these ladings (66).
a$
ATOMIC ENERGY APPLICATIONS
The relatively new heavy-water reactor near Oslo, Nornay, utilizes a considerable amount of aluminum equipment ($4). The reactor tank, which holds 7 tons of heavy water, is made from 99.5% aluminum. Aluminum tube is used to encase the thermometers and uranium slugs xhile they are in the reactor. The storage tank, expansion tank, pipe, pipe fittings, valves, and floats which contact heavy water are aluminum. Aluminum drums also are used to transport the heavy water. The U. S. Atomic Energy Commission has announced a new low-cost, low-power “swimming pool” reactor. It is an assembly of movable fuel elements placed on end in an aluminum grid and suspended over the pool by an aluminum bridge. An aluminum gate, 12 X 21 feet, is located in the 130,000-gallon pool to facilitate draining for repairs and at the same time retain enough water to protect the workers from radioactivity (25,50). Also announced is a new heavy-water plant costing $4,500,000 that will have a large aluminum primary distillation tower and velded aluminum piping (51). PETROLEUM AND PETROCHEMICAL APPLIChTIONS
hpplications of aluminum alloys in the oil industry in England (53) consists of drilling rigs, nheels, pipelines, storage tanks, oil tanker bulkheads, buildings, screening, bubble caps, ti ays lor distillation columns, equipment for subzero temperatures, heat exchangers, and road and rail cars for distribution of fuel and synthetic detergents. Lawrence (58)stated that the corrosion resistance, nonsparking property, and high reflectivity of aluminum are of special importance to the petroleum industry. Mention is made of the use of aluminum for hydrogen sulfide scrubbers, distillation columns and bubble caps, condensers, and other applications.
October 1952
INDUSTRIAL A N D ENGINEERING CHEMISTRY
Containers. Aluminum foil drums have been developed for the petroleum industry by lamination of multiple plys of foil and kraft linerboard to steel tops and bottoms. Appreciable savings in weight and materials are realized with these containers (66). General Metal Work. In a large, high pressure ammonia plant, aluminum sheeting has been used on all piping and vessels requiring insulation. Aluminum coverings are corrosion resistant, require no painting, and cost about the same as 28-gage galvanized sheet before painting (61). Generally, it is good practice to install aluminum sheeting over a moisture barrier to prevent moist insulating materials from contacting the back of the aluminum sheet. Considerable use has been made of aluminum sheet for enclosing cooling towers (6). Kelly ( 3 7 ) described the use of aluminum sheet on several cooling towers, Advantages of aluminum are good resistance to corrosion, freedom from maintenance, and light weight that reduces roof loads and makes erection easier. Another field which is growing rapidly and undoubtedly will be of importance to the process industries is the use of structural aluminum in electrical substations. Baker (9) stated that although the initial cost of aluminum structurals is about twice that of steel, savings on transportation costs and labor alone almost compensate for this difference. Field erection of factoryassembled aluminum members reduces erection time by one fourth, compared to steel structures. In addition, aluminum shows excellent resistance to corrosion in atmospheres containing sulfur and corrosive gases; therefore, it requires no painting. Pipe. Welding techniques, equipment, and materials required, the effect of welding, and typical applications of aluminum alloy piping have been discussed in an article by Cheyney (21). Other than low alloy steel, aluminum is the lowest cost corrosion-resistant piping material available. The use of aluminum pipe and tube for petroleum applications has been discussed in a number of papers recently. Wanderer (64, 66) has described the use of aluminum alloy pipe in a gas-collecting system in the Gulf of Mexico. A 3500-foot length of 63s 4-inch welded line, half of which is unprotected, has been in service for over 20 months. Recent examinations showed that both the exterior and interior surfaces of the pipe were in excellent condition. Aluminum shot hole casting, temporary portable lines, and permanent pipelines offer many economic advantages in petroleum and petrochemical service (49). 811-metal loading and unloading lines using aluminum alloy tube and swivel joints are now available. Advantages claimed are weight saving, ease of handling, and ability to resist both climatic conditions and a variety of chemical products (61). A 40-foot section of an 8-inch aluminum pipeline for carrying natural gas was uncovered recently. Examination after 17 months showed no discoloration or corrosion (34). A special aluminum alloy called invasion pipe ( 4 , 7 ) has been developed The lightweight pipe comes in 20-foot lengths, is durable, resistant to corrosion, and easy to maintain. It is used for carrying fuel, oil, and water to operation areas of mobile Army units and emergency base Air Force groups. Heat Exchangers. The excellent heat transfer characteristics of aluminum alloys and their good resistance to corrosion by sulfur-bearing crudes make them ideal for heat transfer equipment in the petroleum industry. Aluminum heat exchanger tubes give outstanding service in many locations. Picarazzi (64) has described the use of Alclad 35 aluminum heat exchanger tubes to resist the corrosive action of brackish cooling water in a diethanolamine cooler. The use of zinc plates and metallizing on the steel tube sheets appreciably reduced galvanic corrosion on the tube ends. Riesenfeld and Blohm (69) have tested a number of metals for their resistance to corrosion in amine gas-treating plants. Aluminum alloy heat exchangers and columns now are being commercially employed for handling glycol-amine solutions.
