To test how well the Hubbertcurve fits the data, the logistic equation will be plotted against data of cumulative rareearth element production and time (years) for the United States, China and Global production respectively. The data were gathered from the United States Geological Survey and put into an Excel spreadsheet. All rareearth element amounts throughout are in metric tons (t). These data, however, only have annual production data, not cumulative data. To correct this, the earliest point of data was called year 1 and cumulative production was calculated by adding each annual production together up to the desired year. These data were then put into Stata and a nonlinear regression was run to determine the values of 𝑄𝑄𝑄𝑄 𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 , 𝑎𝑎𝑎𝑎 and 𝑏𝑏𝑏𝑏.
which holds about 90% of world production, reaching 2013 to 111,800 t. The figure points out the steady in- crease in the rareearthproduction due mainly to continuous increase of the Chinese market share, particularly since 2002, when the American mine was closed due to environmental problems and low competitiveness be- cause of low Chinese prices . Though the fact that China produces more than 95% of the global production, their share of the reserves is much lower at 38%. Large deposits are also found in the USA, Australia and states of the former Soviet Union.
The present study was investigated to study the impact of Rareearthelements in growth of wheat. The soil samples were collected from rareearth environments and analyzed by ICP-MS to know constituents of the rareearthelements. Cerium and Neodymium are abundant in the analyzed samples. The physical parameters of the wheat biomass are evaluated with and without treatment of REEs and also treated with REEs and a bacterial strain (Pseudomonas sp.,). From the results it is evident that a significant increase in root and shoot length, dry weight and wet weight of plants treated with REEs. The production stress resistant end product (phenol) is measured and the total content of soluble phenols is calculated. Seeds treated with element alone show two fold increases in the production of phenol. The diverse parts of plant samples (root, shoot and leaves) are digested analyzed by ICP-OES analysis. It reveals that a maximum accumulation of REEs (Cerium and Neodymium) in plant tissues and higher input of REEs yields high accumulation and lower inputs yield low accumulation. The seeds treated with culture are shown drastic change in the accumulation of REEs by wheat.
for the detection of possible adulterations. In this work, a simple, cheap and reliable high performance liquid chromatography method with ultraviolet detection (HPLC-UV) for the determination of polyphenolic profiles in the classification and authentication of olive oils was developed. A total of 138 olive oils were processed by liquid- liquid extraction using ethanol:water 70:30 v/v solution and defatted with hexane . The extracts were then analyzed by reversed-phase chromatography using a Zorbax Eclipse XDB-C8 column under gradient elution with 0.1% formic acid aqueous solution and methanol as mobile phase. First, 72 vegetable oils including 47 EVOOs, 16 sunflower oils, 2 corn oils, 2 soy oils, and 5 vegetable oils produced from mixtures of seeds were analyzed. HPLC-UV chromatographic fingerprints recorded at different acquisition wavelengths were submitted to exploratory principal component analysis (PCA). Good classification and discrimination of EVOOs against other vegetable oils was achieved. Then, characterization and classification of EVOOs regarding the olive cultivar of origin was attempted. For that purpose, 66 monovarietal EVOOs (23 Arbequina, 19 Picual, 12 Hojiblanca and 12 Cornicabra) were analyzed and the obtained HPLC-UV data submitted to PCA. In this case, the selection of some specific chromatographic time-window segments was required to achieve a satisfactory discrimination of EVOOs regarding the olive cultivar of production.
