BERYLLIUM, LITHIUM AND MAGNESIUM AND THEIR ALLOYS, WITH REFERENCE TO THE POSSIBILITY OF THEIR MANUFACTURE IN INDIA

K. K. DAR Mining Geologist , Atomic Energy Commission, Bombay

Abstract some of them may in course of time become possible. India is well placed as regards its The paper deals with the possibility of the manu- facture of light metals beryllium, lithium and sources of aluminium and magnesium and magnesium and their alloys in India. The Indian recent surveys have shown that our beryl- occurrences of the source materials of these metals lium resources are also fairly adequate. are reviewed along with the part these metals play The position of lithium minerals is, however, in world peace-time and war-time industries. The not so good and we have to await the results results of over-production of magnesium in the United States as an incentive for finding new of further work in this direction. applications for the metal are drawn attention to. The writer has already drawn attention to It is pointed out that while Indian magnesite the future of aluminium industry in India'. reserves are good, and those of beryl are proving In the present paper he has attempted to to be fairly good, the position with regard to the assess the position of the other three im- reserves of lithium minerals is not so good, but may improve with future investigations, The main portant light metals, beryllium, lithium and metallurgical aspects of the problem have been magnesium. The importance of a material briefly correlated with the new hydro-electricity is best judged by a consideration of its use- projects now under development. fulness, the manner in which it can be ob- Since the author believes that the importance of a tained, and the problems connected with its material is best judged by its utilitarian aspects, he has laid stress rather on the uses of these metals applications. Attention has, therefore, been and their alloys, etc., with the object of drawing the concentrated on these and similar aspects of attention of the Indian geologist and metallurgist the light metal industry in India; the object to the subject.. is to draw the attention of the Indian geologist and the metallurgist to these Introductory Remarks problems rather than to solve them. The sources from which the data for the present S OME light metals have acquired a thesis are derived unreservedly have been unique position in the metallurgical and acknowledged at the end of the paper. engineering industries today on account of their several useful properties. Amongst these aluminium, beryllium, lithium and Beryllium magnesium appear to be the most important. Our Five Year Plan incorporates aluminium Beryl, a silicate of beryllium and alumi- and magnesium in the mineral development nium, 3BeO.Al203.6SiO3, occurs as an ac- schemes and beryllium and lithium have not cessory mineral in acid igneous rocks, granites been mentioned. and pegmatites, and sometimes in metamor- While the general position of non-ferrous phic rocks such as schists and crystalline metal resources of the country is far from limestones. Economically workable beryl satisfactory, recent investigations have tend- occurrences, however, are confined largely ed to show that the domestic utilization of to pegmatites. 174 DAR - BERYLLIUM, LITHIUM AND MAGNESIUM AND THEIR ALLOYS 175

Theoretically, beryl contains 5 per cent The author and his colleagues have also beryllium metal of which usually not more located beryl occurrences recently in some than 3 per cent can be recovered. Krishnan2 parts of Gujerat and in Bombay State. states that beryllium produced by the In Bihar, beryl-bearing pegmatites are German process is only 60 per cent of the known in Gaya, Hazaribagh and Monghyr metal content of the original ore. Amongst districts. the several beryllium minerals known, the Several sources of beryl, particularly those following contain high amounts of the ele- of Nellore, are known in South India. ment, although they are commonly not met Other beryl occurrences are reported from with in appreciable quantities3. the Sutlej and Chandra valleys in north- western Himalayas. TABLE 1 - SOME HIGH - BERYLLIUM Large prospective tracts await investiga- MINERALS tion in Hyderabad, Madhya Pradesh, Orissa

