Recovery of coal from preparation plant effluents using a packed column
The feasibility of recovering coal from coal preparation plant waste (or effluent) streams at the pilot scale using the packed column flotation process is demonstrated. In Phase I of the project, a total of four effluent samples were tested at the bench scale with the objective of recovering low-ash, low-sulfur clean coal products that were, at a minimum, compatible with the quality of the clean coal produced by the preparation plants supplying the waste stream samples. Phase II of the project comprised demonstration of the technology at the pilot scale using a 4-in. I.D. {times} 20-ft tall column installed at the Applied Laboratory of the Illinois State Geological Survey. A large effluent sample was conducted, consisting of particle size distribution, proximate and complete analyses, and batch froth flotation testing. Ash, total and pyritic sulfur, and calorific value of the effluent sample were also determined. The effluent feed sample contained 50-55% ash and 2.2% total sulfur. Confirmatory tests were conducted at Michigan Technological University using a bench-scale packed column. A product containing 5.4% ash was obtained at 97.5% ash rejection and 71.8% combustible matter recovery. Changing the process operating parameters allowed the quality of the product to be controlled such that its ash content ranged between 6 and 10%, with combustible matter recoveries in the 71-77% range. Pilot testing was conducted using a test matrix designed to study the effects of primary variables (feed rate, percent solids, and reagent dosage) and operating variables (air rate, wash water, and pulp level) with the objective of optimizing the process performance. Feed rates of 20-108 lb/hour were tested, with very good performance being obtained at a feed rate of 32 lb/hour (374 lb/h/ft{sup 2}).
- OSTI ID:
- 45095
- Report Number(s):
- CONF-930413-; TRN: 95:003334-0022
- Resource Relation:
- Conference: 18. international technical conference on coal utilization and fuel systems, Clearwater, FL (United States), 26-29 Apr 1993; Other Information: PBD: 1993; Related Information: Is Part Of Proceedings of the 18th international technical conference on coal utilization & fuel systems; PB: 926 p.
- Country of Publication:
- United States
- Language:
- English
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