Browsing Faculty of Natural and Agricultural Sciences by Author "Lachmann, G."
Now showing items 1-6 of 6
-
Comparison of extractants for the separation of TaF5 and NbF5 in different acidic media
Ungerer, M.J.; Van der Westhuizen, D.J.; Lachmann, G.; Krieg, H.M. (Elsevier, 2014)To optimise the solvent extraction (SX) of Ta and Nb, eight different extractants were investigated, including the cation exchangers di-iso-octyl-phosphinic acid (PA) and di-(2-ethylhexyl)-phosphoric acid (D2EHPA), the ... -
Cr(VI) generation during sample preparation of solid samples - a chromite ore case study
Glastonbury, R.I.; Van der Merwe, W.; Beukes, J.P.; Van Zyl, P.G.; Lachmann, G.; Steenkamp, C.J.H. (WRC, 2010)South Africa holds more than 70% of the world's viable chromite ore reserves and produces ~46.2% of the world's high carbon ferrochrome. It was recently reported that beneficiated South African chromite ores contained ... -
A dual-channel gas chromatography method for the quantitation of low and high concentrations of NF3 and CF4 to study membrane separation of the two compounds
Branken, D.J.; Le Roux, J.P.; Krieg, H.M.; Lachmann, G. (Elsevier, 2013)A dual-channel gas chromatographic method is described in this paper that can be conveniently used for quantitation of NF3/CF4 mixtures with a thermal conductivity detector (TCD) on one channel for the quantitation of ... -
Modelling sorption and diffusion of NF3 and CF4 in Teflon AF perfluoropolymer membranes
Branken, D.J.; Krieg, H.M.; Lachmann, G.; Carstens, P.A.B. (Elsevier, 2014)Molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) simulations with Teflon AF2400 and Teflon AF1600 predicted diffusivities and solubilities of He and N2 that corresponded reasonably with available experimental ... -
The reduction of hexavalent chromium by sulphite in wastewater
Beukes, J.P.; Pienaar, J.J.; Lachmann, G.; Giesekke, E.W. (WRC, 1999)The reduction of hexavalent chromium, Cr(VI), in unbuffered aqueous solution by sulphite was investigated as a function of pH, possible dosage and contact time required to reach equilibrium. Dissolved Na2Cr2O7.2H2O served ... -
Separation of NF3 and CF4 using amorphous glassy perfluoropolymer Teflon AF and Hyflon AD60 membranes
Branken, D.J.; Krieg, H.M.; Lachmann, G.; Le Roux, J.P. (Elsevier, 2014)In this study, the pure and mixed gas permeabilities of Teflon AF2400, Teflon AF1600 and Hyflon AD60 membranes towards NF3 and CF4 were measured to determine whether membrane gas separation can be applied to purify NF3 of ...