This Small Business Innovation Research (SBIR) Phase I project will develop inexpensive methods to pretreat commercial powdered activated carbons (PAC) used for power plant mercury control so that they will not interfere with effective use of fly ash in concretes. The objective of this project is to screen and optimize such pretreatment methods. Major project tasks include producing pretreated samples; testing for effects on AEAs, resulting cements, and mercury removal performance; and developing a fundamental understanding of the chemical processes involved. Carbon materials researchers at Brown University and their Energy and Environmental Technologies Laboratory will assist in the effort. Commercially the substitution of fly ash wastes for cement in construction applications is one of America.s biggest recycling successes. Unfortunately, it was recently discovered that if even minimal PAC is injected into power plant flue gases for mercury emission control, the fly ash will be rendered unusable for concrete. The highly-adsorbent carbons severely interfere with the air-entraining admixtures (AEAs) added to concrete for air entrainment and stabilization. The economic implications for utilities may be huge. Thus the PAC pretreatments developed here which minimize adverse effects on AEA while enhancing, or at least not degrading, PAC mercury removal performance are of prime importance.
