# US 7,410,537 B2 · Process for the production of Portland slag cement using granulated blast furnace slag

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- Number: US 7,410,537 B2
- Document ID: US7410537B2
- Status: Granted
- Kind: B2
- Application number: 11/491,916
- Filed: 2006-07-25
- Published: 2008-01-31
- Granted: 2008-08-12
- Earliest claimed: 2006-07-25
- Assignees: Council of Scientific and Industrial Research
- Inventors: Rakesh Kumar; Sanjay Kumar; Amitava Bandopadhaya; Surya Pratap Mehrotra
- Web page: https://patentgrep.com/patent/US7410537B2

## CPC

- C04B 28/04: Portland cements
- C04B 18/141: {Slags}
- Y02W 30/91: Use of waste materials as fillers for mortars or concrete
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT

## Abstract

Accordingly, the present invention provides an improved process for the production of Portland slag cement using granulated blast furnace slag, which comprises: (viii) forming of cement clinker by known process, (ix) ball-milling of cement clinker for a period ranging between 30-60 minutes in dry condition, (x) reducing size of granulated blast furnace slag by any process to obtain the size in the range between 210 to 100 μm for using as feed for attrition mill, (xi) wet milling of granulated blast furnace slag for a period ranging between 5-15 minutes in an attrition mill using granulated blast furnace slag to water ratio in the range of 1:1 to 1:2 and granulated blast furnace slag to grinding bail ratio in the range of 1:5 to 1:15, (xii) removing water from the slurry obtained after attrition milling by known process, (xiii) drying of the obtained slurry by known process, (xiv) mixing intimately of: attrition milled slag obtain in step (vi) in the range of: 50 to 95% by weight ball-milled clinker obtain in step (ii) in the range of: 05 to 45% by weight gypsum in the range of: 01 to 05% by weight for a period in the range of 15 to 30 minutes.

## Claims

### Claim 1

An improved process for the production of Portland slag cement using of granulated blast furnace slag, the said process comprising the steps of:
(i) preparing cement clinker
(ii) ball-milling of cement clinker for a period ranging between 30-60 minutes under dry condition,
(iii) reducing size of granulated blast furnace slag to a size of ranging between 210 to 100 μm, for using as feed for attrition mill,
(iv) wet milling of granulated blast furnace slag for a period ranging between 5-15 minutes, in an attrition mill with granulated blast furnace slag to water ratio in the range of 1:1 to 1:2 and granulated blast furnace slag to grinding ball ratio in the range of 1:5 to 1:15 to obtain a slurry,
(v) removing water from the above said slurry after attrition milling followed by drying to obtain the attrition milled slag,
(vi) mixing intimately
attrition milled slag obtain in step (v) in the range of: 50 to 95% by weight,
ball-milled clinker obtain in step (ii) in the range of: 05 to 45% by weight,
and gypsum in the range of: 01 to 05% by weight,
for a period in the range of 15 to 30 minutes, to obtain the Portland slag cement.

### Claim 2 (depends on 1)

An improved process as claimed in claim 1 wherein the granulated blast furnace slag has a following composition:
range: SiO2-20 to 40%, Al2O3-20 to 40%, Fe2O3-0 to 2%, CaO-20 to 40%, MgO-5 to 17%, MnO-0 to 5%, SO3-0 to 2% and glass content >85%.

### Claim 3 (depends on 1)

An improved process as claimed in claim 1, wherein the cement clinker has a following composition range: SiO2-20 to 25%, Al2O3-3 to 8%, Fe2O3-2 to 4%, CaO-60 to 70%, MgO-0 to 6%, MnO-0 to 4%, SO3 <1.5%.

### Claim 4 (depends on 1)

An improved process as claimed in claim 1, wherein the gypsum has a following composition range: CaO-25 to 40%, SO3-30 to 60%.