SEI"IY3MBEI1, 1940
INDUSTRIAL AND ENGINEERING CHEMISTRY
While many rnetallurgists have been active in the improvement of older materials of construction and the introduction of new ones, others in the industry, in cooperation with chemists and chemical engineers, have been engaged in increasing the knowledge of the corrosion-resisting properties of both old and new materials and in defining their fields of usefulness. A review of published data on corrosion will show a tremendous increase in the information available in 1940 as compared with 1918. This better understanding of the proper use of corrosion-resisting metals and alloys should be of value in ensuring the most efficient use of availahlo materials in connection with the expansion of the chemical industry that will form part of the general preparedness program.
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it may he stated, therefore, with considerable assurance that the corrosion-resisting alloy industry is in an excellent position not only to take care of a considerable increase in demand for their present products, but also to produce new a.lloys to meet new demands and to guide the chemical industry in tlicir proper selection, fabrication, and use.
Literature Cited (1) Lipport. T . W., Iron Age. 145, 33-40 (Mag. 23. 1940). (2) Kohinson.C. S.. Chern. & Met. Eng., 46, i64 (1939).
(3) Woiciman, N. E.. and Uernbhtt, A. J., "Engineering Alioys", Am. SOC.for Metais, 1936.
PLANT EQUIPMENT I). H. KILLEFFER 60 East 422nd Street. New York, N.
Y.
as possible for the same reason, design requiring necessarily to be fitted to the material used. Within the past two decades of swift development of chemical industries, the variety of construction materials available to the equipment builder has increased substantially. 1. Standard equipment of various kinds can be produced Whereas two decades ago the materials available for resisting more easily and quickly than special designs. chemical attack were strictly limited in number, today the 2. Special metals and alloys are important but not vital in list is very broad. Among the materials likely to be difficult the preparedness picture. to provide, chromium is outstanding. Otl~erwiseit seems nn3. In general, the chemical process industries have relikely that any important shortage of a material considered cently modernized and are in excellent condition for of strategic importance will occur. Trouble may he exassuming the burden of added output. perienced in getting par4. Where special skills ticular alloys of various arc involved, as in types on account of deceramic and special mand for other purposes. machine work, esThese troubles must be tablishment of prihandled by priorityestabority systems ,and lished by government orrelief from present der. IIowever, with the legislative res t r i cvariety of alloys and other tions on hours of corrosion-resistant matework may he essenrials available SOT building tial to meeting fast chemical PTOCW equipproduction schedment, even low-priority ules. jobs should he handled without serious difficulty. It should hardly he At worst, this might renecessary to amplify a quire return to some of the statement 80 obvious as corrosion-resistant met.& onr first Doint. Yet observations by numerous and matt.rials which have builders OS equipment exbeen discarded in favor of modern alloys, but even tending over tong periods that is not fatal to the of time suggest that in picture. peace and war the ongiFurthermore, the quanneers' arbitrary departure tities of alloys required in from standard or nearstandard design is their equipment for PTOCISS industries is small as comgreatest trouble. Changes from s t a i i d a r d designs pared with other demands. which seem to be minor Recent modernization DTOgrams have placed indusmay actually involve seritries of this kind in exous losses of time when cellent position. This speed is essential. SimiPhotograph Ivan Wide World Pholoa, Ino. Iarlv. would tend to minimize ~.materialsusedshould be standardized as nearly requirements for normal WELDINQSTAINLX~SS STEELTO FORM AN INTEORAL MASS
S
EVERAL important points are emphasized by a recent
surrey of nearly three hundred firms manufacturing equipment for chemical processing.
