Title of Invention

CEMENT PHOSPHOGYPSUM BLOCKS AND A METHOD OF MANUFACTURE THEREOF

Abstract A method of manufacture of building blocks from phosphogypsum, obtained as a by product in the preparation of phosphoric acid by contacting sulphuric acid with rock phosphate, comprising the steps of thoroughly mixing 25% -to 50 % by volume of the said phosphogypsum, manually or under power, with upto 75% by volume of coarse aggregate of various sizes, 0 to 40% by volume of granite quarry dust and upto 10% by volume of cement, adjusting the consistency of the mix, if necessary, to mouldable conditions by the addition of water to the mix; moulding the mix in block moulds and allowing the same to set; demoulding the set moulded blocks before drying the same; and moistening the dried blocks thereafter with water to obtain the fmished blocks AND a product of Cement Phospho gypsum Block or Building block. '
Full Text

This invention basically relates to the field of building blocks containing phosphogypsum and method of manufacture of the same from Phosphogypsum obtained as a by product, during the course of manufacture of Phosphoric Acid by wet method by contacting rock phosphate with sulphuric acid. The invention is a breakthrough after extensive and successful test/trial runs and being cost effective, addresses the problem of ecological imbalance caused by depletion of scarce river sand. The invention focuses on creating a substitute for cement blocks manufactured from the increasingly scarce river sand and utilizes only industrial waste viz., Phospliogypsum for the purpose.
BACKGROUND OF INVENTION WITH REGARD TO THE DRAWBACKS OF KNOWN ART;
BACKGROUND OF INVENTION:
At present, building block viz., blocks used for construction and- building are made of cement and river sand. Therefore, the dependence on river sand for constructional and building purposes is very heavy resulting in huge demand. This has also necessitated mining of river sand to a great extent causing environmental hazards to mankind, besides the fact that traders hold consumers and public to ransom by quoting arbitrary and exhorbitant prices.
DRAWBACKS OF EXISTING METHODS:
The currently available methods of production of cement block consists of mining of river sand and using them for production of cement block. Undoubtedly the drawbacks of the currently available method to produce cement blocks from river sand are as under:
a. Mining of river sand for production of cement block resulting
in depletion of natural resources viz., river sand.
b. This accelerates the process of denudation and increases
rate of loss of topsoil.
c. The consequent ecological problems are difficult to
surmount.

d. The prices of river sand in the market always vary
depending on weather conditions and is at peak during
monsoon periods.
e. Over a period of time, continued use of river sand for
cement block for construction arid building purposes
would not only make river sand scarce but the whole
ecosystem will be impaired beyond redemption.
f. Truck operators in various cities, resort to unlawful river
sand excavation, during nights thus promoting illegal,
nocturnal, antisocial practices.
g. It causes reduction in agricultural production also.
OBJECTS OF THE INVENTION;
Accordingly, it is the primary object of the invention to invent building blocks - "Cement Phosphogypsum blocks" and method of manufacture of the same from phosphogypsum, more particularly, from phosphogypsum obtained as a by product during the course of manufacture of phosphoric acid by wet method by contacting rock phosphate with sulphuric acid.
It is another objection the invention to invent a cost saving and value added product viz.. Cement Phosphogypsum block.
It is another object of the invention to evolve ecofriendly methods of manufacture of building block viz., Cement phosphogypsum blocks.
It is another object of the invention to preclude misuse of natural resources viz., river sand.
It is another object of the invention to address the problem of scarcity of river sand by providing suitable substitute for cement blocks manufactured from river sand.

It is another object of the invention to provide viable substitutes for building & construction technologies.
It is another object of the invention to use the bye product phosphogypsum obtained from phosphoric acid plant for not only producing Ammonium Sulphate by merseberg process but also use it for manufacturing building blocks.
Further objects of the invention will be clear from the following description. Now the invention will be described in detail in the following description. The nature of invention is described in detail in this complete specification.
SUMMARY OF INVENTION:
The novel invention consisting of Building blocks/cement phosphogypsum blocks, invented by us after years of research and development in the industry, is the result of extensive research, investigation, constant study, meticulous labour and unstinted effort.
It is a unique product and there is no other product, which carries out the functions of such cement blocks/building blocks for construction and in the process also conserving nature entii^ely. Vast and extensive trials establish the use of our invention, in no uncertain terms.
The novel invention consists of a manufacture of building blocks for building and construction purposes, and method thereof from Phosphogypsum obtained as by product in the preparation of phosphoric acid, by contacting sulphuric acid with rock phosphate comprising the steps of thoroughly mixing 25 - 50% by volume of said phosphogypsum manually or by power, with up to 75% In-volume of coarse aggregate of various sizes, 0-40% by volume of granite quarry dust and upto 10% by volume of cement, adjusting the consistency of the mix, if necessary, to mouldability conditions by diluting with water to the mix; moulding the mix in block moulds and allowing them to set; demoulding the set moulded blocks, before drying the same and moistening the dried block thereafter with water to obtain finished blocks.

