Title of Invention	''A PROCESS FOR THE MANUFACTURE OF BUILDING BLOCK''
Abstract	The present invention relates to a process for the manufacture of building block. The building blocks are used for making buildings. In particular sizes, the blocks may be used as wall tiles. The process steps are: characterized in that mixing freshly prepared CaO from waste marble dust, reactive silica source such as fly ash, rice husk ash and cement in the proportion 1 to 5 : 2 to 15: 0 to 15 by weight., milling by known method the mixture for a period in the range of 1 to 6 hours to obtain an intimately mixed material, mixing the intimately mixed material with water in the proportion 10 to 30% of the solid mix, ageing the water mixed material so obtained for a period in the range of 0.5 hours to 4 hours, forming blocks, curing the blocks under water for a period in the range of 12 hours - 168 hours, treating the blocks hydro thermally for a period in the range of 0 -24 hours under steam pressure above 3 kgf/cm2.

Title of Invention

''A PROCESS FOR THE MANUFACTURE OF BUILDING BLOCK''

Abstract

The present invention relates to a process for the manufacture of building block. The building blocks are used for making buildings. In particular sizes, the blocks may be used as wall tiles. The process steps are: characterized in that mixing freshly prepared CaO from waste marble dust, reactive silica source such as fly ash, rice husk ash and cement in the proportion 1 to 5 : 2 to 15: 0 to 15 by weight., milling by known method the mixture for a period in the range of 1 to 6 hours to obtain an intimately mixed material, mixing the intimately mixed material with water in the proportion 10 to 30% of the solid mix, ageing the water mixed material so obtained for a period in the range of 0.5 hours to 4 hours, forming blocks, curing the blocks under water for a period in the range of 12 hours - 168 hours, treating the blocks hydro thermally for a period in the range of 0 -24 hours under steam pressure above 3 kgf/cm2.

Full Text	The presort invention relates to a process for 1he manufacture ofbuilding block. The building blocks are used for making buildings. In particular sizes, the blocks may be used as wall tiles. The present day method of making building blocks involves Ihe use of common clay and sand, appropriately proportion formed or cast in specified sizes. The cast or formed blocks are dried and fired at a temperature in the range of 750°C to 950°C to obtain building blocks. Reference for which may be made to United Nations Industrial Development organization, Vienna, "Development and Transfer at Technology series No. 10 - Brick making Plant: Industry Profile" pp 9-22 (1978), Sukhthankar, D.M., 'National Overview on IYSH". Proc. Intl. Seminar On Low cost Housing & Alternate Materials, New Delhi, India pp 10-11. (Feb, 1988), Kumar, A., Sen, S., Biswas, S.K., Singh, N., Ghosh, S., Chakarabarti, S., "Non-conventional materials and process for Brick manufacture" Seminar 90 on Bricks, Pub. Bengal Brick Field Owners' Association, Kolkata, India(1990). An alternative method of making building blocks involves die use of slaked lime, calcium hydroxide in combination with silica sand Slaked lime is mixed with silica and blocks are formed Those blocks are men hydro thermally treated under steam pressure ranging from 5-10 atmosphere. Hydro thermally treated blocks exhibit strength comparable to normal clay based bricks. Main drawbacks of the manufactured brick are its low strength and cost escalation due to hydrothermal treatment of the formed blocks. Still another method of making such bricks utilizes fly ash from thermal power plants. In such system bricks are made from crushed coal ash mixed with clay generally in two proportions 60:40 & 50:50. After forming, bricks are fired at a temperature in the range of 900 -1060° C, depending on the nature of the raw materials. Drawbacks of the process are low strength of bricks and escalation of cost due to the requirement of firing. The process also suffers from polluting the environment and disturbing the ecological balance. The main drawbacks of the above mentioned processes are: removal of heat of reaction by intermediate ageing of the mixture consisting of lime, silica and water for a considerable period. These steps also eliminate the steps of hydrothermal treatment as is conventionally done for such products. The novelty of the process of the present invention is to prepare building blocks or wall tiles by using waste materials in a cheaper way. The novelty is realized by non obvious inventive steps of combining freshly prepared CaO obtained from waste marble dust with reactive silica obtained from fly ash or rice husk ash combined with the essential step of intermediate ageing of the reacting mixture for a sufficient/optimum time. Accordingly the present invention provides a process for the manufacture of building block, which comprises mixing freshly prepared CaO from waste marble dust, reactive silica source such as fly ash, rice husk ash and cement in the proportion 1 to 5 : 2 to 15: 0 to 15 ( by weight), milling by known method the mixture for a period in the range of 1 to 6 hours to obtain an intimately mixed material, mixing the intimately mixed material with water in the proportion 10 to 30% of the solid mix, ageing the water mixed material so obtained for a period in the range of 0.5 hours to 4 hours, forming blocks, curing the blocks under water for a period in the range of 12 hours - 168 hours, treating the blocks hydro thermally for a period in the range of 0- 24 hours under steam pressure above 3 kgf/cm2. In an embodiment of the present invention the freshly prepared CaO from marble dust may be obtained by conventional calcinations of marble dust waste. The details of present invention are given below: a) CaO is freshly prepared from marble dust by conventional method. The CaO is mixed with reactive silica source such as fly ash, rice husk ash and cement in the proportion 1-5 (by wt.): 2-15 (by wt.) b) The mixture at step 'a' is mixed thoroughly for a period at 1-6 hrs by known process such as pot milling, ball milling. We Claim: 1. A process for the manufacture of building block, which comprises mixing freshly prepared CaO from waste marble dust, reactive silica source such as fly ash, rice husk ash and cement in the proportion 1 to 5 : 2 to 15: 0 to 15 ( by weight), milling by known method the mixture for a period in the range of 1 to 6 hours to obtain an intimately mixed material, mixing the intimately mixed material with water in the proportion 10 to 30% of the solid mix, ageing the water mixed material so obtained for a period in the range of 0.5 hours to 4 hours, forming blocks, curing the blocks under water for a period in the range of 12 hours - 168 hours, treating the blocks hydro thermally for a period in the range of 0-24 hours under steam pressure above 3 kgf/cm2. 2. A process for the manufacture of building block substantially as herein described with reference to the examples.

