• Author / Uploaded
• Tamer Fathy

• Categories
• Molino (molienda)
• Kilovatio Hora
• Energía y recursos
• Naturaleza

Citation preview

Ball Mill Optimization The Ball Mill

The Ball Mill

Gas + dust outlet

Intermediate diaphragm Outlet diaphragm Reject return Inlet head C2 liners C1 liners chute

Discharge box

Fresh feed Outlet seal Material discharge

Shell Central or ventilation ring Fresh air inlet Central Ventilation ring grate Supports

Feed Arrangements Mill Heads Mill Bearings Drive types Mill Shell

Trunnion

The Ball mill / ATC Process

March 2004

2

The Ball Mill Leff C2 Leff C1 Leff TOT D

Deff

L

- L/D : Ratio between 3 and 5 - Length of C1/Total Length : ratio between 27 and 40% except for birotators - Ball diameter in C1 from 100-90 mm to 70-60 mm (4 / 3-1/2” to 2-1/2 / 2”) - Ball diameter in C2 from 60-50 mm to 20-17 mm (2-1/2” / 2” to 3/4 / 5/8”)

The Ball mill / ATC Process

March 2004

3

Conditions of the lifting liners 

Purpose 



Plate conditions (breaks, chips, attachments)

Criterion 



Step

General condition of liners 



Insuring proper cascading of the balls and hence crushing of material

Performance should be checked when step < 40% of initial step (wear=60%)

Corrective measure 

rotation

Replacement

The Ball mill / ATC Process

March 2004

4

The step size (lifting power) depends on  Mill rotation speed (% critical speed)  Volume load

Direction of rotation

 Grindability of feed material BOLTLESS STEP CHAMBER 1 LINER  Less material spillage  Avoids bolt breakage The Ball mill / ATC Process

March 2004

5

Example of bolted liner

The Ball mill / ATC Process

March 2004

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Effect of delayed mill maintenance Replacing

worn out liners in a cement mill

–increase of the mill output +15% –decrease of the electricity consumption Delayed

replacement of lifting liners (