Caracterização mineralógica e beneficiamento do caulim de Equador (RN) e Junco do Seridó (PB) visando a elevação de índice de alvura

Caulim is the rock constituted mainly by kaolinite. It is used principally in the industries of paper and ceramic. In some places, as well Junco do Serido (PB) and Equador (RN), the kaolin is still explored in rudimentary way due plants of beneficiament fewer efficient and insufficient studies about the ore. The goal of the study was the mineralogical and technological characterization of the kaolin of these regions aiming 52 2016 - XXIV – Jornada de Iniciacao Cientifica-CETEM the elevation of whiteness index. Two samples of Equador (RN) and one of Junco do Serido (PB) were submitted to granulometric classification in wet conditions in sieves of 44 µm, magnetic separation in field of 14000 Gauss and chemical bleaching with sodium dithionite. The resultant fractions were studied by X ray diffractometric, chemical analysis by X ray fluorescence, granulometric analysis, scanning electron microscopy and determination of whiteness index. The three samples are composed by kaolinite, muscovite, quartz and feldspar. The two samples of Equador (RN) and one of Junco do Serido (PB) showed yields of 61.28, 21.96 and 19.49%. The magnetic separation was responsible for increases of 78.2 to 78.5% and 91.3 to 92.5% in the whiteness index of the samples of Equador (RN) and for the non-alteration of 86.9% of the sample of Junco do Serido (PB). The 30 initial minutes of chemical bleaching were responsible for the largest elevations of 78.5 to 90.9%, 92.5 to 93.8% and 86.9 to 88.4%, respectively. These results indicate it is possible to remove part of the iron oxides and hydroxides by magnetic separation and chemical bleaching promoting increases in the whiteness index of kaolin, though there are differences in the efficiency of them.