BACKGROUNDMetal activity state measurement method is one of the effective means to find hidden ore. However, during the application of the method, it was found that the types of effective activity states of gold in different geochemical landscape conditions were not the same. Moreover, it was found that the conditions such as solid-liquid ratio, temperature and time during the extraction would have a significant impact on the active state extraction data.

OBJECTIVESTo solve the problems of selective extraction and accurate determination of the active state of gold.

METHODSA comparative study of different experimental conditions and samples of different grain sizes for the active state extraction of gold from the Wangjiaping gold deposit in the Qinling area using ICP-MS analysis.

RESULTSThe optimal extraction conditions for gold element water extraction state, clay adsorption state, organic binding state and iron manganese oxide state were determined. Solid-liquid ratio was 1:5, the extraction time was 24h, the extraction temperature was 35℃ and the sample size range was -80 mesh. The method detection limits for the four phase states of elemental gold were 0.03ng/g for water extraction state 0.03ng/g for clay adsorption state, 0.04ng/g for organic binding state, 0.05ng/g for iron manganese oxide state. The relative standard deviation (RSD) was 7.25%-9.02%. In the 23rd line of the Wangjiaping gold deposit, the average content of the water extracted state gold was 0.19×10^-9, the average clay adsorption state gold was 0.30×10^-9, the average organic binding state gold was 11.16×10^-9, and the average iron manganese oxide state gold was 0.20×10^-9.

CONCLUSIONSThe organic binding state is the main active phase state of gold in the soil of the mining area, and the abnormality of the organic binding state of gold is consistent with the position of the hidden gold ore body.