INDUSTRIAL AND ENGINEERING CHEAIISTRY
1162
Toluene suitable for nitration and now available should be diverted from the lacquer industry and other solvents substituted. The diverted toluene should be stored so as to have some backlog for an emergency. Increase of supplies should, as far as possible, make use of existing equipment to avoid excess capacity after the emergency is past. One suggestion is to add bunker C oil to the coal charged to by-product coke ovens after treatment of the coal by the hammer mills. This oil would be cracked in the coking operation and materially increase the light oil yield. If this is practical, a great addition to our benzene and toluene supply could be obtained with moderate capital expense. Further supplies can be obtained by scrubbing coal gas and carbureted water gas at existing gas plants where recovery is not now practiced. It is estimated that from 8 to 10 million gallons of additional toluene can be secured in this way. If still more toluene is required, we have additional large potential sources in our petroleum. Toluene can be produced by controlled cracking of petroleum; in fact, this was actually done to a small extent in the United States during 1917-18. The yields from the oil handled are estimated as of the order of 5-10 per cent, and the gasoline and gas produced as byproducts are usable. The advances in the art of cracking petroleum and purifying the products in the last twenty years are such as to make large-scale operations along this line feasible. Toluene so produced would probably be more costly than toluene from normal sources of production, but the cost
TIN C. L. MANTELL 136 Liberty Street, New York, N. Y.
T
I S is classed as a strategic material in that the United States, the major consumer, produces none, while the major producers consume little. From the advent of tin metallurgy to the present, about three quarters of all the metal has been obtained from ores originating in a relatively small geographic area which includes the Federated Malay States, the Xetherlands Indies, Siam, Burma, Indo-China, and lower China. South America (mostly Bolivia) has contributed 12 per cent, all of Europe (including the British Isles) less than 11 per cent, Africa less than 11 per cent, and Xorth America 0.02 per cent. All of the tin won in North America from the birth of the United States would satisfy normal American consumption for less than a week. The United States industry is more completely dependent on faraway sources of supply of tin than is the case with any other material. Insurance against interruption must take the form of adequate stock piles. The United States uses nearly half of the world’s production of tin, an amount which is greater than that of all the other leading industrial nations combined. It depends on smelters a t Singapore in the Federated Malay States and a t Bootle, England; formerly supplies also came from a smelter in the Netherlands. Ore originating in Bolivia crosses the Atlantic Ocean to England so that later in the form of tin it may recross the Atlantic to New York. For practical purposes, smelters do not yet exist in the United States, although all the technical information, plant experience, and completed development work are available to enable us to treat “foul” Bolivian ores and produce satisfactory metal. During the first World War several successful smelters operated, but
VOL. 32, NO. 9
should not be so high as to be prohibitive. The production of toluene from benzene by the alkylation methods now used in the petroleum industry t o produce high-octane gas is another possibility which should not be overlooked. But it should be emphasized that plants to produce toluene by this means require time to build, and time in an emergency is of utmost importance. Complete preparedness for any contingency means that we should have a t least one large-scale petroleum cracking unit in operation with the primary purpose of producing toluene as a routine operation. K i t h this, all the data necessary for expansion of the operation and its efficiency under various operating conditions and with various crudes could be secured. The product should be actually used in T N T manufacture, to be sure of its quality. Loose talk about the astronomical amounts of high explosives available from our petroleum resources without consideration of all that is required to get them in usable form and of how long it would take is dangerous, in that it gives the uninformed a false sense of security. Our situation on the coal-tar hydrocarbons is today far better than in 1914, but we should not rest on the assumption that this is enough. The amounts of material which look large from a 19 -18 viibpoint re woefully inadequate in war as it is wage d# oday, and pla s cannot be built overnight. We must be prepared with knowledge and plants for all possible cod’ingencies. Foresight plus a%ion are required.
