Title of Invention	"A PROCESS FOR PRODUCTION OF NICKEL CONCENTRATE FROM CHROMITE OVERBURDEN/NICKELIFERROUS LATERITIC ORES"
Abstract	A process for the production of nickel concentrate from chromite overburden/nickel ferrous lateritic ores which comprises grinding chromite overburden and lateritic ores to a size in the range of 60 to 150 microns, granulating in the presence of water and powdered coke breeze, reducing the granulated material in a pan using down draft sinter in process at a temperature in the range and size reducing the resultant product to below 100 microns by known methods and separating the nickel concentrate by magnetic separation.

Title of Invention

"A PROCESS FOR PRODUCTION OF NICKEL CONCENTRATE FROM CHROMITE OVERBURDEN/NICKELIFERROUS LATERITIC ORES"

Abstract

A process for the production of nickel concentrate from chromite overburden/nickel ferrous lateritic ores which comprises grinding chromite overburden and lateritic ores to a size in the range of 60 to 150 microns, granulating in the presence of water and powdered coke breeze, reducing the granulated material in a pan using down draft sinter in process at a temperature in the range and size reducing the resultant product to below 100 microns by known methods and separating the nickel concentrate by magnetic separation.

Full Text	This invention relates to a process for the production of nickel concentrate from chromite overburden/nickeliferrous lateritic ores. India is seriously looking for a process to produce nickel or ferro-nickel since three decades, but no commercial plant has come up so far. The source of nickel in India is concentrated largely in the chromite' overburden (COB) material which is being generated while mining the chromite ore. The average nickel content in chromite overburden is around 0.5%. There are also around 100 million tonnes of nickeliferrous lateritic ores with an average grade of 1.15% nickel. Both of these are found in the Sukinda region of Orissa. Due to high iron to nickel ratio, these materials are not suitable directly for ferro-nickel making. The solution lies in beneficiation of such materials to a desired level of nickel content by preferentially eliminating a large part of iron and other gangue materials. It has been found difficult to upgrade the nickel content in the material by physical beneficiation process as the nickel is intimately associated with other mineral bodies in finely disseminated forms. Treatment of such complex ores by the judicious combination of pyrometallurgical pretreatment and mineral processing is the possible alternative for the production of this material. Pyrometallurgical pretreatment such as magnetising roasting, direct reduction, sintering, sulphidising roasting, segregation roasting, chlori-dising roasting etc. have been applied by many scientific workers to overcome the process limitations arising due to diversity of ores and complex mineralogical compositions. These methods in combination with mineral beneficiation techniques to many diffi-cult-to-treat ores are widely applied all over the world. So, what is required now is to make the Indian nickel bearing lateritic ores/COB amenable to concentration for ferro-nickel making. The objective of the present invention is to provide a process for the production of nickel concentrate from chromite overburden/nickeliferrous lateritic ores generated while mining the chromite ore. Another objective of the present invention is to provide a process for the production of a material having 1.6-2.1% Ni, 40-52% Fe (Ni : Fe ~ 25) with 70-80% Ni recovery from a feed containing around 0.5-1.15% Ni using down draft sintering followed by magnetic separation techniques. R&D efforts in India to upgrade low rank ferruginous lateritic nickel ore/chromite overburden of Indian origin could not bring the nickel grade to the desired limit with substantial recovery. References can be made to many workers, Jiroh Onodera et al., Int. J. of Min. Processing, 19 (1987), pp. 25-42; Das B. and Reddy P.S.R., Indian Min. & Eng. Journal, 4 (1989), pp. 30; Narasimhan K.S., Rao R.B. and Das B., Mineral Engineering, 2, 3 (1989), pp. 425-429; Ranen Sen et al., Int. J. Min. Process 19 (1987), pp. 43-67, who followed classification, gravity concentration, magnetic separation and flotation processes but could not upgrade this type of material to above 1.15% nickel and that too nickel recovery was not more than 60%. Direct reduction of nickel ore containing nickel > 1.5% for production of ferro-nickel has been done by many workers and many commercial plants are being operated abroad. At Yakin Kogyo Co. Ltd., Oheyama Works, ferro-nickel is produced by direct reduction of Garnierite ore in a rotary kiln. The plant, however, is being operated with 12% Fe