Phosphonium/ammonium-based ionic liquids for rare earth minerals beneficiation : case of monazite and bastnäsite

Tableau d'honneur de la Faculté des études supérieures et postdoctorales, 2017-2018Cette thèse de doctorat porte sur l'application des liquides ioniques à base de phosphonium et d'ammonium pour l'enrichissement des minéraux à base d'éléments de terres rares. Le manuscrit de thèse a été divisé en quatre parties principales. Tout d'abord, l'utilisation des liquides ioniques à base de phosphonium et d'ammonium a été explorée dans trois procédés différents pour la valorisation des minéraux de terres rares. Ces trois approches ont été examinées pour des minéraux à base d’éléments de terres rares contenus dans un minerai complexe en provenance du gisement Niobec au Québec ainsi que des minéraux modèles de monazite et de bastnäsite associés à la gangue du minerai Niobec. Par la suite, l'application de ces liquides ioniques à l'extraction par solvant des éléments des terres rares a été étudiée par simulation à l’aide d’outil de chimie quantique. Dans le premier cas de valorisation des minéraux de terres rares, l'application d'un liquide ionique à base de phosphonium /ammonium comme collecteur aqueux pour la flottation par moussage de minéraux des terres rares a été étudiée. Dans cette étude, le liquide ionique a été identifié pour posséder des performances supérieures à celles offertes par les collecteurs classiques utilisés en industrie comme les collecteurs dérivés de l'acide hydroxamique industriel. Les interactions anioniques et cationiques du liquide ionique durant la flottation des minéraux d’éléments de terres rares ont été scrutées en détail pour révéler qu’une voie de synergie interne explique en partie les résultats de la flottation en terme de chimisorption de la partie anionique et de la physisorption et de la partie cationique du liquide ionique. Dans le deuxième cas d'enrichissement des minéraux de terres rares, le potentiel de la séparation minérale liquide (aqueuse)-liquide (organique) au moyen de trois types de liquides ioniques à base de phosphonium /ammonium a été étudié. Cette approche s'est avérée supérieure à la micro-flottation conventionnelle appliquée aux mêmes minéraux en termes de sélectivité. De même, il a été démontré que ce procédé peut être appliqué avec efficacité sur une large gamme de pH (4-9) et pour des particules finement broyées (- 105 μm) pour fins de valorisation des minéraux de terres rares. Il a été révélé que l'interaction du liquide ionique sur les surfaces minérales se produisait en phase aqueuse, en phase aqueuse-organique et également en phase organique favorisant ainsi l'activation des minéraux et la séparation subséquente. Dans le troisième cas d'enrichissement des minéraux de terres rares, le potentiel de séparation dans un mélange de deux liquides ioniques immiscibles a enfin été exploré. Un liquide ionique à base de phosphonium / ammonium comme phase dispersées sous forme de gouttelettes et trois liquides ioniques différents faisaint office de phase continue ont été utilisés pour évaluer cette nouvelle approche d'enrichissement des minéraux d’éléments de terres rares. Ce processus s’est avéré très prometteur en tant qu'alternative d'enrichissement des minéraux à base d’éléments de terres rares comparativment aux deux approches précédentes en termes de sélectivité et de récupération des éléments de terres rares. Enfin dans la dernière partie de la thèse, des simulations de type chimie quantique basée sur la théorie de la densité fonctionnelle (DFT) ont été mises en oeuvre pour proposer une méthode de classification reposant sur la stabilité de la formation de complexes à partir de trente différents liquides ioniques à base de phosphonium aidant à l'extraction par solvant des éléments de terres rares solvatés. Cette étude a d'une part montré que les liquides ioniques choisis peuvent être appliqués plus efficacement pour l'extraction par solvant des éléments de terres rares contenus dans les solutions aqueuses après digestion acide des minéraux par l’acide nitrique ou chlorhydrique plus que lors d’un recours à l'acide sulfurique. Il a ensuite été démontré que les groupements anioniques des liquides ioniques testés sont capables de former directement des liaisons covalentes par complexation avec les éléments des terres rares solvatés. Au contraire, les interactions des groupements cationiques ont été plus faibles se résumant à des interactions de sphère externe par rapport au complexes formés. Ce travail de recherche a permis d’explorer la faisabilité dans l'application des liquides ioniques à base de phosphonium au traitement des minéraux et des métaux de terres rares. Les résultats obtenus durant cette étude pourront contribuer à une meilleure compréhension de l’apport des liquides ioniques au secteur des industries des terres rares afin en ayant pour cible l'amélioration de l'efficacité des procédés d'enrichissement des minéraux et d'extraction par solvant des éléments de terres rares dissous.This Ph.D. thesis examines the application of phosphonium/ammonium based ionic liquids in the beneficiation of rare earth element bearing minerals. It has been divided into four main parts. Firstly, the use of phosphonium/ammonium based ionic liquids in three different approaches for rare earth element minerals beneficiation has been explored. These three processes were examined for actual rare earth elements bearing complex ore from Niobec deposit as well as for its constitutive model minerals consisting of monazite and bastnäsite associated with other gangue minerals. Subsequently, application of phosphonium based ionic liquids in rare earth elements solvent extraction has been studied from quantumchemistry point of view. In the first process in rare earth element minerals beneficiation, application of a phosphonium/ammonium based ionic liquid as an aqueous collector for froth flotation of rare earth element minerals was studied. In this study, the ionic liquid revealed superior performance to recover rare earth elements bearing minerals as compared with industrial hydroxamic acid collectors. The ionic liquid anionic and cationic moieties interactions during rare earth element minerals flotation were rationalized in terms of an inner synergistic pathway, meaning that the uptake of both cationic and anionic moieties through ionic liquid collector adsorption occurred altogether. In the second process in rare earth element minerals beneficiation, the potential of liquid-liquid mineral separation mediated by means of three types of phosphonium/ammonium based ionic liquids to beneficiate rare earth elements bearing minerals was studied. This process was found to outperform micro-flotation of the same minerals in terms of selectivity. Likewise, it was shown that this process can be effectively applied over a wide range of pH (4-9) and for fine particle sizes (-105 μm) in rare earth element minerals beneficiation. Interaction of the ionic liquid on the mineral surfaces occurred in aqueous phase, aqueousorganic phases interface and also in the organic phase thereby promoting minerals activation and next separation. In the third process in rare earth element minerals beneficiation, the potential of ionic liquid-ionic liquid mineral separation process as a novel ionic liquid-based system to beneficiate rare earth elements bearing minerals was investigated. A phosphonium/ammonium based ionic liquid as droplet phase and three different ionic liquids as continuous phase were used to assess this approach of beneficiation of rare earth elements bearing minerals. This process revealed high potential, as an alternative, to beneficiate rare earth elements bearing ore as it even outperformed the two previous processes in terms of selectivity and rare earth elements recovery. In the last part of this thesis, quantum chemistry simulations based on DFT have been undertaken to rank the complex-forming ability of thirty different phosphonium based ionic liquids in solvent extraction of rare earth elements. This study firstly indicated that phosphonium based ionic liquids can be applied more effectively for solvent extraction of rare earth elements in pregnant solutions resulting from nitric and hydrochloride acids leaching process, and less by means of sulfuric acid leaching. It was also demonstrated that while anionic moieties of phosphonium based ionic liquids are able to make directly covalent bonds during complexation with rare earth elements, their cationic moieties can be involved in complexation through outer-sphere interactions. The implications of this research work include new insights towards application of phosphonium based ionic liquids into mineral and metal processing especially rare earth elements processing. Finding from this work can contribute to the rare earth industry in order to improve efficiency of mineral beneficiation and solvent extraction processes

