FRANCIS C. FRARY Aluminum Company of America, New Kensington, Pa.
ONE OF
THE
HYDRAULIC POWER PROJECTS OF THE ALUMINUMCOWPANY OF AMERICAON LITTLETENNESSEE RIVERSYSTEM
THE
ECONOMICS OF THE
ALUMINUM INDUSTRY LUMINUM, the only common commercial metal which has not been known or used for hundreds or thousands of years, is of particular interest to the industrial scientist, Isolated a little over a hundred years ago, it remained a laboratory curiosity until after the middle of the nineteenth century. Concentrated scientific and technical advances have since made possible its commercial production, first as a precious and later as a semi-precious metal. February 23,1886, marked a turning point in the aluminum industry. Twenty-two-year old Charles Martin Hall announced the discovery of a process for making the metal a t such a cost that it could compete with the every-day metals of commerce. He had been intensely interested in chemistry, even before entering college, and had been for several years actively studying and experimenting on the reduction of alumina. Nine months after his graduation from Oberlin, Hall found that aluminum oxide in a fused cryolite bath could be reduced to metallic aluminum electrolytically; this is the basic principle of the process for the production of aluminum in all parts of the world today. Hail also shared, until his untimely death, in the solution of the absorbing technical and commercial problems involved in transforming his laboratory experiments into a full-fledged metal-producing and -fabricating industry. Fortunately, too, he was able to share in the financial results of his labors and those of his associates, and lived to realize his dream of a fortune made in commercializing this new metal for the benefit of mankind. It is perhaps typical of the scientific
CHARLES MARTINHALL,DISCOVERER O F ELECTROLYTI P R O C E SFS OR A L U M I N U M MANUFACTURE
spirit that he left most of this fortune to support the cause of higher education in this and other lands, a large share of it going to his Alma Mater, Oberlin College. The economic advantage of Hall’s process as compared with the previous processes was due to certain fundamental factors inherent in it. One of the most important, from the standpoint of cost, was the use of aluminum oxide as the “ore” to be reduced, instead of the chloride or fluoride which had previously been used. Not only does the oxide contain practically twice as much metal per pound as the chloride or the double fluoride, but it is much easier to prepare a t a low cost and with a high degree of purity. The latter item is important because all metallic impurities except the alkali metals are reduced with the aluminum and appear in the finished product. Moreover, the process is such that a nearly quantitative yield of the metal in the aluminum oxide can be commercially obtained, whereas the yields from the other salts were far from quantitative. Another large saving in cost was obtained by substituting electric current for the chemically or electrolytically produced sodium as the reducing agent. The continuous production and tapping of the molten metal a t relatively long intervals, permitted by the electrolytic process, naturally saves much labor and material as compared with the chemical processes which were necessarily operated discontinuously. The elimination of halogen or halide by-products is another factor of considerable commercial importance. In considering the economics of the production of aluminum, we might first analyze the principal factors involved in the 146
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INDUSTRIAL AND ENGINEERING CHEMISTRY
production of the pig metal a t the reduction plant: the cost of the materials consumed (aluminum oxide, electrodes, and electrolyte materials), cost of power, repairs and maintenance, labor, and overhead.
