zinc ind

8/3/2019 zinc ind

http://slidepdf.com/reader/full/zinc-ind 1/6

EXECUTIVE SUMMARY

1.0 Zinc is widely use d metal and used in protecting steel, diecasting an dalso as chemical compound. While zinc was known to the ancients,its produ ction with modern technology started in India only in 1966,with the Sm elter at D ebari, While the zinc produ ction w orldwide w as7.2 million tonne in 1989, the Indian p rodu ction capacity of zinc w asonly 99,000 tonne.

1.1 Zinc metal us es are base d on a num ber of properties and theseproperties are being exploited for variety of applications in defenceand other essential industries.

1.2 The principal proc esse s for m anuf acturing are horizontal retor ts,

electrolysis, vertical retorts, electrothermic, overpelt and blast fur-nace (Imperial Smelting Process). Out of these, most importantproc esses are electrothermic and blast furnace m anu facturin g,covering 93 % of the total zinc pro duc tion in the wo rld. Th e electrolyticzinc process consists of dissolving zinc bearing materials to zincsulphate solution which is purified to satisfactory electrolyte andrecovered as metallic zinc by electrolysis. The Imperial Smeltingprocess is pyro-metallurgical process for combined production oflead and zinc. Th is will include raw m aterial han dling plan t, sm elterand gas cleaning plant, smelting blast furnace, zinc refinery, lead

refinery, and recovery of high value metals.1.3 Zinc con cen trate s are the raw m aterial for zinc sm elter. Zinc ore

cons ists of sulp hate , sulph ide mineral with galena, chalcop yrtite andcopper sulphide minerals. Zinc concentrates from zinc-lead orescontain abo ut 59% zinc andd complex ores have 54% zinc.

1.4 Th e energy req uire m ents for zinc prod uction by a m ode rn electrolyticprocess and the Imperial Smelting process are 47.5 x 10 6 Btu and42.5 x 10

6Btu respectively. The pollution control/environmental

requ irem ents in term s of water, air, sulfur dioxide emission, etc., a re

important.1.5 Second ary zinc produ ction ha s started in India in the last few yea rs.

Secondary zinc is recycling process and thus adds to the economy.The main sources of secondary zinc are scraps, drosses and fluxes.The process of electrolyzing is similar to primary zinc products. Alarge nu m be r of recovery un its w ith capacity of 1 tone per day to 15

xiii

8/3/2019 zinc ind


tonne per day have started a nd they are importing basic raw m aterial(zinc ashe) from abroad.

2 .0 STRUCTURE OF INDUSTRY AND STATE OF ART

2.1 The zinc sm elter capacity in India is 1,69,000 tonne per annu m . Thesecondary producers may add about 15,000 tonne per ann um . Theprod uction of zinc in India is increasing; it w as 2 8,0 00 to nn e in 1976and 1,50,000 tonn e in 1992. The overall performan ce of ind us try isgood and rate of growth and financial health is strong. The presentdem and for zinc in India is in th e rang e of 1,50,000 tonne per annu m .The projected d em and worked out are 1,98,000 tonne per annu m by1994-95 and 2,40,000 tonne per ann um by 1999-2000 AD.

2.2 The four smelters are located atD eba ri.Visa kha patm an and Cha nderiaof Hindustan Zinc Limited and at Benanipuram of Benani ZincLimited. The two smelters in Ra jasthan are base d on indigen ous lead-

zinc ores and Visak hap atnam smelter wa s being worked on im portedcon cen trates, bu t now is being worked on concen trate from Ra jasthanas well as imported concen trates. Ben anipuram smelter is based onpartly imported con cen trates. The econom ics of scale is base d on typ eof technology, quality of con cen trates . All the sm elters were starte dwith foreign collaborations and subsequently collaboration arrange-m en ts were entered with specific a rea s of imp rovem ents. B asically allsmelters have done well and technology has been absorbed. R&Defforts have been made to modernize the plants and modifications,innovations and expansions have been made. Imperial Smeltingfurnace technology for zinc and lead smelting on pyrometallurgicalprocess was imported.

2.3 The struc ture of down stream industry consists of galvanizing un its,alloy die casting units, brass/bronze industry and chemical manu-facturers.

