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  Ball Charges Composition
  (For cement mills with 3 chambers)          
                 
  Date           No separator
  Company     First generation
  Cement plant     Second generation
  Mill N°           Third generation
                 
  Type of circuit  
      Open  
  Kind of separator  
    Closed  
                 
  Mill diameter   m        
  Mill length   m       Clinker
  L/D ratio           White clinker
  Speed   rpm       Alumina clinker
  Critical speed   rpm       Gypsum
  % of the critical speed   %       Anhydrite
                Limestone
  Cement type (1)       Pozzolana
  (1) If various cements are produced, choose the cement with the highest output (t/h) rate or the cement the most  Trass
  important or having the highest production (tons/year) rate.     Slag
  Total mill's output   t/h       Fly ash
  Composition of the alimentation: Percentage:   Moisture:     Limestone filler
 
  % %
 
  % %
 
  % %
 
  % %
 
  % %
  Total   % %    
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  Real mill's output (2)   t/h        
  (2) It is the total output less the fly ash/limestone filler fraction      
  (2) We consider that fly ash and limestone filler don't need to be crushed in the 1st chamber and/or are directly
  introduced after the mill              
  Granulometry fresh feed (3):      
     
  Residue cumulated on 20mm   %   20  
  Residue cumulated on 8mm   %   8  
  Residue cumulated on 4mm   %   4  
  Residue cumulated on 2,5mm   %   2,5  
  (3) Total fresh feed (all the componants)          
  (3) Granulometry after pre-grinding system if it exists!        
  Clinker hardness (4)   cm        
  (4) Hardness of reference is Slegten hardness which is probably the most well-known and used in the world. To know 
  better about this test, go to: http://www.thecementgrindingoffice.com/hardness.html  
  (4) Typical values of the Slegten hardness test:          
 
         
           
           
           
           
           
  (4) A majority of clinkers has a hardness around 120        
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  Chamber 1:              
  Useful length   m        
  Kind of lifting lining  
         
  Average thickness of lining   mm   Weak  
  Volume load   %   Normal  
  Tonnage of balls   t   Agressive  
  Absorbed power of chamber 1   kW      
  Specific power consumption (5)   kWh/t        
  (5) The specific power consumption is generally comprised between 9 and 12 kWh/t. If there is a pre-grinding system,
  this value can be reduced. For white cement, a value close to 8 kWh/t is widely accepted. At the contrary, the value
  must be close to 12 kWh/t for alumina cement.      
  (5) The specific power consumption is calculated with the real mill's output (without fly ash and/or limestone filler)
  Composition of the charge of chamber 1:          
  Accept ball with 100mm diameter
         
  Accept ball with 60mm diameter
  Yes      
  Accept ball with 50mm diameter
  No   Make-up  
  Diameter 100mm   t    or % %
  Diameter 90mm   t    or % %
  Diameter 80mm   t    or % %
  Diameter 70mm   t    or % %
  Diameter 60mm   t    or % %
  Diameter 50mm   t    or % %
  Total   t    or % %
                 
  Average weight   gr/ball        
  Balls number            
  Surface of the ball charge   m2        
  Surface by ton of balls   m2/t        
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  Chamber 2 (6):              
  Useful length   m        
  Average thickness of lining   mm      
  Volume load   %      
  Tonnage of balls   t        
  (6) The second chamber is like a barrage (dam).      
  (6) The second chamber allows to crushed the last big particles coming from chamber 1.    
  (6) The lining of this chamber can be a lifting lining or a simple plate without any effect.   
  (6) A classifying lining is useless because the chamber is too short.  
  (6) Balls of 50, 40 and 30mm are normally used.          
  Grinding media wear   gr/t        
  Mill running hours/year   h        
                 
  Composition of the charge of chamber 2:   Yes      
  Accept ball with 60mm diameter  
  No   Make-up  
  Diameter 60mm   t    or % %
  Diameter 50mm   t    or % %
  Diameter 40mm   t    or % %
  Diameter 30mm   t    or % %
  Total   t    or %  
                 
  Average weight   gr/ball        
  Balls number            
  Surface of the ball charge   m2        
  Surface by ton of balls   m2/t        
                 
  Similar composition in case of cylpebs:         Make-up  
  45 x 45 mm   t    or % %
  40 x 40 mm   t    or % %
  32 x 32 mm   t    or % %
  28 x 28 mm   t    or % %
  Total   t    or % %
                 
  Average weight   gr/cylpebs      
  Cylpebs number            
  Surface of the grinding charge   m2        
Surface by ton of cylpebs
m2/t
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  Chamber 3:              
  Useful length   m     Classifying  
  Type of lining  
      Not classifying  
  Average thickness of lining   mm      
  Volume load   %      
  Tonnage of balls   t      
                 
  Fineness at chamber 3 inlet   Blaine (cm2/gr)    
  Fineness at chamber 3 outlet   Blaine (cm2/gr)    
      0          
  Grinding media wear   gr/t        
  Mill running hours/year   h        
                 
  Composition of the charge of chamber 3:       Make-up  
  Diameter 30mm   t    or % %
  Diameter 25mm   t    or % %
  Diameter 20mm   t    or % %
  Diameter 17mm   t    or % %
  Diameter 15mm   t    or % %
  Total   t    or % %
                 
  Average weight   gr/ball        
  Balls number            
  Surface of the ball charge   m2        
  Surface by ton of balls   m2/t        
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  Similar composition in case of cylpebs (7):          
  (7) Only without classifying lining Make-up  
  24 x 24 mm   t    or % %
  20 x 20 mm   t    or % %
16 x 16 mm
t    or % %
  12 x 12 mm   t    or % %
  Total   t    or % %
                 
  Average weight   gr/cylpebs      
  Cylpebs number            
  Surface of the grinding charge   m2        
  Surface by ton of cylpebs   m2/t        
                 
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