Raw Materials Alumina (commonly called “ore”) is the principal raw material from the standpoint of both weight and cost. Although theoretically only l .89 pounds are required to produce a pound of metal, the presence of a certain amount of moisture and soda in the oxide, and certain mechanical losses inherent in handling such a material, bring the actual consumption up to nearly 2 pounds per pound of metal. It is by far the purest of the raw materials used; and really deserves to rank with c. P. chemicals, in that it ordinarily contains less than 0.015 per cent each of the oxides of iron and silicon, which are the harmful impurities, and only a few tenths per cent of soda. The presence of appreciable amounts of water not only increases freight costs but causes loss of fluorine from the molten fluoride electrolyte by hydrolysis when the alumina is used. It is therefore necessary to balance these two costs against the cost of calcining the aluminum hydrate at a higher temperature or for a longer time during its manufacture. The Bayer process of extracting aluminum hydrate from bauxite is one of those fundamentally simple chemical processes which, because of their simplicity, hold the field in spite of the efforts of a multitude of inventors with rival processes. The steps of dissolving the aluminum hydrate out of the bauxite with caustic soda and separating the insoluble red mud (thus discarding in one step all of the iron and titanium oxides and substantially all of the silica) can be carried out in ordinary steel equipment. So, also, can the subsequent precipitation or crystallization of the hydrate A120diHz0. In its granular, sandy form this hydrate is easily filtered or separated by decantation, and after washing requires only calcination to produce the finished oxide. It is only with such an inherently simple process that the extraction costs can be kept down to the minimum. The problems of the assembly of the raw materials for alumina production and the l o c a t i o n of t h e alumina plant with respect to the reduction plant are i m p o r t a n t . About two tons of the present commercial grade of bauxite, a couple of tons of coal (or its equivalent in other fuels), a n d s o m e t h i n g like 200 pounds of soda ash per ton of alumina produced are required. Where it is possible to f i n d a b a u x i t e field, as coal m i n e , a n d water power all within a radius of 100 miles or so, as in southern France, the freight problem is considerably s i m p l i f i e d . In America, with our magnificent distances between the b a u x i t e f i e l d s , the coal
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fields, and the water powers, transportation costs play a large part in the cost of the finished alumina. For any given alumina plant location, the cost of transporting to the plant the relatively large weights of raw materials required must be considered, along with the cost of transporting the finished alumina to the reduction plant, in comparing its advantages with those of any other location. For example, bauxites are assembled from Arkansas and from British and Dutch Guiana a t East St. Louis, where they meet the necessary coal, oil, and gas to raise the steam, produce the power, and furnish the heat required to calcine the finished hydrate, where soda ash may be obtained reasonably, and where an adequate supply of labor is available. The finished alumina must then be shipped across the country to reduction plants in eastern Tennessee, central North Carolina, or northern New York, in order to carry it to the necessary source of cheap power. Large deposits of brown coal, which can be mined at a low cost by open-cut methods, and the absence of much cheap water power allow some of the German plants to combine the alumina and aluminum plants at a single location, thus benefiting from unified control and a n efficient utiIization of fuel in the combined production of power and steam. The only other raw materials to be considered are water (an abundant supply low in lime and magnesia must beavailable), lime, and filter cloths. Although the latter is a minor item in weight, it is not a small item of the expense.
Repair and Maintenance The amount and quality of labor required will depend upon the type of equipment installed and the size of the plant. Our relatively expensive American labor naturally encourages the development of large units of equipment and arrangements for the automatic control and automatic handling of the materials in process. All of these methods of reducing labor costs are tempting; but the fact must not be overlooked that the interest and depreciation on such equipment runs a t the same rate when the equipment is idle as when it is operating. With the fluctuating requirements of the metal market, the cost of maintaining idle equipment during the periods of low production may be more than the labor saving involved in its use during periods of high demand. Repairs and maintenance on a chemical plant are too well appreciated by t h e AND readers of INDUSTRIAL
EKGINEER~NG CHEMISTRY to justify much comment. In view of the fact that
MINIR’GBAUXITE,THE ORE ALUMIKUM,BY OPEN-PIT METHODS
OF
a week to take inventory, as might easily be done by a different sort of manufacturing enterprise. It has frequently been said that the aluminum industry cannot afford to use power costing more than $10.00 to $15.00 per horsepower year. This figure rules out not only all fuelfired power installations, except under the most unusual circumstances, but also most of the available water powers. NaturaIly, you cannot afford to sell power to yourself a t $10.00 per horsepower year if you have within easy transmission distance a city or other group of customers who are willing to pay two or three times that amount. The aluminum industry is therefore driven to the wilderness, in most cases, to find locations a t which power can be developed cheaply enough and cannot be sold a t a higher price. The major items of cost in most hydroelectric developments are the land and water rights and the dam and power house. To obtain a steady supply of power the year around, large water storage must usually be provided; this involves the purchase not only of the land which will be overflowed by the rising waters when the dam is closed, but also of much adjoining land which may be damaged, or allegedly damaged, by the lake. When we consider that one of the aluminum plants in this country is provided with two storage lakes covering 16,000 and 5000 acres, respectively, and even then is frequently compelled to reduce its metal production substantially in the dry season because of lack of water, the influence of the cost of land and the taxes and interest thereon may be appreciated. To obtain low-cost power, the water must be used under a considerable head, and locations where such lakes can be formed a t points where a fall of 100 to 200 feet or more may be utilized are not common. This explains the importance of the construction of a series of such reservoirs on the same river, so that the water impounded in the uppermost reservoirs may pass through a series of power houses on its way to the sea. A classic example of cheap power, which illustrates this point, is the Rjukan development of Xorsk Hydro, where water from the natural lake a t the head of the river drops about 2000 feet through two power houses a few miles apart and then passes through a series of a t least half a dozen more power houses on its short path to the ocean. It has been publicly stated that this power is produced a t a cost of less than $3.00 per horsepower year; the reasons are undoubtedly the low development cost and the high head under which the water can be used. The location of the power plant is significant, not only from the standpoint of the cost of transporting the alumina and other materials (including materials for the construction of the dam, power house, etc.) to the site, and shipping finished aluminum to market, but also because of the labor situation. In remote localities it is usually necessary to build and operate towns as well as plants, and such “townsite expense” is no small amount of the burden to be carried by the industry. All of these fixed charges pile up a t a tremendous rate in periods of depression when the metal production must be drastically reduced, while taxes and depreciation run on and the water runs over the dams instead of through the turbines.
