Magnetic recovery of sulphur from coal in Brasil

Magnetic recovery of pyritic sulphur and coal from mine rejects has been envisaged as a two-step sequence of processes. 1) A thermal decomposition of the mixture rich in pyrites at about 700°C which produces a magnetic pyrrhotite and liberates sulphur; 2) air transport of the solid product into a high-gradient magnetic separator to separate coal from the minerals. Analysis is made of results reported separately on the kinetics of thermal decomposition of pyrites, carried out in thermo-balance, and on the wet slurry magnetic processing of coals. A suggestion is made to pursue sulphur recovery from coal mine rejects by using a proposed all-dry fluidized bed process, after the previous effort of other authors on dry magnetic processing of pyrites mentioned in the literature. This suggestion is the principal aim of this work.