The invention is described/illustrated in the enclosed flow chart, marked Drawing 2.
The unique invention and method of performing it is now illustrated by an example:-
Phosphogypsum obtained during the course of manufacture of phosphoric acid by the wet process, by contacting rock phosphate by sulphuric acid, and subsequent filtration and washing, is discharged from the filter This gypsum may contain some impurities like phosphoric acid.
The gypsum aforesaid normally contains around 30% moisture 37.5% volume of the said phosphogypsum is thoroughly mixed imth 56.25% by volume of coarse aggregate of 6mm size and 6.25% by
volume of cement (53 grade) in a concrete mixer Normally aromd 30% of water present in the bye product - phosphogypsum wouh I be sufficient for the mix. However, if need be, the consistency of the mix can be adjusted to mouldable conditions by the addition of further water to the mix.
The stock thus obtained as aforesaid is moulded using standard moulds or moulds prepared to the size desired for any specific application. The mouldmg operation is carried out ei Iter manually or under power
After moulding the blocks are demoulded and air dried or such dried.
After about two days of drying, the blocks are kept moist by spraying water for 8 to 10 days to get the finished product.
According to the method proposed herein, the phosphogypsum obtained from the phosphoric acid plant can be utilized directly for the manufacture of blocks without any intermediate processing or washing operation and the resultant blocks do not shrink on drying.

This apart, the resultant cement phosphogypsum blocks/building blocks have water absorbing characteristics and compressive strength comparable with the co7wentional country blocks.
The illustration, elaborated by way of example hereinbefore, is described/illustrated in the enclosed flow chart, marked Drawing 1.
The terms and expressions in this specification are of description and not of limitation, there being no intention in the use of such terms and expressions of excluding any equivalents of the features illustrated and described, but it is understood that various other modes of carrying out the method proposed herein are possible, without departing from the scope and ambit of this invention.
Obvious equivalents known to persons skilled in the art are included in the scope of the above description and appended claims.



We Claim:
1. A method of manufacture of building blocks from phosphogypsum, obtained as a by product in the preparation of phosphoric acid by contacting sulphuric acid with rock phosphate, comprising the steps of thoroughly mixing 25% -to 50 % by volume of the said phosphogypsum, manually or under power, with upto 75% by volume of coarse aggregate of various sizes, 0 to 40% by volume of granite quarry dust and upto 10% by volume of cem.ent, adjusting the consistency of the mix, if necessary, to mouldable conditions by the addition of water to the mix; moulding the mix in block moulds and allowing the same to set; demoulding the set moulded blocks before drying the same; and moistening the dried blocks thereafter with water to obtain the finished blocks.
2. A method as claimed in Claim 1 wherein the moulding of the mix is carried out manually.
3. A method as claimed in Claim 1 wherein the moulding of the mix is carried out with the aid of power.
4. A method as claimed in Claim 1 wherein the Phosphogypsum having 30% of water content may be sufficient in moisture without requiring additional water.
5. A method as claimed in Claim 1 wherein the Phosphogypsum may require water additional to the moisture content existend in the phosphogypsum, for block formation.
6. A method as claimed in Claim 1 wherein the blocks are air-dried.
7. A method as claimed in Claim 1 wherein the blocks are sun dried.

8. A method as claimed in Claim 1 wherein the cement used
may be 53 grade cement.
9. A method as claimed in Claim 1 wherein the cement used
may be any suitable grade cement.
10. A method as claimed in any one of the preceding claims
wherein the blocks are moistened with water for 8 to 10 days.
11. A method as claimed in Claim 1, wherein the coarse aggregate may have a dimension of 6 mm.
12. A method of manufacture of Cement Phosphogypsum Block or Building Block as claimed in claim 1, wherein mould may be of standard size.
13. A method of manufacture of Cement Phosphogypsum Block
or Building Block as claimed in claim 1, wherein mould may
be of specified size.
14. A method of manufacturing cement phosphogypsum block or
building block and product of cement phosphogypsum block
or building block substantially as described in this
specification with reference to the accompanying drawings.
Dated this the 24th day of OCTOBER 2003.


Documents:

966-che-2003-abstract.pdf

966-che-2003-claims duplicate.pdf

966-che-2003-claims original.pdf

966-che-2003-correspondence others.pdf

966-che-2003-correspondence po.pdf

966-che-2003-description complete duplicate.pdf

966-che-2003-description complete original.pdf

966-che-2003-drawings.pdf

966-che-2003-form 1.pdf

966-che-2003-form 19.pdf

966-che-2003-form 26.pdf


Patent Number 204222
Indian Patent Application Number 966/CHE/2003
PG Journal Number 27/2007
Publication Date 06-Jul-2007
Grant Date 13-Feb-2007
Date of Filing 25-Nov-2003
Name of Patentee M/S. THE FERTILISERS AND CHEMICALS TRAVANCORE LIMITED
Applicant Address UDYOGAMANDAL-683 501, KOCHI
Inventors:
# Inventor's Name Inventor's Address
1 MATHURAI NAYAKAM NATARAJAN CHIEF MANAGER (R&D)M/S. FACT UDYOGAMANDAL-683501
2 KOTTIPPALLI GOVINDA MENON UNNIKRISHNAN MANAGER(R&D), FACT UDYOGAMANDAL-683501
3 NARAYANAN NAIR MURALEEDHARAN DEPUTY MANAGER(R&D),FACT UDYOGAMANDAL-683501
4 PUSHPAMANGALAM GEORGEKUTTY RAJANBABU ASSISTANT MANAGER(R&D),FACT UDYOGAMANDAL-683501
5 ATTANATH GOPALAN NAIR UNNI ASSISTANT MANAGER(R&D), FACT UDYOGAMANDAL-683501
6 BATHIRDHEEN SALIM ASSISTANT MANAGER(R&D), FACT UDYOGAMANDAL-683501
7 KOLLENGODE SUBRAMANIA SASTRY RAMACHANDRAN ASSISTANT MANAGER(R&D), FACT UDYOGAMANDAL-683501
PCT International Classification Number E04C 1/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA