Extraction and Determination Methods for Mobile Forms of Precious Metals in Soil Samples

The extraction techniques and determination methods for the mobile forms of platinum, palladium and gold in soil samples are developed. The detection limits for precious metals in soil samples were 0.03 ng/g for Pt, 0.01 ng/g for Pd and Au in mobile forms of water extractable, clay absorbed and exchangeable, organic phase and Fe-Mn oxides bonded metals. The stability of trace platinum, palladium and gold with various mobile forms in a variety of extraction media was tested. And the solid-liquid separation methods, the effect of extraction temperature on the precious metal extraction, as well as the treatment of the extractants were also tested. The method was successfully applied to the identification of buried platinum and palladium deposits in South Africa with satisfactory results and will provide guidance in searching for hidden mineral deposits.