Iron Oxide Mineralogy of Asnawa Soils, Sulaimani Province, Kurdistan region

Volume 17 , Issue 2 , June 2015 , Pages 105-118

Authors

¹ Department of Soil Science, College of Agriculture, Salahaddin University, KRG,

Forty soil samples from three different zones (A, B and C) in Asnawa area were

studied to identify and characterize the forms of Fe oxides in the <2 mm soil fractions

using chemical extractions and XRDA technique. Neither citrate dithionite nor aqua

regia solution were not effective enough to extract free Fe oxides in the soil samples. The

maximum amounts of Fe oxides obtained were when five successive treatments with

aqua regia solution had done. Soils of the quarry area (zone A) contained the highest

amount of Fe oxides followed by soils from zone B and C. They were ranged from

52.1%, 38.6% and 15.1% respectively. XRD traces of the studied soils showed peaks

characteristics of magnetite at 0.297, 0.256, 0.210, 0.161 and 0.147 nm. Other peaks of

hematite at 0.271 nm, and wustite (Fe(1-X)O at 0.88 were also present. Diffraction peaks

of magnetite after a single treatment with citrate dithionite and aqua regia were still

evident on the X-ray chart whereas the diffraction peaks of hematite and wustite were

disappeared.

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