Magnetic desulfurization of coal

This work is probably the first systematic attempt at using high gradient magnetic separation techniques in coal slurries. The rationale for magnetic desulfurization of coal resides in the paramagnetism of pyrites and their liberation from the coal substance. Principles of magnetic separation are discussed. A model based on the balance of forces acting on a particle in the vicinity of a magnetized strand is developed. The experimental separator consisted of a laboratory column, packed with either steel wool or screens, inserted in the bore of a solenoid magnet. Experimental results, confirmed the effects of coal particle size and slurry velocity as predicted by the model. Evidence of magnetic action was obtained from the magnetization curves of the coal minerals in the products of separation. Preliminary economic analysis shows promise for the commercial application of the process. Directions for future research are indicated.