and 2.5% Ni (Tetsuya Watanable et al., Int. J. Min. Process 19 (1987), pp. 173-187). At Hyuga Smelting Co. Ltd., Miyazaki, Japan, Fe-Ni is produced by the rotary kiln - electrical furnace process by using the nickel ore from New Caledonia (Ni 2.5%, Fe 12%), Indonesia (Ni 2.55%, Fe 14%) and Philippines (Ni 2.3%, Fe 12.55%) (Ogura T. et al., Int. J. Min. Proc. 19 (1987), pp. 189-198). P.T. INCO, Indonesia produces ferro-nickel from a ore of 2% Ni at a SiO : MgO ratio of 1.9 (J. D. Guiry and A.D. Dalvi, Int. J. Min. Process 19 (1987), pp. 199-214). The Pacific Metals, in Hachimohe, produces ferro-nickel by utilising the lateritic nickel ore from New Caledonia, Indonesia and Philippines (Yamada K. and Hiyama T., Int. J. Min. Processing, 19 (1987), pp. 215-221. MINPRO, a R & D Company in Sweden, and PAMCO, Pacific Metals Co. of Japan, have developed a nickel segregation process by using a new type of furnaces called a mechanical kiln. The segregation process works at a much lower temperature than melting using the nickel ores mentioned above. Generally, nickel ores used abroad are high grade in nature, whereas the reserves of those of Indian origin are low grade with respect to Ni/Fe ratio and mineralogical composition. The reserves available in India is limonitic in nature. In India, the chromite overburden or nickeliferrous lateritic ore have not been exploited so far for the production of nickel/ferro-nickel and the country imports nickel and its alloys to meet its internal requirement. Ni/Fe ratio plays an important role in the smelting operation to produce a suitable grade of nickel. The Ni/Fe ratio in the material available in Sukinda region is around 50 which is to be considerably improved for use in ferro-nickel making. The process developed according to the present invention is suitable for making ferro-nickel. The process can utilise appreciable quantity of waste materials resulting from COB/nickelifer-rous lateritic ores thereby reducing the environmental pollution to a great extent. The process of the present invention involves conversion of oxide phase of iron partly into magnetite by reduction roasting of the ore with solid reductant like charcoal/coke breeze/coal followed by magnetic separation of the calcined material by applying low intensity magnetic separation technique. The mineralogical study has established that most of the nickel values are concentrated in the iron phases namely, goe- thite, limonite and hematite. So, conversion of the same to artificial magnetite was carried out by using solid reductant, i.e. coke breeze. Unlike the conventional roasting device used for production of the ore in the temperature range of 1000- o 1200 C, simple pan sintering techniques employed for reduction roasting purpose. The specific equipment for reduction roasting was a modified pan sintering unit employing down draft flow of air through the bed. The magnetic separation tests of the calcined material was carried out using a magnetic separator, designed by Sala International Ltd., Sweden, specifically to treat magnetite minerals. If all the nickel and iron present in the ore get completely reduced, then proportion of iron in the alloy will be very high which is of no commercial value. In view of this selective reduction of iron (partly) was carried out where nickel is reduced preferentially and sits over magnetic phase. The main processing steps involved in the present invention are size reduction of the ore to below 150 microns, granulation of the same by mixing with coke breeze powder and moisture, reduction roasting by using down draft sintering technique, subjecting the calcine to grinding ( Accordingly, the present invention provides a process for the production of nickel concentrate from chromite overburden/ nickeliferrous lateritic ores which comprises grinding chromite overburden and lateritic ore to around 60-150 micron size, granulating in the presence of water and powdered coke breeze, reducing the granulated material in a pan using down draft sintering o process at a temperature in the range of 1000-1200 C, size reduce ing the resultant product to below 100 micron by known methods and separating the nickel concentrate by magnetic separation. The concentrate from the first magnetic stage is further cleaned in the second and third magnetic separator. The final product after cleaning operation in magnetic separator contains 1.6-2.1% Ni with an overall recovery of 65-90% depending on the nature of feed. The ore used may contain 0.5-1.15% Ni. The water used in the granulating step may range from 8-12% and the powdered coke breeze 8-15%. The sintering process may be effected for a period in the range of 15-25 minutes. The temperature of sintering may vary depending on the bed height, suction