A STEPIN THE PURIF~CATION OF BAUXITE-FILTERING IMPURITIES FROM THE SODIUM ALUMINATE SOLUTIONWASHING CAKEFROM KELLYPRESS
the alumina recovered in a single 5- or 6-day cycle from the sodium aluminate solution is only about 60 grams per liter, it is obvious that such a plant can easily become a “pipe fitter’s paradise.” Adequate technical control and supervision are naturally essential to the economical operation of the plant.
Power The cost of power is one of the relatively large items in the cost of the metal because it requires a t least 10 kw-hr. delivered to the rotary station or other source of direct current, to produce each pound of aluminum. When public utilities talk about cheap (‘off-peak power” a t from 0.6 to 1 cent per kw-hr., it is obvious that no aluminum producer would be interested. The fact, that the electrolytic process operates a t approximately 960” C. and that the cells will freeze in a very short time if the normal input of power is stopped or largely diminished, dictates the requirement of a completely uniform and continuous supply of power at all times. The industry operates a t an electrical “load factor” so high as to seem ideal from the standpoint of the power plant, until we consider the necessity of carrying “stand-by” equipment to allow shutdowns for repairs, etc., without interruption, and the inability to use, in the case of water power, much more than the minimum supply which can be guaranteed in the dry periods. Shutting down a “line” of aluminum cells or ‘(pots” operating a t 900” to 1000”C. and taking 20,000 or 30,000 amperes a t 500 volts is not a difficult or lengthy operation if properly performed. However, t o start that line again a t a later date may involve a tremendous amount of hard labor in digging out the frozen bath, relining many of the pots, etc., as well as the unavoidable production of large amounts of low-grade metal for the first few weeks of the new operation. An aluminum reduction plant cannot, therefore, be shut down for
Carbon Electrodes Next to alumina, carbon electrodes are the most important material consumed in the process, With poor operAion, or under conditions prevailing thirty years ago, as much as a pound of carbon electrode might be consumed per pound of metal produced, but modern and efficiently operated plants average only around 60 per cent of this amount. Even at this figure the aluminum industry probably manufactures and consumes a greater tonnage of carbon electrodes than all other industries put together. 148
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Since all of the impurities in the ash of these electrodes find their way into the bath, and their metallic portions go into the metal, the importance of purity of the electrodes is apparent. The highest grade of low-ash petroleum coke is calcined in special furnaces, ground, and mixed with carefully chosen proportions of pitch and tar to produce the raw electrode mass from which the electrodes are pressed or extruded. They are then baked in gas-fired furnaces or electric furnaces under such conditions as to give the best ohtainahle physical properties-i. e., high electrical conductivity and low rate of burning in air. The latter is important because the electrodes project up through the crust on the top of the molten electrolyte and, if the electrode quality is poor, very serious losses of carbon and contamination of the bath are caused by burning. The air s e e m to attack preferentially the binding material and disintegrate the red-hot electrode, so that the pulverized coke particles alone are left. The maintenance of a proper electrode quality to rninimiae this loss, the utilization of “green” or unbaked scrap and of baked scrap, including “butts” (the unused ends of the electrodes), all require close control and cooperation with the carbon plant in order to reduce costs. This is one reason why i t is advantageous to build an electrode plant in conjunction with an aluminum plant. An economically important development in the electrodes for aluminum pots is the Soderbeg continuous self-haking electrode. Eere the electrode mass is tamped into an aluminum shell supported over the pot in such a way that the baked lower end of the electrode extends into the fused bath, while the material above it is graduatly baked by the heat fzom the bath in proportion as the bottom end is consumed. The fundamental economy in the use of this electrode resides in the elimination of the operations of pressing and baking electrodes, and the capital investment for presses, ba.king furnaces, etc. The extra cost of the aluminum mantle and the expense of removing and handling the current-carrying inserts or other means of introducing the current into the large electrode must be offset against this saving. While this electrode has been used in several plants, it is still relabively new and has not yet been generally adopted.
