Title of Invention	AN IMPROVED PROCESS FOR PREPARATION OF SUPERFINE WHITE ALUMINIUM TRI-HYDROXIDE FROM BAYER PROCESS LIQUOR
Abstract	An improved process for preparation of superfine white aluminium tri-hydroxide from Bayer plant liquor which comprises agitating the Buyer liquor in a reactor at constant temperature of about 50°C,characterised in that adding 5 to 20 g/l of modifier as A12(S04) 3.18 H2O and 7.5 to 15 g/l of seed having size and specific surface area in the range of 10 to 20 µm and 1 to 1.2 m2/cm3 respectively, to the above said agitated Bayer liquor and stirring the above reaction mixture for a period ranging from 5 to 10 hrs followed by filtration to obtain the desired product

Title of Invention

AN IMPROVED PROCESS FOR PREPARATION OF SUPERFINE WHITE ALUMINIUM TRI-HYDROXIDE FROM BAYER PROCESS LIQUOR

Abstract

An improved process for preparation of superfine white aluminium tri-hydroxide from Bayer plant liquor which comprises agitating the Buyer liquor in a reactor at constant temperature of about 50°C,characterised in that adding 5 to 20 g/l of modifier as A12(S04) 3.18 H2O and 7.5 to 15 g/l of seed having size and specific surface area in the range of 10 to 20 µm and 1 to 1.2 m2/cm3 respectively, to the above said agitated Bayer liquor and stirring the above reaction mixture for a period ranging from 5 to 10 hrs followed by filtration to obtain the desired product

