New process removes impurities from coal.

A process for cleaning coal that improves its quality and recovers 10% more of the energy-producing mineral than current methods has been developed by scientists from Southern Illinois University. It combines three commercially available technologies in a single, integrated process to separate pyritic sulfur and other impurities from raw coal. The resulting coal produces less ash and sulfur by-products while yielding a higher energy output. Coal-fired power plants supply more of the nation's electric power--about 55%--than any other source. Cleaner coal helps power plants meet sulfur dioxide emission standards required by the Clean Air Act Amendments of 1990.

The new process begins with tailings from a preparation plant. Coal is fed into a hydrosizer, which uses a stream of water to isolate and remove...