Bath Materials The bath mat.erials employed comprise chiefly cryoiite (Na3AIFn)and aluminum fluoride; the latter is required to neutralize the effect of a certain amount of soda present in the alumina fed into the pot. Although natural cryolite occurs only in Greenland and hence is relatively expensive, a good demand for high-purity cryolite for other industries leaves a relatively large amount of lower grade material to be sold to the aluminum industry at a reasonable price. The cost of this material and the disadvantages of the impurities which it contains must be weighed against the cost of manufacturing the artificial salt. The aluminum fluoride is made by the reaction between aluminum hydroxide and hydrofluoric acid. The cost of its use must be balanced against the cost of more completely removing the soda from the alumina by further washing or acid treatment. Apparently, however, there is a limit below which such soda removalisnot feasible. The amount of bath materials consumed per pound of aluminum naturally varies considerably, depending upon operating conditions. One of the largest lasses is due to the fact that the pot linings a.bsorb large amounts of the molten bath, and when the pot has to be relined this bath is lost. The bath consumption is thus dependent to a considerable extent upon the pot-lining life which may vary from a few weeks to several years. Under commercial condit,ions the total consumption of bath materials may vary between 5 and 15 per cent of the weight. of metal produced, and is therefore
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air important item of expense to be coiit.rolled by good operating practice. Probably the largest it,enrs in tlie repairs and maintenance account are the pot linings and repairs to the steel shelLs of the pots. $It.hough these sirells are made of heavy steel, the electrical endosmosis causes the developmcnt uf tremendous pressures inside the lining so that the steel plates are bent o~~toS~liiipe,rivetsareshearcdoff,et.c.,duri~~gtlielifeofapot. Anode and cathode connections also require frequent repair or renmwd, and the design and use of proper types of such contacts are important in good pot rooiii management’.
Labor Labor is naturally a much more important item under American conditions than it vvtiuld be io some other countries, and a vastly greater one than in the production of pig iron, for example. The reason is obvioiis when we consider that one blast furnace with a nioderat,e sized crew may produce a thousand tons of iroii per 24 hours, while a pot room containing about ninety 20,OOQampere pots would produce less than 15 tons of aluniinuin in the same time. Ehch of these ninety pots requires considerable individual at,tention; every few hours its bath becomes impovcrislred in alumina, an “anode effect” occurs and is iirdicated by the flashing on of an electric light, and several men with crowbars or other heavy tools must immediately break in tlie frozen crust of electrolyte upon which the next charge of ahnnina has heen heating. Aft,erthoroughly stirring the inoiteii bath, changing some electrodes, and readjusting others, the pot inay be given more alumina and left with a minimum OS attention for a number of hours, until the anode effect again appears. Some of tlie work of changing the electrodes may he (acilitated by the use of a crane: especially when large electrodes are used, and the crane is aiso serviceable in connection with tapping orit the niiiltcir metal and pouring it into pigs. l h x i vit.11 all modern Ialm=iavin~drvi COLD ROLLINtrp did not takc up this burden and where sheet and plant which is operating. In addition to the iisiial CXIII?IISP wire production, for example, were carried out in mills denigried for hraw and copper work, the industry was handifor superintendence, technical control, and laboratory, tlie is,>Lated location of the plants adds a large and variable airiorint products resulting from the rolling tides of foreign metals, scale, etc. of townsite expense for land and buildings to Iionsc workmeii, clectrolyt.ic corrosion in t.he finislied stores, etc., and for recruiting and Iirinxiiig iii fniiii time til time the necessary labor when eonditiiiuq rquire an iiicri!:wo nrticlr \s-lieii it ~KIS espir~cdto water or to the weather. in force. T h e s e o v e r h e a d One problcni in the fihricaitems are easily overlooked by tioii of aluminnin is itssoftness outsiders but are very real to which is sucli that the metal the indiistry. is more easily scratched than most of its c o m p e t i t o r s in Development of a storage or handling. Specid Market yrecautious in the mill and the aroidance of large warehouse When the Pittsburgh Bediicstocks becorne necessary. This tion Company had fiiially tnaiimeans, howerer, that the inaged to get Hall’s process into dividual custorrier must gencroperation and had aecutnulated ally have his material fabria ton or so of aluminurn, they cated to his order and cannot Sound t h e m s e l v e s vitlr a. obtain iuaterial “off the shelf.” white elephant on their hands. T h i s course delays his depiow that they Iiad produced liveries and, if l i e is ordering the metal as the result of great small lots of material, increases efforts, no one knew what to his costs. do wit.li it or mould buy it for a n y e x c e p t “jewelry store” A limited amount of standard types and sizes of m a t e d uses. I n order to make any kind of a success of the aluniican becarried in thewarehouse; num reduction process, it was but because of the relatively riecessa.ry to develop a niarkeb high cost per pound for the for the metal. Sinceobviously finished product, most convery few of the ultimate consumers desire to obtain mates u m e r s could use the pig rial of specified special dimenmetal, it was at once necessions so as to leave all the scrap sary to fabricak it into other for the mill to handle and thus forms. reduce their own investment. Here tlrc natural conservaThis inevitably requires a large tism of existittg nietal fabrieab number of special orders. At ing plants was a real obstacle. one time in recent years, the A 32-Cnern-Y~n~SHOVEL DIPPER,LARGEET IN TEE They had copper and brass and average size of the order going WORLD,CONSTRUCTED or STROUO ALUMIN~M ALLOYS
