fjalali
70 posts
TimePosted 13/06/2011 10:19:37
fjalali says

Mono Chamber Raw Mill Ball Charge Design

Hi experts,

I want to design a ball charge for a mono-chamber raw mill in a white cement plant and wanted to know your opinion about it.

The raw material is pre-ground by to a hammer crusher and after separation by a third generation separator the course material is fed to the mono-chamber raw mill.

 The technical data of the mill is as follows:

Mill diameter: 3.2 m

Mill Length:  6.37 m

Effective Mill diameter:  3 m (the mill liners are 95 mm)

Effective Mill Length:  6 m

Liner: Lifting plates

Mill Speed:  17 rpm

Mill Feed Residue Analysis:

mm

Ave.

12.7

0.4

9.5

1.0

8.0

1.9

6.4

4.3

4.8

8.5

2.4

20.3

1.2

32.5

0.8

41.7

0.6

52.6

0.2

70.8

0.1

88.5

 

What is the maximum ball size required? What is the ball charge design?

I appreciate any help you can provide me.

Best regards;

FJ

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Vikpro
77 posts
TimePosted 14/06/2011 07:49:39
Vikpro says

Re: Mono Chamber Raw Mill Ball Charge Design

This is the first time I'm calculting mono chamber mill with white cement clinker, it may  not be so accurate. I will wait for other's comments also.

I have considered, white cement clinker WI index @ 16.9 and specific gravity of 2.42 feed size 1.87 mm and rest of the mill specification as per your mail.

The maximum grinding media ball size should be - steel media =28 mm

                                                                             - ceramic balls = 45 mm

Thanks

Vikpro

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fjalali
70 posts
TimePosted 14/06/2011 09:53:05
fjalali says

Re: Mono Chamber Raw Mill Ball Charge Design

Hi,

This is the raw mill not the finish mill. So Wi should be 10.6 and density of 2.67 as normal kiln feed. I used d80 of 3000 micron to be on safe side and got max ball dia. of 37 mm (use 40 mm steel balls).

But this does not match the mill original ball charge that had 80 mm as its max ball charge?!?

Dose everyone agree with this?

Also considering 40 mm as max ball diameter what will you recommend for charge composition knowing that the liners are lifting not classifying so we are limited by number of ball and the fact that mono chamber mill charges are usually courser than two compartment mills?

Is this a good start?

40 mm             30%

30 mm             30%

25 mm             40%

All your comments are welcome.

Thx.

 

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