Full Text	The present invention relates to an improved process for the preparation of superfine white alumina trihydrate from Bayer process liquor. More particularly the present invention relates to a process for the preparation of superfine and white alumina trihydrate of 1 to 1.5 µm (d50) size by precipitation from Bayer process liquor to be used in non-metallurgical field such as paper coating, paint and other related industries. The historical utilization of alumina hydrate though started with smelting of alumina, its application in non-metallurgical field realized much later stage. Alumina hydrate and its derivative, alumina used in these sectors are commonly known as specialty hydrates and alumina or chemical grade alumina, hydrate. In the present patent our focus is mainly preparation of superfine aluminium trihydroxide (A TH). In the recent years, the market for metallurgical grade A TH/alumina is very much competitive and there is frequent drop in international price. At this juncture many alumina producers sustain to a great extent through the production of special products as these have a stable and increasing market. In 1995 world's non-metallurgical A TH/alumina requirement was 25 million tons and the demand is increasing at a rate of 4% per year. The yearly domestic demand of above material is estimated to be around 75,000 tons and the demand is growing rapidly. A TH obtained by precipitation from Bayer liquor is generally yellowish in colour and coarser in size with significant amount of soda (Na20). But many non- metallurgical grade require white product with finer size particles of less than lum to 10-15 µm (d50) size depending upon its application. At present these, products are obtained by grinding the dried coarser material followed by size classification. But by grinding chemical characteristics.:, cannot be changed and product of 1 to 5 µm size particles are very difficult to produce simply by grinding. In the present case attempts were made for direct precipitation of above products. In general production or finer size particles with higher purity are carried out from Bayer liquor or other aluminate liquor by precipitation with seed and size refining modifier. The reference may be made to J.Csige, J. Matyari, M.T. Banerjee and G. Kaptay, Light Metals 1990 wherein the work had been done on the development of non-metallurgical grades alumina trihydrate by grinding. Soda is a major impurity in such type of products. Soda in A TH available in two forms, the teachable portion which can be removed by washing and non-leachable portion, which is difficult to remove by washing. The reference may also be made to J. Ohkawa, T. Tsuneizumi and T. Hirao, Light Metals, 1985, p345, K. Wcfcrs, Erzmctals, 18(19), 1965, p453, J.V.Sang, Light Metals, 1999, p 147 wherein workers studied this aspect and most often agreed, on the role of temperature and alumina concentration. But still uncertainties exist in the role of caustic concentration, seed, size of product and organic and inorganic impurities. Another reference may be made to G. Baksa, G. Szalay and P. Siklosi, Second International Alumina workshop, 1990, p 39 wherein the workers have produced A TH particles of (a) 5 -10 µm (dso) size in air jet mill by impact grinding and classification (b ) 1 -5 µm product by precipitation with additives such as aluminium sulphate. They found that lower precipitation temperature ( 40°C - 50°C), lower pregnant liquor concentration (Na20=110 gpl) and the additives of 1% A12(SO4)3 as AI203 are advantageous. Baksa et al. IIU 49, 543 (CI. COIF7/02) 30th Oct. 1989. App. 88/842, 23rd Feb, prepared a product of average size 2.7 µm (d50) containing 0.007% Fe203 from a solution containing 127.6 gpl of Na20 at Na20: AI2O3 ratio of 1.49 and 6 ppm Fe203. This solution was mixed with 24.72 g of AI2(SO4)3.14 H2O crystals for 72 hours while the temperature was decreased from 50°C to 40°C. The product was used as additive in cosmetics, toothpaste, etc. Martinswerk GmbH, Germany started SGA (special grade alumina) production in 1970 and attained a leading position in the field. They are the suppliers of 1 ~ m precipitated A TH world over. These precipitates are used as an extender or alternative to titanium dioxide for the paper industry. Satapathy et al. Light Metals, 1991, p 145, produced alumina trihydroxide from Bayer liquor of around 4 pm size. Precipitation time was 45 hours. Comparing the above products the present invention was a modified and simpler method where precipitation time is much reduced and a higher pregnant liquor concentration was used. Purity of the product is also comparable to above products. This patent relates to the preparation of I -1. 5 urn (dso) aluminium trihydrate (gibbsite) particles of brightness > 90% and bulk density 0.3 to 0.35 g/cm3 (apparent) by precipitation from plant Bayer liquor. This type of product finds use in paper coating and paints industries. The main object of the present invention is to providea process for the preparation of 1-1.5 µm (d50) size aluminium hydroxide particles with brightness > 90% and bulk density 0.3 to 0.35 g/cm3 by precipitation from Bayer plant liquor having Al2O3/Na2O ratio 1. Another object of the present invention is to establish optimum conditions to prepare A TH of above grade by chemical precipitation from Na-aluminate liquor. Accordingly the present invention provides an improved process for preparation of superfine white aluminium tri-hydroxide from Bayer plant liquor which comprises agitating the Bayer liquor in a reactor at constant temperature of about 50°C,characterised in that adding 5 to 20 g/1 of Al2(S04) 3.18 H2O as modifier and 7.5 to 15 g/1 of seed such as herein described, having size and specific surface area in the range of 10 to 20 µm and 1 to 1.2 m2/cm3 respectively, to the above said agitated Bayer liquor and stirring the above reaction mixture for a period ranging from 5 to 10 hrs followed by filtration to obtain the desired product. In an embodiment of the present invention the size and specific surface area of the seed (Aluminium trihydroxide A10H3) used is in the range of 10 to 20 µm and 1 to 1.2 m2/cm3 respectively. In yet another embodiment the Bayer liquor used is comprising 150 -160 g/1 of Al2O3 and 150 - 155g/lNa2O. In yet another embodiment the bulk density of the aluminium tri-hydroxide obtained is in the range of 0.30 to 0.35 g/cm3. In yet another embodiment the size of the ATH particles obtained is in the range of 1 -1.5 µm, The novelty of the findings is as follows 1. Precipitation time has been reduced to 7.5 hours from 40 -50 obtained by other investigators. 