The Magnetizing Roasting of Pyrite Bearing Concentrates

This research investigates the processing of pyrite concentrates through a preliminary enrichment step that involves magnetic separation to remove iron sulfides. The conversion of non-magnetic pyrite to magnetic pyrrhotites is achieved via roasting, which removes a portion of sulfur, resulting in ferromagnetic pyrrhotites with hexagonal structure. The study examines the magnetic properties of the pyrrhotites and their behavior upon decomposition of the initial pyrite, alongside the homogenization of the product and its hardening in liquid nitrogen. The research identifies the relationship between sulfur content and the magnetic properties of the pyrrhotites, noting a transition from ferromagnetic to antiferromagnetic characteristics, and also assesses the influence of various roasting conditions. Techniques such as chemical, thermogravimetric, Mössbauer spectroscopy, and X-ray analysis were employed to characterize the materials. The results indicate that the magnetic susceptibility of the products is dependent on the degree of pyrite dissociation, achieving peak values suitable for magnetic separation. This technology is poised for application in industrial settings, facilitating efficient separation of ferromagnetic pyrrhotites from gangue minerals.