FEBRUARY. 1936
INDUSTRIAL AND ENGINEERING CHEMISTRY
through one large mill was in the neighborhood of only 200 pounds. Obviously, the fabrication of a carload of sheet of uniform gage, dimensions, composition, and temper is more economical than the fabrication of a 200-pound lot; it is to be hoped that eventually increasing use can be made of standard warehouse sheet. The amount of research and technical control required to develop the technic of manufacturing and fabricating the multitude of special alloys and products, to maintain their quality a t a point where they would meet specifications, and to accomplish in fifty years what other metals have been developing through many generations may be imagined. As competition between the different metals and alloys becomes general, the consumers’ demands will become more and more exacting, and new alloys and new fabricating processes must be invented and developed in order to make progress. In the case of a new metal such as aluminum, there is a great advantage in being able to select for a given user the most economical fabricating process and furnish him its product. In most of the older metals any given manufacturer generally specialkes in one type of fabricating process, such as casting, forging, rolling, extrusion, screw machine work, etc.; consequently the customer must depend on his own ingenuity and knowledge to determine which one of the possible processes would make the best and cheapest product, as well as which competing fabricator should have the job. Varying technical efficiency in the different plants complicates the picture. A large producer who has available in his own organization adequate facilities for carrying out all types of fabrication is in a position to advise a customer impartially as to the best and cheapest method, since he is not required to push a given method because it is the only one that he can carry out. The increasing variety of aluminum alloys brings in its train a scrap problem which is serious and can be economically solved only where the mill is producing enough of each type of alloy so that the segregation of its scrap does not become too great a burden. Very often the scrap may amount to as much as 40 per cent of the ingot weight, and it is obvious that the proper segregation of the different grades of scrap and their remelting and reworking into suitable products are vital to the economic success of the fabricating plant. As long as the manufacturer keeps the metal within his own plant, he can, by taking proper precautions, be reasonably sure of the quality of the different lots of scrap which he produces. Consequently, if he has the proper knowledge and facilities, he can rework that scrap into entirely satisfactory products. However, when used material from all sorts of sources is offered as scrap, there is no economical way of determining the composition and quality of each piece, and sorting and grading involves considerable guesswork. Moreover, such scrap is often contaminated with other metals, grease. and dirt. These present special problems to the melter and result in a material that may be less desirable in both composition and physical qualities than the material made from new metal. Such “secondary metal,” however, is naturally cheaper than new metal and is therefore used where possible. Fortunately the casting field offers an opportunity to use alloys of a great variety of compositions, and most of the secondary metal production goes into this field. The reworking of a manufacturer’s own scrap in his own plant naturally tends to maintain the supply of high-grade metal and thus to reduce the amount of secondary metal available. If any large portion of the fabricating scrap had to be sold for remelting into secondary metal, the cost of fabricated articles would be considerably increased. In considering the economics of fabrication, we must not overlook the cost of carrying out research and development in new fields and processes which present themselves from time
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30 FEETIN DIAMETER AND ACETICACID STORAGE TANKS, 30 FEET HIGH,FABRICATED FROM ALUMINUM
