Technological characterization of kaolin: Study of the case of the Borborema–Seridó region (Brazil)

The technological characterization of kaolin from the Borborema–Seridó region has shown that it is predominantly kaolinitic, pseudoplastic and thixotropic; approximately 50% of its particles size is less than 2 μm. By using electronic paramagnetic resonance (EPR) and Mössbauer spectroscopy (ME), it was observed that Fe2+ and Fe3+ substitute Al3+ in octahedral sites of kaolinite. After magnetic separation followed by chemical bleaching, kaolin reached a brightness index of 87.72% ISO and an opacity index of 85.58% ISO, indicating that it can be used mainly as a filler and a coating in the paper industry, paint and pottery, among other industries.