This paper presents a laboratory procedure to concentrate epidote from fragments associated with country rocks of the scheelite mineralization in the Borborema Province (Rio Grande do Norte, Brazil). A block weighting 17.5 kg was crushed and classified in grain sizes ranging from 150 to 600 µm. The concentration was carried out in a shaking table followed by four cycles of magnetic separation using a Frantz isodynamic separator with currents ranging from 0.5 and 0.6 A (0.5 to 0.6 T). The mineralogical characterization of the pre-concentrate and the fractions resultant from magnetic separation were carried out by X-ray powder diffractometry and X-ray fluorescence spectrometry. The separation of the epidote allowed close to 75% epidote for the 150x300 µm size class. The fraction with the highest magnetic susceptibility in the mineral assemblage was mainly composed of andradite. Calcite, andradite and quartz were found to be the contaminants within the concentrate.
Epidote; tactite; magnetic separation; andradite; X-ray powder diffractometry