2.4 M odernization of the zinc sm elters are esse ntial for the im prove m entsin prod uction a nd productivity, energy reduction, improving environ-mental conditions and cost effective methods of production. Theemphasis should be for mechanized and automatic methods andrecoveiy of precious and valuable metals.

3 . 0 INTERNATIONAL SCENARIO

The two contemporary technologies are roast-leaching electrolysisand Imperial Smelting process (ISP). 80% of production of zinc inworld is by electro-winning process and 14% by ISP. The globalproduction at pres ent is abo ut 7.2 million tonne (28% produc tion is

xiv

8/3/2019 zinc ind


from W estern Eu rope , 2 2% from USA, 21 % i s from A sia an d erstw hileUSSR and China produces about 27-28%).

3.1 Produc tion of zinc in USA, Europ e and UK have dec reased a s a resu ltof decline in mining of zinc ore and con cen trates. M anufa cture of Zincin these cou ntries is depe nden t on import of conc entrates. Ca nada ,Peru, China, former USSR have increased their production of zinc

and there is increase in capacity build-up in Can ada , Peru, China,India, Brazil, Mexico and some other countries. Addition of invest-ment in zinc production is not expected.

3.2 Zinc con sum ption in the world h as declined du e to the technologiesof economizing materials. The present consumption is only 27%.Sub stitution and economy of m aterials have reduced the con sum p-tion.

4.0 R&D EFFORTS, TECHNOLOGY ABSORPTION AND GAPS.

4.1 R&D activities in zinc development is in-ho use, in nation al labo rato-ries /ins titutio ns /un ive rsitie s. HZL ha s well developed facilities ofresearch and developments. The activities include exploration, im-provem ent in flow she ets, co ntrol on opera tional activities, d esign ofmining, operation of process parameters and recovery of variousmetals. Priority for R&D activities should be for exploration andenergy conservation. Bureau of Stan dard s have issued a num ber ofIndian Standards for zinc in confirmation with other world stan-dards .

4.2 Indigenisation of par ts, sub-assem blies, capital equipm ents have

take n place in zinc industry. 55-60% of capital eq uipm ents have beenindigenized. Now perhaps basic engineering and know-how may berequired to be impo rted. HZL h a s th us expand ed Deb ari smelter from18,000 tonne per annum to 49,000 tonne per annum capacity.Utilization has also improved steadily. Improvements have beenproved in productionizing and yields better c onc entra tes. Power andwater ha s been constraints in the production and this ha s been ta ke nca re of broadly. Technology abs orp tion efforts hav e by the way of zincdust production from cathodes, drum filters, injection oxygen haveimproved on productivity and cost reduction. Recovery of various

valuable metals has improved the cost of production.4.3 G aps in technology are cost effective zinc con cen trates, com puteriza-

tion and autom ation, b etter zinc value s, better leaching, purificationand cell-house yields, energy reduction, environmental issues andproductivity. The gap c an be bridged by selected m ining, m odern iza-

X V

8/3/2019 zinc ind


tion and benefication, application of computerized energy audit,pollution control audit and by automation.

4.4 The thr us t area s should be concentrated on productivity throughimproved technology, induction of higher mechanization, and con-servation of energy. A nu m be r of th ru st a re as of res ea rch and

development have a lready been identified by the Indian Zinc in du stryin the fields of geology, mining, benefication, metallurgy and newerapplication areas to face changes. Promotional activities for zincconsum ption by the way of new application is also a thr us t area .

4. 5 Th e targ et definition will requ ire acq uisition of late st technology ,design drawings, know-how, adoption of latest technology, andpromotional activities. The R&D efforts have to be increased bycompletion of R&D projects and investing in R&D efforts. Promo-tional activities are to be take n vigorously by allocating m aje funds .Software for control system needs to be developed in India.