4.1 Adsorption isotherm of Nd ion onto the phormidium Kinetic studies involve eﬀect of major parameters such as adsorbent dosage and contact time on the uptake of REEs by phormidium. The production volume of Nd has dramatically increased since the development of a Nd-Fe-B permanent magnet, which had the strongest magnet power, in the 1980s. Presently, more than 10,000 tons of Nd-Fe-B alloy magnets are annually produced in Japan. Therefore, the kinetic studies were focused on Nd ion. 8,9) Adsorbent dosage has a great
detectable signal. The latter leads to lower plasma temperature and associated increased oxide rates. The ThO/Th + ratio was monitored for experiments run in both standard and KED mode and found to be consistently below 0.2% in standard mode and below 2% in KED mode. No correction for oxide interference was employed but possible analytical artefacts due to unaccounted oxide interference were tested by quantifying the data with two reference materials with very different relative REE abundance: BHVO-2G (Basalt, Hawaiian Volcanic Observatory, a natural reference material with Oddo-Harkins effect abundances) and NIST SRM 612 (an artificial equal atom reference material). The resulting REE patterns of samples were statistically not resolvable despite the very different relative production rates of LREE and MREE oxides from these reference materials, showing that oxide formation had a negligible effect on final measured values. The agreement between REE concentrations for those samples run in both standard and KED mode provides additional support for uncorrected oxide
China has managed to capitalize on the rareearth element industry by developing the resources (technology, techniques and an experienced labor force) required to efficiently and effectively mine, extract, separate and refine rareearth minerals at more operationally feasible costs than other countries. As a result, it became more economically viable for countries, such as the United States, to cease production of rareearth minerals and import them from China. This operational efficiency has caused China to effectively emerge as the leading supplier of rareearth minerals to an extent that could be easily equated to a monopoly. The fact that China controls the global supply of rareearth metal allows the country to effectively control quality, quantity and ultimately the prices of these rareearthelements through export quotas and trade tariffs.
been inferred to have a bulk solid/liquid distribution coeﬃ- cient (D) similar to that of the light to middle rareearth ele- ments, Ce, Nd, and Pr, based on the constancy of the Mo/Ce, Mo/Nd, Mo/Pr ratios observed in various terres- trial samples (Sims et al., 1990; Newsom and Palme, 1984; Newsom et al., 1986). Hekla lavas show that although statis- tically indistinguishable, the Ce/Mo ratio decreases system- atically from 50 to 36 from basalts to rhyolites, indicating that Mo is slightly more incompatible than Ce during mag- matic diﬀerentiation (Fig. 3a). Both elements remain incom- patible (bulk D < 1) throughout the sequence however. In contrast to the relative incompatibility expected for mantle melting (Sun and McDonough, 1989), Mo is more incom- patible than Nb and Ta during magmatic diﬀerentiation at Hekla (Fig. 3c and d), with a decrease from 29 to 17 for Nb/Mo and 1.7 to 0.4 for Ta/Mo. This presumably reﬂects the removal of accessory phases that fractionate high ﬁeld strength elements (HFSE). Rubidium is more incompatible than Mo, the Rb/Mo nearly doubling from 8 to 14 from basalt to rhyolite (Fig. 3e). The K/Rb displays a concomi- tant decrease from 430 to 350. As a result, the K/Mo ratio increases only slightly from 4; 000 to 5; 000 (Fig. 3f). Therefore, the bulk D for Mo these in magmas must lie between that of K and that of Ce. This is conﬁrmed by inspection of the La/Mo ratio, which is relatively uniform in Hekla lavas (Fig. 3b). There seems to be a hint of diﬀer- ences in La/Mo and Ce/Mo ratios between basalt and dacite (Fig. 3a and b), and the ratios of andesite fall in between them, which could be an indication of mixing eﬀect. This concurs with the proposed three-stages model for Hekla magmas (Sigmarsson et al., 1992). The diﬀerence between basalt and dacite in La/Mo or Ce/Mo may have resulted from processes related to partial melting. While this is con- sistent with the three-stage model, it should be noted that the eﬀect is small; the LREE/Mo ratios for all Hekla lavas are very similar.
