Title of Invention	''A PROCESS FOR THE PRODUCTION OF MICROPORUS INSULATING MATERIALS"
Abstract	A process for the production of micro porous insulating material which comprises mixing intimately 40-50 wt% ground aluminosilicate minerals, alumina or mixture thereof, 2-15 wt% fire clay, 45 to 55 wt% naphthalene powder with 12-20% dilute organic liquid binder; shaping the product by hydraulic pressing, drying the shaped products such as herein described and finally firing the products in a furnace at a temperature in the range of 1450° - 1650°C for a soaking period of 2 to 5 hrs

Title of Invention

''A PROCESS FOR THE PRODUCTION OF MICROPORUS INSULATING MATERIALS"

Abstract

A process for the production of micro porous insulating material which comprises mixing intimately 40-50 wt% ground aluminosilicate minerals, alumina or mixture thereof, 2-15 wt% fire clay, 45 to 55 wt% naphthalene powder with 12-20% dilute organic liquid binder; shaping the product by hydraulic pressing, drying the shaped products such as herein described and finally firing the products in a furnace at a temperature in the range of 1450° - 1650°C for a soaking period of 2 to 5 hrs

Full Text	The present invention relates to a process for the production of inicroporous insulating materials. The present invention is uselui for producing microporous insulation materials which can be used as high temperature insulating materials and has wide ranging application Besides its potential application in iron & steel industries, the microporous nature of the products finds many special applications such as ceramic filter for nitrogen gas filtration in laser application and sample collector for the study of environmental pollution The present day method for the production of porous insulating materials use substances such as saw dust, coke, polystyrene bails, coal. These substances when incorporated in a ceramic mixture are burnt out during a firing process making the finished product porous which acts as insulating materials. Reference may be made to the work of A.P. Stavoyko et al, Investor's Certificate No. 220122, Byull, Izobret, No. 19, 1968 and G.F,. Karas ct al, Ogneopory, No. 9, 1972, Russia, wherein a light weight porous insulating material is produced from a mix of unealcined commercial alumina & saw dust. \;iicalcined commercial alumina undergoes volume expansion followed by high shrinkage and development of cracks. Thei vvork was slightly improved by A.A. Pirogov et al, (Ogneupory No 5, 1978) earned out at Ukaranian Scientific Research Institute of Refractories, Russia wherein calcined alumina was used in place of unealcined alumina with saw dust to improve recovery of (he product with respect to physical defects, such as cracks. They also used water soluble methyl cellulose as a surface active ngent into the slip of calcined Al2O & saw dust to introduce air into the slip which increases the number of pores and stabilizes the porous structure of the slip being prepared in the mixer. The main disadvantages of the above processes are : (a) During the firing process, saw dust leaves ash residue in the finished product as foreign inclusion which deteriorates the ultimate properties. (b) The processes are unable to produce microporous product (finely distributed pores) (C ) Presence of widely varied pore sizes (few microns to hundred microns to few millimeter) causes poor mechanical strength in the above processes. Martin Heumuller & C. Otto of West Germany (UNITECR proceeding volume 1989) used solid Naphthalene for making porous insulating fireclay bricks. In this process fireclay raw materials in various particle sizes with Naphthalene powder are used. Depending on the brick type the mix is given to a shape by both plastic and semi plastic pressing process. 15 to 65% naphthalene powder has been used. Use of naphthalene powder as a pore forming agent in the above type of fireclay insulating bricks have the following disadvantages. a) use of sophisticated nathelene technology for low value added products makes the process techno economically unviable. b) Limits the service temperature application only upto 1400°C as against very high temperature insulation requirement in the modern day technologies. The main object of the present invention is to provide a process for the production of rnicroporous insulating materials which obviates the drawbacks as detailed above. Another object is to provide a ceramic matrix having high temperature withstanding capability beyond 1400°C as heat insulating material. Yet another object is to provide an insulating material of lower bulk density, higher mechanical strength and well distributed micropores. Accordingly, the present invention provides a A process for the production of micro porous insulating material which comprises mixing intimately 40-50 wt% ground aluminosilicate minerals, alumina or mixture thereof, 2-15 wt% fire clay, 45 to 55 wt% naphthalene powder with 12-20% dilute organic liquid binder; shaping the product by hydraulic pressing, drying the shaped products such as herein described and finally firing the products in a furnace at a temperature in the range of 1450° - 1650°C for a soaking period of 2 to 5 hrs. In an embodiment of the present invention, alumino-silicate minerals used may be selected from raw materials such as kyanite, sillianite sand, mullite, fireclay or mixture thereof. In another embodiment of the present invention alumina used may be selected from calcined Al2O3, reactive Al2O3 or mixture thereof. In yet another embodiment of the present invention the particle size distribution of the ground alimino-silicate minerals