Experimental determination of zirconium speciation in hydrothermal solutions

An experimental study of the solubility of baddeleyite (ZrO2) in fluoride-bearing solutions at elevated temperature

“…Consequently, the observations of natural systems, suggesting an important role for fluorine in the hydrothermal transport of zirconium, have not been supported by theoretical predictions. The reliability of these predictions is now in question, however, as a result of recent experiments at 500°C and 1000 bar by (Ryzhenko et al, 2008) showing that the solubility of zirconium in fluoride-bearing solutions is many orders of magnitude higher than theoretically predicted. In view of this and to further test the hypothesis that zirconium mobility in hydrothermal fluids is significantly increased by the presence of fluoride ions, we have performed a set of experiments designed to determine the solubility of baddeleyite (ZrO 2 ) and speciation of zirconium in fluoride-bearing aqueous solutions at temperatures ranging from 100 to 400°C, and pressures up to 700 bars.…”

“…In order to relate the data obtained from the experiments conducted at 100-250°C and saturated vapor pressure with the data reported by (Ryzhenko et al, 2008) for 500°C and 1000 bars, experiments were also performed at 400°C and 700 bars. These experiments were performed in a custom-built, standard cold-seal apparatus using water as the pressure medium.…”

Behavior and Impact of Zirconium in the Soil–Plant System: Plant Uptake and Phytotoxicity

“…Zr exists in several forms in the soil and in liquid media, and these forms have different levels of solubility and bioavailability (Fodor et al 2005 ;Davydov et al 2006 ;Ryzhenko et al 2008 ;Prisyagina et al 2008 ;Louvel et al 2009 ) . Different Zr species affect the solubility, mobility, and uptake of Zr by plants (Davydov et al 2006 ;Ferrand et al 2006 ;Ryzhenko et al 2008 ) . Therefore, although it is relatively easier to measure, one cannot rely on the total Zr content in a plant as an indicator of uptake and toxicity (Shahid et al 2012b ) .…”

“…The biogeochemical behavior of an inorganic element in an ecosystem, and its potential effects on plants, are strongly in fl uenced by its speciation (Stojilovic et al 2005 ;Fodor et al 2005 ;Davydov et al 2006 ;Dumat et al 2006 ;Ryzhenko et al 2008 ;Prisyagina et al 2008 ;Kopittke et al 2008 ;Louvel et al 2009 ;Uzu et al 2009 ;Shahid et al 2012b, c ) . Speciation is the existence of a metal in different chemical forms as a result of being exposed to different environmental conditions Louvel et al 2009 ;Shahid et al 2011c ) .…”

“…This is because Zr hydrolyses and precipitates as polynuclear species in strongly acidic solutions (pH < 1) (Baes and Mesmer 1986 ;Ekberg et al 2004 ) . Davydov et al ( 2006 ) and Ryzhenko et al ( 2008 ) evaluated the hydrolysis and precipitation of Zr as a function of pHs between 0 and 14 and generally show that Zr precipitation reactions occur at low pH (about 2) Prisyagina et al 2008 …”