pressure, bed permeability etc. The uniqueness of this process is the selective reduction of the iron oxide phases to magnetite containing nickel to enhance the nickel grade with simultaneous formation of fahelite where a part of iron combines with silicates during roasting reactions and gets separated as tailings in the magnetic separator along with the other gangue materials. The magnetic separation was carried out in a low intensity magnetic separator with wash water system to avoid the entrainment of gangue particles in the product. As a result, it was possible to increase the nickel level to 1.6-2.1% from the feed of 0.5-1.15% and thus reducing the overall iron to nickel ratio in the order of 22-29. The present invention which consists of pyrometallurgical pretreatment for beneficiation of complex nickel bearing COB and ferruginous ore is expected to be used for ferro-nickel making which can be further used for making nickel steel having various uses. The process can be applied to any nickeliferrous lateritic ores with low nickel content. However, in order to achieve this objective, percentage of reductant and moisture, particle size of the feed and reductant, suction applied, granulometry of the bed etc. in down draft sintering technique are to be suitably adjusted. The treatment of this type of material by down draft sintering technique results in conversion of iron phases to magnetite and partly to metallic iron, wustite and fahelite. The nickel values are mostly concentrated in the magnetite phases. Fe/Fe-Ni are separated by applying low intensity magnetic separators. The wustite and fahelite and other gangue materials containing sili- ca, alumina, magnesia and calcium go into the non-magnetic fractions. This has been confirmed by microscopy and X-ray diffraction studies. The overall recovery of 65-90% at 1.6-2.1% nickel content has been achieved. The details of the process of the present invention are given in the Examples which are provided to illustrate the invention only and should not be constrained to limit the scope of the present invention. Example-1 20 kg of Sukinda chromite overburden containing 0.5% Ni and 28% Fe is crushed and then ground to below 100 microns, the product from ball mill is mixed with water (10%) in a mixture. Then the material is fed to the granulator along with coke breeze (15%) to obtain granules of 3 to 6 mm dia. It is then fed into the pan sintering unit. The sintering is carried out by down o draft technigue for 25 minutes at 1200 C. The initial ignition .of the charge is carried out by means of charcoal spread over the top of the charge. The sinter product is ground in a ball mill to pass 80% below 100 microns and separated in a magnetic separator. The product is then cleaned in second and third magnetic separators using the same conditions as in the first stage. The product obtained contains 1.62% Ni and 39% Fe with 75% nickel recovery. Example-2. The nickeliferrous lateritic ore containing 1.15% Ni and 55% Fe has been ground to below 100 microns. The charge is granulated to 3 to 6 mm size using 10% water and 15% powdered coke breeze and then it is reduced by down draft sintering technique for 25 o minutes at 1200 C with a bed height of 300 mm. The sinter product is then crushed to below 100 microns. The product in this case contains 2.1% Ni and 60% Fe with an overall recovery of 86% of nickel., We Claim : 1. A process for the production of nickel concentrate from chro mite overburden/nickeliferrous lateritic ores which comprises grinding chromite overburden and lateritic ores to a size in the range of 60 to 150 microns, granulating in the presence of water and powdered coke breeze, reducing the granulated material in a pan using down draft sintering process at a temperature in the o range of 1000-1200 C and size reducing the resultant product to below 100 microns by known methods and separating the nickel concentrate by magnetic separation. 2. A process as claimed in claim 1, wherein the ore containing 0.5-1.15% nickel is used. 3. A process as claimed in claims 1 and 2, whereiri the amount of water used in the granulating step is in the range of 8-12%. 4. A process as claimed in claims 1 to 3, wherein the amount of coke breeze used is in the range of 8-15%. 5. A process as claimed in claims 1 to 4, wherein the magnetic separation is effected using a magnetic seprator repeatedly till the desired concentration of nickel in the end product is obtained. 6. A process as claimed in claims 1 to 5, wherein the intensity of the magnetic field employed is in the range of 1500-2000 gauss. 7. A process for the production of nickel concentrate from chro-mite overburden/nickeliferrous lateritic ores substantially as herein described with reference to the Examples.

