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      Production vs Blaine and Specific energy vs Residue        
                           
      1 Introduction:                
        - Various formulas have been developed to predict the new output of a cement or raw mill when the Blaine
          fineness or the residue of reference is increased or decreased.        
        - These formulas can be considered relatively reliable for reasonable changes of fineness target.  
          On the contrary, if the new Blaine fineness or the new residue of reference is very different, laboratory 
          tests are required to have an answer which is close to the reality.      
        - Here below, some formulas used in the cement industry to predict the mill's output vs Blaine or residue.
        - This list is not exhaustive.            
      2 Production vs Blaine:              
      2.1   First formula:              
         
     
                 
                       
                       
        - Example:                
          Current output (P1): 65t/h            
          Current Blaine (B1): 3000 cm2/gr            
          New Blaine (B2): 3200 Blaine            
          New output:              
         
     
             
                   
                   
         - In another form:              
         
     
               
                     
                     
        - Example:                
          Current output (P1): 65t/h            
          Current Blaine (B1): 3000 cm2/gr            
          New Blaine (B2): 3200 Blaine            
          New output:              
         
     
             
                   
                   
      2.2   Second formula:              
         
     
                 
                       
                       
        - Example:                
          Current output (P1): 65t/h            
          Current Blaine (B1): 3000 cm2/gr            
          New Blaine (B2): 3200 Blaine            
          New output:              
         
     
             
                   
                   
        - This formula is well accepted between 2700 and 3200 Blaine.        
     
      2.3   Third formula:              
         
     
                 
                       
                       
        - Example:                
          Current output (P1): 65t/h            
          Current Blaine (B1): 3500 cm2/gr            
          New Blaine (B2): 4000 Blaine            
          New output:              
         
     
             
                   
                   
        - This formula is well accepted for Blaine figures higher than 3200cm2/gr.      
        Note: Second and third formulas are also used to define the new production with a conventional separator 
        or a high efficiency separator:            
          Exponent 1,3: high efficiency separator          
          Exponent 1,6: Conventional separator            
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      3 Production vs Residue:              
         
     
               
                     
                     
        - Example:                
          Current output (P1): 65 t/h            
          Current Residue (R1): 3,5%            
          New Residue (R2): 2%              
                           
          New output:              
         
     
             
                   
                   
      4 Specific energy vs Residue (Bond):            
        - Bond Formula:               
         
     
               
                     
                     
          Where E is the specific energy in kWh/t,          
          Wi is the work index              
          P80 is the size for 80% of passing of the product and          
          F80 is the size for 80% of passing of the feed          
        - Then we have:              
         
     
               
                     
                     
          and:                
         
     
               
                     
                     
          where:                
          E1 is the specific energy of the current situation in kWh/t,        
          P1 is the size for 80% of passing of the product of the current situation in µm,      
          E2 is the specific energy of the new situation in kWh/t and        
          P2 is the size for 80% of passing of the product of the new situation in µm      
        - F80 is considered to be constant            
        - In function of E1, P1 and P2 known, find E2:          
         
     
               
                     
                     
                     
                     
        - Example:                
          Current specific power (E1): 30 kWh/t t/h          
          Current P80 (P1): 30µm              
          Current and new F80: 10mm or 10000µm          
          New P80 (P2): 20µm              
         
     
             
                   
                   
                   
                   
          Warning:                
          These methods give an initial and rough idea of the new specific power consumption in function of the   
          new fineness target, but shoud be followed by laboratory tests or/and real tests.    
                           
               
     
         
          A calculator is available here:      
                     
                     
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