and calcined alumina may be in the range from 2-8 µm more than 90%. In still another embodiment the particle size distribution of reactive alumina may be in the rnage from 1-2 urn more than 90%. In yet another embodiment of the present6 invention the pore forming agent used may be such as naphthalene powder fo commercial grade and passed through 50 BS-sieve. In another embodiment of the present invention, the organic liquid binder used may be selected from material such as molasses, dextrin, polyvinyl alcohol, carbomethoxy cellulose. In still another embodiment of the present invention pressing fro making samples may be done at pressure of 40 - 50 Kg/cm2. In still another embodiment of the present intention drying of the shaped products may be done at a temperature in the range of 70 - 90°C for a period of 20 - 25 hrs followed by 100 - 110°C for period of 10 - 12 hrs. The detail process steps of the present invention are mixing intimately 40-50 wt% ground aluminosilieale minerals, alumina o; mixture thereof, 2-15 wl% tire clay, 45 to 55 wl % napthelene powder with 12-20% dilute organic liquid binder ; shaping the product by hydraulic pressing ; drying the shaped products and finally firing the products in a liiinace at a temperature in UK; range of 450" •- 1650oC for a soaking period of 2 to 5 his The novelty of the present invention resides in the novel high alumina ( 60 to 95% Al2O3) matrix with well distributed microporocs useful for heat insulation beyond 1400"C. The inventive steps lies in using of a particular size fraction (- 50 BS sieve) of Naplhelene powder with high alumina ceramic composition resulting in a microporous insulating material having high temperature withstanding capability. 'I'hc following examples are given by way of illustration and should not be construed to limit the scope of the present invention. Example - 1 100 gm of vibroground sillimanitc sand, , 10 gin of fireclay, 90 gm of naphthalene powder were thoroughly dry mixed for a period of 10 minutes. Then 20 cc of dilute polyvinyl alcohol and 16 cc of water were added and uniformly mixed again. The final mixture was then taken in a mould and pressed :' a pressure of 50 Kg/cm7 for making samples having dimension 50 mm x 50 mm cylindrical shape. The green products were then oven dried at about 90oC for 2/1 his followed by 110oC for 12 hrs The dried samples were finally fired in an electric furnace at a temperature of 1450"C for a period of 2 hours. The resultant product, charactcrisalics were : Bulk density : 0.6 gm/cc Porosity : 80% Cold crushing strength : 40 Kg/cm2 Mean pore radius : 10 - 12 pm Pore size distribution : 90% of total pores smaller than 20 um Example -2 85 gins of calcined alumina, 10 gin of reactive alumina, 105 gms of naphthalene powder were throughly diy mixed for a period of 10 minutes. Then 16 ce of dilute polyvinyl alcohol and 18 cc water were added and uniformly mixed again. The final mixture was then taken in a mould and pressed at a pressure of 50 Kg/cm2 for making samples having dimensions 50 mm x 50 mm cylindrical shape. The green products were then oven dried al about 80oC for a period of 25 hrs followed by 1 10oC for a period of 12 hrs. The dried samples were finally fired in an electric furnace at a temperature of 1600oC for a period of 3 hours. The resultant product characteristic were : Bulk density : 1.00 gm/cc Porosity : 70% Cold crushing strength : l00Kg/cm2 Mean pore nidius : "" - '2 µm Pore size distribution : 90% of total pores smaller than 20 µm The main advantages of the present invention are : 1. The present process utilizes an unique ceramic matrix containing well distributed microoores with higher percentages of Alumina and thereby a superior quality product is obtained 2. The present process pioduces an insulating product of lower bulk density with higher mechanical strength capable of withstanding high temperature beyond 1400oC. 3. The present process produces a product which can be usod as a sample collector for the study of environmental pollution. We Claim: 1. A process for the production of micro porous insulating material which comprises mixing intimately 40-50 wt% ground aluminosilicate minerals, alumina or mixture thereof, 2-15 wt% fire clay, 45 to 55 wt% naphthalene powder with 12- 20% dilute organic liquid binder; shaping the product by hydraulic pressing, drying the shaped products such as herein described and finally firing the products in a furnace at a temperature in the range of 1450° - 1650°C for a soaking period of 2 to 5 hrs. 2. A process as claimed in claim 1 wherein the alumino-silicate mineral used is selected from raw materials kyanite, sillimanite sand, mullite, fireclay and alumina is selected from calcined AI2O3, reactive Al2O3. 3. A process as claimed in claims 1 & 2 wherein the particle size distribution of the ground Alumino silicate minerals and calcined AI2O3 ranges from 2-8 urn more than 90% and reactive alumina ranges from 1-2 µrn more tan 90%. 4. A process as claimed in claims 1 to 3 wherein the naphthalene powder of commercial grade passing through 50 BSS is used as a poreforming agent. 5. A process as claimed in claims 1 to 4 wherein the organic liquid binder used is selected from material molasses, dextrin, polyvinyl alcohol, carbomethoxy cellulose. 6. A process as claimed in claims 1 to 5 wherein the drying of shaped products is done at a temperature in the range of 70 - 90°C for a period of 20 - 25 hrs followed by 100 - 110°C for a period of 10 - 12 hrs. 7. A process for the production of microporous insulating materials substantially as herein described with reference to the examples.

