Indigenous production of nickel and cobalt

* S. K. S. Pashine and *K., S. Narasimhan

INTRODUCTION

Production of nickel and cobalt in the

country has been engaging the attention of the

Government of India for more than two decades

now. Indigenous production is needed to meet

the domestic demand of nickel, cobalt and their

compounds worth Rs. 400 million presently

being imported 1 as detailed in Table-1. These

imports account for nearly 8,000 tonnes of con-

tained nickel most of which is used in stainless

steel making. Till recently major requirement

has been for unwrought nickel compared to

class (II) products like oxide sinters and ferro

Table-1 : Import statistics of nickel,

cobalt and other compounds( 1 '

Item Quantity Tonnes

Value in million Rs.

Nickel ore and

concentrates

28 1.49

Nickel matte 250 10.25

Ferro nickel 1869 24.51

Unwrought nickel 2871 142.00

Monel metal 6.7 0.66

Cupro-nickel 94 5.42

Nickel alloys (40%) 183 9.21

German silver 8.6 0.50

Nickel alloys (10-40%) 3252 162.79

Waste nickel scrap

and alloys

2056 23.49

Cobalt and alloys 102 44.99

Naste scrap cobalt 5.1 1.99

Cobalt oxide 2.9 1.04

Cobalt hydroxide 0.05 0.02

nickel. The international prices being on the basis of contained nickel2 , the relative domestic

demand for pure nickel ( class I and class II )

products fluctuates depending on prevalent duty

levies. At present more of ferro nickel and nickel

oxide sinters are being consumed compared to

the situation a few years ago. However, from the

point of view of economics of making nickel

bearing alloy steels, while the class (I!) products

would be cheaper, from the technical point of

view, with the advent of carbon bearing charge

chrome usage, it is advisable to use carbon free

oxide sinters.

Primary sources for nickel (and cobalt)

are either sulphide ores in which these metals

occur as sulphides or laterite ore bodies in which

these occur as oxides. 75% of the total world

nickel is derived from sulphides and the balance

originate from laterites. The former is not rele-

vant to India which has only nickel and cobalt

bearing laterites as potential source.

Status .

As of now there are at least 21 operating

plants in the world extracting nickel and cobalt

based on their oxide ores, with an estimated

installed capacity of 0.4 million tonnes of nickel

equivalent. Some details of these plants are

indicated in Table-2. Four of them use hydro-

metallurgical route accounting for 18% of the

capacity whereas the rest adopt pyrometallurgy.

Two plants based on hydrometallurgy and three

on pyrometallurgy have recently been closed

down. Two plants based on hydrometallurgy

to produce 60,000 tonnes nickel equivalent per

year are coming up in Cuba3 . In addition a

plant to produce 8,500 tonnes is being set up

in the United States, which will simultaneously

* Mineral Development Board, Deptt. of Steel, New Delhi

Plant Remarks

Installed capacity tonnes of contained nickel per/year

Ni Co Ale 03 Mg0 Fe

Feed io

Table-2 Details of world operating plants(15)

1.

2.

3.

A. PYROMETALLURGY

Nippon Mining 11,350

Sagaroseki,

Japan.

Societe-Le-Nickel 65,850

Doniambo,

New Caledonia.

Morro-do-Niquel 2,500

Petropolis (MG)

Brazil.

— —

2.8 0.06

'1.4 --

— —

24.0

—

13.0

61.4

Blast furnace (SLN); ferro-

nickel; ore from Phillipines

and New Caledonia.

Production partly by elec-

tric furnace (SLN); nickel

matte and ferro-nickel.

Electric furnace (R K E F);

crude and refined ferro-

nickel.

4. Cerro-Matasso 22,500

Montelibane,

Colombia.

— — — Electric furnace (R K E F);

ferro-nickel.

5. Pacific Metals 25,000

Hachinohe,

Japan.

— Electric furnace (R K E F);

ferro-nickel; ore from Phi-

Ilipines and New Caledonia.

6. Nippon Nickel 4,500

Tsuruga

— Electric furnace (SLN)

nickel oxide; ore from Phi-

Japan. Ilipines and New Caledonia.

7. PT International 22,700 1.5to — 20 15.20 Selective reduction (INCO)

Nickel, EL-ESTOR 2.2 ferro nickel

Guatemala.

