Skip to main content

The effect of clay minerals on the formation of goethite and hematite from ferrihydrite after 16 years' ageing at 25°C and pH 4-7

Buy Article:

$12.42 plus tax (Refund Policy)

In soils and other weathering environments, hematite and goethite are usually formed in the presence of clay minerals. Two-line ferrihydrite was aged in the presence of six different clay minerals in aqueous suspension at 25°C and pH 4, 5, 6 and 7 for 16 years. The transformation into hematite/goethite mixtures was complete in the systems with gibbsite, kaolinite, illite and smectite, but incomplete in those with soil smectite and allophane. Soil smectite and allophane, as well as increasing pH, favoured hematite over goethite. The grainy and multi-domainic hematite crystals in the allophane system contained Si and Al (EDX) and showed a Si-O vibration at ~920 cm-1 (FTIR). The unit-cell contraction due to structural Al was counteracted by structural OH, which was removed at 200°C. Heating also increased the magnetic hyperfine field at RT by 1.2-1.6 T. Hematite crystals with irregular shape and grainy interior have also been observed in soils.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Data/Media
No Metrics

Keywords: GOETHITE; HEMATITE; ILLITE; KAOLINITE; SMECTITE; SOIL; WEATHERING

Document Type: Research Article

Publication date: 2000-09-01

More about this publication?
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
UA-1313315-23
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more