Full Text

The presort invention relates to a process for 1he manufacture ofbuilding block.
The building blocks are used for making buildings. In particular sizes, the blocks may be used as wall
tiles.
The present day method of making building blocks involves Ihe use of common clay and sand,
appropriately proportion formed or cast in specified sizes. The cast or formed blocks are dried and
fired at a temperature in the range of 750°C to 950°C to obtain building blocks. Reference for
which may be made to United Nations Industrial Development organization, Vienna,
"Development and Transfer at Technology series No. 10 - Brick making Plant: Industry Profile" pp
9-22 (1978), Sukhthankar, D.M., 'National Overview on IYSH". Proc. Intl. Seminar On Low cost
Housing & Alternate Materials, New Delhi, India pp 10-11. (Feb, 1988), Kumar, A., Sen, S., Biswas,
S.K., Singh, N., Ghosh, S., Chakarabarti, S., "Non-conventional materials and process for Brick
manufacture" Seminar 90 on Bricks, Pub. Bengal Brick Field Owners' Association, Kolkata,
India(1990).
An alternative method of making building blocks involves die use of slaked lime, calcium hydroxide in
combination with silica sand Slaked lime is mixed with silica and blocks are formed Those blocks are
men hydro thermally treated under steam pressure ranging from 5-10 atmosphere. Hydro thermally
treated blocks exhibit strength comparable to normal clay based bricks. Main drawbacks of the
manufactured brick are its low strength and cost escalation due to hydrothermal treatment of the formed
blocks.
Still another method of making such bricks utilizes fly ash from thermal power plants. In such system
bricks are made from crushed coal ash mixed with clay generally in two proportions 60:40 & 50:50.
After forming, bricks are fired at a temperature in the range of 900 -1060° C, depending on the nature of
the raw materials. Drawbacks of the process are low strength of bricks and escalation of cost due to the
requirement of firing. The process also suffers from polluting the environment and disturbing the
ecological balance.
The main drawbacks of the above mentioned processes are:

