A method of producing enhanced coal combustion ash for use in pozzolanic applications or cement manufacture, in which the enhanced combustion ash has lower mercury content. A slurry is formed of the combustion ash and water and is subjected to froth flotation to form a mercury-enriched ash slurry and a mercury-depleted ash slurry. The product mercury-depleted ash slurry is isolated and may optionally be dried. The combustion ash may be pulverized prior to being used to form the slurry, reducing its mean particle size. The mercury-depleted combustion ash product has reduced levels of mercury and ammonia, and reduced particle size.