Química Nova (Jan 2011)

Alvejamento químico de caulins Brasileiros: efeito do potencial eletroquímico da polpa e do ajuste do pH

  • Fernanda Arruda Nogueira Gomes da Silva,
  • Francisco Manoel dos Santos Garrido,
  • Marta Eloísa Medeiros,
  • João Alves Sampaio,
  • Adão Benvindo da Luz,
  • Lívia da Silva Mello,
  • Flávio Teixeira da Silva

DOI
https://doi.org/10.1590/S0100-40422011000200017
Journal volume & issue
Vol. 34, no. 2
pp. 262 – 267

Abstract

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Samples of Kaolin from different regions in Brazil were characterized by XRD, SEM and chemical analysis. A chemical bleaching study with pH adjustment was accomplished with the fractions below 37 μm, after classification by screening. The main objective was to evaluate the conditions of chemical bleaching that most increase the brightness of these kaolin's samples. Increases between 2.63 and 2.98% in the brightness (ISO) were observed after the chemical bleaching. We could say that the reduction of Fe3+ to Fe2+ during the chemical bleaching promoted an increase in the brightness, based on the Pourbaix Diagrams.

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