FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention. - IMPROVED PORTLAND SLAG CEMENT
COMPOSITION
2. Applicant(s)
(a) NAME : Alcolab (India) Pvt. Ltd.
(b) NATIONALITY : An Indian Company
(c) ADDRESS: Sukerkar Mansion, First floor, M.G. Road, Panaji,
Goa-403 001, India.
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed.

TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improved Portland slag cement composition comprising a supplementary Cementitious Material (designated herein as ALCCOFINE 1203) as an additive, which acts as a performance enhancer, and an activator to activate slag reactivity of ground granulated blast furnace slag (GGBS). The Supplementary Cementitious Material, ALCCOFINE 1203 when incorporated into Portland Slag Cement, during its manufacturing process, i.e. during the grinding/ blending stage helps in achieving the higher strength of Portland Slag Cement at all ages.
BACKGROUND OF THE INVENTION
The most commonly used cement in the world is Portland cement, which is formed at high temperatures that chemically combine the ingredients into new components, including calcium silicates and calcium aluminates. When the cement clinkers are ground with approximately 5% gypsum, they form Portland cement. These compounds allow cement to set when combined with water and to form strong bonds that can withstand pressure, water immersion, and other elements. Clinker is ground (usually with the addition of a little gypsum, that is, calcium sulfate dihydrate) to become Portland cement. It may also be combined with other active ingredients or chemical admixtures to produce ground granulated blast furnace slag cement, pozzolana cement, and silica fume cement.
US Patent No. 3,147,129 discloses a process for making cement from an aluminous source containing fluorine, which cement is based on C12A7 type material with fluorine compound which cement may attain high ultimate strength properties upon addition of certain additives.

US Patent No. 3,251,701 discloses C4A3S Portland type cement, which is expansive and may or may not develop early strength, and does not develop very high early strength.
US Patent No. 3,510,326 discloses C4A3S containing additives to be admixed with normal cement to obtain expansion, and the resulting materials were very expansive and did not develop high early strength.
US Patent No. 4173487 discloses the operation of the rotary kiln at high back end temperatures and under reducing conditions. The technique of operating the kiln under reducing conditions is undesirable because it requires additional fuel input, most of which is wasted in the kiln exhaust gas in the form of CO and H2. A second undesirable trend has been the heavy concentration of SO2 and SO3 in the kiln exhaust, which would have to be removed before emitting the gas to atmosphere. However, present invention helps in reducing clinker consumption per unit weight of cement and reduces all the negative aspects of the above patent.
US 7,410,537 relates to a process for the production of Portland slag cement using cement clinker and higher proportion of ground granulated blast furnace slag, which comprises: forming of cement clinker by known process, ball-milling of cement clinker for a period ranging between 30-60 minutes in dry condition, reducing size of granulated blast furnace slag by any process to obtain the size in the range between 210 to 100 urn for using as feed for attrition mill, wet milling of granulated blast furnace slag using granulated blast furnace slag to water. It discloses the use of cement clinker in the range of 55-90% by weight and granulated blast furnace slag in the range of 5-40% by weight.
The above invention has cement clinker dry ground and slag wet ground both combining to give cement in a paste condition, which has limited shelf life.

Portland cement manufacture can cause environmental impacts at all stages of the process. These include emissions of airborne pollution in the form of dust, gases, noise and vibration when operating machinery and during blasting in quarries, consumption of large quantities of fuel during manufacture, release of CO2 from the raw materials during manufacture, and damage to countryside from quarrying.
So there is a need to formulate a composition of the cement, which eliminates all these disadvantages, and provide better result with respect to the durability, strength and non-hazardous component to environment.
The Portland type hydraulic cements have achieved only limited success in terms of early strength only. They functionally result in expansive or shrinkage compensating additives. Unlike prior art the present inventors have surprisingly found that ALCCOFINE-1203 of the present invention is an improved supplementary cementitious material which provides increased strengths at all ages, and not only higher early strength. ALCCOFINE-1203 of the present invention performs by improved packing, which helps in dense microstructure, which is intrinsic and larger amount of hydration, which gives the improved quanta of strengths. The present invention uses a finely ground dry powder acting as an activator and results in a cement having long shelf life.
OBJECTIVE OF THE INVENTION
It is an object of the present invention to overcome the disadvantages of the prior art.
It is another object of the present invention to provide an improved Portland slag
cement composition comprising supplementary cementitious material.
It is yet another object of the present invention to increase the quantity of granulated
slag that can be incorporated into blended cement production, and minimize clinker
absorption.