MINERAL THEORE- CHEMICAL FORMULA and Assam. TICAL The Indian beryl has an average analysis of % Be 11-13 per cent BeO, and our resources of the Euklase 6-2 2Be O. A1a02.2 SiO2. H 20 mineral appear to be sufficient for a domestic Chrysoberyl 7-0 BeO. A120a beryllium industry. It will be useful to recall Phenakite 16-2 2BeO.Si0% in this connection that the French beryllium Bertrandite 15-2 4BeO.2SiO2.H20 Beryllonite 7-0 BeO.NaPO3 refinery in 1946 was drawing upon the meagre Herderit 5.0 Be(F, OH)PO2.CaO 500-ton beryl stock in Germany following Hambergite 19-1 4BeO.B2O3.H30 the prohibition of beryllium manufacture in Bromellite 36-0 BeO that country by the Allied Occupation Authorities in February 19464. With the India has -not been the largest beryl pro- embargo on Indian beryl, supply of this rare ducer, Brazil making the largest contri- mineral for the domestic beryllium industry bution to world production of the mineral. is assured. This small production is, however, not due Importance of Beryllium and Its Products in to the paucity of the mineral in the country Modern Industry - The importance of beryl- or to the general poorness of the pegmatites, lium in modern industry can be assessed from but rather to the importance of the rare DeMille's5 statement that war demands minerals not having been recognized till very accounted for 99 per cent of the available recent years and the difficulties of working beryllium, and it is expected to find wider them consequent upon their sporadic and industrial application in peace-time. The uncertain occurrence. importance of a material can only be judged Indian Beryl Occurrences -Workable oc- by the variety of uses to which it, or its pro- currences of beryl so far found in India are ducts, can be put. From some of these out- confined to the pegmatites intruding rocks lined below, it will be observed that this of the Dharwarian age. Rajasthan, Bihar metal can serve many useful national and South India are potential areas for beryl requirements. production- At present the biggest beryl If metallic beryllium could be produced in producer in India is Rajasthan, but there is larger quantities, its use in the metal industry reason to believe that production of this would now rapidly increase. It is slightly mineral will considerably increase in the near heavier than magnesium and considerably future in Bihar and in South India. lighter than aluminium ( density : Mg, 1-75; In Rajasthan, important sources of beryl Be, 1-85; Al, 2-7)_ Other valuable pro- are in Mewar, Jaipur, Tonk, Kishangarh, perties are its strength, resistance to heat parts of jodhpur, Dungarpur and Banswara. and corrosion, and unexcelled resilience,

ine' with water is evaporates to _yiela crystal- the volume 01 inc leL: C11L WCLl-LLLLLG c. uL.^.uL, 176 SYMPOSI UM ON NON-FERROUS METAL INDUSTRY IN INDIA which are imparted in greater or lesser Cu-Be alloys are now available in standard measure to its alloys. commercial forms which include plates, Metallic beryllium is used as a deoxidizer sheets, wires, tools, leaf, helical, contact, and desulphurizer in steel-making, in the and Bourbon springs, valve guides for casting of copper, and in limited amounts in engines, pumps, liquid meters, gears, plastic the manufacture of 'windows' for X-ray moulds, die-casting dies and welding elec- tubes, for the production of neutrons for the trodes. Other uses of Be-Cu alloys are in splitting of uranium atoms, and for slowing the setting of industrial diamonds, hubs of down the high-speed fission neutrons emit- adjustable steel aircraft propellers, switch ted from uranium to control the chain re- blades and jaws for electrical range switches, action involved in the explosion of an atom etc., camera parts, appliance plug clips, fuse bomb. clips, optical alloys, vibrator arms, petrol Due to its high fusion point and high and oil pump parts, relays, brush holders, vapour pressure at a temperature not much thermostatic controls, etc. above the fusion point, beryllium can be hot- Other useful copper alloys are those con- worked. Extreme lightness causes it to taining 0.4-0.5 per cent Be and 2-3 per

178 SYMPOSIUM ON NON-FERROUS METAL INDUSTRY IN INDIA

Lithium Ores -The chief sources of lithium lead to further discoveries of source minerals are spodumene (LiA1Si2Og ), 3-8-5.6 per cent of lithium. It is also possible that further Li; amblygonite [Li( A1F) PO4 ] ; and lithia exploration and prospecting at depth in mica, lepidolite (Li, K, Na)2A12(&iO3)3(F, OH)2. Bastar may reveal greater reserves of lepido- Amblygonite contains about 9 per cent and lite than are available now in the scattered lepidolite about 4 per cent Li2O on the boulders on the surface. The present lepi- average. Other occasionally mined sources dolite deposits are about 180 miles from the are triphylite, (Li, Na)3PO4± (Fe, Mn)3 (P04)2, railhead at Dhamtari, but the distance from 1.6-3.7 per cent Li; petalite, LiAl( Si2O5 )2, the Vizianagaram-Raipur chord is consider- 2-7-3.7 per cent Li; lithiophilite and zinnzval- ably