Full Text

This invention relates to a process for the production of nickel concentrate from chromite overburden/nickeliferrous lateritic ores.
India is seriously looking for a process to produce nickel or ferro-nickel since three decades, but no commercial plant has come up so far. The source of nickel in India is concentrated
largely in the chromite' overburden (COB) material which is being

generated while mining the chromite ore. The average nickel content in chromite overburden is around 0.5%. There are also around 100 million tonnes of nickeliferrous lateritic ores with an average grade of 1.15% nickel. Both of these are found in the Sukinda region of Orissa. Due to high iron to nickel ratio, these materials are not suitable directly for ferro-nickel making. The solution lies in beneficiation of such materials to a desired level of nickel content by preferentially eliminating a large part of iron and other gangue materials. It has been found difficult to upgrade the nickel content in the material by physical beneficiation process as the nickel is intimately associated with other mineral bodies in finely disseminated forms. Treatment of such complex ores by the judicious combination of pyrometallurgical pretreatment and mineral processing is the possible alternative for the production of this material. Pyrometallurgical pretreatment such as magnetising roasting, direct reduction, sintering, sulphidising roasting, segregation roasting, chlori-dising roasting etc. have been applied by many scientific workers to overcome the process limitations arising due to diversity of ores and complex mineralogical compositions. These methods in
combination with mineral beneficiation techniques to many diffi-cult-to-treat ores are widely applied all over the world. So, what is required now is to make the Indian nickel bearing lateritic ores/COB amenable to concentration for ferro-nickel making.
The objective of the present invention is to provide a process for the production of nickel concentrate from chromite overburden/nickeliferrous lateritic ores generated while mining the chromite ore. Another objective of the present invention is to provide a process for the production of a material having 1.6-2.1% Ni, 40-52% Fe (Ni : Fe ~ 25) with 70-80% Ni recovery from a feed containing around 0.5-1.15% Ni using down draft sintering followed by magnetic separation techniques.
R&D efforts in India to upgrade low rank ferruginous lateritic nickel ore/chromite overburden of Indian origin could not bring the nickel grade to the desired limit with substantial recovery. References can be made to many workers, Jiroh Onodera et al., Int. J. of Min. Processing, 19 (1987), pp. 25-42; Das B. and Reddy P.S.R., Indian Min. & Eng. Journal, 4 (1989), pp. 30; Narasimhan K.S., Rao R.B. and Das B., Mineral Engineering, 2, 3 (1989), pp. 425-429; Ranen Sen et al., Int. J. Min. Process 19 (1987), pp. 43-67, who followed classification, gravity concentration, magnetic separation and flotation processes but could not upgrade this type of material to above 1.15% nickel and that too nickel recovery was not more than 60%.
Direct reduction of nickel ore containing nickel > 1.5% for production of ferro-nickel has been done by many workers and many commercial plants are being operated abroad. At Yakin Kogyo Co. Ltd., Oheyama Works, ferro-nickel is produced by direct
reduction of Garnierite ore in a rotary kiln. The plant, however,
is being operated with 12% Fe and 2.5% Ni (Tetsuya Watanable et
al., Int. J. Min. Process 19 (1987), pp. 173-187). At Hyuga
Smelting Co. Ltd., Miyazaki, Japan, Fe-Ni is produced by the
rotary kiln - electrical furnace process by using the nickel ore
from New Caledonia (Ni 2.5%, Fe 12%), Indonesia (Ni 2.55%, Fe
14%) and Philippines (Ni 2.3%, Fe 12.55%) (Ogura T. et al., Int.
J. Min. Proc. 19 (1987), pp. 189-198). P.T. INCO, Indonesia
produces ferro-nickel from a ore of 2% Ni at a SiO : MgO ratio
of 1.9 (J. D. Guiry and A.D. Dalvi, Int. J. Min. Process 19 (1987), pp. 199-214). The Pacific Metals, in Hachimohe, produces ferro-nickel by utilising the lateritic nickel ore from New Caledonia, Indonesia and Philippines (Yamada K. and Hiyama T., Int. J. Min. Processing, 19 (1987), pp. 215-221. MINPRO, a R & D Company in Sweden, and PAMCO, Pacific Metals Co. of Japan, have developed a nickel segregation process by using a new type of furnaces called a mechanical kiln.
The segregation process works at a much lower temperature than melting using the nickel ores mentioned above. Generally, nickel ores used abroad are high grade in nature, whereas the reserves of those of Indian origin are low grade with respect to Ni/Fe ratio and mineralogical composition. The reserves available in India is limonitic in nature. In India, the chromite overburden or nickeliferrous lateritic ore have not been exploited so far for the production of nickel/ferro-nickel and the country imports nickel and its alloys to meet its internal requirement. Ni/Fe ratio plays an important role in the smelting operation to
produce a suitable grade of nickel. The Ni/Fe ratio in the material available in Sukinda region is around 50 which is to be considerably improved for use in ferro-nickel making.
The process developed according to the present invention is suitable for making ferro-nickel. The process can utilise appreciable quantity of waste materials resulting from COB/nickelifer-rous lateritic ores thereby reducing the environmental pollution to a great extent.
The process of the present invention involves conversion of oxide phase of iron partly into magnetite by reduction roasting of the ore with solid reductant like charcoal/coke breeze/coal followed by magnetic separation of the calcined material by applying low intensity magnetic separation technique.
The mineralogical study has established that most of the