2. Higher pregnant liquor concentration (Al2O3 -153 gpl and Na2O - 152.85 gpl) was used for preparation of the product. 3. Precipitation of- 1 µm A TH particles from Bayer liquor using specialty prepared seed and adding A12(S04) 3.18 H20 as size refining modifier. 4. Brightness of the product obtained was > 90% 5. A TH yield achieved was 1 (10 g/1) The following examples are given by the way of illustration and should not be construed to limit the scope of the invention. Example 1 The Bayer liquor obtained from M/s National Aluminium Company Limited (NALCO), Bhubaneswar was used for precipitation studies. The precipitation reactor includes a 1000 ml capacity polycarbonate vessel having a fitting lid. The lid had provision for accommodating a stirrer and a thermometer. The stirrer was made up of a Perspex rod and an impeller. Agitation of the liquor was performed with a laboratory model Remi stirrer having variable speed control. For maintaining precipitation temperature, a constant temperature bath of Siskin Julabo make was used. The Bayer liquor received from M/s NALCO, Bhubaneswar was filtered for, removing precipitated iron hydroxide and stored for precipitation studies. The clear liquor was then analysed for alumina, soda and Fe203. Required quantity of liquor was poured into the reactor and the reactor was kept in the constant temperature bath with agitation (150 rpm). The measured quantity of seed and modifier was added to it. The precipitation reaction was then continued for the desired time (6 -7.5h). After the reaction was completed the precipitate was filtered using Whatman filter paper (No. 1 ). The precipitate after filtration was repulped using 200-250 ml of water and filtered again. The process was repeated till the pH of the filtrate reached around 7. Finally, the precipitate (A TH) was dried at 110°C for 24 hrs. Analysis of Al2O3in liquor was carried out by EDT A-Zn sulphate method and determination of RP=Al2O3/Na20 (AC) of sodium aluminate liquor by manual pH meter. Estimation of alkalis, silica, iron in the product A TH and brightness was measured by standard methods. The seed supplied by M/s NALCO was wet ground in a ceramic ball mill with ceramic balls to avoid iron contamination. The material was ground for various intervals of time to get different size seed. A Malvern particle sizer model 3600-E was used to measure the particle size of seed and precipitated A TH. The Al2O3 concentration of the Bayer liquor taken for precipitation studies was from 146.5 gpl to 153 gpl and corresponding alumina/caustic (A/C) ratios were from 0.99 to 1.025. The caustic concentration was fixed according to AC ratios. The size and specific surface areas of seed used were around 12.5 µm, 17.4 µm and 0.99, 1.17 m2 /cm3 respectively. The amount of seed added was between 7.5 to 15 gpl and modifier Al2(SO4)3.l8 H2O (E. Merck. India, Ltd.) between 15 to 20 g.p.l. Various parameters such as temperature, seed size, seed quantity , precipitation time and amount of size refining modifier were studied and optimum conditions were noted. It has been observed from various experiments that temperature plays a vital role on precipitation process. At higher temperature, product purity was better than at lower temperature but productivity and size of precipitate showed poorer results. The higher the amount of seed better was the productivity and product size was also lower. The specific surface area of seed played a major role in productivity and the product size. The effect of caustic concentration in the liquor showed higher the concentration, better the productivity and size. The single most important parameter influenced the precipitation process in respect to productivity, particle size and particle purity was the effect of size refining modifier (aluminium sulphate). Example 2 500 ml of filtered Bayer liquor was poured into the reactor and kept in the constant temperature bath at 50°C with agitation. The Bayer liquor composition taken in this case was AI2O3-153 g.p.l and A/C ratio was 1.001.8 g of A12(SO4)3.18 H2O dissolved in 10 -15 ml of distilled water was added to it next when the solution reached required temperature of 50°C. Around 7.5 g of seed was added to it next. The seed size used was 17.4 µm and specific surface area of the seed was 1.17 m2/cm3. The experiment was continued for 7.5 hrs and after which slurry was taken out from the temperature bath and filtered. Filtration was performed under gravity in a funnel with Whatman filter paper (No.l ). After filtration precipitate was taken out and repulped with 250-300 ml demineralised water and filtered. The process was repeated several times till the pH of the filtrate became around 7. Finally the precipitated A TH was dried in an oven at 110°C for 24 h. The yield of A TH precipitation noted was 160 g.p.l. The size of the product was analysed in a Malvern particle size analyser and found to be 1.49 µm (d50). Example 3 500 ml of filtered Bayer liquor was poured into the reactor and kept in the constant temperature bath at 50°C with agitation. The Bayer liquor composition taken was same as earlier as described in (a). 10 g of Al2SO4)3.18 H2O was dissolved in 10-15 ml of demineralised water and added to the reactor. Stirring continued till the experiment was over. The experiment was continued for 7.5 hrs. The filtration and washing of the product was performed as described in example 2. The precipitate was dried in an oven for 24 hours at 110°C. The yield of ATH precipitation was found to be 160 g.p.l. The size of the product analysed in a Malvern particle size analyser was 1.12 µm(d5o). We Claim 1. An improved process for preparation of superfine white aluminium tri-hydroxide from Bayer plant liquor which comprises agitating the Bayer liquor in a reactor at constant temperature of about 50°C,characterised in that adding 5 to 20 g/1 of A12(S04) 3.18 H2O as modifier and 7.5 to 15 g/1 of seed such as herein described, having size and specific surface area in the range of 10 to 20 µm. and 1 to 1.2 m2/cm3 respectively, to the above said agitated Bayer liquor and stirring the above reaction mixture for a period ranging from 5 to 10 hrs followed by filtration to obtain the desired product. 2. A process as claimed in claims 1, wherein the Bayer liquor used is comprising 150 -160 g/1 of Al203and l50-155g/l of Na2O. 3. An improved process for preparation of superfine white aluminium tri-hydroxide from Bayer plant liquor substantially as herein described with reference to the examples.