Full Text

The present invention relates to a process for the production of inicroporous insulating
materials.
The present invention is uselui for producing microporous insulation materials which can be used as high temperature insulating materials and has wide ranging application Besides its potential application in iron & steel industries, the microporous nature of the products finds many special applications such as ceramic filter for nitrogen gas filtration in laser application and sample collector for the study of environmental pollution
The present day method for the production of porous insulating materials use substances such as saw dust, coke, polystyrene bails, coal. These substances when incorporated in a ceramic mixture are burnt out during a firing process making the finished product porous which acts as insulating materials. Reference may be made to the work of A.P. Stavoyko et al, Investor's Certificate No. 220122, Byull, Izobret, No. 19, 1968 and G.F,. Karas ct al, Ogneopory, No. 9, 1972, Russia, wherein a light weight porous insulating material is produced from a mix of unealcined commercial alumina & saw dust. \;iicalcined commercial alumina undergoes volume expansion followed by high shrinkage and development of cracks. Thei vvork was slightly improved by A.A. Pirogov et al, (Ogneupory No 5, 1978) earned out at Ukaranian Scientific Research Institute of Refractories, Russia wherein calcined alumina was used in place of unealcined alumina with saw dust to improve recovery of (he product with respect to physical defects, such as cracks. They also used water soluble methyl cellulose as a surface active ngent into the slip of calcined Al2O & saw dust to introduce air into the slip which increases the number of pores and stabilizes the porous structure of the slip being prepared in the mixer. The main disadvantages of the above processes are :
(a) During the firing process, saw dust leaves ash residue in the finished product as
foreign inclusion which deteriorates the ultimate properties.
(b) The processes are unable to produce microporous product (finely distributed pores)
(C ) Presence of widely varied pore sizes (few microns to hundred microns to few millimeter) causes poor mechanical strength in the above processes.
Martin Heumuller & C. Otto of West Germany (UNITECR proceeding volume 1989) used solid Naphthalene for making porous insulating fireclay bricks. In this process fireclay raw materials in various particle sizes with Naphthalene powder are used. Depending on the brick type the mix is given to a shape by both plastic and semi plastic pressing process. 15 to 65% naphthalene powder has been used. Use of naphthalene powder as a pore forming agent in the above type of fireclay insulating bricks have the following disadvantages.
a) use of sophisticated nathelene technology for low value added products makes
the process techno economically unviable.
b) Limits the service temperature application only upto 1400°C as against very high
temperature insulation requirement in the modern day technologies.
The main object of the present invention is to provide a process for the production of rnicroporous insulating materials which obviates the drawbacks as detailed above.
Another object is to provide a ceramic matrix having high temperature withstanding capability beyond 1400°C as heat insulating material.
Yet another object is to provide an insulating material of lower bulk density, higher mechanical strength and well distributed micropores.
Accordingly, the present invention provides a A process for the production of micro porous insulating material which comprises mixing intimately 40-50 wt% ground aluminosilicate minerals, alumina or mixture thereof, 2-15 wt% fire clay, 45 to 55 wt% naphthalene powder with 12-20% dilute organic liquid binder; shaping the product by hydraulic pressing, drying the shaped products such as herein described and finally firing the products in a furnace at a temperature in the range of 1450° - 1650°C for a soaking period of 2 to 5 hrs.
In an embodiment of the present invention, alumino-silicate minerals used may be selected from raw materials such as kyanite, sillianite sand, mullite, fireclay or mixture thereof.