In the Nechalacho deposit, rare-metal mineralization was initially concentrated magmatically in eudialyte and possibly other zirconosilicates. Monazite-(Ce) chemistry does not support the hypothesis that LREE in the Upper Zone were sourced from the Basal Zone. The presence of possible zirconosilicate pseudomorphs in the Upper Zone, suggests that the Upper Zone contained eudialyte. Two alteration events have been identified that were responsible for the redistribution of the rare-metals from the eudialyte in both the Upper and Basal zones. The first was a magnetite-biotite-quartz alteration event during which zircon, columnar monazite-(Ce), fergusonite-(Y), xenotime-(Y), columbite-(Fe) and allanite-(Ce) were precipitated. This alteration event transported LREE, and to a lesser extent, HREE and Nb, over distances of at least 20 m. In parts of the Basal Zone, Zr was also mobile on the scale of at least decimetres, which is significantly farther than the several millimetres suggested previously. The fluids responsible for the magnetite-biotite-quartz alteration had temperatures of ~240-590 °C and salinities of ~8.5-13 wt. % NaCl (equiv.) . Alteration reactions indicate that these fluids contained Mg, P, and F. The need
Rods of magnetrostructive alloys of iron with rareearthelements are formed by flowing a body of rareearth- iron alloy in a crucible enclosed in a chamber maintained under an inert gas atmosphere, forcing such molten rare-earth-iron alloy into a hollow mold tube of refractory material positioned with its lower end portion within the molten body by means of a pressure differential between the chamber and mold tube and
(1) The binary eutectic-pairs and the e=a-invariant criteria are applied to the Mg-Cu-Gd based amorphous alloys. The experimental results are partly consistent with the predictions, but the models would fail when an excessive amount of the large-sized rare-earth element is added, as a result of crystallization tendency between Gd and Cu with a higher heat of mixing.
of significant removal of uranium and related elements from the host rocks around or adjacent to ore deposits, and this is due to the fact that all these objects were exposed to erosion, and we observe the upper parts of the ore sections where redistribution of uranium and associated ore elements occurs, therefore, their constant gain occurs. Therefore, in our opinion, this feature can be considered as a fairly obvious geochemical criterion for the formation of industrial mineralization at a depth. More precisely, the absence of uranium anomalies on the surface during the presence of abnormal concentrations of the above elements, the absence of radioactive anomalies cannot be a reason for refusing to study this area to a depth by drilling. Geochemical halos of elevated concentrations of uranium and related elements (Mo, Zn, Cd, Ag, TR, Se, Sc, etc.), which are clearly superimposed in the Altaintau field, as well as in the Boztau, SE-Boztau and Ustuk sections, are established different rocks of the black shale sequence. Such halos and anomalies developed within or around known uranium deposits and ore occurrences apparently reflect dispersion halos, which can be considered as geochemical criteria for the presence of mineralization exposed by erosion. Geochemical studies of vertical supergenic zoning in the ore occurrences of Boztau, Ustuk and some areas within the eastern part of the Altyntau ore field revealed certain differences in the behaviour of a number of related ore elements in it. So, we managed to find out that for each lateral type of uranium ores certain indicator elements are characteristic that form abnormal concentrations: for uranium-micaceous - molybdenum, REE, for pitchblende- black - selenium, lead, chromium, REE, for pitchblende- coffinite - zinc. At the same time, in all mineral associations of different types of ores, the presence of “through” elements-
Several studies have shown that wells in areas with particular geological features yield water that does not meet established drinking water norms without any in- fluence from anthropogenic contamination e.g. Misund et al., 1999 ; Frengstad et al., 2000 , Reimann et al. 2003 . This work is a continuation of a previous work where heavy metal contamination of the groundwater of south West Bank in Palestine was assessed by analysis of different heavy metals (Tl, Pb, Bi, Cr, Mn, Co, Ni, Cu, Zn, Mo, Al, Ag, and Cd) and results showed that 93% of all samples analyzed contained one or more of the 13 metals studied each in varying concentration, and some metals (Pb Cd, and Al) are found to be higher than the allowed WHO limits in some samples. The present paper reports analytical results for some rareelements (Rb, Zr, U, P, Ti, V, La, Ce, and Nd) as well as other common elements (Ca, Mg, K, Sr, Ba, and Bi) which most of them have no maximum allowed concentrations by WHO or any other regulation agencies. The current study also document that quite a number of elements for which no drinking water guideline values or maximum acceptable concentration limits have been established can occur at unpleasantly high levels in natural well waters (e.g. Li, Na, Mg, Ca, Sr, Ba, K, Bi).
