• Login
    View Item 
    •   KovsieScholar Home
    • Electronic Theses and Dissertations
    • All Electronic Theses and Dissertations
    • View Item
    •   KovsieScholar Home
    • Electronic Theses and Dissertations
    • All Electronic Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Quantification of tantalum in series of tantalum-containing compounds

    Thumbnail
    View/Open
    TheronTA.pdf (2.508Mb)
    Date
    2010
    Author
    Theron, Thomas Arnoldus
    Metadata
    Show full item record
    Abstract
    The main objective of this research was firstly the successful digestion of a series of tantalum containing compounds, with specific exclusion of HF, and secondly, the accurate quantification of tantalum with the help of inductively-coupled plasma optical-emission spectrometry (ICP-OES). The series of tantalum containing compounds include TaF5, TaCl5, Ta2O5, Ta-metal, Ta-CRM (certified reference material), as well as two types of tantalite-ore. The goal of the study of the pentahalide compounds was to verify the use of ICP-OES as analytical method in terms of tantalum recovery. The aqueous dissolution and subsequent quantification of both these compounds was very successful and yielded recovery results of 96 % and 100 % for the fluoride and chloride salts respectively. Validation of the dissolution and quantification of the pentafluoride was within an acceptable range, while the dissolution and quantification methods for the pentachloride was considered exceptionally successful with a recovery of 100.05 % and a t-value = 0.95. Digestion results showed that tantalum pentoxide was considerably more difficult to dissolve than the pentahalides, but good results were eventually obtained after experimentation with various digestion methods. The most successful digestion method was obtained with the help of a high temperature (1100 °C) lithium tetraborate flux, after which the pentoxide melt was dissolved with a mixture of phosphoric acid and methanol. Tantalum recoveries of ca. 97 % were obtained with this method. This study also showed that the CRM and the tantalum metal did not dissolve easily with any of the developed digestion methods. Despite the fact that tantalum is present in the CRM in the form of tantalum pentoxide (0.236 %), the method developed for tantalum pentoxide dissolution did not succeed in completely dissolving the CRM. A qualitative study showed that there are a variety of elements present in the CRM, including Al, Si and Fe, of which especially Al has the potential of interfering with tantalum quantifications at certain chosen wavelengths. Tantalum recoveries of 89.75 % were obtained for the CRM. Tantalum metal is known to be chemically inert in some of the most extreme chemical environments. Therefore it was no surprise that none of the digestion methods investigated during this study could achieve complete dissolution of the metal, and a maximum recovery of only 90 % was obtained for the most successful method. Of the two types of ore analysed, Tan-A yielded the best result with a calculated tantalum pentoxide content of 27.69 % compared to the accepted value of 27.17 %. The Sample 1 ore yielded an average tantalum pentoxide content of 29.98 % and although this result was not statistically the same as the results obtained by previous studies, the digestion and subsequent recovery was still considered successful. The natural magnetic characteristics of the Sample 1 ore were used to separate some of the impurities from the original ore before digestion. This magnetic separation was seen as a huge success and indicated possibilities for future studies. The two main components that were almost completely separated from the original ore were the iron- and titanium-associated ores. The metal oxide content after separation was 1.41 % and 0.83 % for ironand titanium oxides respectively, where it was 18.48 % and 10.68 % before separation. Lastly, complete method validation was performed on all the developed digestion and quantification methods for all the tantalum containing compounds to determine efficiency, accuracy and precision in order to statistically judge the effectiveness of each method. This validation has also identified a few gaps in this study, which indicated excellent opportunities for interesting and insightful future studies.
    URI
    http://hdl.handle.net/11660/1593
    Collections
    • All Electronic Theses and Dissertations
    • Masters Degrees (Chemistry)

    Related items

    Showing items related by title, author, creator and subject.

    • Coordination chemistry of niobium(v) and tantalum(v) with hard o-donor ligands: a solution and solid state investigation 

      Belay, Alebel Nibret (University of the Free State, 2018-02)
      English: This thesis describes the study directed towards the synthesis, characterization and substitution kinetics of novel niobium(V) and tantalum(V) complexes containing selected O,O’-bidentate ligands that could ...
    • Separation and purification of niobium and tantalum from synthetic and natural compounds 

      Nete, Motlalepula (University of the Free State, 2013-05)
      English: The aim of this project was to investigate the possible dissolution, separation and purification of tantalum and niobium in synthetic ((Ta/Nb)F5 and (Ta/Nb)2O5) and natural (tantalite minerals) compounds using ...
    • High oxidation state niobium and tantalum coordination chemistry: a solution and solid state investigation 

      Koen, R. (University of the Free State, 2016-01)
      English: Niobium and tantalum, chemical twins of the vanadium triad of the periodic table, are notoriously difficult to separate from one another and from their naturally occurring ores due to their near identical chemical ...

    DSpace software copyright © 2002-2016  DuraSpace
    Contact Us | Send Feedback
     

     

    Browse

    All of KovsieScholarCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    LoginRegister

    Statistics

    View Usage Statistics

    DSpace software copyright © 2002-2016  DuraSpace
    Contact Us | Send Feedback