SUMMARY OF THE INVENTION
It is an object of the invention to provide a portland slag cement composition comprising:
a) 2 to 10 % by weight of supplementary cementitious material acting as activator and having desired fineness and particle size,
b) 60 to 68 % by weight of ground granulated blast furnace slag such that total amount of component a and b do not exceed 70% by weight of the total composition and
c) 30 to 38% by weight of clinker and
d) 5 % by weight of Gypsum;
such that said supplementary cementitious material has an average particle size of 4 to 5 microns and fineness ranging from 6000 to 20000 sq cm/gm
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a supplementary cementitious material having a composition typical of granulated blast furnace slag but with defined particle size so that the D50 of about less than 5μ. is achieved and has a fineness of 8000 to 16000 sq cm / gm, which when incorporated into Portland slag cement acts as an activator to activate slag reactivity.
Portland Slag Cement is slag-based blended cement that imparts strength and durability to all structures. It is manufactured by inter-grinding ordinary Portland cement (OPC) clinker and granulated slag and gypsum in suitable proportions. It can also be made by blending ordinary Portland cement with GGBS. PSC has many superior performance characteristics which give it certain extra advantages when compared to Ordinary Portland Cement. All these factors make for a strong, durable, and longer lasting construction. It is well known that Portland Slag cements provide much superior cement for producing long term durable concrete.

With ordinary portland cement (OPC), supplementary cementitious materials (SCMs) like fly ash, ground granulated blast furnace slag (GGBS) etc may be added along with aggregates during the process of making concrete. In this case also the strength is inversely proportional to the water/cementitious content (OPC+SCM). The 28-day strength of concrete is taken as the 'bench-mark' strength universally and strengths at ID, 3D, & 7D etc provide the rate of strength development. The specific strength attained in the latter case is dependent upon the nature/ characteristics of the SCMs GGBS, a well-known SCM, is generally used at a fineness of 4000 sq.cm/gm (Blaine value). It is believed that increasing the fineness to about 6000 (Blaine) only increases the strength only marginally.
Present invention ALCCOFINE- 1203 is a product largely based on GGBS, but processed by grinding to a high surface area (Blaine-value but computed based on PSD) of 8000 to 16,000 sq.cm/gm. The word SCM is used when it is used in concrete to replace part of the cement. When used in manufacture of cement SCM term is not used and "Granulated blast furnace slag" stands. ALCCOFINE 1203 is a SCM and this is applied whether in concrete or in cement.
It is generally known that per 1 MT of clinker production approximately 1.5 MT CO2
is released from the limestone used. The present invention on the other hand can
produce PSC of the same quality by reducing the clinker utilized by 20%. Thus CO2
emission is reduced in the same proportion.
Other important aspect of the invention is to activate slag reactivity of ground granulated blast furnace slag (GGBS), which is achieved by incorporating the supplementary cementitious material, ALCCOFINE 1203, which acts as a performance enhancer.
The American Concrete Institutes defines blast furnace slag as follows: Blast furnace
slag - the non-metallic product, consisting essentially of silicates and

aluDDFFmmosilicates of calcium and other bases, which is developed in a molten condition simultaneously with iron in a blast furnace.
Granulated blast furnace slag is the glassy, granular material formed when molten blast furnace slag is rapidly chilled, as by immersion in water.
The purpose of the present invention is to use abundantly available waste materials such as granulated blast furnace slag, which is causing environmental pollution, as major constituent to produce value added product such as Portland slag cement.
The present invention thus provides an improved portland slag cement composition comprising:
a) 2 to 10 % by weight supplementary cementitious material acting as activator and having desired fineness and particle size,
b) 60 to 68 % by weight ground granulated blast furnace slag such that total amount of component a and b do not exceed 70% by weight of the total composition and
c) 30 to 38% by weight of clinker and
d) 5 % by weight of Gypsum.
Supplementary cementitious material according to the present invention, which itself is based on granulated slag in the cement activates the granulated blast furnace slag and its reactivity is increased. The increased reactivity leads to enhanced hydraulic activity of slag. As soon as water is added, slag particles undergo hydration along with cement clinker and gypsum. Due to combined hydration reactions, a complex C--S--H gel (OCaO, S=Si02, H=H20) with very dense microstructure is formed, which results in development of early strength. Also due to increased reactivity, higher percentage of granulated blast furnace slag is used in the Portland slag cement. With only 2% ALCCOFINE 1203 addition the clinker content is possible to reduce from 55 to 35% while meeting the same strength levels, according to details in table 1 A.