8. Hanna Mining 14,000 1.7to 1 to 24to 10to French-ugine ferro-nickel Riddle, Oregon USA 0.8 3 32 15

9. Codemin Niguel- 7,500

andia. Brazil

— Electric furnace ferro-nickel

10. Falconbridge 27,250 Falconbridge (similar to Dominicana Bonac INCO) ferro-nickel Dominican Republic

11 PT International 49,000

nickel, Soroako

2.1 — 16.2 19.1 Selective reduction (INCO)

75% nickel matte Indonesia

352

Table— : contd.)

Plant

Installed capacity Feed% tonnes of contained Ni Co Ale 03 Mgo Fe nickel per/year

Remarks

12. Larco, Larymna 27,000 --

-

— Ferro-nickel. Greece

13., PT Aneka, Tambang 5,000 2.5

-

— Ferro-nickel. Pomalaa, Indonesia

14. Nippon Yakin

Ohayama, Japan

15. Shimura Kako

Shimura, Japan

16. USSR

17. Ferro niki

Kosovo, Glogovac

Yugoslavia

36,360

-

— Ferro-nickel, ore from Phi- llipines and New Caledonia.

5,000 — — Electrolytic nickel.

25,000 1.4

-

— Ferro metal; three plants.

12,000 Ferro-nickel.

B. HYDROMETALLURGY (Ammonia leach

18. Greenvale

22,700 1.6 0.1 — 50 Sheritts Ammonia Leach

Yabulu, Australia nickel-cobalt sulphide,nickel

oxide.

19. Niquelandia 5,000 — Sheritts Ammonia Leach

Brazil nickel oxide, high iron ore

20. Nicarro 25,000 1.5 to-- 20to Carron; nickel oxide granule

Cuba 1.8 — 25 sinter.

21. Surigo Nickel

20,440 1.2 0.1

38.5 Sheritts Ammonia Leach,

Refining, Nonac nickel powder briquetts.

Island, Phillipines

Recently closed; likely to

reopen.

C. HYDROMETALLURGY 9 (Acid leach)

22. Moa Bay

17,500 1.3 0.15 8.5 1.7 47.5 Freeport sulphur; nickel- Cuba cobalt sulphide.

(SLN— Societe le Nickel Anonyme; 1NCO—International Nickel Company;

RKEF --Rotary Kiln Electric Furnace)

353

produce cobalt, chromite and high pure

magnesia4 .

All operating plants working on hydrometa-

llurgical route are based essentially on one of

the two alternatives involving acid leaching

under pressure or reduction-roast followed by

leaching with ammonia with minor modifications

in the process steps depending upon the raw

material availability and final product required.

Similarly, all pyrometallurgical operations either

adopt a blast furnace or an electric furnace with

minor modifications based thereon. Besides,

numerous attempts have been made to improve

the efficiency and economy of the processes in

practice as a result many modified processes

tried on a pilot scale have been patented. These

are summarised in Table-3.

Comparative evaluation :

For the purpose of comparative evaluation,

a pyrometallurgical route based on electric smel-

ting, two hydrometallurgical routes one based

on reduction-roast ammonia leach and the other

on acid leach are considered in the present

exercise. Other potential processes narrated in

Table-3 are left out since adoption of any one

of them would mean much more in-country

developmental work compared to operating one

of the commercially established processes.

Besides, the economics of the process will not

be drastically altered with minor modifications

brought out over the basic processes considered.

Electric furnace process (as practiced in

Brazil by Morro-do-NiqueI5,6 ) :

The oxide ore is treated in ore washing

plant for removal of SiO2 . The nickel values

are limited to the serpentinic fraction, the quartz

veins and silica box work is barren. This allows

beneficiation using hydrocyclones and spiral

classifier. The overall nickel recovery in washing

is 50%. The concentrate has 2% Ni and the

reject has 0.6-0.7% Ni and 80% SiO2. This

concentrate is mixed with normal ore such that

final SiO 2/ MgO ratio does not exceed 1,7_

Such a feed has 1.2 to 1.7% Ni. The feed is

mixed with below 12 mm charcoal fines and

miniballed. The miniballs are dried for a day

in shed and then calcined in rotary kilns

where drying also takes place. Calcined

miniballs, discharged at 850'C are smelted

in electric furnace to crude ferro-nickel,

seventy percent of which is sold as it is,

and. remaining is refined first by desulfurizing in

spouts and ladles by lime and soda and is then

oxygen blown in L. D. converters to remove C.

Si and P to the desired levels. The alloy is cast

into 10-20 kg ingots in an ingot casting ma-

chine. The slags obtained on desulfurizing and

converter treatment are recycled to electric

furnace.

A flow sheet of the processes followed in

Pratopolis, Brazil by Morro-do-Niquel is shown

in Figure 1.

Ammonia leach process (as practiced in

Phillipines by Surigo nickel refinery)?

The ore is crushed and dried in rotary

kilns to 2.5% free moisture and then milled in

ball mills to 85% below 74 microns. Fine ore is

roasted in multiple hearth roasters. Roasted ore

is cooled and sent for two stage leaching in

leach circuits with ammonium carbonate (80 WI

ammonia and 50 g/I CO2 ). The leach solution

is sent for nickel recovery after two stage cobalt

recovery. Cobalt is recovered as sulphide. For

nickel recovery, cobalt free solution is stripped

in boil columns to precipitate basic nickel carbo-

nate (BNC). Any nickel which escapes precipita-

tion in boil columns is recovered by ion exchange.

The BNC is dissolved in ammonium sulphate and

the solution is passed through a oxidation pipe

reactor to ensure that all nickel is in the sulphate

state. It is then reduced in autoclave under

hydrogen pressure to obtain nickel powder

which is further briquetted and sintered. A flow

sheet of the process as practiced by Surigo Ni-

ckel refinery in Phillipines is shown in Figure 2.

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358

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LIME

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SLAG

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FIGURE 1 ; ELECTJ IC FURNACE PROCESS

FINE ORE STOCKPILE

DAY SINS

ROTARY KILN

METAL

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REFINED FERRDNICKEL

360

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361

Acid leach process (as practiced in Cuba

at Moa Bay)8

capital return rate and value of realisation, the

acid leach process affords greatest margin to

make the process economically viable.

R.o.m. ore is screened and log washed to

obtain a slurry containing 30% of solids which is

heated in stages to reaction temperature of 200°C

and then acid leached. Leach liquor after solids

removal is neutralised with lime and heated with

H2 S to precipitate nickel and cobalt sulphides.

Nickel and cobalt extraction into leach liquor is

96%. The mixed nickel cobalt sulphide which

analyses 55% Ni, 6% Co, 36% S, along with •

minor impurities is redissolved in dilute

sulphuric acid in an autoclave under aeration to

convert sulphides into water soluble sulphates.

Nickel powder is obtained by reducing nickel sul-

phate to nickel metal with hydrogen at elevated

temperature and pressure. The remaining liquor

with certain other impurities is evaporated to

crystallize Co, Ni and Zn as double salts with

ammonium sulphate. The salts are redissolved

with ammonia and the solution is aerated in oxi-

dation autoclaves after which Ni and Zn are

precipitated by H2 SO4 . The precipitate is re-

cycled and the solution containing Co as

sulphate is treated with hydrogen for recovery of

cobalt powder.

Economics :

On the basis of the details available for

the three processes enumerated above, a rough

estimate is made on the economics for adopting

them to produce 15,000 tonnes nickel equivalent

in the country.

The capital cost has been worked out

using 0.6 power9 scale down factor based on

the data provided by O'kanel 0. Operating costs

are cosidered to be proportional to estimated

inputs of raw materials and utilities. It is seen

that the capital cost expressed as million rupees

per annual tonne of nickel works out to be 0.35,

0.33, and 0.24 for the electric furnace, ammonia

and acid leach processes respectively. Similarly

the estimated cost of inputs per tonne of nickel

recovered is Rs. 62,000, Rs. 43,000 and

Rs. 37,000 respectively. Taking into account the

Salient information is given in Table-4 and

the details in Table-5.

Mineral Source :

As mentioned earlier, the only primary

potential source for nickel and cobalt in the

country is their oxide contained in the laterites

associated with chromite deposits in Orissa.

There are 154 million tonnes deposit in Sukinda

averaging 1.03% nickel and 0.01 % cobalt at 0.7%

Ni cut-off11 ,which has been under consideration by the Government as a source to be developed

into a mine. In the past, one of the reasons attri-

buted for not being able to harness the resources is the lower cut-off grade of nickel12. At the same time no report is available of any syste-

matic attempt to enrich the nickel and cobalt

content in the ore. In fact, much is to be under-

stood about the mineralogy.

As an alternative, the overburden associ-

ated with chromite mining is also considered to

be a potential source and could be preferred if

properly harnessed since the same being amena-

ble to physical enrichment provides a better

grade material with attendant improvement in

the economy of chromite mining.

It is estimated that the accumulated over-

burden can be a source for 75,000 tonnes

of nickel and 7,500 tonnes of cobalt. The

raisings at the current rate can be a source for

15,000 tonnes of nickel and 1,500 tonnes of

cobalt 13. This is likely to increase. The

projected production of chromite from the

major mines in the country which is likely to

touch 0.35 million tonnes per year in 1987 is

indicated in Table- 614.

Choise of technology

Beside the viability on the basis of eco-

nomics, even though more than 80% of world

nickel production from oxide ores is derived from

pyrometallurgical operations no new ventures

362

Table-4 : Salient features of the three alternatives(16) (feed grade : Nickel 1.0%; Cobalt 0.03%)

Pyrometallurgy Hydrometallurgy

Electric furnace Ammonia leach Acid leach

Recovery %

Nickel

Cobalt

95

0

80 40

90

85

Production (T. per year)

Nickel 15,000* 15,000** 15,000** Cobalt 226 480

Ore throughput

(million T. per year) 1.57 1.88 1.66

Capital cost

(million Rs./annual 0.35 0.33 0.24 Tonne of nickel)

Capital return rate (Rs. Tonne of nickel) 18,000 16,000 12,000

Raw material and utility costs

Rs./Tonne of nickel 62,000 43,000 37,000

Realisation 55,000 59,000 63,000

* As ferro-nickel; ** As nickel metal/briquettes

Table-6 : Projected production of chromite from different operating mines in Orissa

Mine Chromite ore Tonnes/year

Overburden m3 / Tonne

of ore Location

South Kaliapani, Q-D 150 to 200,000 3.5 Sukinda valley

Kathpal 25,000 4.0 — do —

Kalarangi 30,000 3.0 — do

Kaliapani Q-3 30,000 4.5 do —

Bangur 25,000 3.5 Nuasahi-Baula

363

Table-5 : Raw material and utility requirements(17)

Unit Rate per per Tonne unit of con- Rs. tained nickel

Electric furnace Qty. Value

Rs.

Ammonia leach Acid leach Qty. Value

Rs. Qty. Value

Rs.

Ore through T

put

30 105 3150 125 3750 111 3330

A. Energy

Fuel Oil T 3000 7.35 22050 14 42,000 4.329 12900

Charcoal T 1000 3.885 3885

Coal T 350 (24.00)* (8400)* 45 (15750)* 7.1 (22) 2485(7700)

Power KWH 0.60 60375 36225 6250 3,750 5550 3330

Total Energy 62160 45.750 18805

(Rs.) (48510) * (19500) (11030)

B. Others

Electrode T 8000 0.525 4200 Paste

Soda ash T 5100 0.063 321 — — _

Lime T 250 0.762 190 4 (1000) 11.1 2775

Oxygen M3 1 5775 5775 — — ....._.

Ammonia T 9500 — 1.875 17812 NA NA

Hydrogen M3 — — 11250 NA NA NA

Hydrogen Kg — NA NA 555 NA Sulphide

Sulphur T . 2000 0.25 500 9.8 19600

for H2 SO4 and H2 S

Nitrogen — — NA NA

Carbon dioxide—

Sulphuric acid — — NA NA NA NA

Total others (Rs.) 10486 18312 (19312) 22375

Grand Total 75796 67812 44510 (Rs.) (62146) (42562) (36735)

(Figures in parenthesis represent usage of Coal)

364

are being thought of in view of high energy

requirement. Besides, basic conditions for pyro-

metallurgy are a higher percentage of nickel of

2.0% or more in the feed and the need for the

feed to be in a lumpy form. Both these condi-

tions are not satisfied in the Indian context,

since not only the grade is low (below 1%) but

also the mineral occurs in extremely fine form.

In the event pyrometallurigical route is to be

considered it would not only be necessary to

enrich the nickel content but also the need for

agglomeration is to be taken into account. The

latter under the prevalent conditions of high

energy cost would become prohibitive. In addi-

tion, in established pyrometallurgical operations

cobalt is not separately recovered and also the

product obtainable as ferro nickel is less preferred.

The chemical composition of chromite

overburden as potential source is compared with

the typical feed composition for each of the

processes in Table-5. As stated earlier, the

granulometry of the material is ideally suitable

for the acid leach process. While the material

from either of the source is suitable for the acid

leach process it is desirable to reduce the alumina

content15 in the overburden material a point to

be borne during attempts to physically enrich

the over burden from chromite mines which

appears feasible from the results of some bene-

ficiated products shown in Table-7.

