Non-radioactive scandium oxide receiving out of uranium ISR solutions

The task of the research was to study and determine an effective method for the preparation of non-radioactive scandium compounds from uranium In-Situ Recovery (ISR) solutions. The widespread use of scandium is restrained by the high price due to its small production volumes, low content in the raw materials (scandium is a scattered element and does not form its own deposits), as well as the complexity of technological schemes for its extraction. Scandium receiving out of uranium reverses ISR solutions technological scheme was experimental tested, including sorption on MTS 9580 (Purolite’s production) ion exchanger with recurrent ballast impurities desorption and receiving concentrate that contains scandium. New radiation cleaning technological sequencing based on different solubility of radioactive elements and scandium in carbonate solutions, that accompanied by insoluble macro components complex formation, that contains in deactivated scandium concentrate and allows to get scandium oxide with desired component maintenance more than 94 % and less than 0,3 kilobecquerels/kg specific activity level was developed. The developed technology is based on the ability to form soluble carbonate complexes of scandium and radioactive elements, while the main macro components of the concentrate - ferrum, aluminum, calcium, silicon and others under the conditions of carbonation of the concentrate are inert or form insoluble compounds. Optimal radioactive impurity removing from concentrate conditions and scandium leaching from deactivated residue of scandium and macro impurity were studied and identified in laboratory conditions and during pilot tests.

Processing of formate solutions obtained from red mud leaching

The paper determines the indicators of the developed process flow for the complex processing of red sludge via the formate method: recovery of components; yield and composition of products when processing a sample of formate solution obtained from red mud leaching. The conducted experiments used red mud generated in the production of alumina at the Urals Aluminium Smelter. The samples of formate solution obtained in the course of red mud leaching were analyzed using an Optima 8000 ICP-OES Spectrometer, a Sartorius MA-30 Moisture Analyzer to measure moisture content, as well as an ARL 9800 XRF Spectrometer to ascertain the mass fraction of elements in metal and nonmetal specimens found in one of three states (solid, liquid, or powder). These experiments were performed while continuously measuring and monitoring pH values by means of a pH meter having a thermal compensation function. The performed experiments involved the total recovery of valuable elements from formate solutions produced during red mud leaching. A concentrate containing Al, Sc, and rare earth elements (REEs) was processed to produce scandium oxide and rare earth metal concentrate (after dissolving aluminum in an alkali). Rare earth metals and scandium were shown to concentrate in the solid phase; scandium was then selectively leached with a sodium bicarbonate solution to form water-soluble carbonate complexes [Sc(CO3)4]5- having carbonate ions СО32- and НСО3-. When using the proposed technology, the overall recovery of scandium and REEs amounts to 98–99%, whereas that of aluminum, calcium formate, and sodium formate from the produced solution reaches 99%. The processing of formate solution yields the following end products: scandium oxide (99 wt% Sc2O3) and REE concentrate (content of 56.1%). The paper demonstrates the possibility in pri nciple to process solutions obtained from the flow-through leaching of red mud via the formate method.

A multifunctional separator based on scandium oxide nanocrystal decorated carbon nanotubes for high performance lithium–sulfur batteries

Rare earth oxides, for example scandium oxide, may open up a new prospect towards the development of advanced Li–S batteries and other energy storage systems.

Влияние термообработки на теплопроводность монокристаллов твердых растворов на основе ZrO-=SUB=-2-=/SUB=-, стабилизированных оксидами скандия и иттрия

The effect of heat treatment at 1000° C for 400 hours on the thermal conductivity of crystals stabilized with scandium oxide, (ZrO2)1-x(Sc2O3)x (x = 0.08–0.10), and together with scandium and yttrium oxides, (ZrO2)1-x-y(Sc2O3)x(Y2O3)y (x = 0.003−0.20; y = 0.02−0.025). For crystals of zirconium dioxide stabilized with scandium oxide, the most noticeable changes in thermal conductivity concern 9ScSZ crystals, in which changes in the phase composition occur, and a noticeable amount of rhombohedral phase appears. For 8ScSZ crystals, these changes are less noticeable and are mainly caused by the ordering of oxygen vacancies and changes in the microstructure of the samples, while for 10ScSZ crystals they are practically absent. The 10ScSZ crystals have the minimum electrical conductivity, both before and after annealing, which is determined by the highest content of scandium oxide in the solid solution. Small changes in thermal conductivity concern crystals of partially stabilized zirconia codoped with scandium and yttrium oxides. For cubic crystals 8Sc2YSZ and 10Sc2YSZ, there are practically no changes in the value of thermal conductivity, the nature of the temperature dependence of thermal conductivity, and the phase composition of crystals. The introduction of yttrium oxide into solid solutions based on zirconium dioxide along with scandium oxide makes it possible to increase the stability of its phase composition and structurally dependent thermal and electrophysical characteristics.

Relationship between Oxygen Defects and Properties of Scandium Oxide Films Prepared by Ion-Beam Sputtering

Scandium oxide (Sc2O3) thin films with different numbers of oxygen defects were prepared by ion-beam sputtering under different oxygen flow rates. The results showed that the oxygen defects heavily affected crystal phases, optical properties, laser-induced damage threshold (LIDT) and surface quality of Sc2O3 films. The thin film under 0 standard-state cubic centimeter per minute (sccm) oxygen flow rate had the largest number of oxygen defects, which resulted in the lowest transmittance, LIDT and the worst surface quality. In addition, the refractive index of 0 sccm Sc2O3 film could not be measured in the same way. When the oxygen flow rate was 15 sccm, the Sc2O3 film possessed the best transmittance, refractive index, LIDT and surface roughness due to the lowest number of oxygen defects. This work elucidated the relationship between oxygen defects and properties of Sc2O3 films. Controlling oxygen flow rate was an important step of limiting the number of oxygen defects, which is of great significance for industrial production.