Production of inorganic pellet binders from fly-ash. Technical report, March 1--May 31, 1995

Fly-ash is produced by all coal-fired utilities, and it must be removed from the plant exhaust gases, collected, and disposed of. While much work has been done in the past to utilize fly-ash rather than disposing of it, we nevertheless do not find widespread examples of successful industrial utilization. This is because past work has tended to find uses only for high-quality, easily-utilized fly-ashes, which account for less than 25% of the fly-ash that is produced. The main factor which makes fly-ashes unusable is a high unburned carbon content. In this project, physical separation technologies are being used to remove this carbon, and to convert these unusable fly-ashes into usable products. The main application being studied for the processed fly-ash is as a binder for inorganic materials, such as iron-ore pellets. In the second quarter, additional fly-ash samples were collected from the E. D. Edwards station (Bartonville, IL). Experimentation was begun to study the removal of carbon from these fly-ashes by froth flotation, and make and test pellets that use fly-ash as binder. During the current quarter, flotation experiments were continued on the fly- ashes. Three types of ashes were studied: 1. Ash from the disposal pond (``wet`` ash); 2. Dry fly-ash collected directly from the standard burners (``low-carbon`` ash); 3. Dry fly-ash collected from the low-NOx burners (``high-carbon`` ash). Each of these was chemically analyzed, and conventional flotation experiments were carried out to determine the optimum reagent dosages for carbon removal. Decarbonized ashes were then made from each ash type, in sufficient quantity to be used in pelletization experiments