removal of heat of reaction by intermediate ageing of the mixture consisting of lime,
silica and water for a considerable period. These steps also eliminate the steps of
hydrothermal treatment as is conventionally done for such products.
The novelty of the process of the present invention is to prepare building blocks or wall
tiles by using waste materials in a cheaper way. The novelty is realized by non obvious
inventive steps of combining freshly prepared CaO obtained from waste marble dust with
reactive silica obtained from fly ash or rice husk ash combined with the essential step of
intermediate ageing of the reacting mixture for a sufficient/optimum time.
Accordingly the present invention provides a process for the manufacture of building
block, which comprises mixing freshly prepared CaO from waste marble dust,
reactive silica source such as fly ash, rice husk ash and cement in the proportion 1 to
5 : 2 to 15: 0 to 15 ( by weight), milling by known method the mixture for a period
in the range of 1 to 6 hours to obtain an intimately mixed material, mixing the
intimately mixed material with water in the proportion 10 to 30% of the solid mix,
ageing the water mixed material so obtained for a period in the range of 0.5 hours to 4
hours, forming blocks, curing the blocks under water for a period in the range of 12
hours - 168 hours, treating the blocks hydro thermally for a period in the range of 0-
24 hours under steam pressure above 3 kgf/cm2.
In an embodiment of the present invention the freshly prepared CaO from marble dust
may be obtained by conventional calcinations of marble dust waste.
The details of present invention are given below:
a) CaO is freshly prepared from marble dust by conventional method. The CaO is
mixed with reactive silica source such as fly ash, rice husk ash and cement in the
proportion 1-5 (by wt.): 2-15 (by wt.)
b) The mixture at step 'a' is mixed thoroughly for a period at 1-6 hrs by known
process such as pot milling, ball milling.

We Claim:
1. A process for the manufacture of building block, which comprises mixing freshly
prepared CaO from waste marble dust, reactive silica source such as fly ash, rice
husk ash and cement in the proportion 1 to 5 : 2 to 15: 0 to 15 ( by weight),
milling by known method the mixture for a period in the range of 1 to 6 hours to
obtain an intimately mixed material, mixing the intimately mixed material with
water in the proportion 10 to 30% of the solid mix, ageing the water mixed
material so obtained for a period in the range of 0.5 hours to 4 hours, forming
blocks, curing the blocks under water for a period in the range of 12 hours - 168
hours, treating the blocks hydro thermally for a period in the range of 0-24 hours
under steam pressure above 3 kgf/cm2.
2. A process for the manufacture of building block substantially as herein described
with reference to the examples.

Documents:

352-DEL-2002-Abstract-07-05-2008.pdf

352-del-2002-abstract.pdf

352-DEL-2002-Claims-07-05-2008.pdf

352-del-2002-claims.pdf

352-DEL-2002-Correspondence-Others-07-05-2008.pdf

352-del-2002-correspondence-others.pdf

352-del-2002-correspondence-po.pdf

352-del-2002-description (complete)-07-05-2008.pdf

352-del-2002-description (complete).pdf

352-DEL-2002-Form-1-07-05-2008.pdf

352-del-2002-form-1.pdf

352-DEL-2002-Form-18-07-05-2008.pdf

352-del-2002-form-18.pdf

352-DEL-2002-Form-2-07-05-2008.pdf

352-del-2002-form-2.pdf

352-DEL-2002-Form-3-07-05-2008.pdf

352-del-2002-form-3.pdf

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Patent Number

219640

Indian Patent Application Number

352/DEL/2002

PG Journal Number

28/2008

Publication Date

11-Jul-2008

Grant Date

12-May-2008

Date of Filing

27-Mar-2002

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

Inventors:

#	Inventor's Name	Inventor's Address
1	MIHIR DAS
2	CHITTYABRATA CHAUDHURY
3	SACHCHIDANANDA CHAKRABARTI
4	SYAMAL GHOSH
5	SANKAR GHATAK

PCT International Classification Number

E04C 2/04

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA