Development of high-gradient and open-gradient magnet separation of dry fine coal

High gradient magnetic separation of pyritic sulfur and ash forming minerals from dry, fine coal has been developed on a laboratory scale and demonstrated at commercial scale. Similarly, open gradient magnetic separation of dry, fine coal has been demonstrated on a laboratory scale and extrapolated to 300 kg per hour in a solenoidal configuration magnet. A modeling technique has been developed to analyze magnet design, separating forces, and particle trajectories, and has been experimentally verified. Practical magnet designs have been shown which can exert separating forces several times those in existing magnets and in large processing volumes.