The proportion of the water-soluble fraction decreased to 13% when 5% FeSO4 was added, which decreased to 0% when 10% FeSO4 was added. In the experiment performed with 10% FeSO4, Cr was intensely bonded to Fe/Mn oxide (66.26%), followed by organic matter (25.05%) and carbonate (7.00%...
The chemical composition shows 0.76% total copper, 0.67% soluble copper, 0.46% manganese, 0.1% magnesium, 0.62% calcium, 0.21% aluminum, and 5.37% iron. X-ray diffraction using a Bruker D8 Advance X-ray diffractometer (XRD; Bruker, Billerica, MA, USA) determined the primary mineralogical ...