Top PDF Electropolishing the rare earth metals

Electropolishing the rare earth metals

Electropolishing the rare earth metals

Chemical oxidation is the principle method of etching a metal surface for microscopic examination and the rare earths were etched in this manner... At room temperature, the nitric acid-a[r]

18 Read more

Extraction of rare earth and heavy metals, using ionic solvents as extraction medium (A Review)

Extraction of rare earth and heavy metals, using ionic solvents as extraction medium (A Review)

Nowadays, rare earth elements and heavy metals are big challenges for industries both environmentally and economically with the increasing demand of rare earth elements. This work listed the different techniques used to extract them from aqueous solution with the goal to reuse those metals after their extraction in wastes.

18 Read more

Analysis of Different Rare Metals, Rare Earth Elements, and other Common Metals in Groundwater of South West Bank/Palestine by ICP/MS Data and Health Aspects

Analysis of Different Rare Metals, Rare Earth Elements, and other Common Metals in Groundwater of South West Bank/Palestine by ICP/MS Data and Health Aspects

No drinking water standards are defined by EU, WHO or US EPA for Rb, Zr, La, Ce, Nd, P, Ti, and V. Several of these elements have documented health effects [13]. For others, for example the rare earth elements, knowl- edge about health effects are rather limited [24]. How- ever all of these elements are detected in all groundwater samples analyzed in this study. Additionally, some of these elements are unexpectedly and surprisingly detected with high concentrations e.g. P, V; the concentration of P ranges from 0.31 to 9.66 ppb with an average of 5.70 ppb, and the concentration of V ranges from 1.90 to 4.99 ppb with an average of 3.34 ppb. The concentration of Rb, Zr, La, Ce, Nd, and Ti was found to be in the range of 0.28 - 1.0 (average = 0.61 ppb), 0.02 - 1.13 (average = 0.30 ppb), 0.01 - 0.02 (average = 0.01 ppb), 0.02 - 0.09 (av- erage = 0.05 ppb), 0.01 - 0.03 (average = 0.01 ppb), 0.09 - 0.32 (average = 0.21 ppb), respectively. In addition to the potential pollution of groundwater with these rare elements, the concentrations of these elements such Bi, and rare earth elements, which are extremely low in na- tural waters, are of particular interest to fingerprint the groundwater sources [25].
Show more

8 Read more

Distribution of Rare Earth Metals in Technogenic Wastes of Energy Enterprises (Results of the Laboratory Studies)

Distribution of Rare Earth Metals in Technogenic Wastes of Energy Enterprises (Results of the Laboratory Studies)

The results of the research interaction between ash and slag samples from Vladivostok TPP’s landfills saturated with underburning and ammonium hydrodifluoride were given. It was found out that the reactions of the main components of a concentrate with NH 4 HF 2 are flowing with creation of complex ammonium fluoro-metalate. It is shown that the distribution of REM (rare earth metals) between foam and heavier products is going during the flotation process of carbon-containing ash and slag samples without significant concentrating. It is shown that the water leaching of fluoridated product lets transfer silicone, aluminum and iron salts into solution and concentrate rare earth elements in insoluble residue in the form of complex salts of NaLnF 4 general formula. We propose a schematic diagram of hydrodifluoride recycling of carbon-containing sample, which provides concentrating of REM with incomplete separation of macro-components.
Show more

6 Read more

Reclaim of Rare Earth Metals from Bond Magnets by Means of Thermally Activated Semiconductors (TASC)

Reclaim of Rare Earth Metals from Bond Magnets by Means of Thermally Activated Semiconductors (TASC)

atmosphere. Then, the tablet was placed in a mortar and ground easily into powders with a pestle. In this way, we have succeeded in reclaiming rare earth metals from bond magnets. We believe that our assumption (i.e., slight sintering of the magnetic particles) was right and that the dissolution of the sintered layer led to the successful pulverization of the lightly-sintered particles. It should also be noted that the use of a diluted acid is crucially important for the dissolution of metals, because concentrated acids often lead to the passivation of the metals.
Show more

6 Read more

Analysis of Different Rare Metals, and Rare Earth Metals in Harvested Rain Water in Gaza Strip/Palestine by ICP/MS Data and Health Aspects