In another embodiment of the present invention alumina used may be selected from calcined Al2O3, reactive Al2O3 or mixture thereof.
In yet another embodiment of the present invention the particle size distribution of the ground alimino-silicate minerals and calcined alumina may be in the range from 2-8 µm more than 90%.
In still another embodiment the particle size distribution of reactive alumina may be in the rnage from 1-2 urn more than 90%.
In yet another embodiment of the present6 invention the pore forming agent used may be such as naphthalene powder fo commercial grade and passed through 50 BS-sieve.
In another embodiment of the present invention, the organic liquid binder used may be selected from material such as molasses, dextrin, polyvinyl alcohol, carbomethoxy cellulose.
In still another embodiment of the present invention pressing fro making samples may be done at pressure of 40 - 50 Kg/cm2.
In still another embodiment of the present intention drying of the shaped products may be done at a temperature in the range of 70 - 90°C for a period of 20 - 25 hrs followed by 100 - 110°C for period of 10 - 12 hrs.
The detail process steps of the present invention are mixing intimately 40-50 wt% ground aluminosilieale minerals, alumina o; mixture thereof, 2-15 wl% tire clay, 45 to 55 wl % napthelene powder with 12-20% dilute organic liquid binder ; shaping the product by hydraulic pressing ; drying the shaped products and finally firing the products in a liiinace at a temperature in UK; range of 450" •- 1650oC for a soaking period of 2 to 5 his
The novelty of the present invention resides in the novel high alumina ( 60 to 95% Al2O3) matrix with well distributed microporocs useful for heat insulation beyond 1400"C.
The inventive steps lies in using of a particular size fraction (- 50 BS sieve) of Naplhelene powder with high alumina ceramic composition resulting in a microporous insulating material having high temperature withstanding capability.
'I'hc following examples are given by way of illustration and should not be construed to limit the scope of the present invention.
Example - 1
100 gm of vibroground sillimanitc sand, , 10 gin of fireclay, 90 gm of naphthalene powder were thoroughly dry mixed for a period of 10 minutes. Then 20 cc of dilute polyvinyl alcohol and 16 cc of water were added and uniformly mixed again. The final mixture was then taken in a mould and pressed :' a pressure of 50 Kg/cm7 for making samples having dimension 50 mm x 50 mm cylindrical shape. The green products were then oven dried at about 90oC for 2/1 his followed by 110oC for 12 hrs The dried samples were finally fired in an electric furnace at a temperature of 1450"C for a period of 2 hours. The resultant product, charactcrisalics were :
Bulk density : 0.6 gm/cc Porosity : 80% Cold crushing strength : 40 Kg/cm2 Mean pore radius : 10 - 12 pm Pore size distribution : 90% of total pores smaller than 20 um
Example -2
85 gins of calcined alumina, 10 gin of reactive alumina, 105 gms of naphthalene powder were throughly diy mixed for a period of 10 minutes. Then 16 ce of dilute polyvinyl alcohol and 18 cc water were added and uniformly mixed again. The final mixture was then taken in a mould and pressed at a pressure of 50 Kg/cm2 for making samples having dimensions 50 mm x 50 mm cylindrical shape. The green products were then oven dried al about 80oC for a period of 25 hrs followed by 1 10oC for a period of 12 hrs. The dried samples were finally fired in an electric furnace at a temperature of 1600oC for a period of 3 hours. The resultant product characteristic were :
Bulk density : 1.00 gm/cc Porosity : 70% Cold crushing strength : l00Kg/cm2 Mean pore nidius : "" - '2 µm Pore size distribution : 90% of total pores smaller than 20 µm
The main advantages of the present invention are :
1. The present process utilizes an unique ceramic matrix containing well distributed
microoores with higher percentages of Alumina and thereby a superior quality product
is obtained
2. The present process pioduces an insulating product of lower bulk density with higher
mechanical strength capable of withstanding high temperature beyond 1400oC.
3. The present process produces a product which can be usod as a sample collector for the
study of environmental pollution.

