My Account: Log In | Join | Renew
Search
Author
Title
Vol.
Issue
Year
1st Page

Abstract

 

This article in SSSAJ

  1. Vol. 50 No. 6, p. 1633-1639
     
    Received: Feb 3, 1986
    Published: Nov, 1986


 View
 Download
 Alerts
 Permissions
 Share

doi:10.2136/sssaj1986.03615995005000060049x

Concentration of Iron Oxides from Soil Clays by Density Gradient Centrifugation1

  1. W. F. Jaynes and
  2. J. M. Bigham2

Abstract

Abstract

High speed centrifugation with a large-scale zonal rotor and a linear, tetrabromoethane-ethanol density gradient (1.0–2.8 Mg m−3) was utilized to fractionate the <0.2µm clay materials from three soils with differing Fe-oxide mineralogy. Hematite, goethite, and lepidocrocite were concentrated 4- to 10-fold in the high density range (>2.4 Mg m−3) while the low density fractions (<2.2 Mg m−3) were depleted in reductant-soluble Fe. Density gradient centrifugation also produced useful mineralogical separations of the soil phyllosilicates. In particular, smectite was concentrated in the 1.8 to 2.1 Mg m−3 density range whereas the 2.1 to 2.3 Mg m−3 density range was enriched with kaolinite, vermiculite, and clay mica. Electron microscopy and x-ray diffraction analyses indicated that Fe-oxides were present in the materials studied as discrete particles rather than as “coatings” on associated minerals.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © . Soil Science Society of America