less. dite. Application of Lithium - Lithium re- The chief lithia-producing countries in sembles the other alkali metals in its pro- order of importance are the U.S.A. (which perties, is the lightest element which retains supplied 50 per cent of the pre-war world its form at ordinary temperature, and enters output of ores ), South-west Africa and into numerous chemical combinations. Be- Argentina. Canada, Sweden, Germany, cause it imparts additional hardness, tough- Czechoslovakia, France, Spain, Portugal and ness and tensile strength, it is important in Western Australia are comparatively minor the manufacture of bearing metal alloys, contributors. War demand led to starting copper electrodes and lead cable-sheaths. production in Argentina where its occurrence When used alone or as an alloy in molten in commercial quantity was not reported metals, it acts as a refining agent for them. previously. The U.S.S.R., Madagascar and It is employed with electric furnace carbon India have deposits of commercial value. steels for steel castings, replacing aluminium Indian Sources of Lithium - In India, as a deoxidizes. Both steel and copper very few and small occurrences of lithium castings which contain lithium can be poured ores are known. Lepidolite is recorded at lower temperatures with high fluidity. in the Bihar mica belt',s.`'. The Bastar Lead-lithium, the best known of the alloys occurrence of Mundaval ( 18°39': 81°56') is ( Bahn metal ), contains only 0.04 per cent the biggest among the Indian lepidolite Li (with a little of sodium and calcium) deposits so far known, the next occurrence which increases the hardness at higher tem- being that of Bihar. In Bastar lepidolite peratures and makes the products suitable occurs in large masses which, except for a for railway bearings. Other alloys, alumi- little quartz, is free from impurities and has nium and magnesium, are reported to have DAR - BERYLLIUM, LITHIUM AND MAGNESIUM AND THEIR ALLOYS 177 and 188,000 lb. per sq. in, respectively and their physical properties such as ductility, acquires a hardness of 600 Brinell. strength and uniformity. It densifies the Beryllium-aluminium alloys (70-80 per grain in the metal and eliminates porosity in cent Be) have high strength, are easily cast high-pressure- castings. It is the only metal and worked, but soon become work-hardened which, on combination with hydrogen and owing to segregation of Be and Al-rich other gases, produces an initial alloy in a grains. Addition of one or more metals may super-refined state. DeMille has quoted remove this defect. Dr. W. G. Pollard as saying, while discussing Strong beryllium-magnesium alloys have the chain-reacting pile at Oak Ridge, Ten- not yet been produced, but an alloy con- nessee ( U.S.A.), that one pound of lithium taining 90 per cent Be and 10 per cent Mg is burned with hydrogen would serve as a fuel used for making certain Mg-Al alloys. for a year in a furnace requiring more than Small amounts of Be added to 18-carat 4000 tons of coal to provide an equivalent gold increases the hardness of the product. amount of heat. The importance of the An alloy of 92-5 per cent Ag, 7.1 per cent metal can be judged from the lithium ores Cu and 0.4 per cent Be makes the silver re- mined in U.S.A. in pre-1946 years". sistant to tarnish while retaining the colour of silver. Platinum metals can be conserved by the TABLE 2 -LITHIUM . ORES MINED IN addition of small amounts of beryllium. U.S.A. WITH THEIR APPROXIMATE . LITHIA CONTENT Extraction of Beryllium - Beryllium of 99-5 per cent purity is obtained by the YEAR LITHI UM ORES APPROX . Li2O electrolysis of the molten fluoride in graphite (short tons ) CONTENTS (short tons) crucibles to which barium or sodium fluoride is added. Beryllium separates out 1935 -39 (av.) 1327 88 on a water-cooled iron tube serving as a 1942 5405 299 1943 $155 463 cathode; the slag inclusions are eliminated 1944 13319 848 by remelting with mixtures of alkaline-earth 1945 2446 274 halides. The fluoride (2BeO.5BeF2) is pre- 1946 3065 323 pared by fusing finely ground beryl with sodium-silica fluoride for several hours at 650°C. ; the solution obtained after leach- Gwinn6 states that ` although far below ing with water is evaporated to yield crystal- the volume of the recent war-time output, line beryllium fluoride, which is dissolved in shipments in 1946 were 131 per cent above water containing lime in excess and the 1935-39 average, and the lithia content was beryllium oxyfluoride precipitate is drawn 267 per cent greater '. into solution with HF. The current density During World War II, lithium was listed is 2-4 amp. per sq. cm. of cathode area. as