BACKGROUNDMicrobeam analytical technology can be used to accurately analyze the petrography, morphology, structure, component and isotopic composition of ore minerals on the micro-nano scale, which plays a vital role in supporting the detailed research of geoscience.
OBJECTIVESTo provide a practical technology for visually and quickly identifying the cobalt-bearing minerals and to understand the occurrence of cobalt in the Chambishi copper-cobalt deposit.
METHODSMicroscopy was combined with microbeam analytical technologies of micro-XRF, EPMA, LA-ICP-MS to develop a method for quickly identifying the cobalt-bearing minerals from copper-cobalt deposits. First, representative thin sections were selected by polarized light microscopy, micro-XRF map scanning was then used to obtain the distribution characteristics of cobalt and combined elements in the thin sections. The polarized light microscopy was used again to identify independent cobalt minerals and cobalt-bearing minerals based on the characteristics of element distribution. Finally, the representative minerals were circled and the main and trace elements were determined by EPMA and LA-ICP-MS.
RESULTSThe results showed that in the Chambishi Southeast orebody the cobalt not only existed in the form of independent minerals (pentlandite, linnaeite, carrollite), but also occurred in pyrite and pyrrhotite in the form of isomorphism, while the cobalt in the Chambishi West orebody mainly existed in the form of independent mineral—carrollite with a small amount.
CONCLUSIONSThe combined microbeam analysis method is proposed to quickly and easily identify cobalt-bearing minerals and to study the occurrence of cobalt in the Chambishi Southeast orebody and Chambishi West orebody. It can effectively save the time of identifying minerals by traditional polarized light microscopy and avoid missing identification of some independent cobalt minerals or cobalt-bearing minerals with small particle size or without obvious optical characteristics.