FERROMAGNETIC PROPERTIES OF PYRITE FROM THE SOUTHERN BRAZIL COAL MINING INDUSTRY AT DIFERENT HEATING TEMPERATURES

摘要

The Southern of Santa Catarina State is the leading coal producer at Brazil. In The region of Criciuma city are the more importantcoal mine industries representing a great amount of the Brazil coal production. Years of coal mining were extremely detrimental forthe environment at this region. Acid Mine drainage (AMD) is still a problem and the coal mine industries are doing treatment systemsfor this dangerous effluent. The AMD behavior in the nature is well known and at the southern Santa Catarina region are a lot ofproblems with it; the pyrite oxidation from the coal mining produces 1m~3 of AMD for each ton of coal mined (ROM). The LMPP(Materials laboratory of Universidade do Extremo Sul Catarinense) had developed new ways for the pyrite use as a material. Thisstudy was done with a sample of pyrite from the coal mining industry. The characterization took place with chemical andmineralogical analysis (XRF and XRD) and the determination of magnetic properties of the “In Natura” samples and the samples thatwere heated at several temperatures in a reactor under controlled atmosphere (with N_2 – 50 cm~3min). The objective of the thermaltreatment was the production of a ferromagnetic phase from the In Natura pyrite sample, the reaction studied was the loss of sulfurunder controlled atmosphere conditions at a reactor. The results showed temperatures around 550 °C for the first ferromagneticproperties for this reaction. The LMPP Laboratory is now studying the possibility to use this material in other industries at the region.Acknowledgments: Carbonífera Criciúma, Centro de Tecnologia Mineral – CETEM, FINEP.