Analysis of Different Rare Metals, and Rare Earth Metals in Harvested Rain Water in Gaza Strip/Palestine by ICP/MS Data and Health Aspects

of 1.0 ml of the water samples to 10.0 mL with 0.3% ultrapure nitric acid and analyzed by ICP/MS. Each sample was analyzed three times and the results are expressed as mean ± SD (SD: standard deviation). Relative standard deviation (RSD) of the three results are calculated and found to be less than 5% for all samples for all heavy metals analyzed in this study, reflecting the precision of the method for the analysis of these heavy metals. Calibration curves for all heavy metals analyzed were constructed by plotting the ratio of the intensity of the analyte heavy metal to that of the internal stan- dard vs. concentration of the heavy metal (in ppb), and results showed that the calibra- tion curves are linear with correlation coefficient (r 2 ) greater than 0.999 for the heavy
Show more

8 Read more

Rare earth metals asecofriendly corrosion inhibitors for mild steel in 
produced water

Rare earth metals asecofriendly corrosion inhibitors for mild steel in produced water

Spectrophotometric determination of the amounts of dissolved ironin produced water without and in the existence of 400 ppm of rare earth metals after exposing coupons for 6 days at 25°C are summarized in Table (5). Iron content in the produced water before immersion of coupons is 0.30 ppm represented in Table (1). After data correction and rounded, the amount of dissolved iron is low in the case of rare earth metals with respect to blank. The dissolution of metal in the existence of rare earth metals is low with respect to the blank. From the amount of dissolved iron, the surface coverage (ϴ) and %IE were calculated as follows [35]:
Show more

14 Read more

Distribution of Heavy Metals and Rare Earth Elements in the Surface Sediments of Penang River Estuary, Malaysia

Distribution of Heavy Metals and Rare Earth Elements in the Surface Sediments of Penang River Estuary, Malaysia

Pinang River is one of the seven most contaminated river basins in Malaysia and is classified as Class-IV by the Interim National Water Quality Standards for Malaysia [12] [13]. Mostly the wastewater discharges do not undergo appropriated water treatment. Land cover and land use change have also enhanced the removal, trans- port and accumulation of metals in sediments. The shore has been extended outwards through successive land reclamation which has moved the estuary seaward and the resultant changes of saline water intrusion during high tides which may affect the distribution of heavy metals and REE [14]. In tropical settings (marked by high rainfall and temperature), the contaminated river sediments pose even greater risk of becoming the secondary source of pollutants to the ocean as it may re-dissolve back from sediments into water column via remobilization through disturbance of physical, chemical and biological process. This work is important because Penang River provides many services such as drinking water, source of proteins (e.g. fish), transportation, agriculture, electric- ity generation and tourism. The primary aim of this study is, therefore, to determine the concentration of heavy metals and rare earth elements in surficial sediments of Penang River, and to assess the pollution level by using enrichment factor (EF) and Index of Geoaccumulation (I geo ).
Show more

14 Read more

Study of iron stripping from DEHPA 
		solutions during the process of rare earth metals extraction from 
		phosphoric acid

Study of iron stripping from DEHPA solutions during the process of rare earth metals extraction from phosphoric acid

During the processing of apatite concentrate, the distribution of REM in solutions of phosphoric acid (15-20%) and solid industrial waste - phosphogypsum (85-80%) occurs. Therein the larger half of more valuable heavy subgroup of REM, including Y, Yb, Er and Dy compounds, are dissolved in the phosphoric acid solutions. Complex composition of the apatite concentrate processing products and low concentration of heavy REM subgroup relatively to metal impurities and light REM inhibits REM extraction and separation process, and, probable, is responsible for low extractant capacity for individual compounds of REM. Iron (3+) ions have a significant impact on rare-earth metals extraction process. This impact is caused by the competitive participation of these ions in the extraction process, which, with account of their much higher concentration in EPA solutions, compared with rare-earth ions, leads to decrease in the extractant capacity for REM. Therefore, the study of the purification of the extract from iron ions (3+) is a relevant problem.
Show more

5 Read more

Recycling of Rare Earth Magnet Waste by Removing Rare Earth Oxide with Molten Fluoride