Full Text

The present invention relates to an improved process for the preparation of superfine white alumina trihydrate from Bayer process liquor. More particularly the present invention relates to a process for the preparation of superfine and white alumina trihydrate of 1 to 1.5 µm (d50) size by precipitation from Bayer process liquor to be used in non-metallurgical field such as paper coating, paint and other related industries.
The historical utilization of alumina hydrate though started with smelting of alumina, its application in non-metallurgical field realized much later stage. Alumina hydrate and its derivative, alumina used in these sectors are commonly known as specialty hydrates and alumina or chemical grade alumina, hydrate. In the present patent our focus is mainly preparation of superfine aluminium trihydroxide (A TH). In the recent years, the market for metallurgical grade A TH/alumina is very much competitive and there is frequent drop in international price. At this juncture many alumina producers sustain to a great extent through the production of special products as these have a stable and increasing market. In 1995 world's non-metallurgical A TH/alumina requirement was 25 million tons and the demand is increasing at a rate of 4% per year. The yearly domestic demand of above material is estimated to be around 75,000 tons and the demand is growing rapidly. A TH obtained by precipitation from Bayer liquor is generally yellowish in colour and coarser in size with significant amount of soda (Na20). But many non- metallurgical grade require white product with finer size particles of less than lum to 10-15 µm (d50) size depending upon its application. At present these, products are obtained by grinding the dried coarser material followed by size classification. But by grinding chemical characteristics.:, cannot be changed and product of 1 to 5 µm size particles are very difficult to produce simply by grinding. In the present case attempts were made for direct precipitation of above

products. In general production or finer size particles with higher purity are carried out from Bayer liquor or other aluminate liquor by precipitation with seed and size refining modifier.
The reference may be made to J.Csige, J. Matyari, M.T. Banerjee and G. Kaptay, Light Metals 1990 wherein the work had been done on the development of non-metallurgical grades alumina trihydrate by grinding. Soda is a major impurity in such type of products. Soda in A TH available in two forms, the teachable portion which can be removed by washing and non-leachable portion, which is difficult to remove by washing. The reference may also be made to J. Ohkawa, T. Tsuneizumi and T. Hirao, Light Metals, 1985, p345, K. Wcfcrs, Erzmctals, 18(19), 1965, p453, J.V.Sang, Light Metals, 1999, p 147 wherein workers studied this aspect and most often agreed, on the role of temperature and alumina concentration. But still uncertainties exist in the role of caustic concentration, seed, size of product and organic and inorganic impurities. Another reference may be made to G. Baksa, G. Szalay and P. Siklosi, Second International Alumina workshop, 1990, p 39 wherein the workers have produced A TH particles of (a) 5 -10 µm (dso) size in air jet mill by impact grinding and classification (b ) 1 -5 µm product by precipitation with additives such as aluminium sulphate. They found that lower precipitation temperature ( 40°C - 50°C), lower pregnant liquor concentration (Na20=110 gpl) and the additives of 1% A12(SO4)3 as AI203 are advantageous. Baksa et al. IIU 49, 543 (CI. COIF7/02) 30th Oct. 1989. App. 88/842, 23rd Feb, prepared a product of average size 2.7 µm (d50) containing 0.007% Fe203 from a solution containing 127.6 gpl of Na20 at Na20: AI2O3 ratio of 1.49 and 6 ppm Fe203. This solution was mixed with 24.72 g of AI2(SO4)3.14 H2O crystals for 72 hours while the temperature was decreased from 50°C to 40°C. The product was used as additive in cosmetics, toothpaste, etc. Martinswerk GmbH,