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Tank Roofs. A large-span aluminum alloy roof on an oil tank has been built by a British firm. This is reported to be the largest aluminum oil tank roof in the world (47). Various materials were tested in an attempt to prolong the serviceable life of refinery tank roofs and it was concluded that the additional cost of aluminum roofs over mild steel is warranted in cases where severe corrosive conditions exist (46). FOOD PROCESS INDUSTRIES
Elliott (26) has reviewed some applications of aluminum in the food industry. The great majority of foods have no action on aluminum because of the naturally formed oxide film. For some applications, aluminum’s resistance can be increased by anodizing. Beer. One company has installed 21 new aluminum fermenting vats, 27 feet high by 20 feet in diameter (41). Dairy Products. Much new aluminum alloy dairy equipment is being used in Germany. It is easily cleaned, resistant to corrosion, nontoxic, easily fabricated, and less expensive than other equipment (63). Dry Foods. An efficient system for handling dry, bulk foods is built around the use of aluminum containers. Advantages claimed for the system are lower delivered price, less deterioration of ingredients during storage, improved in-plant materiale handling, better sanitation, and no infestation. At present these aluminum bins are employed for materials such as sugar, flour, powdered milk, cocoa, and salt (28). ACTION OF MERCURY
Mercury and its compounds have been known for many years
to be a serious corrosion hazard to nonferrous metals including aluminum, Investigations by Broqm, Binger, and Brown (14) disclosed a number of ways by which mercury can be transferred through a system. Mercury or its compounds have no doubt caused many of the heretofore unexplained failures of nonferrous alloy units. Engineers are cautioned to design processes to prevent accidental mercury contamination from blown manometers, broken thermometers, or other mercury-containing instruments. LITERATURE CITED (1) Alcoa Digest, 22, No. 2, 7 (1952). (2) Aluminio, 20, No. 5, 470 (1951). (3) Aluminum Co. of America, “Alcoa Aluminum News-Letter,” July 1951. (4) Ibid., September 1951. (5) Aluminum Co. of America, unpublished information. (6) Aluminum Co. of Canada, Ltd., “Aluminum with Food and Chemicals,” February 1951. (7) Am. Metal ;Market (June 29, 1951). (8) Arnold, P. C., Welding Engr., 36, No.7,29-31 (1951). (9) Baker, A. M., Modern Metals, 6, No. 4 , 23-4 (1950). (IO) Balash, J. P., and Verink, E. D., Jr., Chem. Eng., 58, NO. 1 1 9 302-4 (1951). (11) Binger, W. W., Corrosion, 8, No. 1, 1 (1951). (12) Binger, W. W., and Brown, R. H., Chem. Eng., 58, No. 8, 224 (1951). (13) Brit. Aluminium Co., Ltd., “Aluminum in the Chemical and Food Industries,” London, Salisbury House, 1951. (14) Brown, M. H., Binger, mi. W., and Brown, R. H., Corrosion, 8, NO.5, 155-64 (1952). (15) Chem. Eng., 58, No. 9, 184 (1951). (16) Ibid., 58, No. 12, 234 (1951). (17) Ibid., 59, No. 2, 218 (1952). (18) Chem. Eng. News, 30, No.22,2344 (1952). (19) Chem. Processing, 14, No. 12, 40 (1951). (20) Ibid., 15, No. 1, 142 (1952). (21) Cheyney, D. R., Metal Ind., 79, No. 21, 441-5 (1951). (22) Coleman, W. P., and Binger, W. W., Chem. Eng., 58, No. 6,220 (1951). (23) Conway, M. J., Iron Steel Engr., 28, 58 (1951). (24) Dahl, O., and Randers, G., Nucleonics, 9, No. 5, 5-17 (1951). (25) Defense Production Record, 2, No.21, 6 (1952) (26) Elliott, E., Food Munuf., 27, No. 2, 69-72 (1952).
