Applied mineralogy of zirconium minerals: a case study of alkaline intrusion in SE-Brazil

Abstract Brazil has important zirconium resources when compared with other countries. However, most of the zirconium production in Brazil occurs as coproduct of the mining and processing of heavy mineral sands for the titanium minerals. This paper reports mineral and technological characterization studies associated with an alkaline intrusion in SE-Brazil. The data were obtained in a complex local rock known as “caldasite,” probably formed during hydrothermal alteration associated with post-magmatic events. The results obtained by multi-element analysis and X-ray diffraction analysis, petrography and scanning electronic microscopy indicated that zirconium concentration is about 66 wt%, having zircon and baddeleyite as most relevant minerals; gibbsite and anatase are found in minor proportions. The mineral assemblage developed a complex rock texture and structure associated with hydrothermal fluids percolation indicated by remobilization of zirconium in primary rocks. Caldasite presented concentric growth banding texture, revealed by zircon nucleation and baddeleyite microcrystalline interlaying. Results obtained indicate that caldasite has a high potential as zirconium resource due to concentration and mineral associations. Article Highlights This paper focused on the results of several techniques of mineralogical and technological characterization applied in an enriched-zirconium rock formed during hydrothermal alteration in alkaline intrusion in SE-Brazil. The results showed the rock is found in veins and has a mineral assemblage of zirconium, baddeleyite, gibbsite and anatase presented in a concentric growth banding texture. ZrO2 content is about 66% and preliminary results indicated the rock has a high potential for industry application.