to time. Every manufacturer, large or small, must do such work if he is to make progress. The proper choice of the fields to be entered, the processes to be studied, and the new products to be developed, so that the resulting sales may be sufficiently profitable to justify the investment and return a profit on it, have an important bearing on the economics of fabrication. In the fabrication process itself, one of the important economic factors is the location of the plant. Not only must it be well located with respect to its probable market, with adequate railroad facilities to ship its products and receive the raw materials; it must also be in a position to obtain economically the necessary metal, fuel, and power, as well as an adequate supply of suitable labor. The possibility of combining plants using a number of different fabricating processes on one site, so that they may use a common melting room, shop, engineering and control departments, and power plant, must always be considered. The economics of the utilization of the scrap from each particular plant must be carefully studied. The utilization of alloy scrap, in particular, must be carefully planned for, and foil scrap must be handled in a different way from sheet scrap. The types of materials to be produced and the sizes that the customers in the district will be likely to require, as well as the variety of products to be made, will naturally determine the equipment and layout of the plant. Good planning in these respects can do much to reduce costs. Technical control and development must provide not only for the needs of the plant itself, but also for a considerable amount of customer service, if the industry is to make progress.
Future of the Industry But what of the future? If in fifty years the productive capacity of the United States has increased from nothing to about 250,000,000 pounds of aluminum per year, what will happen in the next fifty years? Large tonnages of bauxite have been consumed. Will we run short of raw materials? Can we use clay or alunite or something else in place of bauxite? At present, the industry is drawing a considerable amount of its bauxite from foreign sources and thus conserving the domestic supply to a certain extent against the time of need. There are, however, tremendous deposits throughout most of the tropical countries, and it is conservatively estimated that the world’s bauxite supply is adequate for a t least another thousand years. There is nothing impossible chemically a bout the production of alumina from clay or alunite, but a t the moment alumina from bauxite is cheaper. The slightly lower first cost of clay is offset by its lower alumina content and the
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greater cost of extracting this alumina in the proper purity by any known process. The possible value of the potash in the alunite is largely offset by the high cost of transporting both the potash and the alumina to market, from the localities where the alunite occurs and where it must naturally be processed. One of the fundamental problems of the industry is that of the strategic location of future plants. Reduction plants have to be located at or near the water power; but it must be determined whether it is more economical to pay a higher water power price and have the plant nearer to its customers and to its source of supply of alumina, or to go to a remote point for cheaper power. The latter alternative is exemplified by the plants in Xorway. There geographical conditions make power very cheap, but natural conditions require the importation of all the raw materials, and the local use of the metal is relatively small. Can an aluminum reduction plant be economically installed and operated on the Pacific Coast, for example, taking into consideration the probable cost of shipment of the metal to market, as well as the transportation of raw materials? It is evident that the right answers to these fundamental questions are of great importance in determining the eventual future of the industry. One of the important problems of the future, as well as of the past, is that of the relationship between productive capacity and average demand. The increasing supply of aluminum in a variety of manufactured forms in the country naturally provides an increasing source of secondary metal, and in times of depression everybody tries to realize on such scrap material. The result is that excessive amounts are forced on the market at a time when the demand is low, prices are forced down, and the secondary metal tends to take a greatly increased share of what business there may be. In good times the demand for new metal may be three or four times the demand during the depression. Upon what basis shall capacity be adjusted to demand so as best to serve the public? The disastrous effects of over-capacity in times of depression are too well known to require discussion. With approximately a dollar invested per pound of aluminum produced per year, the aluminum industry must needs consider carefully the wisdom of further expansion in boom times and must carry a heavy burden when each depression arrives. This modern age has become an age of metals and the curve of production has been rising steadily for all metals. For aluminum the slope of this curve has been about twice as steep as for most of its competitors. Will this rate of growth continue, or mrill the intensive work of recent years in broadening the structural uses of aluminum in the transportation field make this curve turn upward a t a still steeper angle? At one time the needs of the automobile industry were such a large proportion of the total sales of aluminum that fluctuations in this highly sensitive field could be (and were) very costly to the aluminum industry, The broadening of the use of aluminum into other fields of transportation is undoubtedly a stabilizing factor as far as the aluminum industry is concerned. Any metal that is dependent for a major part of its market upon one industry is likely t o be in a precarious situation.