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(27) Faith, W. L., Keyes, D. B., and Clark, R. L., “Industrial Chemicals,” New York, John Wiley &T Sons, 1950. (28) Food Engr., 23, No. 9,83-5, 179 (1951). (29) Furtune, 43 No. 6 , 9 3 (June 1951). (30) Fritts, H. W., and Verink, E. D., Jr., IND. ENG.CHEM.,43,2197 (1951). (31) Gresillon, R., Rea. ahmiiiiunz, 28, 18+7 (May 1951). (32) Nartmann, E. C., and Plummer, F. L., Civil Eng., 22, 123-5 (1952). (33) Hoglund, G. O., Welcliw J . ( N . Y . ) 30, , No. 4, 331-46 (1951). (34) Iron Age, 168, No. 5,104 (1951). (35) Ibid., 168, NO. 14, 318-20 (1951). (36) Juniere, P., Aluminium SzLisse, No. 5, 163-72 (September 1951). (37) Kelly, R. C., Heating, Piping, A i r Conditio?ting, 24, No. 1 , 124-9 (1952). (38) Lawrence, S. M., I d . Cheniist, 27,219-24 (1951). (39) Lee, J. A., “Materials of Construction for the Chemical Process Industries,” New York, McGraw-Hill, 1950. (40) Lees, D. C. G., Light Metals, 14, No. 162,494-502 (1951). (41) Light Metals, 14,229-31 (1951). (42) Ibid., 14, NO. 163, 541--6 (1951), (43) Ibid., 14, No. 164, 639-43 (1951). (44) Ibid., 14, NO. 165,662-7 (1951). (45) Loo, K. J. van de, Polytech. Tijdsehr., 7,Y-lOa (Jan. 8, 1952). (46) McConomy, H. F., and E n r , J. J., Petroleum Refiner, 31, No. 5, 124-6 (1952). (47) Manning, Q. P.,Civil Eng. Public W o r k s Rm., 47, 547 (1952). (48) Modern Melals, 7, No. 9, 25 (1951). (49) Moore, W. B., Jr., Petroleum Engr., 24, No. 4, D28, 30, 32 (1 952). (50) Nucleonics, 10, No. 6 . 75-6 (1952).
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(51) Ibid., p. 96. (52) OiZGasJ.,50, No. 11, 122 (1951). (53) Petro T i m e s , 54,320-3 (May 5 , 1950). (54) Picarazzi, J. J., OaZ Gas J . , 50, No. 45, 271-82 (1952). (55) Plant Eq.n ., 6 , No. 4, 38-9 (1952). (.56) Pogacar, C. F., and Tice, E. A., Corrosion, 7 , No. 3 , 7 6 4 4 (1951). (57) Rabald, EI ich, “Corrosion Guide,” Amsterdam, Elsevier Publishing Co., Inc., 1951. (58) Reichert, J. S., and Pete, R. H., Chem. Esag., 58, KO,10, 263 (1951). i59) Riesenfeld, F. C., and Blohm, C. L., Petrotezrm Refiner, 30, No. 2, 97-106 (1951). (60) Schueler, R. C., Corrosion, 7, No. 7, 6 (1951). (61) Shearon, W.H., and Thompson, H. L., 1x1).ENG.CHEW.,44, 254-64 (1952). (62) Shepard, S. VI.,Corrosion, 7, No. 8, 279-82 (1951). (63) Soldmann, D., Milk Plant Monthly, 40, No. 10, 88 (1951). (64) Wanderer, E. T., paper presented at the 8th Annual Conference of the N.A.C.E., March 1952. (65) Wanderer, E. T., Oil Gas J.,50, KO,9, 58-9, 76 (1951). (66) West, J. R., Chem. Eng., 58, No. 9, 276 (1951). (67) Whitabet., AI., MetuZInd., 80, No. 10, 183-6 (1952). (68) Ibid., NO. 11, 207-12 (1952). (69) Ibid., NO. 12, 227-30 (1952). (70) Ibid., NO. 13, 247-51 (1962). (71) Ibid., NO.14, 263-6 (1952). (72) Ibid., NO. 15, 288-9 (1952). (73) Ibid., NO. 16, 303-5 (1952). (74) Ibid., No. 17, 331-2 (1952). (75) Ibid., No. 18, 346-9 (1952). (76) Ibid., S O .19, 387-8 (1952). RECEIYBD for review July 21, 1952.
