Microanalysis of raw materials: Best student poster award
News of 18 September 2017
Haosheng Wu, a PhD student at Helmholtz Institute Freiberg for Resource Technology (HIF), won a best student presentation award at the 21st International Conference on Secondary Ion Mass Spectrometry (SIMS). Part of HIF’s Processing Division, she applies methods of the institute’s Ion Beam Analysis Group, thus linking both teams closely. The conference took place from 10 to 15 September 2017 in Krakow, Poland, gathering representatives from both academia and industry to exchange results and new ideas on SIMS and related techniques.
SIMS is one of the most important microanalytical methods, able to determine the concentration of trace elements in very small samples and used, for instance, for raw material analysis. Haosheng Wu, who studied chemical engineering, joined HIF in 2015, then working with the Ion Beam Analysis Group. The team use and develop – in close cooperation with HZDR's Ion Beam Center – analytical methods for a wide range of research fields, operating a SIMS facility.
The PhD student deals with the synthesis of homogenous low titanium concentration in silica glass by ion implantation as reference materials for SIMS. Even though using ion implantation to produce reference materials is well known in semiconductor industry, it is still rare for mineral analysis. Furthermore, using multi-energy ion implantation to achieve a homogenous distribution of the element of interest in a certain depth in a bulk material is barely used or published in any kind of paper. “The first quantification results of the multi-energy implanted samples are very promising, but further quantification is still needed”, explains the researcher.
Ion beam analysis for optimizing ore processing
In her PhD Haosheng Wu will focus on the characterization of surface properties of cassiterite, an important tin ore. These properties are determined by the composition of trace elements contained in the mineral and then again determine the recovery of cassiterite during flotation processes. During her studies she will use various SIMS methods and produce her own adapted reference materials.
While the scope of the conference ranged from organic and biological substances to semiconductors, metals and nanomaterials, Haosheng Wu is the only student awardee in the field of non-biological SIMS research. “This award came totally unexpected, obviously showing the big interest in our research, which we are very proud of”, says the PhD student.
How SIMS works:
SIMS allows, for example, the determination of tiny traces of precious metals in sulphide mineral, from which the formation of ore deposits can be explored. First, ions are focused onto the surface of a polished sample which is under vacuum. This removes surface atoms, a fraction of which are in turn ionized. Such "secondary ions" can then be analyzed using a mass spectrometer and with the help of reference materials. The achieved detection limit: Out of even twenty million atoms, a single one can be observed. Reference materials need to be used for precise quantification. This information can help find new mineral resources.