The process of Portland slag cement manufacture involves grinding of Portland cement clinker and granulated slag along with gypsum. Alternately clinker and slag and gypsum may be ground separately and blended together. To achieve the specified level of strengths a certain minimum quantity of clinker has to be incorporated into the mix, below which level strengths are not met. As per IS 455-1989 the minimum strength levels of Portland Slag Cement are 16, 23 and 33 MPa minimum at 3, 7 and 28 days respectively according to test procedure therein.
The cost of clinker is relatively high compared to granulated slag and reduction of clinker quantity has been the aim of cement producers from economy viewpoint and CO2 emission. The latter is reduced by using lesser clinker and increasing slag.
At the same time it provides a very superior contribution to the performance on account of both chemical and physical properties being modified. The chemical composition especially the non-glassy part and the improved fineness in relation to the compactness resulting from the modification of the particle sizes and their very distribution, contribute synergistically to the superior performance of the invention. Generally Ground Granulated Blast Furnace Slag used has a fineness of 4000 sq cm/gm and an average particle size of (D 50) about 25 microns. Alccofine 1203 has a much higher fineness 8000 to 16000 sq cm/gm and particle size (D50) less than 5 microns, in the range of 4 to 5 microns.
Composition of the invention:
The improved portland slag cement composition comprises
a) 2 to 10 % by weight, preferably 2 to 5 % by weight of supplementary cementitious material acting as activator and having desired fineness and particle size,
b) 60 to 68 % by weight ground granulated blast furnace slag such that total amount of component a and b do not exceed 70% by weight of the total composition and

c) 30 to 38% by weight, preferably 30 % by weight of clinker and
d) 5 % by weight of Gypsum.
The supplementary cementitious material (ALCCOFINE 1203) based on blast furnace slag of the following composition:
The oxide composition of the granulated slag, (including glassy and non glassy) is:
CaO 30 - 40%
Si02 30-35%
A12O3 15-22%
Fe203 1.0-3%
MgO 8-10%
S03 0 to 4 %
Mn203 0.23 - 0.26%
Na20 0.08 to 0.12%
K20 0.02 to 0.22%
Glass content (Min ) 90 %
The purpose of adding fibrous glass etc. is to enhance the reactivity of ALCCOFINE
1203.
The product is obtained from hot blast Furnace slag which is subject at controlled temperature to water granulation to result in high glass content and the low non glassy part is of optimum mineralogical type to provide high reactivity of the
resulting granulated slag.
The above granulated slag is processed by the size reduction process using conventional mills having particle separation classifiers. The slag is processed along with addition of:
a) Fibrous glass 0-35%
b) Gypsum (CaS04.2H20
Or anhydrite 0-10%
c) Potassium Aluminum 0-5%

Silicate
d) Nano-silica 0-5%
e) Poly carboxylate Ether 0 - 5%
The above are added either all or in any combination to result in an extremely high fineness with a computed 'Blaine' value of 6000 to 20000 sq.cm/gm more specifically between 8000-16000 sq. cm /gm based on particle size values determined experimentally through appropriate instruments i.e. Particle size analyzers.
The present invention is now demonstrated by way of illustrative non limiting examples. The following specific examples will serve further to illustrate the practice and advantages of this invention.
Examples:
The process of PSC manufacture involves grinding of Portland cement clinker and
granulated slag along with gypsum. Alternately clinker and slag and gypsum may be
ground separately and blended together. The evaluation was done on a lab scale. The
material ground in a lab ball mill for the duration of 1.5 hrs. The material ground for
reference blend were clinker - 55%, Granulated slag - 40%, Gypsum - 5%.
ALCCOFINE blend consists of clinker - 35%, Granulated slag - 58%, Gypsum - 5%
and ALCCOFINE 1203 - 2%. The surface area of the resulted PSC was measured by
Blaine Air Permeability Apparatus.
This relates to the addition of ALCCOFINE 1203 to Portland Slag cement (PSC) to obtain improved properties of resulting concrete.