Recycling of Rare Earth Magnet Waste by Removing Rare Earth Oxide with Molten Fluoride

is shown in Fig. 1. The magnet wastes are dissolved in acid solution such as sulfuric acid at first. Iron is precipitated to be removed by charging much alkali solution. A rare earth element isolated by using solvent extraction is precipitated as oxalates to be recovered. The oxalate is oxidized into an oxide to be a raw material of molten salt electrolysis. Rare earth metals are regenerated by using the molten salt electrolysis. Rare earth metals with trace oxygen (major impurity of magnet waste) are regenerated in the recycling process. Separation of rare earth elements is also possible. However, much waste water is generated because not only rare earth metals but also iron is dissolved by using acid solution. Furthermore, energy consumption is huge because molten salt electrolysis requires much electricity. Location for recycling operation is also limited to a country bearing a smelting facility for rare earth metals.
Show more

8 Read more

The Market For The "Not-So-Rare" Rare Earth Elements

The Market For The "Not-So-Rare" Rare Earth Elements

There are several supply chain risks inherent in a global market wherein the supply of virtually all of a raw material critical to the development of many products is largely controlled by one supplier. At present, “both production of rare earth materials in China and export of those materials outside of China are strictly controlled by government imposed quotas” (Molycorp Minerals, 2009). Japan, a country that manufactures and exports many products that use rare earth metals, was exposed to and negatively impacted by one such risk. In September 2010, China placed what seemed to be an unannounced and unofficial embargo on the export of rare earth metals to Japan—a claim that was repeatedly denied by the Chinese government (Humphries, 2010). An incident that was initially thought to be related to longstanding maritime wars between China and Japan was heightened when China subsequently began halting exports to other countries as well. China’s export quotas continued to be reduced in 2011 and this has created significant upward price pressure on many of the scarce metals.
Show more

8 Read more

Small scale heterogeneity of trace metals including rare earth elements and yttrium in deep sea sediments and porewaters of the Peru Basin, southeastern equatorial Pacific

Small scale heterogeneity of trace metals including rare earth elements and yttrium in deep sea sediments and porewaters of the Peru Basin, southeastern equatorial Pacific

The solid phase and dissolved U, V, and Cu concentra- tion peaks in DEA Black Patch suggest the presence of a Cu- rich uranium–vanadium phase. This is known from oxidation fronts in turbidites in North Atlantic clays, where U, V, and Cu are enriched in the solid phase (Colley et al., 1984; Col- ley and Thomson, 1985). The metals are mobilized during or- ganic oxidation of the turbidite material, migrate downwards, and are immobilized at depth (Colley et al., 1984). They are preserved by burial of other material on top (Colley and Thomson, 1985). In the Peru Basin, solid-phase peaks of Cd, Cu, and V have been attributed to the downward progression of the oxic–suboxic boundary during glacial–interglacial cy- cles, which is slowed down by the reactive Fe(II) layer in the clay minerals, and where this oxic front reaches the reactive Fe(II) layer, heavy metals such as V and Cu can be precipi- tated (authigenic precipitation of U, V, and Cu) (König et al., 2001; Koschinsky, 2001). A similar process during organic oxidation might have taken place at Reference East.
Show more

21 Read more

World Hydrogen Energy Conference174-179

World Hydrogen Energy Conference174-179

Some 40 papers attested to the continued importance of the platinum group and rare earth metals in hydrogen storage, separation, catalytic and fuel cell technologies, and those paper[r]

6 Read more

Effect of Rare-Earth Incorporation in Ferromagnetic Metals for Magnetic Domain Wall Devices.

Effect of Rare-Earth Incorporation in Ferromagnetic Metals for Magnetic Domain Wall Devices.