MicroRNAs and pro-inflammatory cytokines as candidate biomarkers for recent-onset psychosis

Background: Recent studies on the schizophrenia spectrum and other psychotic disorders showed that alternation of immune system components, particularly microRNAs (miRNAs) and pro-inflammatory compounds, plays a significant role in developing the illness. The study aimed to evaluate serum expression of the miRNA-26a, miRNA-106a, and miRNA-125b as genetic factors and serum levels of IL-6, IL-1β, and TNF-α as pro-inflammatory factors in an IranianAzeri population. Methods: Forty patients with recent-onset non-affective psychosis and 40 healthy people as a control group were involved. Expression levels of miRNAs and serum levels of the cytokines were measured using RT-qPCR and ELISA, respectively. T-test, receiver operating characteristics (ROC), and spearman correlation coefficient were carried out data analysis. Results: Findings showed higher levels of IL-6, IL-1β, TNF-α, miR-26a, and miR-106a in the plasma of the patients’ group compared with the control. miRNA-26a showed a statistically significant higher level (p &lt;.003) compared to the control group, with AUC = 0.84 (95% CI: 0.77 to 0.93, P &lt;.001) and cut-off point = 0.17 in comparison to other miRNAs as mentioned above; in this regard, it might be a suggestive biomarker for schizophrenia in the early stage of the illness. Moreover, miRNAs’ expression level was not substantially associated with the level of any measured cytokines above. Conclusions: miR-26a might be a suggestive biomarker for schizophrenia in the early stage of the illness. Given that the relationship between other miRNAs and cytokines is not yet well understood; accordingly, there are encouragement and support for continued research in this fascinating field.</p

MicroRNAs and pro-inflammatory cytokines as candidate biomarkers for recent-onset psychosis

Background: Recent studies on the schizophrenia spectrum and other psychotic disorders showed that alternation of immune system components, particularly microRNAs (miRNAs) and pro-inflammatory compounds, plays a significant role in developing the illness. The study aimed to evaluate serum expression of the miRNA-26a, miRNA-106a, and miRNA-125b as genetic factors and serum levels of IL-6, IL-1β, and TNF-α as pro-inflammatory factors in an IranianAzeri population. Methods: Forty patients with recent-onset non-affective psychosis and 40 healthy people as a control group were involved. Expression levels of miRNAs and serum levels of the cytokines were measured using RT-qPCR and ELISA, respectively. T-test, receiver operating characteristics (ROC), and spearman correlation coefficient were carried out data analysis. Results: Findings showed higher levels of IL-6, IL-1β, TNF-α, miR-26a, and miR-106a in the plasma of the patients’ group compared with the control. miRNA-26a showed a statistically significant higher level (p &lt;.003) compared to the control group, with AUC = 0.84 (95% CI: 0.77 to 0.93, P &lt;.001) and cut-off point = 0.17 in comparison to other miRNAs as mentioned above; in this regard, it might be a suggestive biomarker for schizophrenia in the early stage of the illness. Moreover, miRNAs’ expression level was not substantially associated with the level of any measured cytokines above. Conclusions: miR-26a might be a suggestive biomarker for schizophrenia in the early stage of the illness. Given that the relationship between other miRNAs and cytokines is not yet well understood; accordingly, there are encouragement and support for continued research in this fascinating field.</p

Oman Medical Specialty Board Calcium Intervention Ameliorates Experimental Model of Multiple Sclerosis

Abstract Objective: Multiple sclerosis (MS) is the most common inflammatory disease of the CNS. Experimental autoimmune encephalomyelitis (EAE) is a widely used model for MS. In the present research, our aim was to test the therapeutic efficacy of Calcium (Ca) in an experimental model of MS. Methods: In this study the experiment was done on C57BL/6 mice. EAE was induced using 200 μg of the MOG 35-55 peptide emulsified in CFA and injected subcutaneously on day 0 over two flank areas. In addition, 250 ng of pertussis toxin was injected on days 0 and 2. In the treatment group, 30 mg/kg Ca was administered intraperitoneally four times at regular 48 hour intervals. The mice were sacrificed 21 days after EAE induction and blood samples were taken from their hearts. The brains of mice were removed for histological analysis and their isolated splenocytes were cultured. Results: Our results showed that treatment with Ca caused a significant reduction in the severity of the EAE. Histological analysis indicated that there was no plaque in brain sections of Ca treated group of mice whereas 4 ± 1 plaques were detected in brain sections of controls. The density of mononuclear infiltration in the CNS of Ca treated mice was lower than in controls. The serum level of Nitric Oxide in the treatment group was lower than in the control group but was not significant. Moreover, the levels of IFN-γ in cell culture supernatant of splenocytes in treated mice were significantly lower than in the control group. Conclusion: The data indicates that Ca intervention can effectively attenuate EAE progression

Cardiovascular disease, chronic kidney disease, and diabetes mortality burden of cardiometabolic risk factors from 1980 to 2010: A comparative risk assessment

Background: High blood pressure, blood glucose, serum cholesterol, and BMI are risk factors for cardiovascular diseases and some of these factors also increase the risk of chronic kidney disease and diabetes. We estimated mortality from cardiovascular diseases, chronic kidney disease, and diabetes that was attributable to these four cardiometabolic risk factors for all countries and regions from 1980 to 2010. Methods: We used data for exposure to risk factors by country, age group, and sex from pooled analyses of population-based health surveys. We obtained relative risks for the effects of risk factors on cause-specific mortality from meta-analyses of large prospective studies. We calculated the population attributable fractions for each risk factor alone, and for the combination of all risk factors, accounting for multicausality and for mediation of the effects of BMI by the other three risks. We calculated attributable deaths by multiplying the cause-specific population attributable fractions by the number of disease-specific deaths. We obtained cause-specific mortality from the Global Burden of Diseases, Injuries, and Risk Factors 2010 Study. We propagated the uncertainties of all the inputs to the final estimates. Findings: In 2010, high blood pressure was the leading risk factor for deaths due to cardiovascular diseases, chronic kidney disease, and diabetes in every region, causing more than 40% of worldwide deaths from these diseases; high BMI and glucose were each responsible for about 15% of deaths, and high cholesterol for more than 10%. After accounting for multicausality, 63% (10·8 million deaths, 95% CI 10·1-11·5) of deaths from these diseases in 2010 were attributable to the combined effect of these four metabolic risk factors, compared with 67% (7·1 million deaths, 6·6-7·6) in 1980. The mortality burden of high BMI and glucose nearly doubled from 1980 to 2010. At the country level, age-standardised death rates from these diseases attributable to the combined effects of these four risk factors surpassed 925 deaths per 100 000 for men in Belarus, Kazakhstan, and Mongolia, but were less than 130 deaths per 100 000 for women and less than 200 for men in some high-income countries including Australia, Canada, France, Japan, the Netherlands, Singapore, South Korea, and Spain. Interpretation: The salient features of the cardiometabolic disease and risk factor epidemic at the beginning of the 21st century are high blood pressure and an increasing effect of obesity and diabetes. The mortality burden of cardiometabolic risk factors has shifted from high-income to low-income and middle-income countries. Lowering cardiometabolic risks through dietary, behavioural, and pharmacological interventions should be a part of the global response to non-communicable diseases. Funding: UK Medical Research Council, US National Institutes of Health. © 2014 Elsevier Ltd

Cardiovascular disease, chronic kidney disease, and diabetes mortality burden of cardiometabolic risk factors from 1980 to 2010: A comparative risk assessment

Background: High blood pressure, blood glucose, serum cholesterol, and BMI are risk factors for cardiovascular diseases and some of these factors also increase the risk of chronic kidney disease and diabetes. We estimated mortality from cardiovascular diseases, chronic kidney disease, and diabetes that was attributable to these four cardiometabolic risk factors for all countries and regions from 1980 to 2010. Methods: We used data for exposure to risk factors by country, age group, and sex from pooled analyses of population-based health surveys. We obtained relative risks for the effects of risk factors on cause-specific mortality from meta-analyses of large prospective studies. We calculated the population attributable fractions for each risk factor alone, and for the combination of all risk factors, accounting for multicausality and for mediation of the effects of BMI by the other three risks. We calculated attributable deaths by multiplying the cause-specific population attributable fractions by the number of disease-specific deaths. We obtained cause-specific mortality from the Global Burden of Diseases, Injuries, and Risk Factors 2010 Study. We propagated the uncertainties of all the inputs to the final estimates. Findings: In 2010, high blood pressure was the leading risk factor for deaths due to cardiovascular diseases, chronic kidney disease, and diabetes in every region, causing more than 40% of worldwide deaths from these diseases; high BMI and glucose were each responsible for about 15% of deaths, and high cholesterol for more than 10%. After accounting for multicausality, 63% (10·8 million deaths, 95% CI 10·1-11·5) of deaths from these diseases in 2010 were attributable to the combined effect of these four metabolic risk factors, compared with 67% (7·1 million deaths, 6·6-7·6) in 1980. The mortality burden of high BMI and glucose nearly doubled from 1980 to 2010. At the country level, age-standardised death rates from these diseases attributable to the combined effects of these four risk factors surpassed 925 deaths per 100 000 for men in Belarus, Kazakhstan, and Mongolia, but were less than 130 deaths per 100 000 for women and less than 200 for men in some high-income countries including Australia, Canada, France, Japan, the Netherlands, Singapore, South Korea, and Spain. Interpretation: The salient features of the cardiometabolic disease and risk factor epidemic at the beginning of the 21st century are high blood pressure and an increasing effect of obesity and diabetes. The mortality burden of cardiometabolic risk factors has shifted from high-income to low-income and middle-income countries. Lowering cardiometabolic risks through dietary, behavioural, and pharmacological interventions should be a part of the global response to non-communicable diseases. Funding: UK Medical Research Council, US National Institutes of Health. © 2014 Elsevier Ltd

Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

Background: Understanding the health consequences associated with exposure to risk factors is necessary to inform public health policy and practice. To systematically quantify the contributions of risk factor exposures to specific health outcomes, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 aims to provide comprehensive estimates of exposure levels, relative health risks, and attributable burden of disease for 88 risk factors in 204 countries and territories and 811 subnational locations, from 1990 to 2021. Methods: The GBD 2021 risk factor analysis used data from 54 561 total distinct sources to produce epidemiological estimates for 88 risk factors and their associated health outcomes for a total of 631 risk–outcome pairs. Pairs were included on the basis of data-driven determination of a risk–outcome association. Age-sex-location-year-specific estimates were generated at global, regional, and national levels. Our approach followed the comparative risk assessment framework predicated on a causal web of hierarchically organised, potentially combinative, modifiable risks. Relative risks (RRs) of a given outcome occurring as a function of risk factor exposure were estimated separately for each risk–outcome pair, and summary exposure values (SEVs), representing risk-weighted exposure prevalence, and theoretical minimum risk exposure levels (TMRELs) were estimated for each risk factor. These estimates were used to calculate the population attributable fraction (PAF; ie, the proportional change in health risk that would occur if exposure to a risk factor were reduced to the TMREL). The product of PAFs and disease burden associated with a given outcome, measured in disability-adjusted life-years (DALYs), yielded measures of attributable burden (ie, the proportion of total disease burden attributable to a particular risk factor or combination of risk factors). Adjustments for mediation were applied to account for relationships involving risk factors that act indirectly on outcomes via intermediate risks. Attributable burden estimates were stratified by Socio-demographic Index (SDI) quintile and presented as counts, age-standardised rates, and rankings. To complement estimates of RR and attributable burden, newly developed burden of proof risk function (BPRF) methods were applied to yield supplementary, conservative interpretations of risk–outcome associations based on the consistency of underlying evidence, accounting for unexplained heterogeneity between input data from different studies. Estimates reported represent the mean value across 500 draws from the estimate's distribution, with 95% uncertainty intervals (UIs) calculated as the 2·5th and 97·5th percentile values across the draws. Findings: Among the specific risk factors analysed for this study, particulate matter air pollution was the leading contributor to the global disease burden in 2021, contributing 8·0% (95% UI 6·7–9·4) of total DALYs, followed by high systolic blood pressure (SBP; 7·8% [6·4–9·2]), smoking (5·7% [4·7–6·8]), low birthweight and short gestation (5·6% [4·8–6·3]), and high fasting plasma glucose (FPG; 5·4% [4·8–6·0]). For younger demographics (ie, those aged 0–4 years and 5–14 years), risks such as low birthweight and short gestation and unsafe water, sanitation, and handwashing (WaSH) were among the leading risk factors, while for older age groups, metabolic risks such as high SBP, high body-mass index (BMI), high FPG, and high LDL cholesterol had a greater impact. From 2000 to 2021, there was an observable shift in global health challenges, marked by a decline in the number of all-age DALYs broadly attributable to behavioural risks (decrease of 20·7% [13·9–27·7]) and environmental and occupational risks (decrease of 22·0% [15·5–28·8]), coupled with a 49·4% (42·3–56·9) increase in DALYs attributable to metabolic risks, all reflecting ageing populations and changing lifestyles on a global scale. Age-standardised global DALY rates attributable to high BMI and high FPG rose considerably (15·7% [9·9–21·7] for high BMI and 7·9% [3·3–12·9] for high FPG) over this period, with exposure to these risks increasing annually at rates of 1·8% (1·6–1·9) for high BMI and 1·3% (1·1–1·5) for high FPG. By contrast, the global risk-attributable burden and exposure to many other risk factors declined, notably for risks such as child growth failure and unsafe water source, with age-standardised attributable DALYs decreasing by 71·5% (64·4–78·8) for child growth failure and 66·3% (60·2–72·0) for unsafe water source. We separated risk factors into three groups according to trajectory over time: those with a decreasing attributable burden, due largely to declining risk exposure (eg, diet high in trans-fat and household air pollution) but also to proportionally smaller child and youth populations (eg, child and maternal malnutrition); those for which the burden increased moderately in spite of declining risk exposure, due largely to population ageing (eg, smoking); and those for which the burden increased considerably due to both increasing risk exposure and population ageing (eg, ambient particulate matter air pollution, high BMI, high FPG, and high SBP). Interpretation: Substantial progress has been made in reducing the global disease burden attributable to a range of risk factors, particularly those related to maternal and child health, WaSH, and household air pollution. Maintaining efforts to minimise the impact of these risk factors, especially in low SDI locations, is necessary to sustain progress. Successes in moderating the smoking-related burden by reducing risk exposure highlight the need to advance policies that reduce exposure to other leading risk factors such as ambient particulate matter air pollution and high SBP. Troubling increases in high FPG, high BMI, and other risk factors related to obesity and metabolic syndrome indicate an urgent need to identify and implement interventions

Recovery and Recycling of Valuable Metals

Metals have always played a significant role in human life; contemporary global growth and prosperity are directly dependent on these materials [...