ECONOMIC WEEKLY January 26, 1951

Wanted a Non-Ferrous Metal Industry Scope For Its Development in India

G C. Mitter

THE scope of development of a non-ferrous m e t a l indus t ry in

I n d i a depends not on ly on o u r i n ­digenous m i n e r a l resources b u t also on its prospects in re la t ion to the w o r l d t rade i n minerals . T h e table be low shows the posi t ion of such minera ls in our coun t ry and the d i r ec t i on i n w h i c h non-ferrous meta l indus t ry is l ikely to develop

(1 ) M i n e r a l s o f w h i c h our expor t ­able supplies can domina te w o r l d marke t—-Iron and T i t a ­n i u m .

( 2 ) Mine ra l s o f w h i c h our expor t ­able supplies f o r m an i m p o r ­tant part o f w o r l d trade M a n ­ganese and Be ry l l i um.

( 3 ) M i n e r a l s in w h i c h I n d i a may be considered self-sufficient, for present needs—Gold, Rare-earths, C h r o m e Ores, V a n a d i ­u m , A l u m i n i u m and Magnes i ­u m .

( 4 ) Mine ra l s for w h i c h I n d i a has to depend largely on impor ts Silver, Z inc , N icke l , Copper , T i n . Lead , M e r c u r y and Pla­t i n u m .

A very l i m i t e d tonnage of p r i ­m a r y non-ferrous metals are annu­a l ly produced in Ind ia Copper (6,000 tons) , a l u m i n i u m (125,000 tons) a n d lead (100 tons) . A n t i ­m o n y was smelted f rom ores trans­por t ed f rom the C h i t r a l State now in Pakistan and its p r o d u c t i o n to­day depends therefore upon i m p o r t ­ed ore.

E l e c t r o l y t i c C o p p e r

O u r consumpt ion of copper is est imated today between 35,000 to 45,000 tons a year. Against this, the annua l indigenous p r o d u c t i o n of on ly 6,000 tons is indeed ins igni ­f icant . T h e prospect of increasing this o u t p u t is also bleak in v iew of the fact tha t the k n o w n ore-reserve i s very l i m i t e d . T h e on ly a l terna­t ive left, therefore, is to conserve the stock of these metals in w h i c h we are deficient. Th i s can be done in t w o ways. F i rs t ly , by the produc­t i o n of secondary me ta l f r o m scrap a n d secondly, by the app l i ca t ion of

intensive research to f ind out suit­able substitutes. D u r i n g the last wa r not on ly m u n i t i o n p r o d u c t i o n bu t also cer ta in v i t a l wa r a n d c i y i -l i an requirements were seriously hampered in I n d i a due to the short­age of these metals of w h i c h electro­lyt ic copper was the most i m p o r t a n t w h i c h cou ld only be h a d by i m p o r ­t a t ion f r o m abroad. T h i s grave s i tua t ion w o u l d not have occur red i f I n d i a had facil i t ies for the produc­t ion of secondary copper. Between the years 1942-44 the UK produced about. 22,50,000 tons of copper of w h i c h 10,00,000 tons or nearly 42.5 per cent was secondary copper. In the U S A electrolytic: copper ac­counted for 2,21,882 tons of the 9,84,231 tons of the secondary copper produced d u r i n g 1943-44.

N e w A g e I n M e t a l s

The present rate of p roduc t ion of a l u m i n i u m and lead also I alls far short of ou r annua l requirements. T h e posit ion today therefore is that whi le we are at the m o m e n t threat­ened w i t h shortage of copper, n icke l , zinc. t i n . lead, etc., and an even greater shortage of a large class of non-ferrous materials used in engi­neering industries and for domestic purposes, our minera l resources in a l u m i n i u m and magnesium are adequate to support a non-ferrous indust ry of l igh t metals w h i c h can provide substitutes for the deficiency metals enumerated above. A g a i n , recent discoveries of new methods of manufac ture and use of compara ­t ively u n f a m i l i a r metals viz., b c r r y l -l i u m , t i t a n i u m , z i r con ium and m a n ­ganese, workable m i n e r a l deposits of w h i c h are, as has-been ind ica ted , available in this coun t ry , open up wide vistas for the development of a l ight non-ferrous meta l industry based on such indigenous minerals.

Because of their proper ty of being easily reducible to metal l ic state f r o m ore, copper, lead, zinc, mer­cury and tin were discovered as pro-ducts of i n v o l u n t a r y smelt ing in the hear th fires in the s t i l l p r i m i t i v e age of man . T h e y may be consi­dered as the metals of a past age for in the distant past, they played the leading par t in m o u l d i n g the course of h u m a n destny, its c i v i l i ­

sation and cu l tu re . T h e metals t ha t have come i n t o prominence today e.g. a l u m i n i u m and magnesium, are those w h i c h cou ld be h a d in abun­dance on ly when i m p o r t a n t chemi­cal and meta l lu rg ica l discoveries made their ex t rac t ion possible. A l u ­m i n i u m and magnesium, and their alloys, find a wide field of appl ica­t i on o w i n g to the advantage4 of lightness, s trength and resistance to corrosion that they offer. These characteristics enable them to be successfully employed in a surpris­ing ly wide range of industries, in a l l branches of engineering, air, l and , and mar ine t ranspor t , chemical a n d food industries so m u c h so tha t it may be said that we are l i v i n g today in the a l u m i n i u m age.

