Carbon removal through partial carbon burn-out from coal ash used in concrete

Abstract From the Canadian patent

Concrete's durability to freeze-thaw cycles is dependent on its level of air entrainment the appropriate level of which is achieved with the aid of surface active or air entraining agents. These agents promote the fragmentation of large air voids into smaller ones and stabilize air voids in the concrete. The carbon matter found in fly ash when used as a pozzolanic component of concrete adsorbs the air entraining agents, reduces the air voids and concrete's ability to withstand many freeze- thaw cycles. This invention teaches a process for a partial removal of the carbon from the coal ash used in concrete, through a partial combustion of only a fine carbon fraction of the carbon residue of …