Perspective of Obtaining Rare Earth Elements in Poland

Along with the increasing development of electric and electronic industries, the demand for rare earth elements is also growing due to their high position in many applications. In Poland, there are minerals containing REE; however, the concentration of these elements in raw materials is rather low, so they do not have a big impact on the national economy. The potential source of REE is secondary materials; among them are phosphogypsum, uranium tailings, and the waste electrical and electronic equipment (WEEE). Lanthanides as accompanying metals of uranium in Polish uranium ores were leached in the technology of uranium recovery from these resources. The recovery of REE from pregnant liquors was conducted by solvent extraction and ion exchange. Novel apparatus solutions like membrane contactors in extraction stage were tested. Different types of matrices (uranium ore, phosphorites, etc.) were used

Uranium in Poland: Resources and Recovery from Low-Grade Ores

The presented studies deal with an assessment of the possibility of uranium recovery from the low-grade uranium resources in Poland. Uranium was leached from the ground uranium ores with efficiencies in 81–100% range that depend on the type of ore and leaching solution used. In the next step, the post-leaching solution was treated by the solvent extraction or ion exchange chromatography to separate uranium from other metals present in the ore. The novel routes of leaching by using membrane methods were examined. The final product, “yellow cake,” was obtained in precipitation step. The studies of precipitation of uranium as ammonium diuranate or uranium peroxide from diluted uranium solutions are presented in this chapter. The work was completed with tentative economic analysis and environmental impact assessment along with radiation protection issues connected to uranium production

Application of Calixarenes as Macrocyclic Ligands for Uranium(VI): A Review

Calixarenes represent a well-known family of macrocyclic molecules with broad range of potential applications in chemical, analytical, and engineering materials fields. This paper covers the use of calixarenes as complexing agents for uranium(VI). The high effectiveness of calix[6]arenes in comparison to other calixarenes in uranium(VI) separation process is also presented. Processes such as liquid-liquid extraction (LLE), liquid membrane (LM) separation, and ion exchange are considered as potential fields for application of calixarenes as useful agents for binding UO22+ for effective separation from aqueous solutions containing other metal components

Asymmetric reduction of 2,2-dimethyl-6-(2-oxoalkyl/oxoaryl)-1,3-dioxin-4-ones and application to the synthesis of (+)-yashabushitriol

The asymmetric transfer hydrogenation of a series of 2,2-dimethyl-6-(2-oxoalkyl)-1,3-dioxin-4-ones and 2,2-dimethyl-6-(2-oxoaryl)-1,3-dioxin-4-ones was achieved in high enantiomeric excess using a Ru(II) catalyst. The aryl substrates were most compatible with the methodology and this process facilitated a total synthesis of enantiomerically pure (+)-yashabushitriol

The effect of contaminants on the application of polyamine functionalised ion exchange resins for uranium extraction from sulfate based mining process waters

Three in-house produced polyamine functionalised ion exchange resins and Purolite S985 (a commercial ion exchange resin) have been assessed for their ability to extract UO22+ from a variety of aqueous matrices applicable to current and potential future uranium mining processes. The uptake of common contaminant species in uranium processing liquors at variable acid concentrations has been assessed, with Al3+ and MoO42− showing the most extraction, with AsO43−, Eu3+ and Fe3+ showing extractions >10% at low [H+]. Extraction of MoO42−, AsO43−, Eu3+ and Fe3+ was seen to decrease with increasing [H+]. The impact of increasing [Cl−] on UO22+ and Fe3+ extraction has been determined. Fe3+ showed low extractions by all resins, with no dependence on [Cl−]. In contrast, increasing suppression of UO22+ uptake was seen with increasing [Cl−] up to 80 g L−1, with extraction remaining constant beyond this [Cl−]. At high [Cl−] (>50 g L−1) Purolite S985 was seen to remove UO22+ from solution more effectively than all synthesised polyamine resins. The presence of Fe3+ in solution was seen to suppress UO22+ uptake by around 10% when [Fe3+]/[UO22+] increased from 0 to 2. Fe3+ extraction by all studied resins was promoted by the presence of UO22+ in solution. This was most prevalent with Purolite S985, with an extraction of 30% for [Fe3+]/[UO22+] = 2 by Purolite S985. All resins were tested using a process water from a uranium mine and have shown an ability to selectively extract UO22+ from such solutions, with the best synthetic resin recovering 15.7% more uranium than Purolite S985