The SEFA Group has developed a new thermal beneficiation process – Staged Turbulent Air Reactor (STAR®) – and is currently operating a commercial STAR®Plant that is specifically designed and operated to reduce the heterogeneity of fly ash by eliminating or lowering the amount of unburned carbon and other contaminants, including unburned organics from alternative fuels. The STAR® Plant operates at temperatures that are high enough to burn off residual organics comingled in the fly ash, including coal char particles. The STAR® Plant can also be operated to reduce some types of agglomerates, improving particle size distribution, as well as to blend various coal fly ashes in order to reduce variations in ash chemistry or to optimize the performance of coal ash for particular ash utilization opportunities/markets.
STAR® processing can be used by coal fired power plants to reduce the need for expensive disposal operations. The STAR® Plant processes bituminous coal fly ash, sub-bituminous coal fly ash and various blends of bituminous and sub-bituminous coal fly ashes. As a by-product of commercial STAR® Plant operation, a significant amount of excess heat is available for a variety of uses, both internal to the process as well as to outside energy consumers.
The STAR® Plant can be operated to simultaneously collect two separate streams of product fly ash, each of which has slightly different chemical and physical characteristics.
One stream can be processed in such a way as to perform some size classification of the fly ash, tailoring it to the expectations and/or requirements of particular markets, especially high-value mineral filler markets. This product stream will also reduce or remove many contaminants (e.g., mercury), further enhancing its value in certain consumer products and some manufacturing processes, especially high-temperature processes.
The other product stream captures higher concentrations of these contaminants. The STAR®-processed fly ash from this stream is used in products, such as concrete, that do not restrict the presence of these contaminants and which will serve to reduce their potential toxicity and/or sequester them, as in the case of mercury, for example, through entombment in the cementious paste matrix of concrete products.
Our goal is to increase the quality and, therefore, the value of fly ash that is currently used in the commercial marketplace – for example, as STAR® Refined Pozzolan – and to develop new markets beyond the traditional concrete industry, which take advantage of the unique characteristics of the purified mineral matter.