Browsing Chemical Engineering by Author "Pienaar, A.D."

Browsing Chemical Engineering by Author "Pienaar, A.D."

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  • Effect of the value of x in NH4F·xHF on the digestion of plasma-dissociated zircon 
    Du Plessis, W.; Pienaar, A.D.; Postma, C.J.; Crouse, Philippus L. (Elsevier, 2016-02)
    Ammonium acid fluoride (NH4F·xHF) has been identified as an alternative fluorinating agent for zircon, and may provide a method by which a wide variety of anhydrous metal fluorides can be synthesized. Data on the kinetics ...
  • Niobium and tantalum beneficiation using gas-phase fluorination 
    Pienaar, A.D. (University of Pretoria, 2014)
    The processing of minerals containing tantalum and niobium is a challenge that has most modern researchers focused on optimising the processes that have already reached scientific maturity. Ore digestion in aqueous mixtures ...
  • Niobium and tantalum separation by gas-phase fluorination 
    Pienaar, A.D.; Wagener, J.B.; Crouse, Philippus L. (Elsevier, 2012-11)
    The separation of tantalum and niobium compounds has been of interest for many years, with few new developments. Classically separation is achieved by liquid–liquid extraction and most research focuses on optimising this ...
  • Sublimation kinetics of zirconium tetrafluoride 
    Pretorius, C.J.; Pienaar, A.D.; Crouse, Philippus L.; Niemand, H.F. (Trans Tech, 2014)
    An important step of a new process being developed for the beneficiation of the mineral zircon (Zr(Hf)SiO4) to produce nuclear grade zirconium (Zr) metal, is the separation of the Zr from the hafnium (Hf). Zr ores typically ...