TABLE- 1A

Material Reference Blend % values Alccofine Blend
% values Remarks
1 OPC Clinker 55 35
2 Granulated Slag 40 58 By reducing
3 Gypsum 05 05 the amount
4 Alccofine 1203 00 02 of clinker
5 Surface Area m2/Kg 360-380 390-410* and
6 Strength increasing
ID MPa 9-11 9-11 amount of
3D MPa 24-26 24-26 granulated
7D MPa 38-40 38- 40 slag similar
28D MPa 50-52 53-56 or better strength is obtained in the present invention
• The surface of Blend works out to 360-380 m2/kg by adjusting for high fineness of
ALCCOFINE 1203.
In table 1A the reference PSC has 55% clinker with 40% granulated slag and 5%
gypsum on being ground to 360- 380 m2/kg surface area results in a Portland Slag
Cement (PSC) having strengths of 9-11, 24-26, 38-40, and 50-52 MPA at ID, 3D, 7D
and 28D respectively (D refers to number of days). In comparison with only 35%
clinker, 58% granulated, 5% gypsum and the addition of ALCCOFINE-1203 at only

2% and processed to nearly similar surface area as reference, results in PSC having 9-11, 24-26, 38-40, 53-56 MPa at ID, 3D, ID and 28 days respectively. Thus it is evident that addition of only 2% ALCCOFINE1203 can result in PSC with a lower clinker content, which is lower by 20%.
TABLE 1-B
Material Reference Alccofine
Blend % Blend % Remarks
1. OPC Clinker 35 35 By using
2. Granulated Slag 60 58 similar
3. Gypsum 05 05 amount of
4. Alccofine 1203 0 02 clinker and
5. Surface Area m /kg 360-380 390-410* by
6. Strength substituting
lDMPa 8-9 9-11 2%
3DMPa 20-22 24-26 ALCCOFINE
7DMPa 32-34 38-40 1203 for
28DMPa 50-52 53-56 granulated slag a higher strength is achieved in present invention
* The surface area of the Blend works out to 360 - 380 m2/ Kg by adjusting for the high fineness of ALCCOFINE 1203
The evaluation was done on a lab scale. Each of the blend composition was ground in a ball mill for the duration of 1.5 hrs. The material ground for reference blend was clinker- 35%, granulated slag - 60%, Gypsum - 5%. ALCCOFINE blend consists of clinker - 35%, Granulated slag - 58%, Gypsum - 5% and ALCCOFINE 1203 -2%. The surface area of the resultant PSC was measured by Blaine Air Permeability Apparatus. Granulated slag and ALCCOFINE 1203 together add up to 60%, the same value of 60% as in reference blend.
Table 1-B shows that at same fineness, increased amount of slag can be incorporated into the Blended Cement (PSC) production by incorporating just 2 percent of

ALCCOFINE 1203 in the production process of grinding the input ingredients and still achieve higher strengths at all ages at ID, 3D, 7D and 28D, compared to the reference mix. The ALCCOFINE 1203 thus functions as an 'ACTIVATOR'.
Similarly Tables 2A, 2B, 2C give details of trials at a different location - a cement plant using materials which goes into production. Tables 2D & 2E are for a third set of materials from another cement plant and trials were done on a laboratory scale.

