URANIUM SOLVENT EXTRACTION USING TERTIARY AMINES
Enviado por fpanire • 5 de Noviembre de 2012 • Tesis • 3.224 Palabras (13 Páginas) • 511 Visitas
URANIUM SOLVENT EXTRACTION USING
TERTIARY AMINES
by:
Dr J.M.W. Mackenzie
Manager Mining Chemicals
Henkel Australia Pty Ltd
PRESENTED AT
Uranium Ore Yellow Cake Seminar
February 1997
Melbourne, Australia
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Table of Contents
1.0 INTRODUCTION AND HISTORY .............................................................................................. 3
1.1 INTRODUCTION .................................................................................................................... 3
1.2 HISTORY ................................................................................................................................ 3
2.0 ACID LEACH CHEMISTRY FOR URANIUM ......................................................................... 4
3.0 TERTIARY AMINE EXTRACTION OF URANIUM ............................................................... 5
3.1 TYPE OF AMINE USED AND MAXIMUM LOADING CAPACITY .................................. 5
3.2 THE EFFECT OF COMPETING ANIONS ............................................................................. 6
3.3 DILUENTS AND THIRD PHASE INHIBITORS OR MODIFIERS....................................... 7
3.4 SECONDARY AMINES .......................................................................................................... 8
4.0 GENERAL CONCEPTS OF TERTIARY AMINE URANIUM ....EXTRACTION CIRCUITS
9
4.1 GENERAL CIRCUIT LAYOUT.............................................................................................. 9
4.2 LOADED ORGANIC SCRUBBING...................................................................................... 10
4.3 STRIPPING ............................................................................................................................ 10
4.4 REGENERATION OR SCRUBBING OF THE STRIPPED ORGANIC............................... 11
5.0 ASPECTS OF EQUIPMENT SELECTION AND PLANT DESIGN FOR TERTIARY
AMINE URANIUM SX CIRCUITS .................................................................................................. 11
6.0 SPECIAL PROBLEMS DUE TO ORGANIC CONTAMINANTS AND CRUD ................... 12
REFERENCES ................................................................................................................................... 13
TABLES AND FIGURES................................................................................................................... 15
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1.0 INTRODUCTION AND HISTORY
1.1 INTRODUCTION
Uranium was the first metal to be recovered in significant quantities
using solvent extraction. Much of the copper SX equipment technology
is a development from existing uranium technology. Because the
kinetics of extraction via an ion exchange mechanism are much faster
than for a chelation mechanism the mixer residence times are much
longer for copper SX than for uranium.
1.2 HISTORY
Following the development of the nuclear industry during and
immediately after World War II, attention was focussed on developing
technologies which could be used to upgrade and purify uranium from
low grade sources. Initially the nuclear industry had relied on high grade
uranium ores from the Belgium Congo and Canada. One of the main
participants in this development was the Union of South Africa and the
then Prime Minister, Jan Smuts, visited MIT in the USA in this regard.
Research in the USA lead to the first commercial use of amines in
uranium concentration at West Rand Consolidated Mines in South
Africa in 1952. The amines used in this plant were in the form of a
strong base resin and it was not until 1957 that the first commercial
solvent extraction plant using amines was opened in the USA.
Since those early days, the development of uranium hydrometallurgical
processing has developed along three main paths:
1. Ion exchange as the sole on site purification and
concentration route
This used a strong base (quaternary amine) functionality resin to
concentrate and purify the uranium.
2. Ion exchange followed by solvent extraction purification of
the IX concentration eluate
Acid leaching of uranium is a non-selective leach and ion
exchange using strong base resins is a non-selective extraction
process so it was not surprising that metallurgists looked to ways
of purifying the concentrated eluate produced by strong IX.
Attempts to improve the selectivity of the uranium IX process
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using weak base (tertiary amine) resins were not particularly
successful and a circuit based on strong
...