E-beam evaporation utilizes the energy from an electron beam to melt and evaporate a material contained in a crucible. Deposition rates can be easily adjusted by changing the current and energy of the electron beam [2]. Film thicknesses and deposition rates are determined in the systems used by a quartz crystal. Our e-beam evaporator capabilities allow deposition of up to five different materials in situ. Deposition of multiple materials is necessary because capping layers are required to prevent oxidation of magnetic metals. Multiple layers are also necessary to create spin valve structure which can be used to determine the presence and position of a domain wall as described in the next section. E- beam evaporation is a very directional process and consequently is good for lift-off applications. However, one of the limitations of e-beam evaporation is that it is difficult to deposit an alloy because the vapor pressures of the materials are not the same.
Show more

137 Read more

Electrochemical Recovery of Rare Earth Elements from Magnets: Conversion of Rare Earth Based Metals into Rare Earth Fluorides in Molten Salts

Electrochemical Recovery of Rare Earth Elements from Magnets: Conversion of Rare Earth Based Metals into Rare Earth Fluorides in Molten Salts

This research has received funding from the European Communitys Seventh Framework Programme ([FP7/2007- 2013]) under grant agreement n607411 (MC-ITN EREAN: European Rare Earth Magnet Recycling Network, Project website: www.erean.eu). This publication reflects only the authors` view, exempting the Community from any liability. Authors would also like to thank Ruud Hendrikx and Richard Huizenga for the XRD analyses.

6 Read more

Infrared Polarizabilities of 3d Transition and Rare Earth Metals

Infrared Polarizabilities of 3d Transition and Rare Earth Metals

DOI: 10.4236/jmp.2018.92020 295 Journal of Modern Physics The results of these calculations using Equation (35) are displayed for the TMs (Figure 3 and Figure 4), for the intervening metals In, Cs, Xe, and Ba (Figure 5), and for the REMs (Figures 6-8). The breaks in the graphs are those energy input ranges for which there were convergence problems in the numerical procedure. The dashed curves represent the independent particle or non-interacting polari- zabilities in which the Coulomb and exchange-correlation interactions are switched off. The solid curves have those interactions present.
Show more

15 Read more

Heats of solution and related thermochemical properties of some rare earth metals and chlorides

Heats of solution and related thermochemical properties of some rare earth metals and chlorides

An isothermally jacketed calorimeter has been constructed to measure the changes in heat content accompanying the solution of some rare earth metals and compounds. To check the performance of the apparatus, the integral heats of solution of potassium nitrate in water at 25°C have been measured. The values corrected to infinite dilution by use of relative apparent molal heat content data in the literature give 8384 +/- 12 cals/mole. The result agrees well with the values reported by others.

84 Read more

A calculation of the elastic constants of yttrium and the rare earth metals

A calculation of the elastic constants of yttrium and the rare earth metals

A modified cellular method developed by Raimes was extended to scandium, yttrium, and the rare earth metals. The assumption that the valence electrons are free and share the same ground state wave functions at zero wave number, was capable of giving fairly good agreement between the calculated and experimental values of the atomic radii, compressibilities, and total energies of the trivalent rare-earth metals as well as for scandium and yttrium. In addition the calculated variation of atomic radius and compressibility of the hexagonal rare-earth metals with atomic number was in qualitative agreement with experiment. Calculations based on the assumption that europium and ytterbium are divalent in the solid state were capable of giving reasonable agreement with the observed atomic radii and compressibilities of these elements. Calculations for cerium did not give satisfactory agreement with the assumption of either a trivalent or quadrivalent atomic core. This failure probably results from the fact that the assumption of equivalent behavior of the valence electrons at zero wave number is quite poor for this element. The compressibilities of promethium and scandium were predicted.
Show more

114 Read more

Pentadentate N2O3 Schiff Base Complexes of Rare Earth Metals

Pentadentate N2O3 Schiff Base Complexes of Rare Earth Metals

Schiff bases can be considered as a very important class of organic compounds due to their ability to form stable complexes with wide range of transition and rare-earth metal ions in different oxidation states via N and O atoms. They have the potential to be used in many areas such as electrochemistry, bioinorganic, catalysis, metallic deactivators, separation processes, and environmental chemistry. They are becoming important materials in the pharmacological, dye, plastic industries as well as in the field of liquid crystal technology 1 – 5 .
Show more

5 Read more

The heats of combustion of some rare earth metals

The heats of combustion of some rare earth metals

RESULTS OF COMBUSTION OF THE METALS The heat of combustion was determined from the temperature rise of the calorimeter, AT, and the water equivalent, W... where Qc = the heat leakage cor[r]

19 Read more

Show all 10000 documents...