We Claim:
1. A process for the production of micro porous insulating material which comprises
mixing intimately 40-50 wt% ground aluminosilicate minerals, alumina or
mixture thereof, 2-15 wt% fire clay, 45 to 55 wt% naphthalene powder with 12-
20% dilute organic liquid binder; shaping the product by hydraulic pressing,
drying the shaped products such as herein described and finally firing the
products in a furnace at a temperature in the range of 1450° - 1650°C for a
soaking period of 2 to 5 hrs.
2. A process as claimed in claim 1 wherein the alumino-silicate mineral used is
selected from raw materials kyanite, sillimanite sand, mullite, fireclay and
alumina is selected from calcined AI2O3, reactive Al2O3.
3. A process as claimed in claims 1 & 2 wherein the particle size distribution of the
ground Alumino silicate minerals and calcined AI2O3 ranges from 2-8 urn more
than 90% and reactive alumina ranges from 1-2 µrn more tan 90%.
4. A process as claimed in claims 1 to 3 wherein the naphthalene powder of
commercial grade passing through 50 BSS is used as a poreforming agent.
5. A process as claimed in claims 1 to 4 wherein the organic liquid binder used is
selected from material molasses, dextrin, polyvinyl alcohol, carbomethoxy
cellulose.
6. A process as claimed in claims 1 to 5 wherein the drying of shaped products is
done at a temperature in the range of 70 - 90°C for a period of 20 - 25 hrs
followed by 100 - 110°C for a period of 10 - 12 hrs.
7. A process for the production of microporous insulating materials substantially as
herein described with reference to the examples.

Documents:

609-del-2000-abstract.pdf

609-del-2000-claims.pdf

609-del-2000-correspondence-others.pdf

609-del-2000-correspondence-po.pdf

609-del-2000-description (complete).pdf

609-del-2000-form-1.pdf

609-del-2000-form-19.pdf

609-del-2000-form-2.pdf

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Patent Number

217649

Indian Patent Application Number

609/DEL/2000

PG Journal Number

17/2008

Publication Date

25-Apr-2008

Grant Date

28-Mar-2008

Date of Filing

23-Jun-2000

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH.

Applicant Address

RAFI MARG, NEW DELHI-110 001,INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	PRADIP KUMAR MONDAL	CENTRAL GLASS & CERAMIC RESEARCH INSTITUTE, CALCUTTA 700 032,INDIA.
2	SOMNATH MUKHERJEE	CENTRAL GLASS & CERAMIC RESEARCH INSTITUTE, CALCUITA 700 032, ALL ARE INDAN CITZENS.
3	SWAPAN KUMAR DAS.	CEMTRAL GLASS & CERAMIC RESEARCH INSTITUTE,CALCUITA 700 032,ALL ARE INDIAN CITIZENS

PCT International Classification Number

C04B 38/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA