Alternative Dissolution Methods for Analysis of Niobium containing Samples

Inductively coupled plasma optical emission spectrometry was applied for the qualitative and quantitative analyses of the different high purity Nb containing samples such as Nb metal, Nb2O5 and NbF5. Microwave-assisted digestion of the Nb compounds with concentrated H2SO4 in PTFE vessels produced Nb recoveries of 99.90 ± 0.08 % for Nb metal, 98.8 ± 0.7 % for Nb2O5 and 100.7±0.4%for NbF5. Fusion of Nb2O5 with Li2B4O7 flux and the subsequent dissolution of the melt with concentrated H2SO4 resulted in the precipitation of H3BO3 under these conditions. Methanol was added to the reaction mixture to convert the boric acid into the volatile methyl ester in an effort to remove the excess H3BO3. This procedure yielded a recovery of 103±2%for the pure Nb2O5 sample.Keywords: Niobium Samples, Microwave Dissolution, Fusion Dissolution, Qualitative Analysis, Quantitative Analysis, Validatio

Dissolution and Quantification of Tantalum-Containing Compounds: Comparison with Niobium

Dissolution and quantification of different tantalum compounds was undertaken as part of the development of local processes for the beneficiation and separation of tantalum and niobium from different mineral ores. Dissolution of Ta metal powder, TAN-1 CRM, TaF5, TaCl5 and Ta2O5 was undertaken with different acid, alkaline fluxes as well as with microwave digestion while quantification was performed using ICP-OES analysis. The success of the different dissolution methods was evaluated on percentage recovery basis, the results discussed and finally compared with those obtained from the corresponding niobium compounds. Quantification results obtained from this study clearly indicated that the percentage recovery of tantalum depended on i) the type of tantalum source and ii) the dissolution process of the different tantalum compounds. Excellent recoveries were obtained with water soluble TaF5 and TaCl5 with 101(1) and 100(2)% respectively. Low tantalum recovery was obtained for Ta metal and Ta2O5 with microwave digestion in the presence of strong acids (4.1(8) and 9.7(8) %, respectively in the presence of H2SO4) and acidic fluxes (1.5(5) % with K2S2O7). Improved recoveries were obtained using basic fluxes for both the metal and the oxide. Fluxing the metal with KOH resulted in a 85(3) % Ta recovery while a maximum of 68(4) % Ta recovery was obtained for Ta2O5. Tantalum recoveries of between 75(10) and 90(6)% were obtained for TAN-1 CRM (Ta present as Ta2O5) and 95(6)% for Ta2O5 with Li2B4O7 as fluxing agent on the removal of the excess of boric acid prior to analysis. A stability study indicated constant recovery in a basic medium while a decrease of up to 10 % in tantalum recovery was obtained in an acidic environment. A comparison with the niobium results obtained in a previous study highlighted the different acid/base properties of the two oxides as well as a possible alternative dissolution/ separation step for the two elements from the mineral ore.Keywords: Dissolution, microwave, fluxes, tantalum, recover

Possible methodology for niobium, tantalum and scandium separation in ferrocolumbite

© 2018 Elsevier Ltd. Ferrocolumbite is a well-known source of Ta, Nb and Sc. However, separation of these elements from such ores/process tailings, as well from each other is problematic, and typically involves numerous separation steps and very corrosive and hazardous chemicals. An investigation was therefore launched to evaluate alternative separation options. As part of this endeavour it was necessary to investigate accurate quantification methods to be able to trace the elements during any proposed process. Ferrocolumbite was successfully dissolved with NH 4 F⋅HF (1:10 sample to flux ratio at 200 °C for 60 min), which yielded solutions containing 91% Ta, 96% Nb and 99% Sc recoveries while satisfactory LODs (0.07768, 0.01045 and 0.001085 mg/L respectively) were also obtained. Inclusion of a magnetic separation step (only 31% Fe in magnetic portion) to simplify the down-stream beneficiation processes did not contribute to the successful removal of Fe/Ti. Methyl isobutyl ketone (MIBK) successfully extracted the Ta in the ore (94%) into the organic layer and left Nb (88%) and Sc (99%) in the aqueous layer at [H 2 SO 4 ] 10 M) the Sc present in the non-magnetic portion of the ore migrated in significant amounts and quantities (95%) to the organic layer. Thus a possible process for the separation of the three elements from one another was created. Octan-1-ol yielded similar results to MIBK while methyl isoamyl ketone (MIAK) successfully removed Ta from the aqueous layer (87%), but left the two other elements in the aqueous layer, even at 16 M [H 2 SO 4 ]. A much simplified process flow sheet compared to current operational practices for the possible separation of Nb, Ta and Sc from ferrocolumbite and mine tailings is proposed