ACCEPTEDJuly 21, 1952.
CEME
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K. PAYR‘E,
E l e c t r o C h e n t i c a l Engitieering & M a n u f a c t u r i n g Co., 750 Broad S t . , Emmalrs, P a .
acid has been found to be an excellent Condensing agent, resulting in a product of good strength but free from acid-diffusion difficuli,ies encountered with other acidic reagents. Bromine also has advantages a condensing agent. Products having flexural strengths UP to 3800 pounds per square inch havc bcen produced. One mch cement has the unusual property of polymerizing at room tenrpeiature with an alkaline catalyst. This makes it possible to bond a rwin cement directly to alkaline surfaces such as concrete and has resulted in several important industrial applications. h o t h c r cement from this group has greater resistance t o oxidizing acids and sodium hypochlorite than either the furfuryl alcohol or phenol-formaldehyde resin cements. A lower cost is a further possibility, since furfuryl aldehyde is l e s espensive than furfuryl alcohol. Improvements havc been made in Eurfu~ylalcohol cemcnts used for the impregnation oi wood (19). In a filter press handling acids and alkalies, half of the plates and frames were made of wood impregnated with furfuryl alcohol resin cement at room temperature under a pressure of 100 pounds per square inch. The other half n/as not treated. At the end of 1 year the untreated wood had disintegrated to the extent that the plates and frames were discarded. The impregnated plates and frames are still in excellent condition a t the end of 14 months. A furfuryl alcohol resin composition that is satisfactory for impregnating plaster has been described (16). Flexible filter grids made of furfuryl alcohol resin cement reinforced with glass cloth have been under test in a pigment plant and have proved superior t o TTOOd.
Acidproof brick linings continue to use by far tlir greatest tonnage of acidproof cements. Several other important industrial applications have been developed, A successful techdque has been developed for impregnating w o o d with furan resin cement which has increased the life of wood filter-press plates and frames. Filter grids, fabricated from glass clo th-reinforced €uran resin cement, have high strength, light weight, desired flexibility, and chemical resistance. Large diameter steel covers for chemical process equipment have been satisfactorily protected from hydrochloric acid and chlorinated solvents by reinforced furan resin cements. New high solids neoprene cements cut labor costs in tank linings,
A
Vol. 44, No. 10
NUMBER of new industrial applications in chemical plants
have been developed in which various types of ncidpioof cemmts have been used FURAY KSSIN CEMEWTS
Cntil recently most of the furan resin cements used in the constiuction of chemical equipment were based on resins obtained by the acid polymerization of furfuryl alcohol or furfuryl alcoholaldehyde condensation products with or without other materia1,i that inay be considered as additives. Within the pa& 2 years at least two chemical-resistant cements, mhich are based on furfuryl aldehyde condensation products, have been placed on the market. When furfuryl aldehyde is condensed alone by means of acids, the product is a weak porous substance. The effect of various additives on the strength properties of a cement based on the polymerizing tendencies of furfuryl aldehyde has been studied ($9, 41, 85). It has been found that among suitable additives are secondary aromatic amines, certain furan derivatives such as furfurin, methylfuran, furfural acetone, 2,5-dimethylfuran, and furfuryl acetate, and ligninsulfonic wid with one of the other additives. p-Toluene-