Germany started SGA (special grade alumina) production in 1970 and attained a leading position in the field. They are the suppliers of 1 ~ m precipitated A TH world over. These precipitates are used as an extender or alternative to titanium dioxide for the paper industry. Satapathy et al. Light Metals, 1991, p 145, produced alumina trihydroxide from Bayer liquor of around 4 pm size. Precipitation time was 45 hours. Comparing the above products the present invention was a modified and simpler method where precipitation time is much reduced and a higher pregnant liquor concentration was used. Purity of the product is also comparable to above products.
This patent relates to the preparation of I -1. 5 urn (dso) aluminium trihydrate (gibbsite) particles of brightness > 90% and bulk density 0.3 to 0.35 g/cm3 (apparent) by precipitation from plant Bayer liquor. This type of product finds use in paper coating and paints industries.
The main object of the present invention is to providea process for the preparation of 1-1.5 µm (d50) size aluminium hydroxide particles with brightness > 90% and bulk density 0.3 to 0.35 g/cm3 by precipitation from Bayer plant liquor having Al2O3/Na2O ratio 1.
Another object of the present invention is to establish optimum conditions to prepare A TH of above grade by chemical precipitation from Na-aluminate liquor.
Accordingly the present invention provides an improved process for preparation of superfine white aluminium tri-hydroxide from Bayer plant liquor which comprises agitating the Bayer liquor in a reactor at constant temperature of about 50°C,characterised in that adding 5 to 20 g/1 of Al2(S04) 3.18 H2O as modifier and 7.5 to 15 g/1 of seed such as herein described, having size and specific surface area in the range of 10 to 20 µm and 1 to 1.2 m2/cm3 respectively, to the above said agitated Bayer liquor and stirring the above reaction mixture for a period ranging from 5 to 10 hrs followed by filtration to obtain the desired product.

In an embodiment of the present invention the size and specific surface area of the seed (Aluminium trihydroxide A10H3) used is in the range of 10 to 20 µm and 1 to 1.2 m2/cm3 respectively.
In yet another embodiment the Bayer liquor used is comprising 150 -160 g/1 of Al2O3 and 150 -
155g/lNa2O.
In yet another embodiment the bulk density of the aluminium tri-hydroxide obtained is in the range of 0.30 to 0.35 g/cm3.
In yet another embodiment the size of the ATH particles obtained is in the range of 1 -1.5 µm,
The novelty of the findings is as follows
1. Precipitation time has been reduced to 7.5 hours from 40 -50 obtained by other investigators.
2. Higher pregnant liquor concentration (Al2O3 -153 gpl and Na2O - 152.85 gpl) was used for
preparation of the product.
3. Precipitation of- 1 µm A TH particles from Bayer liquor using specialty prepared seed and
adding A12(S04) 3.18 H20 as size refining modifier.
4. Brightness of the product obtained was > 90% 5. A TH yield achieved was 1 (10 g/1)

The following examples are given by the way of illustration and should not be construed to limit the scope of the invention.
Example 1
The Bayer liquor obtained from M/s National Aluminium Company Limited (NALCO), Bhubaneswar was used for precipitation studies. The precipitation reactor includes a 1000 ml capacity polycarbonate vessel having a fitting lid. The lid had provision for accommodating a stirrer and a thermometer. The stirrer was made up of a Perspex rod and an impeller. Agitation of the liquor was performed with a laboratory model Remi stirrer having variable speed control. For maintaining precipitation temperature, a constant temperature bath of Siskin Julabo make was used. The Bayer liquor received from M/s NALCO, Bhubaneswar was filtered for, removing precipitated iron hydroxide and stored for precipitation studies. The clear liquor was then analysed for alumina, soda and Fe203. Required quantity of liquor was poured into the reactor and the reactor was kept in the constant temperature bath with agitation (150 rpm). The measured quantity of seed and modifier was added to it. The precipitation reaction was then continued for the desired time (6 -7.5h). After the reaction was completed the precipitate was filtered using Whatman filter paper (No. 1 ). The precipitate after filtration was repulped using 200-250 ml of water and filtered again. The process was repeated till the pH of the filtrate reached around 7. Finally, the precipitate (A TH) was dried at 110°C for 24 hrs. Analysis of Al2O3in liquor was carried out by EDT A-Zn sulphate method and determination of RP=Al2O3/Na20 (AC) of sodium aluminate liquor by manual pH meter. Estimation of alkalis, silica, iron in the product A TH and brightness was measured by standard methods. The seed supplied by M/s NALCO was wet ground in a ceramic ball mill with ceramic balls to