The prospects of a l igh t me ta l indus t ry can be gauged f rom the one fact alone tha t of' the total v o l u m e of a l u m i n i u m impor t ed and pro­duced in this count ry , nearly 95 per cent is used for the manufac tu re of domestic utensils. C o m p a r e this w i t h the use of a l u m i n i u m in N o r t h Amer i ca , the home of a l u m i n i u m manufac tu r ing , where only 12 per cent of the annua l consumpt ion goes in to ti le m a k i n g of utensils and the bulk of the remainder is used for the manufac ture of equipments and accessories for a l l sorts of transports, the future scope of this metal in this coun t ry , wh ich is still in i ts intancy in regard to transport facilities, can wel l be imagined .

Metals O f T h e F u t u r e

Undoub ted ly , the metals of the fu ture are t i t a n i u m , b e r y l l i u m , tho­r i u m , z i rcon ium (react ive a n d ' r e ­f rac tory) and manganese—structu­ra l ly compl ica ted and pecul iar , me­tals w h i c h are fo r tuna te ly abundan t in I n d i a , bu t yet remains to be p ro ­per ly exploi ted . M e t a l l u r g i c a l p ro ­gress in the t rea tment of the raw materials f r o m w i n c h these metals are extracted and the i r uses have been so remarkable d u r i n g the past few years that a br ief m e n t i o n of the most i m p o r t a n t developments re­g a r d i n g some of them, viz. t i t a n i u m , manganese, and z i r con ium is neces­sary to indicate the role that these metals are destined to play in the fu ture destiny of m a n k i n d .

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E C O N O M I C W E E K L Y January 26, 1951

a n i m p o r t a n t cons t i tuen t i n the t i t a -n i fer rous ores, a t t empts to recover i r o n as p ig i r o n , by m o d i f y i n g the charge before smel t ing has m e t w i t h i n i t i a l success. T h i s m e t h o d , i f c o m m e r c i a l l y successful, can be of i m p o r t a n c e t o the t i t a n i u m p i g m e t i n d u s t r y as the r e m o v a l of i r o n g rea t ly r e d u c e s — ( i ) the a m o u n t o f su lphur ic ac id to d issolv ing t i t a ­n i u m d i o x i d e ; ( 2 ) the subsequent b u r d e n of r e m o v i n g the ferrous sul­pha t e for the solut ions; ( 3 ) the u l t i m a t e disposal p r o b l e m of ferrous sulphate w h i c h has a l i m i t e d mar ­k e t ; a n d ( 4 ) the i r o n ob ta ined as p i g i r o n has a bet ter m a r k e t .

T i t a n i u m m e t a l i s ob ta ined by ( a ) r educ t i on o f t i t a n i u m tetra­c h l o r i d e w i t h sod ium, ( b ) t h e r m a l decompos i t ion o f t i t a n i u m terra-b r o m i d e , or ( c ) the r educ t ion of t i t a n i u m ox ide w i t h c a l c i u m hy­d r i d e . The first and the last are the most w i d e l y used.

Manganese

Insp i t e of reckless diss ipat ion of manganese ore in the past by i n ­d i sc r imina te expor t , ou r resources of h i g h grade ore of above 48 per cent. , is of the order of 10-20 m i l ­l i o n tons. Reserves of low grade ores of manganese content f r o m 30 to 40 per cent, have not been cor­rect ly c o m p u t e d bu t can be safely p u t at at least 5 times larger, M a n ­ganese is an i m p o r t a n t anc i l l a ry m e t a l for the manufac tu re of steel. Steel manufac turers must use m a n ­ganese in greater quant i t ies t h a n any other meta l except i r o n itself. No ma t t e r h o w the steel is made , by Bessemer, electric furnace or by the open hea r th process, 11 to 14 pounds go i n t o every t o n of steel on an average. Of a l l the coun­tries tha t use manganese in substan­t i a l quant i t ies , Russia is the on ly one that is self-sufficient. US con­sumes about a t h i r d of wor ld ' s p r o ­d u c t i o n of this ore. A d d e d to this n o r m a l r equ i rement , the need for stock p i l i n g in that c o u n t r y has created an e x t r a o r d i n a r y d e m a n d o f this ore f r o m I n d i a . Manganese ore is a good do l l a r earner today. B u t i t i s on ly the h i g h grade ore tha t is e x p o r t e d ; the l o w grade ores t h a t have to be m i n e d at the same t i m e are no t u t i l i sed .

