Determination of indium in its mineral resources by comparative neutron activation analysis

The application of comparator instrumental neutron activation analysis (INAA) was considered to determine indium by the short-lived radionuclide In-116m it its mineral resources such as different types of polymetallic ore, copper, lead-zinc, tin, tin-tungsten ores, and similar. Cu and Zn contents of the samples were determined by X-ray fluorescence method (XRF) using a laboratory energy dispersive XRF spectrometer RLP-21T, Kazakhstan. If Cu mass fraction exceeded 0.40.5% or that of Zn exceeded 3% (that is often characteristic of polymetallic, copper, and lead-zinc ores), then their contents were used in comparator INAA as the internal standards measured by an independent method. If none of the conditions were met, then the standard addition method was applied using a 10 mg addition of reagent ZnO to each sample. A range of the samples of polymetallic ore reference material certified for indium content (CRMs) were used to verify accuracy of the method. The proposed variant of comparator INAA was shown to insure accuracy of a routine analysis of indium-bearing ores of nonferrous metals fir indium content by the III category of precision according to the industrial standard OST 41-08-221-04 (Russian Federation). The method was tried out for several dozens of ore samples presenting various indium mineral resources including the ones from the gold-polymetallic deposit Maikain in North-Eastern Kazakhstan.

Automated summary

The application of comparator INAA was considered for determining indium content in various mineral resources, with Cu and Zn contents determined by XRF. Internal standards and standard addition method were used to ensure accuracy, with verification done using certified reference materials. The method was found to provide accurate analysis for indium content in nonferrous metal ores.