avoid iron contamination. The material was ground for various intervals of time to get different size seed. A Malvern particle sizer model 3600-E was used to measure the particle size of seed and precipitated A TH. The Al2O3 concentration of the Bayer liquor taken for precipitation studies was from 146.5 gpl to 153 gpl and corresponding alumina/caustic (A/C) ratios were from 0.99 to 1.025. The caustic concentration was fixed according to AC ratios. The size and specific surface areas of seed used were around 12.5 µm, 17.4 µm and 0.99, 1.17 m2 /cm3 respectively. The amount of seed added was between 7.5 to 15 gpl and modifier Al2(SO4)3.l8 H2O (E. Merck. India, Ltd.) between 15 to 20 g.p.l. Various parameters such as temperature, seed size, seed quantity , precipitation time and amount of size refining modifier were studied and optimum conditions were noted. It has been observed from various experiments that temperature plays a vital role on precipitation process. At higher temperature, product purity was better than at lower temperature but productivity and size of precipitate showed poorer results. The higher the amount of seed better was the productivity and product size was also lower. The specific surface area of seed played a major role in productivity and the product size. The effect of caustic concentration in the liquor showed higher the concentration, better the productivity and size. The single most important parameter influenced the precipitation process in respect to productivity, particle size and particle purity was the effect of size refining modifier (aluminium sulphate).
Example 2
500 ml of filtered Bayer liquor was poured into the reactor and kept in the constant temperature bath at 50°C with agitation. The Bayer liquor composition taken in this case was AI2O3-153 g.p.l and A/C ratio was 1.001.8 g of A12(SO4)3.18 H2O dissolved

in 10 -15 ml of distilled water was added to it next when the solution reached required temperature of 50°C. Around 7.5 g of seed was added to it next. The seed size used was 17.4 µm and specific surface area of the seed was 1.17 m2/cm3. The experiment was continued for 7.5 hrs and after which slurry was taken out from the temperature bath and filtered. Filtration was performed under gravity in a funnel with Whatman filter paper (No.l ). After filtration precipitate was taken out and repulped with 250-300 ml demineralised water and filtered. The process was repeated several times till the pH of the filtrate became around 7. Finally the precipitated A TH was dried in an oven at 110°C for 24 h. The yield of A TH precipitation noted was 160 g.p.l. The size of the product was analysed in a Malvern particle size analyser and found to be 1.49 µm (d50).
Example 3
500 ml of filtered Bayer liquor was poured into the reactor and kept in the constant temperature bath at 50°C with agitation. The Bayer liquor composition taken was same as earlier as described in (a). 10 g of Al2SO4)3.18 H2O was dissolved in 10-15 ml of demineralised water and added to the reactor. Stirring continued till the experiment was over. The experiment was continued for 7.5 hrs. The filtration and washing of the product was performed as described in example 2. The precipitate was dried in an oven for 24 hours at 110°C. The yield of ATH precipitation was found to be 160 g.p.l. The size of the product analysed in a Malvern particle size analyser was 1.12 µm(d5o).

We Claim
1. An improved process for preparation of superfine white aluminium tri-hydroxide from Bayer
plant liquor which comprises agitating the Bayer liquor in a reactor at constant temperature of
about 50°C,characterised in that adding 5 to 20 g/1 of A12(S04) 3.18 H2O as modifier and 7.5 to
15 g/1 of seed such as herein described, having size and specific surface area in the range of 10
to 20 µm. and 1 to 1.2 m2/cm3 respectively, to the above said agitated Bayer liquor and stirring
the above reaction mixture for a period ranging from 5 to 10 hrs followed by filtration to obtain
the desired product.
2. A process as claimed in claims 1, wherein the Bayer liquor used is comprising 150 -160 g/1 of
Al203and l50-155g/l of Na2O.
3. An improved process for preparation of superfine white aluminium tri-hydroxide from Bayer
plant liquor substantially as herein described with reference to the examples.

Documents:

1299-del-2001-abstract.pdf

1299-del-2001-claims.pdf

1299-del-2001-correspondence-others.pdf

1299-del-2001-correspondence-po.pdf

1299-del-2001-description (complete).pdf

1299-del-2001-form-1.pdf

1299-del-2001-form-18.pdf

1299-del-2001-form-2.pdf

1299-del-2001-form-3.pdf

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Patent Number

231033

Indian Patent Application Number

1299/DEL/2001

PG Journal Number

13/2009

Publication Date

27-Mar-2009

Grant Date

28-Feb-2009

Date of Filing

28-Dec-2001

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	INDRA NARAYAN BHATTACHARYA	REGIONAL RESEARCH LABORATORY, BHUBANESHWAR, ORISSA (INDIA)
2	JITENDRA KUMAR PRADHAN	REGIONAL RESEARCH LABORATORY, BHUBANESHWAR, ORISSA (INDIA)
3	SARAT CHANDRA DAS	REGIONAL RESEARCH LABORATORY, BHUBANESHWAR, ORISSA (INDIA)

PCT International Classification Number

C01F 7/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA