Quality Assured Coal Combustion By-Products: Part 2. Carbon Flotation

摘要

Quality control and quality assurance of coal combustion by-products (CCB) are becoming more important in the utilization business as a result of the increased use of NO_X reduction technologies at coal-fired power plants. NO_X reduction technologies typically result in increased levels of unburned carbon (UBC) and other chemical residuals in the fly ash. Electrical utilities, academia, independent researchers, and the coal ash recycling industry have responded to the increase in unburned carbon content in a variety of ways, including beneficiation technologies. Some of these technologies allow for the production of quality assured CCB products for the pozzolan market and other value added applications such as industrial fillers.rnThis paper is a part of a series1 which is intended to address approaches and technologies available to assure and control the quality of marketable fly ash, including: analytical methods and characterization procedures for fly ash quality assurance; challenges of high value-added applications; and specific beneficiation technologies (e.g., electrostatic separation and carbon flotation). This paper will focus on fly ash beneficiation using carbon flotation with emphasis on new findings and process improvements that help assure product quality. With proper control of the complexities of the process chemistry and phenomena governing the system, carbon flotation is considered to be most robust among the available ash beneficiation technologies.