essential both by the United States and Britain owing to its various applications of military importance. War demands for Lithium lithium salts led to an increase in 1942, in Lithium is the lightest of all metals (sp. U.S.A., from 500 to 2000 tons a month in gr. 0-543; m.p. 186°C. ; b.p. 1400°C.) which mill capacity for production of low-grade has found a variety of important peace-time spodumene as a domestic source of lithia. and war-time uses. As it deteriorates rapid- Beneficiation of the ore by froth flotation ly in air, it cannot be used for structural pur- yielded excellent results and the byproducts poses, but amongst other applications may were low-grade feldspar and mica concen- be mentioned its use in alloys to improve trated. 178 SYMPOSIUM ON NON-FERROUS METAL INDUSTRY IN INDIA

Lithium Ores - The chief sources of lithium lead to further discoveries of source minerals are spodumene (LiAlSi2O4 ), 3.8-5.6 per cent of lithium. It is also possible that further Li; amblygonite [Li( A1F )P04 ] ; and lithia exploration and prospecting at depth in mica, lepidolite (Li, K, Na)2A12(SSi03)3(F, OH)2. Bastar may reveal greater reserves of lepido- Amblygonite contains about 9 per cent and lite than are available now in the scattered lepidolite about 4 per cent Li20 on the boulders on the surface . The present lepi- average. Other occasionally mined sources dolite deposits are about 180 miles from the are triphylite, (Li, Na)3P04+(Fe, Mn)3(P04)2, railhead at Dhamtari , but the distance from 1.6-3.7 per cent Li; petalite, LiAl( Si205 )2, the Vizianagaram-Raipur chord is consider- 2.7-3.7 per cent Li; lithiophilite and zinnwal- ably less. dite. Application of Lithium - Lithium re- The chief lithia-producing countries in sembles the other alkali metals in its pro- order of importance are the U.S.A. (which perties, is the lightest element which retains supplied 50 per cent of the pre-war world its form at ordinary temperature , and enters output of ores), South-west Africa and into numerous chemical combinations. Be- Argentina. Canada, Sweden, Germany, cause it imparts additional hardness , tough- Czechoslovakia, France, Spain, Portugal and ness and tensile strength , it is important in Western Australia are comparatively minor the manufacture of bearing metal alloys, contributors. War demand led to starting copper electrodes and lead cable-sheaths, production in Argentina where its occurrence When used alone or as an alloy in molten in commercial quantity was not reported metals, it acts as a refining agent for them. previously. The U.S.S.R., Madagascar and It is employed with electric furnace carbon India have deposits of commercial value. steels for steel castings , replacing aluminium Indian Sources of Lithium - In India, as a deoxidizer . Both steel and copper very few and small occurrences of lithium castings which contain lithium can be poured ores are known . Lepidolite is recorded at lower temperatures with high fluidity. in the Bihar mica belt7'11'9. The Bastar Lead-lithium, the best known of the alloys occurrence of Mundaval ( 18°39': 81°56') is ( Bahn metal ), contains only 0 . 04 per cent the biggest among the Indian lepidolite Li (with a little of sodium and calcium) deposits so far known, the next occurrence which increases the hardness at higher tem- being that of Bihar. In Bastar lepidolite peratures and makes the products suitable occurs in large masses which, except for a for railway bearings . Other alloys, alumi- little quartz, is free from impurities and has nium and magnesium , are reported to have been found by the Geological Survey of superior properties . Lithium is also used in India to analyse lithia 3.34 per cent and F the form of master alloys to produce tin 4.88 per cent. This compares well with the bronze, silicon bronze and pure copper 4 per cent lithia content of the lepidolite from castings of high uniformity and high physical South-west Africa. Wadia10 considers the properties. It has recently been used in present available quantity of lepidolite in developing a neutral atmosphere in heat- Bastar capable of supplying only a small treatment furnaces. lithium salt manufacturing industry rather Lithium compounds are used effectively in than for the manufacture of metallic lithium. glass, optical, ceramic and air-conditioning Amblygonite is reported from Kashmir, industries. Both lithium metal and lithium but the occurrence appears to be insigni- amide can be used as an intermediate in ficant. building molecules for carbonols , nicotinic No other lithium minerals have yet been acid and other organic compounds. It is reported in India. It is, however, within the stated