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the last of them ceased in 1924. Twice in the past tin s m e l t ers were established in the United States. Political control in the shape of an export duty on concentrates caused the failure of the first, while commercial control due to more favorable economic conditions abroad put an end to the second. Of the approximately 80,000 long tons of tin imported into the United States, about 43 per cent is used for tin plate. The place of the tin can is emphasized in our daily life by the destruction of one can per person per day. About 3 per cent of the tin imported is employed for coating other metals, 1.6 per cent for foil, and 4 per cent for collapsible tubes. About 40 per cent of the tin goes into alloys, solder being responsible for 22 per cent of the total imports, bearing metals 7.5, bronzes 7.2, white, type metals, and other alloys 2.6, and terne plate 1.5, while chemicals constitute 3 per cent. For many of these uses substitutes find employment in times of stress. I n the case of foods, other than for esthetic reasons, a considerable number of them may be packed in black plate. I n recent years steel electroplated with silver has been suggested for containers, copper-plated steel for oil cans, aluminum (particularly in connection with fish), stainless irons, as well as base metals carrying organic coatings. Enamelware, aluminum, and nickel have largely replaced tin plate in cooking utensils while copper, zinc, and lead-coated products have supplanted tin and terne plate for roofing. Tin foil has suffered from competition of aluminum, cellophane, transparent papers, and lead, while in collapsible tubes aluminum and lead for nonfood purposes have made inroads. Development work on zinc collapsible tubes has been carried to the stage of commercial usage during emergencies.
of t.lie tin f r o m tin plate clippings is nteiit in the average can is 1( garbage d u m p . Severe {lisloeation of nntural silk by rayon has rnarkedly afTec:teil tlie consuinption of tin r:liernic& ior weightingso that by-product metal, oxjiles, and pl:it,ing cliemicals are prodiircd instend. Tin oxide a3 an oimcifying agent in glass and vitroous cnaniels meek cn'ectivc coinpr:titiiin from oxides of antimony, tit,aniiiiii, mil airconiiiin. In solders, cadmium alloys have lieen proposed rtiid fuiiiid some use, d i i l e bearing IXIetdlS of tlie Labbitt type arc being replaced by other alloys or by mechaiiisms such as ball and roller bearing?. Copper-lend, enlciiiin-lead, cn(lmiiini-copperlead, cadmium-silvcr iilloys are all employed as effective and pmspcctive savers of tin. In the hronzes no satidactorp suhtitiite for tin exi&s, brit other alloys of copper, pnrt,iciilarly with aliiminiiin, silicon, or manganese, can replace bronze. Military uses of tin in general a,re adaptat.ions of the ordinary indiistrial applications, but in times oi conflict between nations the consumption of tin, particularly as tin plate, tin cans, solder, and tin alloys, markedly iricreases. The status of tin in a preparedness program would he improx.ed by the
appearance of commercial smelters in the country, hacked by adequate stock piles to cover normal requirements of two or more years. With tin metal normally available, work on substitutes is largely stimulated by some competitive material which seeks a place in tlie sun. These substances, however, act more :is a brake on the tin price than as a mechanism of elimination oi tin. In times of stress, however, thcy may become important aids. In a commercial sense the United States or its possessions lias never produced any tin ore, although specimen deposits are knowm to exist in a large number of locations. The tin content in a pile of old cans in a refuse heap would show a higher tin value than most of our available ore sources. Inwcitses in supply resulting from increased prices of tin would come ironi secondary sources rather than mining. Until exports acre restricted, tin plate scrap in large quantities left the United States. As a conservation measure, the same procedure sfiould be adopted for drosses, slags, and tin-bearing materids so that tlie tin recovery from these secondary sources may be carried on in the United States to augment our supply.
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OYEN-BAKED AIRPLANEOF THE TIMM AIRCZUFTCoRPoRATloN Except for its metal equipment, the plane is constructed of a IleN material made b saturating and biiidin thin strips $spruce with a liquid $enolformaldehyde lastio and then baking it t o congeal sections without the useof rivets into a rigid unit. The picture a t the u per left shows the resistance to shoe&of the plastic material a t the instant an Spound bell WBS dropped from a hcight of 7 feet; the smne test caused a sheet of Dural (uuoer riaht) to depress fully 8 inches. A i ihe left tho phinolie rwin is boing pressure-sprayed on the surface so that a corndote immeenation of the . nlv.wood I&& is effected.
$1,
