Carbon black pellets and method of forming same

Abstract

A carbon black pellet comprising an inner core of de-aerated carbon black and an outer surrounding shell of an encapsulating material, the shell of the encapsulating material having an average thickness of from about 1% to about 10% of the average thickness of the pellet.

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       11 . A method of forming carbon black pellets comprising:
 de-aerating carbon black aggregates to form de-aerated carbon black;   introducing said de-aerated carbon black into a fluid-solids contactor;   introducing a particulate encapsulating material into said contactor; and   contacting said de-aerated carbon black with said encapsulating material for a period of time sufficient to form encapsulated carbon black pellets comprising an inner core of de-aerated carbon black and an outer surrounding shell of encapsulating material, wherein said shell has an average thickness of about 1% to about 10% of the average thickness of said pellet.   
   
   
       12 . The method of  claim 11 , wherein said contactor comprises a moving-bed system. 
   
   
       13 . The method of  claim 12 , wherein said moving-bed system comprises a rotary drum mixer. 
   
   
       14 . The method of  claim 11 , wherein said contactor comprises a fluidized bed system. 
   
   
       15 . The method of  claim 11 , wherein said particulate encapsulating material is introduced into said contactor in the form of a mist. 
   
   
       16 . The method of  claim 11 , wherein said encapsulating material comprises a single encapsulating agent. 
   
   
       17 . The method of  claim 11 , wherein said encapsulating material comprises multiple encapsulating agents. 
   
   
       18 . The method of  claim 11 , wherein said encapsulated carbon black pellets are removed from said contactor and cooled. 
   
   
       19 . The method of  claim 11 , wherein said carbon black pellets are generally spherical. 
   
   
       20 . The method of  claim 19 , wherein said spherical pellets have a diameter of from 125 to 2000 μm. 
   
   
       21 . The method of  claim 11 , wherein said carbon black aggregates are selected from the carbon black group consisting of I 2 N0 (ASTM D1510) in the 20 g/Kg to 1000 g/Kg range and OAN (ASTM D2414) in the 45 ml/100 g to 500 ml/100 g range. 
   
   
       22 . The method of  claim 11 , wherein said encapsulating material is selected from the group consisting of carbohydrates, lignin oxides, cellulose by-products, natural rubbers, synthetic rubbers, synthetic polymers, waxes, resins, rosins, and mixtures thereof. 
   
   
       23 . The method of  claim 11 , wherein said encapsulating material is present in said pellet at a maximum amount of 10 wt. % based on the total carbon black present in said pellet. 
   
   
       24 . The method of  claim 11 , wherein said encapsulating material in said shell comprises at least 30 wt. % of the total encapsulating material present in said pellet. 
   
   
       25 . The method of  claim 11 , wherein said encapsulating material in said shell comprises at least 90 wt. % of the total encapsulating material present in said pellet.