that the high hydrogen yield from the range of possibility that future surveys may stable solid lithium borohydride ( 66 cu. ft. DAR - ERRYLLIUM , LITHIUM AND MAGNESIUM AND THEIR ALLOYS 179 per lb, on contact with water) and gaseous military uses in peace-time. A new synthetic lithium diborane ( 88 cu. ft. per lb. on contact low temperature grease with a lithium base, with water) gives these derivatives important stable at temperatures from -100° to possibilities in chemical research to deter- +300°C., has been developed. The new re- mine new applications, and the use of the ducing agent, lithium-aluminium hydride, hydride for hydrogen production for balloons first made in June 1945, promises to be an irn- has increased. portant research and industrial tool in organic One of the most hygroscopic compounds, and inorganic chemistry, particularly in the lithium chloride is an essential drying agent reduction of unsaturated compounds as it in air-conditioning units and blast furnace does not attack carbon-to-carbon double efficiency is said to increase by 10 per cent bond. with dried air. Minor uses have been devel- Extraction of Lithium - The metal may be oped in the manufacture of optical, elec- obtained from the electrolysis of a solution trical, pharmaceutical and textile mate- of lithium chloride in pyridine (C5H5N ). rials. Spodumene and lepidolite have been used Magnesium largely in inflating life-rafts, in making cer- tain type of glass, in the ceramic industry Nearly 40 years ago, magnesium had very and for drugs. Spodumene had been used few industrial applications, e.g. in pyro- as a substitute for glass-grade kyanite. technics, as flashlight powder, for deoxidizing Lepidolite is essential in the manufacture of and desulphurizing other metals and alloys, borosilicate glass for electronic tubes and specially nickel, brass and bronze, and in boiler gauges. Spodumene-feldspar mixtures some amount in light alloys such as duralu- have lower melting points than feldspar alone min. In recent years, however, the metal and are useful for ceramic purposes and has acquired great industrial importance and spodumene has been proposed as a substitute its demand has rapidly increased for the for the more costly lithium carbonate in manufacture of light, strong magnesium ceramic body materials, glazes and enamels. alloys. It is the third most abundant of the Amblygonite is used in opaque glass, lepi- engineering metals, surpassed in volume only dolite in flint glass; generally, lepidolite and, by aluminium and iron, and is one of the to a less extent, other lithium minerals are sixteen non-ferrous metals used in sub- employed as opacifying agents in opal and stantial quantities in the pure state or as the white glasses. Lithium and fluorine in base metal for alloys. lepidolite are valuable fluxing agents in Sources of Magnesium - Several sources of facilitating the melt in glass-making for magnesium are available. Major recovery which the scaly light purple varieties of the has been from sea water, brines and salt mineral are used. deposits. A cubic mile of ordinary sea water Lithium salts are employed in the pre- is said to contain nearly 6 million tons of paration of mineral waters, lithia tablets and magnesium and the whole of the Dead Sea medicine, and for many other minor uses. is estimated to contain 5,800,000,000 tons. Lithium hydroxide is used with potassium Carnalite, KC1.MgC12.6H20, an important hydroxide as the electrolyte in the Edison constituent of brines, may contain up to 34 alkaline storage cell; lithium chloride, in per cent magnesium chloride. Sea water signal lights to produce crimson flare ; lithia contains 0-4 per cent carnalite, i.e. 0-13 with strontia and the fluorides is reported to per cent Mg. Dolomitic lime is used for be one of the most important substitutes for precipitation of magnesia from sea water. lead in pottery glazes and it is said that this Byucite, Mg(OH )2, contains 41-6 per cent application may compensate for the loss of Mg; magnesite, MgCO3, 28.7 per cent; hydro- 180 SYMPOSIUM ON NON-FERROUS METAL INDUSTRY IN INDIA magnesite, 3MgCO3.Mg( OH )2.3H20, 26.5 per magnesite, large dolomite deposits are also cent ; dolomite, MgCO3.CaCO3, 13 per cent; known to occur in different parts of the serpentine, 25.8 per cent. The Canadian country. brucite deposits are the largest in the world. World Production and Trends in Mag- The sources of magnesium are abundantly nesium Industry -The importance of mag- distributed the world over. nesium is due to its high strength and its Indian Sources of Magnesite - Krishnan being 37 times lighter than aluminium. Its has described