5.0 CONCLUSIONS AND RECOMMENDATIONS

Conclusions

5.1 Zinc is strategic metal required for variety of ap plica tion s. World zincprodu ction a t pre se nt is 7.2 million tonne per an nu m and is likely torea ch a level of 7.9 million tonne pe r an nu m by the end of the centu ry.All the three grades of zinc slabs are now produced in the country.The total capacity for primary zinc production is 1,69,000 tpa andactu al p roduc tion average a t 85 % of rated capac ity will be 1,45,000

tpa. Secondary zinc production a t prese nt is abo ut 15,000 tpa. Theend users have benefits of availability of prime western grade forgalvanizing, availability of all the thre e g rad es of zinc, availability ofstock centers throughout the country resulting in easy access,availability of sulfuric acid for fertilizer and chemical industry andrecovery of metals.

5.2 The zinc indu stry in India is in good sha pe at pre sen t. Absorption andadoption of imported technology is excellent. Intensive training isvery essential for this industry. The industry has made efforts inindigenisation in terms of spare p arts, assem blies and equipm ents.

The zinc industry being 25 years old has achieved stature andmaturity. The industry will have to expand in coming years.

5.3 There are an um be r of improvements and developments abroad in them ain technological proce ss and eq uipm ents to enh an ce produ ctivity,energy saving, pollution control, etc. Zinc value s by im provem ents ofroasting, leaching, cell-house have to be augmented and all these

xvi

8/3/2019 zinc ind


developments will have to be incorporated in existing and future

smelters. R&D efforts are to be directed for improving quality control,

plant parameters of operations, computerization and use of micro-

processors. R&D efforts will depend on training and talent of

scientists and research workers. The technological gaps have been

identified and efforts will have to be made to bridge them.

RECOMMENDATIONS

(i) In order to develop sufficient zinc concentrates it is recommended

that the following steps may be initiated.

(1) Exploration of lead-zinc deposits in Rajasthan be carried out.

(2) Development of Amberata, Deri and Bamnia Kalan mines to

meet the shortage of lead concentrates.

(3) Utilization of low-grade zinc deposits by development of new

technology process.

(4) Joint sector development of zinc concentratess by participat-

ing in mines abroad to ensure availability of concentrates.

(ii) The existing smelters may be expanded by 50,000 tpa as the gap of

demand is in the range of 30-40,000 tpa and one can also assume

8 5 % capacity utilization.

(iii) Secondary zinc production could be encouraged by financial institu-

tions and the Government. Modvat system may be applied for

secondary zinc manufacturers, which will help to have good stability

of production and revenue. This would also mean advantage to the

manufacturers.

(iv) It maybe necessary to have an exclusive institute devoted to Research

and Development, designs and planning automation and computer-

ization and standardization of equipments. This may act as a nucleus

to get most of the job done through other research institutes/

universities by contract research.

(v) The above mentioned institute for zinc and lead could also be

entrusted with training of personnel as well. Training may consist of

theoretical and practical training in operations, computerization,

modernization, etc.

(vi) Promotional activities by the way of dissimination of information,

development of newer applications for zinc development, recycling/

recovery etc., should be entrusted to organisation like Indian Lead

Zinc Information Center, New Delhi with financial support and co-

xvii

8/3/2019 zinc ind


operation from producers of zinc.

(vli) A R&D program me may be tak en up for developm ent of a res idu etreatm ent p rocess either to recycle higher iron con taining ma terialsto the steel industry or to produce residu e suitable a s environmen-tally safe store.

(viii) A R&D prog ram m e may be taken up for obta ining higher recovery

efficiency in sm elters by optim isation of proc ess p ara m ete rs, me cha -nization, introduc ing online controls etc. The recovery sho uld be atpar with international levels at 94% to 96%.

(ix) A R&D program me may be taken up for energy conserva tion in aneffort to reduce power consumption for electrolysis.

(x) A deve lopm ent project may be initiated for recovery of va riou s m eta lslike germanium, gallium, thallium, iridium etc. from residues.

(xi) Technology up gra da tion efforts sho uld not be limited only to w hattechnology is available in cu rren t yea rs. B ut to identify and develop

new technologies on the anvil internationally and is likely to becommercialised in the coming years.

(xii) A R&D program me may be tkae n up for technology developm ent inelectro deposition of zinc by introduction of hyd rogen diffusion an od e(HDA). By this the voltage may be reduced from 3 .3 -3 .5 volts to ab ou t1.2 - 1.4 volts, thereby reducing consumption of electricitysubstantialy.

xviii

zinc ind

Documents