The experiments were performed on an Agilent 1260 Bio-Inert HPLC system, consisting of two Agilent 1260 Bio-Inert Quaternary pumps, one Agilent Bio-Inert 1260 Autosampler and one Agilent 1260 Bio-Inert UV/Vis detector connected to an Agilent 7700 ICP-MS for detection of the rare earths. The column preparation was performed using a GE Healthcare ÄKTA Purifier 100. The individual rare earths were acquired from Merck at 1 g/L in nitric acid. The concentrated nitric acid of HPLC grade was acquired from Merck. The columns used were Kromasil C18, 100 Å, 16µm columns with immobilized HDEHP acting as ligand. HDEHP was acquired from Merck. Methanol was acquired from Merck. To be able to do higher flow rate experiments, an extra iso- cratic pump was added to the system after the column, and used to feed the ICP-MS with a constant flow of 1 ml/min, the rest going to waste or collection. The heavy mixture of rare earths used in the Thulium optimization was mixed to mimic an industrially relevant REE-stream, with a composition as described in Table 1.
Reserves of REE (metric tons) are mainly found in China (44,000,000), Brazil (22,000,000), Vietnam (22,000,000), Russia (12,000,000), India (6,900,000), Aus- tralia (3,400,000) and United States (1,400,000) , and other countries such as South Africa (860,000), Canada (830,000), Malawi (140,000) and Malaysia (30,000) . In Chile, information about REE ocurrences has increased over the last years due to work of some private companies, as well as studies generated by state research centers. These centers include the Chilean National Mining Cor- poration (ENAMI), Chilean Nuclear Energy Commission (CChEN) and Nation- al Geology and Mining Service (SERNAGEOMIN). The most relevant occur- rences (rare earths and uranium) are three mining projects evaluated by ENAMI and CChEN : Sierra Áspera, Cerro Carmen and Veracruz, in the Coastal Range of the Atacama region, northem Chile. Cerro Carmen, a Skarn deposit related to Cretacic intrusive and volcanic rocks, is considered the most attractive for exploitation. The main minerals found in this deposit are REE, iron-titanium, uranium and thorium oxides, with high concentrations of heavy rareearth ele- ments (HREE), particularly yttrium (140 ppm), dysprosium (20 ppm), holmium (5 ppm), erbium (21 ppm) and ytterbium (36 ppm). The total resources are 8203 tons of REE, with indicated resources of 2944 tons (grade of ~760 ppm), and 1811 tons of uranium.
fresh samples of intrusive rocks collected from Kerabai Volcanics. In order to avoid any contaminations and remove the weathered surfaces, rock samples were trimmed first. For XRF preparation, samples were crushed into a powder of 200 mesh using jaw crusher and corundum mill and a minimum of 5 gram weight powder sample was then fused into glass beads. The major, minor and trace elements were analyzed using X-Ray Fluorescence (XRF, Spectro Xepos) with a decent standard tolerance of Certified Reference Material (CRM), such as NIST40, IGS36 etc.
This mixing model can be checked against other elements by mixing average end- member compositions in the same estimated proportions as determined by Mn. Modeled and measured Ni and U show some deviations from the 1:1 mixing with U having the most deviation during the first ebbing tide (figure 4.7). However, all of the predicted values are well within 40% of the measured values. Given the variability of SF composition for these two elements (>170% for U, and >130% for Ni), the precision of this model using only the average composition is considered to be quite good, and could be improved if we were to arbitrarily pick a SF end-member composition from within the observed variability and optimize it to the best fit of the measured creek waters. The fact that Ni shows a correlation with Mn, suggests that there are similar processes involved in their export to the tidal creek.