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INDUSTRIAL AND ENGINEERING CHEMISTRY
operation and leave unsatisfied only that demand which arises from strictly martial expansion of industry. Beyond that is the fact that present production schedules in the industry stand a t a comfortable margin below capacity. This is true apparently of both the equipment-using and the equipmentbuilding industries. It appears, then, that here again no bottleneck is to be expected. The question of special skill is very different. Here legislative restrictions on the hours of work of adept workers place a rigid frame around operations. Training of new men to expand output is often a matter of years, or months a t best. Thus increased output from special machine shops making instruments, from ceramic kilns producing chemically resistant ware, and other similar operations is difficult to obtain quickly. It is reasonable to suppose that in such cases of stringent necessity the laws prohibiting overtime may be relaxed, but even this permits only a partial solution of the prob-
VOL. 32, NO. 9
lem. No real answer is evident except through long-term cooperative planning by labor and industry working together. The effect of this on a large-scale preparedness program remains a question of the speed required by the program when it gets under way. Several important techniques new since 1918 affect the present picture in important respects. Welding as a method of construction has been developed to a great extent in the period of peace. Its application to all types of industrial work and particularly to handling certain aIloys is one of the marvels of our age. Lately even the construction of ships has been accomplished by welding from sheet metal. Clad metals in which a high-alloy surface is placed on a carbonsteel base tend to give us maximum usefulness from a minimum of alloy. Further, the period of use of alloys is now becoming long enough so that secondary and scrap metals have become important.
ACTIVATED CARBON ARTHUR B. RAY, 30 East 42nd Street, New York, N. Y.
A
CTIVATED carbon is an essential material for use in militarygas masks and all other devices which protect against toxic gases and vapors. It was developed and f i s t used for this purpose during the World War, and since that time has become an essential material for many industrial applications such as the recovery of solvent vapors, recovery of gasoline from natural gas, recovery of light oils from manufactured gas, removal of odors from air, purification of carbon dioxide and other gases, catalyst, etc. Approximately 6,000,000 pounds of activated carbon were produced by a method developed in the United States during the World War for use in military masks. Although the process was capable of producing high-quality carbon, the equipment used in the emergency was such that the carbon made for military purposes had a service life of approximately one third that of present acceptable gas-mask carbon. Because the desired carbon must be relatively dense and hard, such raw materials as coconut shells, other nut shells, fruit pits, and, to some extent, hard coal were used. Since the World War substantially all of the vapor-adsorbent activated carbon manufactured in the United States has been produced from coconut shells. There has been no real incentive to make vaporadsorbent carbon for industrial uses from materials other than coconut shells because the supply of this raw material has been adequate and the quality of the product satisfactory. The normal supply of shells is derived from the coconuts imported as such into the United States. The amount of shells normally available is a small fraction of the amount needed for the production of gas-mask carbon for military gas masks alone in an emergency. Since the importation may be decreased or stopped entirely in an emergency, it is obvious that no dependence can be put upon coconut shells or other tropical nut shells as raw materials. A domestic supply of fruit pits and nut shells is available which can be utilized as raw materials for the production of gas-mask carbon. But data gathered from various sources show that even if all of the fruits pits and domestic nut shells could be collected and utilized for the production of gas-mask carbon, they would still be able to supply only a fraction of the emergency demand.
The Chemical Warfare Service and others interested in the manufacture of activated carbon have long recognized that the available amount of the usual raw materials was inadequate for national defense and industrial purposes during an emergency. A great deal of experimental and development work has been done to develop processes for producing satisfactory vaporadsorbent carbon from readily available domestic raw materials. High-grade gas-mask carbon has been made from practically any kind of wood sawdust, and a large amount of this carbon has been supplied to the Government. It is of considerably higher quality than is required by United States Army specifications. Processes have also been developed for the production of gas-mask carbon from coal and hardwood charcoal, and samples submitted have passed Army tests. Other processes capable of producing acceptable carbon from domestic materials have been developed. There is no question, therefore, but that gas-mask carbon can be produced from domestic materials which are available in quantities far in excess of the requirements. Despite the fact that processes have been developed because of the long-range viewpoint of the Government and interested manufacturers, present plants do not have sufficient capacity to produce the amount of carbon required in an emergency. Manufacturing plants a t present are capable of making acceptable gas-mask carbon a t approximately one fifth of the rate required in an emergency. Furthermore, available plants do not have the proper equipment to manufacture carbon most efficiently from domestic materials such as sawdust, wood charcoal, and coal. The present plants normally produce activated carbon from coconut charcoal for industrial uses, which is different in many respects from the gas-mask carbon required for military purposes. The desirability of manufacturing and storing a supply of activated carbon sufficient for military demands during the first six months of an emergency has been advocated for many years by both the Chemical Warfare Service and the manufacturers. Lack of available money for the purchase or manufacture of this carbon has prevented such a program from being carried out. Recognizing the present situation, the Chemical Warfare Service has purchased two manufacturing plants under the
