Uranium extraction from a pure natural brannerite mineral by acidic ferric sulphate leaching

Costine, Allan; Nikoloski, Aleksandar N.; Costa, Micheal Da; Chong, Kok Fung; Hackl, Ralph Peter

doi:10.1016/j.mineng.2013.07.010

Cited by 27 publications

(21 citation statements)

References 9 publications

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“…The observation that at higher temperatures, the rates of uranium and titanium dissolution were relatively close whereas their difference at lower temperatures also suggests that different reaction mechanisms may be taking place at different temperatures. Costine et al (2013) leached a similar sample of brannerite in 40 g/L H2SO4, at 40, 60 and 80 °C for different ferric ion concentration but did not report the activation energy. Using Costine's data to do this calculation gives an activation energy for the uranium dissolution of 32.9-39.4 kJ/mol, varying with the iron concentration.…”

Section: Activation Energymentioning

confidence: 99%

“…2), crushed to a d80 of 128 μm by a local commercial mineral laboratory. This specimen was used in two earlier studies, the work of Costine et al (2013) as well as that of Nikoloski and Chong (2012). Costine et al's study covered the effects of varied sulphuric acid concentration, varied ferric concentration, varied particle size and varied temperature on the rate of uranium leaching from brannerite over 24 h. The earlier work of Nikoloski and Chong (2012) studied the effects of varied Fe 2 + :Fe 3 + ratio, varied temperature, varied acid concentration and varied total iron concentration on the rate of uranium and titanium leaching over 30 min.…”

Section: Feed Samplementioning

confidence: 99%

“…X-ray diffraction analyses by Costine et al (2013) have shown that the alteration layer consisted of anatase. The pale yellow/brown material appeared to extend inwards below the surface.…”

Section: Feed Samplementioning

confidence: 99%

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Leaching of brannerite in the ferric sulphate system — Part 1: Kinetics and reaction mechanisms

Gilligan

Nikoloski

2015

Hydrometallurgy

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The uranium titanate mineral brannerite, UTi2O6 is the most common of the uranium minerals which is considered refractory. Ore containing brannerite mineralisation has been mined and processed in several locations around the world. Under typical uranium ore processing conditions, brannerite is often lost to tailings. In order to design an effective process for the leaching of high-brannerite uranium ores, it is first necessary to understand the mechanism of the chemical processes through which brannerite dissolves in the absence of interferences from the host rock. In the present study, a specimen of brannerite obtained as a single crystal was leached in sulphuric acid (10-200 g/L) and ferric sulphate (2.8 g/L Fe 3 + ) solution at 25-96 °C for 5 h. The rate of titanium dissolution was monitored along with uranium. Comparisons between the rates at which these two elements dissolved and the morphological changes that were observed to take place during the dissolution process indicated two different sets of leaching reaction mechanisms. At low temperatures, uranium dissolved at a much higher rate than titanium initially, leaving titanium rich areas on the brannerite particles similar to observations reported in earlier investigations which suggest incongruent dissolution. The calculated activation energies for uranium and titanium dissolution were 36 and 48 kJ/mol respectively. At higher temperatures, uranium and titanium dissolved at similar rates in constant proportions suggesting congruent dissolution. The calculated activation energy for this reaction was 23 kJ/mol. The transition between incongruent and congruent dissolution took place at lower temperatures when the acid concentration was higher. Titanium appeared to undergo hydrolysis after dissolution, forming anatase. This side reaction was most favourable at lower acid concentrations and high temperatures.

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Section: Activation Energymentioning

confidence: 99%

Section: Feed Samplementioning

confidence: 99%

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Leaching of brannerite in the ferric sulphate system — Part 1: Kinetics and reaction mechanisms

Gilligan

Nikoloski

2015

Hydrometallurgy

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“…26 The shrinking core model (SCM) considers that the leaching process is controlled by one of these steps. The reaction model between a liquid and a solid may be given as…”

Section: Kinetic Modelsmentioning

confidence: 99%

Kinetics of Uranium Extraction from Uranium Tailings by Oxidative Leaching

Zhang

et al. 2016

JOM

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Extraction of uranium from uranium tailings by oxidative leaching with hydrogen peroxide (H 2 O 2 ) was studied. The effects of various extraction factors were investigated to optimize the dissolution conditions, as well as to determine the leaching kinetic parameters. The behavior of H 2 O 2 in the leaching process was determined through scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX) and x-ray diffraction analysis of leaching residues. Results suggest that H 2 O 2 can significantly improve uranium extraction by decomposing the complex gangue structures in uranium tailings and by enhancing the reaction rate between uranium phases and the leaching agent. The extraction kinetics expression was changed from 1 À 3(1 À a) 2/3 + 2(1 À a) = K 0 (H 2 SO 4 ) À0.14903 (S/L) À1.80435 (R o ) 0.20023 e À1670.93/ T t (t ‡ 5) to 1 À 3(1 À a) 2/3 + 2(1 À a) = K 0 (H 2 SO 4 ) 0.01382 (S/L) À1.83275 (R o ) 0.25763 e À1654.59/T t (t ‡ 5) by the addition of H 2 O 2 in the leaching process. The use of H 2 O 2 in uranium leaching may help in extracting uranium more efficiently and rapidly from low-uranium-containing ores or tailings.

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“…Brannerite is known to be refractory, in that it will dissolve slowly or not at all under the conditions typically used to leach uranium from the other two common minerals (Smits, 1984;Lottering et al, 2008;Costine et al, 2013;Gilligan and Nikoloski, 2015a). In order to develop effective processes for the extraction of uranium from brannerite dominant ores, it is necessary to improve the understanding of the leaching reaction chemistry.…”

Section: Introductionmentioning

confidence: 99%

Leaching of brannerite in the ferric sulphate system. Part 2: Mineralogical transformations during leaching

2016

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT AbstractBrannerite, UTi 2 O 6 , is the most common refractory uranium mineral and is the most important uranium ore mineral after uraninite and coffinite. In order to develop an effective treatment method for the hydrometallurgical extraction of uranium from ores containing brannerite, it is necessary to understand the chemistry of the leaching process. Part 1 of this series described the results of a study of the chemical reaction mechanisms of brannerite under conditions similar to those used industrially. In this paper, the mineralogical data obtained from samples collected during the leaching work is used to derive further insight into the transformations that take place during leaching. Detailed characterisation of the brannerite feed specimen and leach residues were carried out using surface imaging and X-ray diffraction techniques. It was shown that the brannerite specimen is heterogeneous, consisting of at least two phases. The brannerite phase was metamict and showed signs of natural alteration to fine-grained (10-20 nm) crystalline anatase. Comparisons between the feed and residues showed that the X-ray amorphous material, in particular lead and silicon enriched areas identified near the anatase were most susceptible to leaching while the crystalline material was relatively resistant to leaching. These results demonstrate that the extent of brannerite alteration and its texture are important considerations to the hydrometallurgical behaviour of a particular ore along with the typical concerns such as grade, liberation size and gangue mineralogy.

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Uranium extraction from a pure natural brannerite mineral by acidic ferric sulphate leaching

Cited by 27 publications

References 9 publications

Leaching of brannerite in the ferric sulphate system — Part 1: Kinetics and reaction mechanisms

Leaching of brannerite in the ferric sulphate system — Part 1: Kinetics and reaction mechanisms

Kinetics of Uranium Extraction from Uranium Tailings by Oxidative Leaching

Leaching of brannerite in the ferric sulphate system. Part 2: Mineralogical transformations during leaching

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