Contents

# Cement Grinding Important coefficient & Factors

**BLAINE FINENESS FACTOR**

**BLAINE FINENESS FACTOR**

Example

Mill output : 100 t/h

Fineness according to Blaine: 3000 cm²/g

New fineness required: 3500 cm²/g

K = exp ((3500-3000)/1000*0,49)

K= 1,278

Expected mill output = 78,3 t/h

## COMPOSITE CEMENT

OPC (Ordinary Portland Cement)

Composition

96 % CLINKER

4 % GYPSUM

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CPC (Composite Portland Cement)

Type of additives:

Limestone, pouzzolane, trass, slag, fly ash, ….

Properties:

increase of fineness and output, decrease of initial and final strength, increase of concrete plasticity and workability, colour ,modification …

Exemple of the additive influence on the mill output

Production of cement with 15 % of limestone

Composition

81 % CLINKER

4 % GYPSUM

15% LIMESTONE

Cement Mill

Output = 100 t/h of OPC (96 % Clinker – 4% Gypsum)

Fineness = 3200 cm²/g

CPC cement (81% Clinker – 4% Gypsum – 15% Limestone))

Fineness required 3200 cm²/g according to blaine

Calculation of equivalent clinker fineness

We consider that the limestone “gives” 2 times more fineness.

X = equivalent clinker fineness

2.X = limestone fineness

3200 = (0,81+0,04) X + 0,15 2.X

X = 2783 cm²/g

Limestone fineness = 5565 cm²/g

Expected cement mill output with 15% limestone

Fineness factor

K = exp ((3000-2783)/1000*0,49)

K=1,11

Expected mill output = 111 t/h at 3200 cm²/g with 15% limestone

**BALL MILL ABSORBED POWER**

**BALL MILL ABSORBED POWER**

POLYSIUS C Factor

Depends on different parameters: ball charge, kind of material, type of process, type of mill

**HIGH EFFICIENCY SEPARATOR SEPOL**

**HIGH EFFICIENCY SEPARATOR SEPOL**

**TROMP Curve**

**TROMP Curve**

Tau = By pass %

This percentage represents the % of fines which has been considered by the Separator as rejects.

Normal range for a high efficiency separator SEPOL with OPC cement

: 5 –15%

Separation cutting : diameter μm

This point gives where is the limit of accuracy of the SEPOL for the cement produced.

Normal value for standard OPC: 10 – 20 μm

Imperfection

Polysius formula

kapa = d30/d70

Lafarge formula

I = (d75 – d25 ) / 2 (d50)

MohanYes I need. Request you to send list. so that i can select the one I require

With regards,

Mohan Bevin