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Characterization of hydroxyl-bearing magnesium fluoride containing physically bound water

Published online by Cambridge University Press:  05 March 2012

J. L. Booster*
Affiliation:
Delft University of Technology, Applied Earth Sciences, Department of Raw Materials Technology, Mijnbouwstraat 120, 2628 RX, Delft, The Netherlands
J. H. L. Voncken
Affiliation:
Delft University of Technology, Applied Earth Sciences, Department of Raw Materials Technology, Mijnbouwstraat 120, 2628 RX, Delft, The Netherlands
A. van Sandwijk
Affiliation:
Delft University of Technology, Applied Earth Sciences, Department of Raw Materials Technology, Mijnbouwstraat 120, 2628 RX, Delft, The Netherlands
M. A. Reuter
Affiliation:
Delft University of Technology, Applied Earth Sciences, Department of Raw Materials Technology, Mijnbouwstraat 120, 2628 RX, Delft, The Netherlands
*
a)Electronic mail: [email protected]

Abstract

Most electrolytic zinc plants have to deal with dissolved magnesium in their process liquors, as zinc sulphide concentrates contain small amounts of magnesium. Applied magnesium bleed methods are generally expensive and environmentally unfriendly. Recently, a new approach was suggested and discussed, which involves selective magnesium fluoride precipitation from purified zinc sulphate solutions. X-ray fluorescence measurements of these precipitates indicated that the ratio Mg:F is not 1:2 as would be expected if the precipitate was MgF2, which should be formed on a theoretical basis. It was inferred that fluoride was partly substituted by hydroxyl groups. Analytical techniques such as infrared absorption spectrometry, X-ray diffraction, and thermogravimetry were combined in order to verify this hypothesis. The precipitate indeed appeared to be a magnesium fluoro- hydroxide compound containing physically bound water. The results contribute to the understanding of the required operating conditions of the proposed process.

Type
Technical Articles
Copyright
Copyright © Cambridge University Press 2005

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References

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