The overburden from chromite mines as a

source for nickel and cobalt seems to be justi-

fiable for yet another reason. in the acid leach

process both limonitic and some serpentinic ore

is desirable for optimal acid utilisation which is

possible by judicious blending of overburden

material. On the other hand, no nickel rich

serpentine ore is yet found in Sukinda main

lateritic body.

Table-7 Chemical analysis of beneficiated sample from over burden (58)

SI.

No.

Constituents Samples

1 2 3 4 5 6

(per cent)

1. Ni 1.1 0.4 1.0 0.69 0.61 0.72

2. Co 0.04 0.04 0.034 0.024 0.024 0.04

3. Ca0 Trace Trace Trace Trace Trace Trace

4. MgO 9.7 8.8 5.3 4.3 4.95 2.86

5. Al2 03 11.2 9.1 11.5 11.1 20.1 21.1

6. Cr2 03 4.1 18.25 9.05 8.0 13.18 8.0

7. M n2 03 0,45 0.32 0.57 0.53 0.29 0.65

8. H2O 0.18 0.14 0.70 0.20 0.32 0.45

9. LO1 6.52 6.03 9.38 7.92 3.88 9.52

10. Si02 (Quartz) 12.8 7.5 10.2 0.038

it Si02 (others) 3.5 18.3 13.3 18.0 38.12 25.23

12. Fe (Total) 49.3 30.2 38.1 47.0 15.7 31.4

Total 98.9 99.2 99.0 97.8 97.2 100.00

365

Conclusions :

Nickel and cobalt are important strategic

metals. India does not produce any nickel

except as some by-product nickel sulphate.

Annually nickel and cobalt worth Rs. 400 million

are being imported. The quantity of nickel and

cobalt imported should increase with our indus-

trial growth. Lateritic nickel deposits of India

which have been explored in little details do not

constitute a major nickel find by world stan-

dards and is more of a geological curiosity than

anything else at the present moment. On the

contrary overburden material from chromite

mines is amenable to beneficiation and is better

suited to acid leach treatment, a process route

which according to present analysis appears to

be most favourable.

There are no commercial processes which

can be applied directly to each and every nickel

ore. Each one needs a tailor cut process. The

problem is further aggravated when lower grade

materials are to be treated. It is, therefore,

necessary to initiate lot of in-country develop-

ment and process adoption work. The strategy

being adopted in Cal-Nickel, California, USA

involving multi-product recovery appears very

interesting and warrants detailed examination.

REFERNCES

1. Import Export Statistics published by "The Directorate

General of Trade Intelligence, Calcutta.

2. Jim Ainsworth, Nickel - The International Perspective,

published by Financial Times Business Information Limited,

London, P. 42.

3. Jim Ainsworth, Nickel - The International Perspective,

published by Financial Times Business Information Limited,

London, P. 23.

4. Joan C. Todd, Engineering and Mining Journal June; 1983

P. 29

5. Abarham and Hans, Proceedings of International Laterite

Symposium, Louisiana, 1979, published by Society of

Mining Engineers, U. S. A., P. 397.

6. Ernst Langa, Proceedings of International Laterite Sympo-

sium, Louisiana, 1979 published by Society of Mining

Engineers, U. S. A., P. 397.

7. Colvin and Gulyas, Proceedings of International Laterite

Symposium, Louisiana, 1979, published by Society of

Mining Engineers U. S. A., P. 346.

8. Joseph R. Boldt., Jr. The Winning of Nickel. Published by

Methuen and Co. Ltd., London, 1967, P. 346.

9. T. C. Burnett, Trip Report to CIDA, 1981, P. 19.

10. P. T. 0' kana, Proceedings of International Laterite Sympo-

sium, Louisiana, 1979, P. 503.

11. M. D. B., New Delhi, A Status note on Lateritic Nickel

deposits of Orissa, 1981 ( For Private circulation )

12. M. D. B., New Delhi. A Status Report on Nickel 1984

( In House study )

13. R. B. Rao, S. Prakash, G. V. Rao and K. S. Narasimhan

14. K. S. Mahapatra, Private communication

15. AMAX, R&D, Golden Colorado, private communication

16. M. D. B. New Delhi. Inhouse study on Nickel, Vol. II,

Indigenous production of Nickel and Cobalt, P. 9.

17. — do — P. 14

18. — do — P. 15

19. R. B. Rao, Pvt. communication.

366