Publication detail

Preparation of metakaolin with high whiteness

KOTRLA, J. BOJANOVSKÝ, J. OPRAVIL, T. HRUBÝ, P.

Original Title

Preparation of metakaolin with high whiteness

Type

abstract

Language

English

Original Abstract

The term kaolin is used to describe white clays whose main mineral is kaolinite Al2Si2O5(OH)4. Kaolinite is formed by the decomposition of various of feldspars and therefore is usually doped with other minerals (quartz, sulphur, feldspars, micas and iron and titanium oxides). The quality of the clays and over all kaolin is measured in function of iron content, because this element gives the red-brown colour to this type of minerals. This paper summarizes the various possibilities of kaolin bleaching by firing. Kaolin of 20 grams dosage was fired at 1 100 °C for 2 hours. Several types of reducing agents (spar, specially ground quartz (SGQ), alumina and a mixture of graphite and sodium chloride) were used during firing with a goal to reduce the present iron 3+ to less colouring state of Fe2+ thus increase the whiteness of kaolin. It was found that the best effect on increasing the whiteness of kaolin has the firing of the raw material itself. Reducing agents were added in weight rations of 1, 3 and 5 % and have been able to partially increase the whiteness in some cases, but this is an increase of units of percent. Subsequently, the reduction mixture was selected and used for firing in a sintering furnace. The whiteness of kaolin obtained in sintering furnace was not sufficient. The low efficiency of the sintering furnace was mainly due to unsuitable furnace setting.

Keywords

bleaching clay, kaolin, sintering furnace, reducing agent

Authors

KOTRLA, J.; BOJANOVSKÝ, J.; OPRAVIL, T.; HRUBÝ, P.

Released

27. 11. 2020

Publisher

Vysoké učení technické v Brně, Fakulta chemická, Purkyňova 464/118, Brno 612 00

Location

Brno

ISBN

978-80-214-5920-0

Book

Studentská odborná konference - CHEMIE JE ŽIVOT - sborník abstraktů

Edition number

1

Pages from

88

Pages to

89

Pages count

1

URL

https://www.fch.vut.cz/vav/konference/sok/vystupy/sbornik-abstrakty-konference-2020-pdf-p198641?fbclid=IwAR3v2HmV5tOg975FBenm5j2cH6IBJqXzKK5oyXpeLZHImePoTYc7o3ecAws

BibTex

@misc{BUT169257,
  author="Jan {Kotrla} and Jiří {Bojanovský} and Tomáš {Opravil} and Petr {Hrubý}",
  title="Preparation of metakaolin with high whiteness",
  booktitle="Studentská odborná konference - CHEMIE JE ŽIVOT - sborník abstraktů",
  year="2020",
  edition="1",
  pages="88--89",
  publisher="Vysoké učení technické v Brně, Fakulta chemická, Purkyňova 464/118, Brno 612 00",
  address="Brno",
  isbn="978-80-214-5920-0",
  url="https://www.fch.vut.cz/vav/konference/sok/vystupy/sbornik-abstrakty-konference-2020-pdf-p198641?fbclid=IwAR3v2HmV5tOg975FBenm5j2cH6IBJqXzKK5oyXpeLZHImePoTYc7o3ecAws",
  note="abstract"
}