Carbon scavenger fly ash pretreatment method

Abstract

A method for pretreatment of a quantity of fly ash for use in a cementitious composition containing an air entrainment agent. An effective amount of an aromatic carboxylic acid or its salts is added to the fly ash to satiate unburned carbon in the ash. The treatment with the aromatic carboxylic acid (or hydroxy substituted aromatic carboxylic acid or its salts) does not significantly promote or retard the air entrainment functions of the air entrainment agent.

1 . A method for pretreating fly ash for use in cementitious compositions containing an air entrainment agent comprising the steps of: 
 applying an effective amount of benzoic acid to a quantity of fly ash to satiate unburned carbon in said ash without effecting the air entrainment functions of said air entrainment agent.    
     
     
         2 . A method for pretreating fly ash for use in cementitious compositions containing an air entrainment agent comprising the steps of: 
 applying an effective amount of salicylic acid to a quantity of fly ash to satiate unburned carbon in said ash without effecting the air entrainment functions of said air entrainment agent.    
     
     
         3 . The method of  claim 1  wherein said amount of benzoic acid is in the range of about 0.01 g to about 100 g for each 100 g of said fly ash.  
     
     
         4 . The method of claim I wherein said amount of salicylic acid is in the range of about 0.01 g to about 100 g for each 100 g of said fly ash.  
     
     
         5 . A method for pretreating fly ash for use in cementitious compositions containing an air entrainment agent comprising the steps of: 
 applying an effective amount of lithium salicylate to a quantity of fly ash to satiate unburned carbon in said ash without effecting the air entrainment functions of said air entrainment agent, said effective amount of lithium salicylate is about 0.07 g for each 100 g of said fly ash.