Plasma Metabolomics Identifies Markers of Impaired Renal Function: A Meta-analysis of 3089 Persons with Type 2 Diabetes

CONTEXT: There is a need for novel biomarkers and better understanding of the pathophysiology of diabetic kidney disease. OBJECTIVE: To investigate associations between plasma metabolites and kidney function in people with type 2 diabetes (T2D). DESIGN: 3089 samples from individuals with T2D, collected between 1999 and 2015, from 5 independent Dutch cohort studies were included. Up to 7 years follow-up was available in 1100 individuals from 2 of the cohorts. MAIN OUTCOME MEASURES: Plasma metabolites (n = 149) were measured by nuclear magnetic resonance spectroscopy. Associations between metabolites and estimated glomerular filtration rate (eGFR), urinary albumin-to-creatinine ratio (UACR), and eGFR slopes were investigated in each study followed by random effect meta-analysis. Adjustments included traditional cardiovascular risk factors and correction for multiple testing. RESULTS: In total, 125 metabolites were significantly associated (PFDR = 1.5×10-32 - 0.046; β = -11.98-2.17) with eGFR. Inverse associations with eGFR were demonstrated for branched-chain and aromatic amino acids (AAAs), glycoprotein acetyls, triglycerides (TGs), lipids in very low-density lipoproteins (VLDL) subclasses, and fatty acids (PFDR < 0.03). We observed positive associations with cholesterol and phospholipids in high-density lipoproteins (HDL) and apolipoprotein A1 (PFDR < 0.05). Albeit some metabolites were associated with UACR levels (P < 0.05), significance was lost after correction for multiple testing. Tyrosine and HDL-related metabolites were positively associated with eGFR slopes before adjustment for multiple testing (PTyr = 0.003; PHDLrelated < 0.05), but not after. CONCLUSIONS: This study identified metabolites associated with impaired kidney function in T2D, implying involvement of lipid and amino acid metabolism in the pathogenesis. Whether these processes precede or are consequences of renal impairment needs further investigation

Common variants upstream of KDR encoding VEGFR2 and in TTC39B associate with endometriosis.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.We conducted a genome-wide association scan (GWAS) of endometriosis using 25.5 million sequence variants detected through whole-genome sequencing (WGS) of 8,453 Icelanders and imputed into 1,840 cases and 129,016 control women, followed by testing of associated variants in Danish samples. Here we report the discovery of a new endometriosis susceptibility locus on 4q12 (rs17773813[G], OR=1.28; P=3.8 × 10(-11)), upstream of KDR encoding vascular endothelial growth factor receptor 2 (VEGFR2). The variant correlates with disease severity (P=0.0046) when moderate/severe endometriosis cases are tested against minimal/mild cases. We further report association of rs519664[T] in TTC39B on 9p22 with endometriosis (P=4.8 × 10(-10); OR=1.29). The involvement of KDR in endometriosis risk highlights the importance of the VEGF pathway in the pathogenesis of the disease.e Danish National Research Foundation. Additional support for the DNBC has been obtained from the Danish Pharmacists’ Fund, the Egmont Foundation, the March of Dimes Birth Defects Foundation, the Augustinus Foundation and the Health Fund of the Danish Health Insurance Societies. B.F. is supported by an Oak Foundation fellowshi

Long-term effects of a preoperative smoking cessation programme

Introduction: Preoperative smoking intervention programmes reduce post‐operative complications in smokers. Little is known about the long‐term effect upon smoking cessation. Aim: To discover long‐term quit rates and the reasons behind successful cessation. Materials and Methods: 101 one of 120 smokers, randomised to smoking intervention or no intervention before hip and knee surgery, completed questionnaires concerning smoking after 1 year. We selected representative men and women for focus group interviews. Results: Significantly more patients from the intervention group abstained from smoking for 1 year post‐operatively [13 in 60 patients (22%) vs 2 in 60 (3%), P < 0.01]. Sex (male), low nicotine dependency, non‐smoking spouse and preoperative smoking intervention were related to smoking cessation. All patients gave the same reasons for smoking cessation: improved health and saving money. Follow‐up for 5 years showed 17% of the controls and 8% in the intervention group (P = 0.42) had died. Conclusion: The intervention group had a significantly higher quit rate 1 year after a preoperative smoking cessation programme