the Indian magnesite deposits. drawbacks are that it is anodic and the most Brucite and carnalite are not reported in corrosive of metals ( although it resists India, but magnesite deposits occur in the alkalis ), its surface oxidizes easily, it has chalk hills and other places in Salem, at a low modulus of elasticity and cannot freely Seringala in Coorg, on the Cauvery above and easily be cold-worked. Frazepet, at Muddavaram and Musila The world production of metallic mag- Cheruvu in Kurnool, in the Trichinopoly nesium, according to Jones13, was just under district, in Hassan and Mysore, near Dev 20,000 tons, but it doubled in 1940, Germany Mori in Idar, and in Dungarpur, at Bhita producing almost half the total; United Dari in Singhbhum and at Almora. The Kingdom and United States, about one- crude Salem magnesite has the following sixth; and Japan, about one-tenth. Other analysis12 : magnesium-producing countries in order of Per cent importance are: France, the U.S.S.R., Swit- zerland and Italy. 1-86 Silica World production of crude magnesite in Iron oxide and alumina 0-08 1937 was 2,150,000 long tons, to which the Lime 0-81 U.S.S.R. contributed 37 per cent; Australia, Magnesia 46.41 21 per cent; Manchuria, 15 per cent; the Loss on ignition 50.64 U.S.A., 8 per cent; Greece, 7 per cent; 0.20 Moisture Czechoslovakia, 4 per cent; Yugoslavia, It has been stated that magnesium car- 2 per cent ; Chosen, 2 per cent; and India, bonate in ordinary samples averages 96-97 2 per cent. per cent3 and 99 per cent in picked ore. The industrial importance of magnesium So far, only the Salem and Mysore deposits may also be judged from the production and those of Almora appear to be workable. figures given in Table 313 Reserves70'12 of the chalk hills deposits are Nighman and Troughti4 record that, ex- roughly estimated at 90,000,000 tons, ana- cluding exports, shipments of one-third lysing over 96 per cent MgCO3 ( 46.4 per cent million tons of metal from January 1942 Mg). Annual mine output is about 20,000- through June 1945, according to War Pro- 35,000 tons, part of it being used for non- duction Board figures, comprised 44 per metallurgical purpose and a large part ex- cent for production of aircraft, 34 per cent ported. Almora reserves are estimated at for incendiaries, 12 per cent for other mili- at least 20,000,000 tons. In addition to tary uses ( principally tracer and incendiary

TABLE 3 - PRODUCTION OF MAGNESIUM IN THE WORLD AND THE U. S.A., 1942-46

1942 1943 1944 1945 1946

World (short tons) 115300 263000 232700 54500 13200 U.S.A., prin-iary magnesium 48963 183584 157100 32792 5317 (short tons) DAR - BERYLLIUM, LITHIUM AND MAGNESIUM AND THEIR ALLOYS 181 ammunition ), and the remaining 10 per cent the estimated requirement of 362 , 500 tons largely for aluminium alloys and, thus, the which proved to be too excessive and, .at the consumption was roughly half for structural end of 1944, the War Production Board and half for destructive purposes. In 1946, stockpiles were twice the requirement. The the first post-war year, while the primary Truman Committee was to have written off a magnesium production of U.S.A. declined to large part of the magnesium industry as war one-sixth of the 1945 output and one-thirtieth loss unless new peace -time uses for the metal of the war-time record, the consumption of could be found. Dr. W. H. Dow suggested primary metal and alloy was one-fifth that of that the war-emergency plants could main- 1945 and five times the pre-war average. tain capacity for production of magnesium The recovery of secondary metal dropped 45 wheels for automobiles , wheelbarrows and per cent from 1945, but nearly equalled the roller-skates , cigarette machines , printing output of the primary. Estimated world presses, knitting machines, bread- slicing production declined 76 per cent from 1945 machines, various household appliances, port- and was about 5 per cent of the 1943 peak. able hand-tools, radios, office machines and High production of the secondary metal is cameras. A 60 lb. canoe and 70 lb. row-boat considered as having been a powerful de- were under construction in December 1945_ pressant of the primary, -the ratio being In the second meeting of the Magnesium extremely high and virtually double that of Association on 2 October 1945, many labour aluminium. and energy-saving applications for magne- Essentially, magnesium was a war-time sium were suggested which included, amongst metal. DeMille5 states that its incendiary those already mentioned, cages, trucks, and oxidizing characteristics were employed buses, aircraft and railway cars, weaving in World War I for fire bombs and