Table - 2A

No. Material Reference
Blend %
values Alccofine
Blend% values Remarks
1 OPC Clinker 55 35 Reference as
well as
ALCCOFINE
blend trial taken
in plant
2 Granulated Slag 40 58

3 Gypsum 5 5

4 ALCCOFINE -
1203 0 2

5 Surface Area
m2/Kg 340 384

6 Strength(Mpa)

IDay 11.8 10.8

3 Days 26.9 28.3

7 Days 40.3 39.8

28 Days 50.5 51.5

Table - 2B

No. Material Reference
Blend %
values Alccofine
BIend%
values Remarks
1 OPC Clinker 55 35 Reference as well as
2 Granulated Slag 40 58

3
Gypsum 5 5 ALCCOFINE
blend trial taken
in plant
4 ALCCOFINE -1203 0 2

5 Surface Area m2/Kg 350 371

6 Strength(Mpa)

1 Day 12.0 10.6

3 Days 27.1 26.8

7 Days 37.9 37.0

28 Days 50.2 51.0

Table - 2C

No. Material Reference
Blend %
values Alccofine
Blend%
values Remarks
1 OPC Clinker 55 35 Reference as
well as
Alccofine blend
trial taken in
plant
2 Granulated Slag 40 58

3 Gypsum 5 5

4 Alccofine - 1203 0 2

5 Surface Area
m2/Kg 364 424

6 Strength(Mpa)

IDay 12.8 12.0

3 Days 25.2 25.0

7 Days 38.6 38.8

28 Days 53.0 54.5

Table - 2D

No. Material Reference
Blend %
values Alccofine
BIend%
values Remarks
1 OPC clinker 60 43 Reference as

2 Granulated Slag 40 55 well as
Alccofine blend
trial taken in
Laboratory
3 Gypsum 0 0

4 Alccofine - 1203 0 2

5 Surface Area
m2/Kg 403 424

6 Strength(Mpa)

IDay 9.6 11.5

3 Days 20.8 21.6

7 Days 38.3 38.7

28 Days 44.1 58.0

Table - 2E

No. Material Reference
Blend %
values Alccofine
Blend%
values Remarks
1 OPC 60 48 Reference as
well as
Alccofine blend
trial taken in
Laboratory
2 Granulated Slag 40 50

3 Gypsum 0 0

4 Alccofine- 1203 0 2

5 Surface Area
m2/Kg 392 420

6 Strength(Mpa)

IDay 12.8 11.1

3 Days 23.8 21.2

7 Days 37.2 36.3

28 Days 58.9 61.1

Tables 1A and IB are initial laboratory trials whereas Table 2A, 2B, and 2C are trials with materials from different cement plants which again shows that the 28D strength of cement is higher in all cases. This affirms the role of ALCCOFINE1203 as an activator.

We Claim
1. A portland slag cement composition comprising:
a) 2 to 10 % by weight supplementary cementitious material acting as activator and having desired fineness and particle size,
b) 60 to 68 % by weight ground granulated blast furnace slag such that total amount of component a and b do not exceed 70% by weight of the total composition and
c) 30 to 38% by weight of clinker and
d) 5 % by weight of Gypsum, such that said supplementary
cementitious material has an average particle size of 4 to 5 microns and
fineness ranging from 6000 to 20000 sq cm/gm.
2. The portland slag cement composition as claimed in claim 1, wherein fineness of said supplementary cementitious material ranges preferably from 8000 to 16000 sq/cm gm.
3. The portland slag cement composition as claimed in claims 1 or 2, wherein amount of said supplementary cementitious material is preferably 2 to 5% by weight.
4. The portland slag cement composition as claimed in claims 1 or 2, wherein said supplementary cementitious material comprises
30 to 40% by weight CaO, 30 to 35% by weight Si02, 15 to 22% by weight A1203, 1 to 3% by weight Fe203, 8 to 10% by weight MgO, 0 to 4% by weight S03, 0.23 to 0.26% by weight Mn203, 0.08 to 0.12% by weight Na20,

0.02 to 0.22% by weight K20; such that glass content is minimum 90%.
5. The portland slag cement composition as claimed in claim 3, wherein said supplementary cementitious material is further processed with 0 to 35% by weight fibrous glass, 0 to 10% by weight gypsum, 0 to 5% by weight Potassium aluminium silicate, 0 to 5% by weight nano silica , and 0 to 5% by weight poly carboxylate ether.
6. The portland slag cement composition as claimed in claim 1, wherein amount of said clinker is preferably 30% by weight.
7. A portland slag cement composition as herein substantially described and illustrated with reference examples.