Commercialization of the motorless-rotorless flotation cell
With Illinois Clean Coal Institute funding, the ISGS developed and demonstrated a proof-of-concept, lab-scale model of a motorless-rotorless froth flotation cell (MRC) in 2003. The invention was disclosed to the University of Illinois in March 2003, and an updated disclosure was filed in April 2004 in conjunction with a new company, Dynamic Separations, Incorporated (DSI), purchasing an exclusive license to the technology. Because the MRC does not contain any rotors, froth-scrapers and electric motors to drive these components, it consumes much less energy than conventional flotation cells. It also has a higher throughput rate than ordinary froth flotation cells. Work is ongoing to study the impact of different physical features and device configurations for the MRC, its operational parameters, and the effect of feed characteristics on the device’s ability to produce a marketable product. As part of that work, two successful field demonstrations were completed in 2005.
At present, the MRC consists of a 1,000-gallon cell with sixteen 1½-inch feed eductors. A 75 horsepower centrifugal pump capable of 1,000 gallons per minute at 60 pounds per square inch delivers feed slurry to the cell. Air and a frother agent are injected into the feed slurry upstream of four static mixers generating small air bubbles for capturing coal particles conditioned with diesel fuel. Further mixing occurs within the cell as slurry is circulated by the venturi-like action of the eductors.
In the first demonstration at the preparation plant of an active coal mine, the underflow from sieve bends dewatering the plant’s polishing cyclone product was tested in the MRC. Despite poor feed characteristics (19% solids, 28% -325-mesh, 39.38% ash, 6.65% sulfur), testing determined that the 1,000-gallon MRC performed at 95% of optimum as defined by flotation release analyses of the feed material. Best case results indicated that the MRC produced a 12,188 Btu/lb product with 13.19% ash and 6.09% sulfur at a yield of 62.2% and a recovery of 83.5%. This compares favorably with the 10,600 Btu/lb, 8.5% ash, 3.5% sulfur product currently marketed by the mine. The second demonstration is an ongoing commercial venture at a carbon recovery operation where fines are being dredged from an old slurry impoundment, processed in the MRC, and sold on the spot market.
An interim report of this project is available by clicking on the link below:
Pathway to Commercialization of the Motorless Rotorless Cell