flares and machines, typewriters , etc. Magnesium forg- for flashlight for night photography, but ings for aircraft were expected to compete many new military and civilian applications with other metals. The Dow Chemical Com- were developed in World War II. The ex- pany reported to the Congress that post-war panded world demand for magnesium in consumption of magnesium , estimated at World War II is without parallel in the 30,000 tons a year, would be distributed as history of the use of metals - one group of follows: uses being based on its chemical activity; Per cent the other , more important , on the engineering properties of its alloys. The magnesium Manufacture of aircraft 45 structural products were consumed as follows Manufacture of automobiles, 11 in 1940 : trucks and buses Industrial machinery, tools and 21 Per cent manually handled equipment Aircraft industry 75 Furniture and other consumers' 8 Automobile industry 10 goods Tool and equipment industry 6 Alloying element for aluminium 5 Textile, foundry equipment, 9 Chemical industries and photo- 10 and. other industries graphy The distribution of output in 1949 was : Magnesium Alloys - The special methods incendiaries, 40 per cent ;, aircraft and many of casting magnesium and its alloys for their parts of war weapons , 30 per cent. later fabrication into various articles were In 1943 , potential new use requirements mainly pioneered by the Germans. being many times the supply resulted in the Al, the most important alloying element fabrication capacity being expanded to meet for magnesium, is added up to 11 per cent, 182 SYMPOSIUM ON NON- FERROUS METAL INDUSTRY IN INDIA

but variable quantities of manganese are supercharger blower casings. The huge land- used in all the magnesium alloys mainly to ing-wheels of heavy bombers are made of reduce corrosion. about 8 per cent Al; some weigh only 150 lb. There are two types of magnesium alloys - each, which amounts to a saving of 140 lb. the casting and the wrought alloys - of in weight for each bomber. which the casting alloys have again two Extraction of Magnesium - The chemically types: those containing 2 per cent Mn, and active nature of magnesium necessitates un- those with 8-10 per cent Al, 0.5 per cent Zn, usual care in its production to ensure purity. and 0.25 per cent Mn, the latter possessing Due to increased war production, the mag- good mechanical properties which can be nesium industry has undergone a tremendous further improved with heat treatment. The expansion and the two basic processes, former type is usable in the wrought condi- (i) electrolytic reaction and (ii) chemical re- tion. The two widely used wrought alloys duction, have now six variations15, namely: are : one, with 6 per cent Al, 1 per cent Zn, (1) the Dow chloride process; and 0-25 per cent Mn; and the other with 8 (2) the Elektron process ; per cent Al, 0.5 per cent Zn, and 0.25 per (3) the Dow sea-water process; cent Mn. While they possess a maximum (4) the oxide process; tensile strength of about 20 tons per sq. in. (5) the Hansgirg process ; and and are as strong as the finest steel alloys (6) the Pidgeon process. weight for weight, their strength within the It is difficult to say which of these pro- elastic range is not so great. The casings of cesses will continue to meet competitive cost; incendiary bombs are made of a magnesium much will depend on the nature of the raw alloy containing about 5 per cent Al with a materials available, location of the plant, little manganese which also burns fiercely cost of power, etc. It seems possible that the with the bomb explosion. Dow chloride and the Dow sea-water pro- The chief and extremely important engi- cesses may continue successfully. But, in neering advantages of magnesium alloys India, where the raw materials are magnesite are their lightness, easier machinability than and dolomite, application of the Elektron steel or brass, and amenability to all metal- process is indicated. The use of the oxide lurgical treatment, such as shaping, casting, process was given up in 1927 as it could die-casting, rolling, forging, extruding and not compete economically with the chloride pressing. Chemical reactivity of the metal process. causes certain corrosion difficulties, but the The requirements of the Dow chloride pure metal corrodes less than iron and steel process are 8-10 kWh. and 6-9 volts power in the atmosphere. Corrosion can be pre- ordinarily; hydrated magnesium chloride, vented by immersion in cold, sometimes hot, sodium chloride and small amounts of am- solutions of chromate salts which form a monium chloride to prevent breaking up of protective coating or film of chromic oxide. MgC12.6H20 into MgO and HC1 in the first A new anodic coating for magnesium alloys evaporation of brines to crystallize MgC12. was announced in September 1944 and, in 6H2O, and graphite anodes. 