Micro-to nanoscale cobalt occurrence in Co-enriched pyrite:A case study from Dahenglu Cu-Co deposit
Pyrite is an important Co-bearing mineral.The Co content of Co-enriched pyrite in natural cobalt deposits can reach 10％～20％,which is significantly higher than the solid solubility limit of Co in pyrite obtained from experimental and theoretical methods.At present,the mechanism of the dissolution of supersaturated Co in pyrite and whether the Co-supersaturated pyrite underwent cattierite exsolution are not clear.In order to solve the above issues,Co-enriched pyrite from Dahenglu deposit in Jilin Province was selected in this study.EDS elemental mapping and EPMA results show that Co distribution in Dahenglu Co-enriched pyrite is heterogeneous and irregular,and the Co contents of single pyrite grain are variable(4.31％～9.74％for Py108,4.54％～8.83％for Py110).The heterogeneity of Co distribution is probably related to the growth process and crystallization environment of pyrite.The results of TEM and APT show that Co distribution in Dahenglu Co-enriched pyrite is homogeneous at the nanoscale,and no Co-enriched inclusions and cattierite exsolution are identified,implying that Co is incorporated into Co-enriched pyrite by isomorphic substitution for Fe.According to the above results,we propose that the incorporation of supersaturated Co in Dahenglu Co-enriched pyrite is probably related to the crystallite size effect,and the metastable state of Co-supersaturated FeS2-CoS2 solid solution can remain unchanged over a long period of time.
万方数据
维普