T h e disadvantage o f the poor grade manganese ores does n o t l ie i n t he i r lower manganese content alone h u t m a i n l y i n t h e i r h i g h i r o n conten t . I t i s qu i t e l i ke ly there-

m e n t s imi la r t o t he one g i v e n to t i t an i fe r rous ore described earl ier m a y prove successful. I f so, i t w i l l remove the m a i n h a n d i c a p i n the deve lopment o f o u r expor t t rade i n manganese fo r the p r o d u c t of such a t r ea tment w i l l no t o n l y make avai lable a h ighe r grade, b u t also a s e m i - p r o c e e d m a t e r i a l , v iz , fe r ro-manganese in w h i c h f o r m this me ta l is used in steel m a k i n g .

Z i r c o n i u m W e are f a m i l i a r w i t h z i rcon

(ox ide of z i r c o n i u m ) as a semi-pre­cious stone f o u n d in na ture and w i d e l y used in jewel lery . T h e me­t a l z i r c o n i u m , however , is not easily avai lable because of the extreme reactiveness a n d the refractory na­ture of the ore w h i c h resists reduc­t i o n . But on account o f the a v a i l ­ab i l i t y of very h i g h p u r i t y reduc ing agents such as c a l c i u m and magne­s ium, an intensive inves t igat ion of the prepara t ion of rare metals of this type was under taken specially in U S A z i r c o n i u m being one o f the products . In v iew of the ext ra­o r d i n a r y propert ies of this me ta l as a h i g h l y ref rac tory ma te r i a l and the ready ava i l ab i l i t y of z i r c o n i u m bear­ing mine ra l in I n d i a , there is a s t rong case for its p r o d u c t i o n and u t i l i s a t ion . Because of the h igh m e l t i n g point o f z i r c o n i u m , and i t -m e t h o d of manufac tu re , this me ta l l ike t i t a n i u m is usually ob ta ined as a powder of spongy mass. C o n ­sol ida t ion in to meta l compacts is accomplished by cold pressing" in steel dies, fo l lowed by s in ter ing at h i g h temperature . T h i s technique w h i c h has now developed in to science of Powder M e t a l l u r g y is be­i n g used for a large var ie ty of m a n u ­f a c t u r i n g operations.

P o w d e r M e t a l l u r g y The essential feature of Powder

M e t a l l u r g y is the p r o d u c t i o n of a me ta l powder chemica l ly or mecha­nical ly by a number of processes such as castonyh e lect rolyt ic , a t o m ­ised, hydrogen-red need, m i l l ed , etc. T h e meta l powders are then c o m ­pressed i n t o a consol idated mass be, a p p l y i n g mechanica l pressure and finally g iven a heat t rea tment at a t empera tu re w h i c h is below the m e l t i n g po in t of one of its const i ­tuents. T h e technology of the p ro ­d u c t i o n and fab r i ca t ion o f me ta l powders has undergone t remendous i m p r o v e m e n t in recent years. Pow­der me ta l l u rgy began its i n d u s t r i a l career by p r o d u c i n g small articles in useful forms where the ex t r eme ly

high mel t ing points m a k e the usual methods imprac t i cab l e . As exam­ple , tungsten f i laments in incande­scent lamps, m o l y b d e n u m wire,, a n d f o i l in wireless t r ansmi t t e r valves.

Parts can now be made by this technique f r o m aggregates o r m i x ­ture o f metals w h i c h do not f o r m satisfactory alloys, such as copper a n d tungsten, w h i c h have the u n i ­que advantage of m a i n t a i n i n g their i n d i v i d u a l propert ies where the h i g h e lect r ica l c o n d u c t i v i t y of copper is c o m b i n e d w i t h the wear resistance o f tungsten. Powder me ta l lu rgy makes it possible to produce alloys w i t h a very h i g h degree of accuracy w h i c h w o u l d otherwise invo lve very d i f f i cu l t and expensive m a c h i n i n g processes. An example of this is the m a k i n g of the a l loy k n o w n as alnico ( m a g n e t ) , i t is n o w possible to compac t non-metals w i t h metals, v iz . . the p r o d u c t i o n o f carbide t i p ­ped mach ine tools a n d copper car­bon brushes. Powdered me ta l f lakes today are w i d e l y used for pa in t . T h e characterist ic p rope r ty o f parts made by powder me ta l l u rgy process is that there remains d i scon t inua t ion in the body of the ma te r i a l in the f o r m of voids. In cer ta in cases these voids are f i l led w i t h different . metals to change the properties, Bronze powders are f i n d i n g consi­derable app l i ca t ion in the m a n u ­facture of " oil-less " bushes con ta in ­ing about 25 per cent, voids.

The m a i n physical and commer­cial l imi t a t ions w h i c h w o r k a t pre­sent against the use of powde r me-tallurgy technique are:

(a) T h e compara t ive ly poor me­chanical propert ies of the powdered meta l par ts ;

(b ) T h e h i g h cost of equipments . presses, etc.; and

(c) The economic requ i rement of large o u t p u t to off-set did cost.

Inspite of these handicaps. the app l i ca t ion o f p o w d e r m e t a l l u r g y to to indus t ry is destined to g row- in fu ture .

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fore that a pyro-metallurgical treat-