4000 lb. of mag- point of resistance to corrosion or abrasion, nesium chloride produces 1000 lb. of metal. is claimed to be superior to that obtained by Average purity of metal is 99.9 per cent. the acid dichromate and chrome pickle treat- In the Elektron process, magnesia is ment. briquetted with coke and peatmoss, treated Magnesium alloys have been used in crank- with chlorine at 700°-900°C. to produce cases to save weight in lorries, in retractable magnesium chloride, which is subjected to undercarriage parts, pilots' seats, petrol electrolysis; the chlorine is collected for tanks and a number of engine parts such as re-use. III. DAR - BERYLLIUM, LITHIUM AND MAGNESIUM AND THEIR ALLOYS 183

In the Dow sea-water process, magnesium be easily available from the several hydel hydrate is precipitated from sea water, projects now under development in different treated with HCl to form magnesium chloride parts of the country. and subjected to electrolysis. Metal pro= For the beryllium industry drawing its duced has a purity of 9990-99.95 per cent. raw materials from Rajasthan and Bihar, Plant location has to be near the sea and used power would be available from the Chambal water has to be discharged sufficiently far to and Kosi projects respectively. prevent dilution of the entering supply. For the lithium industry, if ultimately The Hansgirg process consists in the re- found to be feasible, it may be possible to duction of finely divided magnesia by finely draw electrical power from the Konya or the divided carbon in an electric furnace at Krishna projects. 2000°-2100°C., immediate chilling of mag- The magnesium industry in the south nesium vapour and CO by natural gas (25 would be able to take electrical power from volumes of natural gas being used for each the Krishna project and that in the north, volume of furnace vapour), collection of based on the Almora magnesite deposits, quenched magnesium in oil or large woollen from the Rihand project. sacks in a cooling chamber, and redistillation of dust still containing about 60-65 per cent References magnesium in electric retorts at 750°C. under high vacuum. Purity of metal may 1. DAR, K_ K., " Industrial Utilization of Bauxite be as high as 99-997± per cent. Power and Its Products ", Symp. on Mineral Raw requirement is about 9.5 kWh. per lb. of Materials and Utilization of Their Byproducts, magnesium. Gas explosions, etc., are dis- Nat. Inst. Sci. India ( 1953 ). 2. KRISHNAN , M. S., " Beryllia ", Bull. Econ. Min., advantages. No. 13; Rec. G.S.I., Vol. LXXVI ( 1946 ). In the Pidgeon ferro-silicon process, Al, 3. AvwERs, Ho VoN, et al., Beryllium and Its CaCl2, C or ferro-silicon are used for direct Alloys, Central Committee on Scientific and chemical reduction to magnesium at 1150°C. Engineering Research of the Siemens Company. from dolomite according to the reversible 4. MATTHEWS, ALLAN F., " Beryl ", Minerals Yearbook, U.S. Bur. Mines (1946). reaction 5. DEMILLE, JOHN B., Strategic Minerals (McGraw- 2MgO + Si ' SiO2 + Mg Hill Book Co. Inc.) ( 1947). 6. GWINN, RI C One lb. of 75 per cent ferro-silicon or its HARDS G ., Minerals Yearbook, U.S. Bur. Mines ( 1946 ). equivalent is required per lb. of magnesium 7. HOLLAND , T. H., Mem. G.S.I., Vol. XXXIV. which contributes substantially to operation 8. MALLET, F. R., Rec . G.S.I., Vol. VII. cost. Power consumption is the lowest of 9. CROOKSHANX , H., Rec. G.S.I.,Vol. LXIX ( 1936). any of the electrolytic processes. A suitable 10 . WADIA, D. N., " Mineral Resources of Ii dia ", Pap. No. A-B 7, 4th metal for the reaction tubes with a reason- Emp. Min. f-Met. Congr., London ( 1949 ). able life offers difficulty and Fe-Ni-Cr heat- 11. KRISHNAN, M. S., " Magnesite ", Bull. Econ. resisting alloys have been used with slight Min., No. 7, Rec. G.S.I., Vol. LXXVI (1942). success because of surface oxidation, and 12. The First Five Year Plan (Planning Commission, collapse under atmospheric pressure working Govt. of India) ( 1952), outside against the vacuum inside. 13. JoNEs, W. R., Minerals in Industry, Pelican Series, Penguin Books, Hammondsworth, England ( 1945 ). Hydro-electric Power 14. NIGHMAN, C. E, & TROUGHT, MARY E., Mine- rals Yearbook, U.S. Bur. Mines Cheap and abundant electrical power is an ( 1946). 15. SAMANS , CARL H_, Engineering Metals & Their essential for the extraction of the three metals Alloys (Macmillan Company, New_ York discussed in the present paper. This should (1952).