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Monazite is one of the main minerals of light rare earth elements and is always associated with the presence of thorium. This brings challenges in processing due to strong radiation but allows for the utilization of thorium as nuclear fuel after the transformation of 232Th into 233U. Therefore, the separation of thorium from rare earth elements, after the leaching of monazite, is an essential step that needs to be optimized. This study addresses the treatment of a leaching solution in a chloride medium obtained from desphosphorized monazite. The separation of thorium from light rare earth elements is performed by solvent extraction using Cyanex 572, 272, 923, 921, and their mixtures. Theoretical modeling using the SPANA and DATABASE software was conducted to compare nitric and chloride media conditions. The samples from the aqueous phase were analyzed by ICP-OES. The results show that the extraction capacity can be improved by using longchain diluents. It was observed that Cyanex 572 and its mixtures preferentially extract thorium in a single stage, while the extractions of light rare earth elements by Cyanex 272 and 572 were negligible. The results demonstrate that thorium can be separated from light rare earth elements in a chloride medium by Cyanex 272 and Cyanex 572, requiring an additional extraction stage when using Cyanex 272. The other extractants did not yield satisfactory results in the separation. [ABSTRACT FROM AUTHOR]

Brazil has the second largest reserve of monazite, which is one of the three main minerals bearing of rare earth elements. In this study, a monazite concentrate, derived from the occurrence of heavy minerals in the coastal strips of the states of Bahia and Espírito Santos, was used. The best way to analyze aqueous solutions rich in rare earths by ICP-OES was also evaluated. In this work, the steps used to obtain an aqueous solution rich in rare earths from the monazite concentrate involved the following steps: addition of NaOH to the concentrate, heating at 400 °C for 3 hours, washing with water and subsequent leaching of the remaining solid phase with HCl. Chemical and mineralogical characterizations were accomplished on the products of this process and the results indicated that the initial concentrate is rich in light rare earths, the alkaline fusion product is predominantly composed of rare earth hydroxides and free of NaOH. The acid leaching tailings showed to be rich in zirconite, indicating that the dissolution of the rare earth hydroxides formed in the previous step was complete. Spectral interferences in the lines of the predominant elements were considered in the ICP-OES analysis using individual patterns of these elements. The following lines were defined for the predominant elements: Ce 456.236 nm, Th 283.730 nm, La 384.902 nm, Nd 430.058 nm, Pr 390.844 nm, and Sm 428,079 nm. The leachate obtained after acid leaching of rare earth hydroxides was analyzed by this method and the concentrations of the predominant elements (in g/L) were: Ce 32.81, Th 14.76, La 8.58, Nd 3.35, Pr 3.02, and Sm 1.28. [ABSTRACT FROM AUTHOR]

Abstract: Ferruginol, a bioactive compound isolated from a Chilean tree (Podocarpaceae), attracts attention as a consequence of its pharmacological properties, which include anti-fungal, anti-bacterial, cardioprotective, anti-oxidative, anti-plasmodial and anti-ulcerogenic actions. Nevertheless, the molecular basis for these actions remains only partly understood and hence we investigated the effects of ferruginol on androgen-independent human prostate cancer cells (PC3), a known model for solid tumor cells with an exceptional resistance to therapy. The results show that ferruginol induces PC3 cell death via activation of caspases as well as apoptosis-inducing factor (AIF) as confirmed by its translocation into the nucleus. In order to clarify the biochemical mechanism responsible for the anti-tumor activity of ferruginol, we analyzed a set of molecular mediators involved in tumor cell survival, progression and aggressiveness. Ferruginol was able to trigger inhibition/downregulation of Ras/PI3K, STAT 3/5, protein tyrosine phosphatase and protein kinases related to cell cycle regulation. Importantly, the toxic effect of ferruginol was dramatically impeded in a more reducing environment, which indicates that at least in part, the anti-tumoral activity of ferruginol might be related to redox status modulation. This study supports further examination of ferruginol as a potential agent for both the prevention and treatment of prostate cancer. [Copyright &y& Elsevier]