One-pot hydrothermal synthesis of micaceous iron oxide pigment from jarosite waste
In an actual study, jarosite waste was adopted as feed material for micaceous iron oxide (MIO) pigment preparation by a one-pot hydrothermal reaction.
The formation of MIO started from jarosite decomposition into akaganeite (β-FeOOH) nanoparticles in alkali solution, which then recrystallised and transformed into MIO crystals under high temperature and OH− concentration.
Increasing the NaOH concentration or reaction temperature led to increased MIO particle size
The influences of NaOH concentration and reaction temperature on MIO formation were investigated. It was found that MIO formed when NaOH concentration and reaction temperature were equal to or higher than 2 M and 180°C, respectively. With an increase of NaOH concentration or reaction temperature, the particle size of MIO increased, leading to darkened color of the product.
Moreover, quality evaluation indicated that the synthesised MIO fulfilled the required characteristics of micaceous iron oxide pigments for paints and the international standard of ISO 10601-2007 MIO-A1.
The study has been published in Journal of Coatings Technology and Research, January 2019, Volume 16.
Image source: Pixabay.