Competition with Other Metals Modern competition is competition between products. What then is the situation of aluminum with regard to competing metals? The only other commercial light metal is magnesium, and it has been making increasing strides in competition in recent years. Successive price reductions have brought it to the point where, given sufficiently large quantities, many castings can be delivered a t prices which make them cost no more than aluminum castings. For some special purposes, magnesium; even a t much higher prices,
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has replaced aluminum and will continue to do so. The inherent difficulties in fabricating sheet and certain other wrought products of magnesium, and the much greater difficulty of protecting it against corrosion, together with the lower strength of its alloys as compared with modern highstrength aluminum alloys, seem definitely to limit its field in some directions. However, research and development may change this picture later. Beryllium, the other contender among the light metals, appears to labor under such handicaps that it is unlikely ever to become a serious competitor as far as tonnage is concerned. While aluminum and magnesium ores are both abundant and rich and easily treated, beryllium occurs only in commercial quantity in beryl, a mineral found as one of the constituents in certain pegmatite rocks. Considering that the average beryl content of a beryl-bearing pegmatite is not over 5 per cent and that the beryllium content of a good grade of beryl is probably about 4 per cent, the original ore as mined contains only 0.2 per cent beryllium. The difficulty and expense of producing the metal from such an ore, as compared with producing aluminum from bauxite containing 60 per cent alumina, are enough to prevent any large invasion of the aluminum market by beryllium. Of the older and heavier metals, copper and its alloys have long been in competition with aluminum. For copper itself, the principal competition has been in the field of high-tension electrical transmission, where over 430,000 miles of steelreinforced aluminum cable have been installed in this country alone. The strong aluminum alloys are coming into increasing competition with brass; the recent commercialization of a free-machining strong aluminum alloy which comes very close t o brass in its machining qualities and at the same time offers a saving of about two-thirds of the weight of the brass part, should give an increasing market for aluminum. Competition with cast iron and ordinary steel, while of no moment to the iron and steel industry because of the fact that the pryent production of aluminum is less than 1 per cent that of iron, has nevertheless been of considerable importance to aluminum. It is exemplified by aluminum crankcases and engine parts in automobile and aircraft engines, and by an increasing use in the structural parts and bodies of railroad cars, trucks, etc. Stainless steel. with its high strength and luster and resistance to corrosion, offers intensive competition to aluminum in many fields. Undoubtedly both of these metals will find many uses where they will displace the older metals. Each will have its own advantages and its own fields where the other cannot economically replace it. Just what those fields will be remains for future competition to determine, and in this connection research and development will have an important part in bringing about improvement in the processes and product and a reduction in the costs of the ultimate consumer. Aluminum could not have grown from a semi-precious metal to its present broad use and low price without a tremendous amount of intensive research and development work. In no other way could the handicap of the experience of the ages in the use of the older metals be overcome. Consequently, the industry has naturally come to place more reliance and dependence on applied science than most of its competitors, and this habit will give it a real advantage in future competition for some time to come. Undoubtedly the other metals will be forced to do an increased amount of such work; as this occurs, competition among the metals will become more severe, and the consumers all over the world will benefit increasingly by having made available to them products which meet their needs in a manner far superior to those a t present obtainable. RECEIVED December 17, 1936.