nickel values are concentrated in the iron phases namely, goe-
thite, limonite and hematite. So, conversion of the same to
artificial magnetite was carried out by using solid reductant,
i.e. coke breeze. Unlike the conventional roasting device used
for production of the ore in the temperature range of 1000-
o 1200 C, simple pan sintering techniques employed for reduction
roasting purpose. The specific equipment for reduction roasting was a modified pan sintering unit employing down draft flow of air through the bed. The magnetic separation tests of the calcined material was carried out using a magnetic separator, designed by Sala International Ltd., Sweden, specifically to treat magnetite minerals. If all the nickel and iron present in the ore get completely reduced, then proportion of iron in the alloy will be very high which is of no commercial value. In view of this
selective reduction of iron (partly) was carried out where nickel is reduced preferentially and sits over magnetic phase.
The main processing steps involved in the present invention are size reduction of the ore to below 150 microns, granulation of the same by mixing with coke breeze powder and moisture, reduction roasting by using down draft sintering technique, subjecting the calcine to grinding ( Accordingly, the present invention provides a process for the production of nickel concentrate from chromite overburden/ nickeliferrous lateritic ores which comprises grinding chromite overburden and lateritic ore to around 60-150 micron size, granulating in the presence of water and powdered coke breeze, reducing the granulated material in a pan using down draft sintering
o process at a temperature in the range of 1000-1200 C, size reduce
ing the resultant product to below 100 micron by known methods and separating the nickel concentrate by magnetic separation.
The concentrate from the first magnetic stage is further cleaned in the second and third magnetic separator. The final product after cleaning operation in magnetic separator contains 1.6-2.1% Ni with an overall recovery of 65-90% depending on the nature of feed.
The ore used may contain 0.5-1.15% Ni. The water used in the granulating step may range from 8-12% and the powdered coke breeze 8-15%. The sintering process may be effected for a period in the range of 15-25 minutes. The temperature of sintering may
vary depending on the bed height, suction pressure, bed permeability etc.
The uniqueness of this process is the selective reduction of the iron oxide phases to magnetite containing nickel to enhance the nickel grade with simultaneous formation of fahelite where a part of iron combines with silicates during roasting reactions and gets separated as tailings in the magnetic separator along with the other gangue materials. The magnetic separation was carried out in a low intensity magnetic separator with wash water system to avoid the entrainment of gangue particles in the product. As a result, it was possible to increase the nickel level to 1.6-2.1% from the feed of 0.5-1.15% and thus reducing the overall iron to nickel ratio in the order of 22-29.
The present invention which consists of pyrometallurgical pretreatment for beneficiation of complex nickel bearing COB and ferruginous ore is expected to be used for ferro-nickel making which can be further used for making nickel steel having various uses. The process can be applied to any nickeliferrous lateritic ores with low nickel content. However, in order to achieve this objective, percentage of reductant and moisture, particle size of the feed and reductant, suction applied, granulometry of the bed etc. in down draft sintering technique are to be suitably adjusted. The treatment of this type of material by down draft sintering technique results in conversion of iron phases to magnetite and partly to metallic iron, wustite and fahelite. The nickel values are mostly concentrated in the magnetite phases. Fe/Fe-Ni are separated by applying low intensity magnetic separators. The wustite and fahelite and other gangue materials containing sili-
ca, alumina, magnesia and calcium go into the non-magnetic fractions. This has been confirmed by microscopy and X-ray diffraction studies. The overall recovery of 65-90% at 1.6-2.1% nickel content has been achieved.
The details of the process of the present invention are given in the Examples which are provided to illustrate the invention only and should not be constrained to limit the scope of the present invention.
Example-1
20 kg of Sukinda chromite overburden containing 0.5% Ni and
28% Fe is crushed and then ground to below 100 microns, the
product from ball mill is mixed with water (10%) in a mixture.
Then the material is fed to the granulator along with coke breeze
(15%) to obtain granules of 3 to 6 mm dia. It is then fed into
the pan sintering unit. The sintering is carried out by down
o draft technigue for 25 minutes at 1200 C. The initial ignition .of
the charge is carried out by means of charcoal spread over the top of the charge. The sinter product is ground in a ball mill to pass 80% below 100 microns and separated in a magnetic separator. The product is then cleaned in second and third magnetic separators using the same conditions as in the first stage. The product obtained contains 1.62% Ni and 39% Fe with 75% nickel recovery.
Example-2.
The nickeliferrous lateritic ore containing 1.15% Ni and 55% Fe has been ground to below 100 microns. The charge is granulated to 3 to 6 mm size using 10% water and 15% powdered coke breeze
and then it is reduced by down draft sintering technique for 25
o minutes at 1200 C with a bed height of 300 mm. The sinter product
is then crushed to below 100 microns. The product in this case
contains 2.1% Ni and 60% Fe with an overall recovery of 86% of
nickel.,

