The leaching of uranium from betafite

Nettleton, Kylie C.A.; Nikoloski, Aleksandar N.; Costa, Micheal Da

doi:10.1016/j.hydromet.2015.09.008

Cited by 23 publications

(5 citation statements)

References 15 publications

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“…However, if a metamict material is recrystallised by heating, the material becomes less soluble. This has been documented for brannerite [23], betafite [11] and synthetic zirconolite [26].…”

Section: Crystallinity and Leachabilitymentioning

confidence: 70%

“…Under similar leaching conditions, the synthetic zirconolite dissolved much more slowly than natural brannerite [9,12,23] and betafite [11,24,25]. Cerium extraction from zirconolite followed linear kinetics in sulphuric acid ( Figure 5).…”

Section: Leaching Kineticsmentioning

confidence: 96%

“…Brannerite is known to dissolve quickly in sulphuric and hydrochloric acids under oxidising conditions [9,10], while betafite (pyrochlore) will dissolve at a lower rate under similar conditions [11]. By comparing the leaching of zirconolite with the leaching of brannerite and betafite under these conditions, the stability of zirconolite as a host for actinides can be evaluated and demonstrated.…”

Section: Introductionmentioning

confidence: 99%

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Chemical Stability of Zirconolite for Proliferation Resistance under Conditions Typically Required for the Leaching of Highly Refractory Uranium Minerals

Nikoloski

Gilligan

Squire

et al. 2019

Metals

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In this study, synthetic zirconolite samples with a target composition Ca0.75Ce0.25ZrTi2O7, prepared using two different methods, were used to study the stability of zirconolite for nuclear waste immobilisation. Particular focus was on plutonium, with cerium used as a substitute. The testing of destabilisation was conducted under conditions previously applied to other highly refractory uranium minerals that have been considered for safe storage of nuclear waste, brannerite and betafite. Acid (HCl, H2SO4) leaching for up to 5 h and alkaline (NaHCO₃, Na2CO3) leaching for up to 24 h was done to enable comparison with brannerite leached under the same conditions. Ferric ion was added as an oxidant. Under these conditions, the synthetic zirconolite dissolved much slower than brannerite and betafite. While the most intense conditions were observed previously to result in near complete dissolution of brannerite in under 5 h, zirconolite was not observed to undergo significant attack over this timescale. Fine zirconolite dissolved faster than the coarse material, indicating that dissolution rate is related to surface area. This data and the long term stability of zirconolite indicate that it is a good material for long-term sequestration of radioisotopes. Besides its long term durability in the disposal environment, a wasteform for fissile material immobilisation must demonstrate proliferation resistance such that the fissile elements cannot be retrieved by leaching of the wasteform. This study, in conjunction with the previous studies on brannerite and betafite leaching, strongly indicates that the addition of depleted uranium to the wasteform, to avert long term criticality events, is detrimental to proliferation resistance. Given the demonstrated durability of zirconolite, long term criticality risks in the disposal environment seem a remote possibility, which supports its selection, above brannerite or betafite, as the optimal wasteform for the disposition of nuclear waste, including of surplus plutonium.

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Section: Crystallinity and Leachabilitymentioning

confidence: 70%

Section: Leaching Kineticsmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Chemical Stability of Zirconolite for Proliferation Resistance under Conditions Typically Required for the Leaching of Highly Refractory Uranium Minerals

Nikoloski

Gilligan

Squire

et al. 2019

Metals

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“…The recovery of metals from ores or residues involved, among others, bioleaching (Abhilash et al, 2009;Brisson et al, 2016;Mishra et al, 2009;Watling, 2015;Zammit et al, 2014) and/or chemical leaching (Mirjalili and Roshani, 2007;Nettleton et al, 2015;Satybaldiyev et al, 2015) (Borra et al, 2015). Depending on the ore grade, the concentration of the metal ions in the leachates may strongly vary and different processes can be used for metal recovery.…”

Section: Introductionmentioning

confidence: 99%

Integrated treatment of tailing material for the selective recovery of uranium, rare earth elements and heavy metals

Hamza

El-Aassy

Guibal³

2019

Minerals Engineering

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Processed ores may contain substantial amounts of residual valuable metals. In the case of the mining wastes issued from the exploitation of gibbsite bearing shale ore in the Southwestern Sinai, the characterization of the residue shows the presence of uranium, rare-earth elements (REEs), aluminum and zinc that can be valorized. Pug leaching at 120°C with an acid consumption of about 200 kg H 2 SO 4 per ton of ore succeeded in leaching more than 94% of U(VI) and REEs (in addition to substantial amounts of Al(III) and Zn(II)). A series of selective precipitation steps allowed successively recovering (almost quantitatively) Zn(II), Fe(III) and Al(III). In a second step, a magnetic resin has been used for enriching the pregnant leaching solution (by a factor close to 19) through sorption/desorption steps. In the last stage of the process, REEs were recovered by selective precipitation using 25% (w/w) oxalate solution at pH 1.5, while uranium was fully recovered by precipitation with NaOH at pH 9. Energy dispersive X-ray analysis performed on the different precipitates showed purity grades systematically superior to 93%.

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“…The geological and mineralogical features of deposits and their economic minerals are the main ones in choosing a rational mining technology and extracting associated valuable components from them. Such indicators are the basis for choosing a technology for the development of both technogenic [ [8], [9]] and natural ores [ [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21]]. Industrial uranium mineralization of the Semizbai deposit is represented by stratiform ore bodies, which are established in the lower part of the section of the Semizbai suite -from its basal layers to the silt-sand horizon inclusive.…”

Section: Introductionmentioning

confidence: 99%

On the matter of composition and technological properties of uranium ores of the Semizbai deposit (North Kazakhstan)

Baibatsha¹,

Bashilova²

2023

KIMS/CUMR/MShKP

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Currently, uranium production occupies a decisive place in the world energy industry. In Kazakhstan, to meet the demand for uranium, hydrogenous deposits with technologically and economically favorable natural indicators are being developed, including the large Semizbai deposit. The deposit by genesis belongs to the hydrothermal-hydrogenous polygenic type in terrigenous sandy-clayey deposits. As a result of geological studies, the stratification of the ore-bearing deposits of the Semizbai suite was established: the lower and upper ore-bearing sub suites, the geometrization of the deposit was performed, and the morphology, number, and size of ore bodies were identified. Most of the balance reserves of the Semizbai deposit are concentrated in large and medium ore bodies. Analytical work and description of thin sections and polished sections under a microscope determined the material composition, textures, and structures of uranium ores, the main ore minerals, and their distribution in ores. When carrying out field and laboratory work, geological indicators of the deposit were obtained to select the technology for extracting ores. To select and justify the field development technology, special technological studies were carried out in the experimental area. Based on the geological indicators of uranium ores for the Semizbay deposit, well-in-situ leaching was chosen as the most rational for hydrogenous deposits. The characteristic of associated useful components of uranium ores is given, and the increased content of selenium, germanium, and scandium in them is established. The obtained research results can serve as a basis for improving the technology used for mining uranium ores and extracting associated components from them.

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The leaching of uranium from betafite

Cited by 23 publications

References 15 publications

Chemical Stability of Zirconolite for Proliferation Resistance under Conditions Typically Required for the Leaching of Highly Refractory Uranium Minerals

Chemical Stability of Zirconolite for Proliferation Resistance under Conditions Typically Required for the Leaching of Highly Refractory Uranium Minerals

Integrated treatment of tailing material for the selective recovery of uranium, rare earth elements and heavy metals

On the matter of composition and technological properties of uranium ores of the Semizbai deposit (North Kazakhstan)

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