We Claim :
1. A process for the production of nickel concentrate from chro
mite overburden/nickeliferrous lateritic ores which comprises
grinding chromite overburden and lateritic ores to a size in the
range of 60 to 150 microns, granulating in the presence of water
and powdered coke breeze, reducing the granulated material in a
pan using down draft sintering process at a temperature in the
o range of 1000-1200 C and size reducing the resultant product to
below 100 microns by known methods and separating the nickel
concentrate by magnetic separation.
2. A process as claimed in claim 1, wherein the ore containing
0.5-1.15% nickel is used.
3. A process as claimed in claims 1 and 2, whereiri the amount of water used in the granulating step is in the range of 8-12%.
4. A process as claimed in claims 1 to 3, wherein the amount of coke breeze used is in the range of 8-15%.
5. A process as claimed in claims 1 to 4, wherein the magnetic separation is effected using a magnetic seprator repeatedly till the desired concentration of nickel in the end product is obtained.
6. A process as claimed in claims 1 to 5, wherein the intensity of the magnetic field employed is in the range of 1500-2000 gauss.
7. A process for the production of nickel concentrate from chro-mite overburden/nickeliferrous lateritic ores substantially as herein described with reference to the Examples.

Documents:

1921-del-1995-abstract.pdf

1921-del-1995-claims.pdf

1921-del-1995-complete specification (granted).pdf

1921-del-1995-correspondence-others.pdf

1921-del-1995-correspondence-po.pdf

1921-del-1995-description (complete).pdf

1921-del-1995-form-1.pdf

1921-del-1995-form-2.pdf

1921-DEL-1995-Form-3.pdf

1921-del-1995-form-4.pdf

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Patent Number

232116

Indian Patent Application Number

1921/DEL/1995

PG Journal Number

13/2009

Publication Date

27-Mar-2009

Grant Date

15-Mar-2009

Date of Filing

19-Oct-1995

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH.

Applicant Address

RAFI MARG, NEW DELHI-110001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	BHAGYADHAR BHOI	REGIONAL RESEARCH LABORATORY, BHUBANESWAR-13 (CSIR), INDIA.
2	BISWESWAR DAS	REGIONAL RESEARCH LABORATORY, BHUBANESWAR-13 (CSIR), INDIA.
3	DIPENDRA NARAYAN DEY	REGIONAL RESEARCH LABORATORY, BHUBANESWAR-13 (CSIR), INDIA.
4	RAMACHANDRA REDDY	REGIONAL RESEARCH LABORATORY, BHUBANESWAR-13 (CSIR), INDIA.
5	BHASKARA VENKATA RAMANA MURTHY	REGIONAL RESEARCH LABORATORY, BHUBANESWAR-13 (CSIR), INDIA.
6	ANIL KANTA TRIPATHY	REGIONAL RESEARCH LABORATORY, BHUBANESWAR-13 (CSIR), INDIA.
7	BANSIDHAR NAYAK	REGIONAL RESEARCH LABORATORY, BHUBANESWAR-13 (CSIR), INDIA.

PCT International Classification Number

C25C1/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA