Most REEs are not as rare as the group's name suggests. They were named "rare-earth elements" because most were identified during the 18th and 19th centuries as "earths" (originally defined as materials that could not be changed further by heat) and in comparison to other "earths," such as lime or magnesia, they were relatively rare.

Rare earths make up 3 to 14% of the mass of a battery cell inclusive of its casing, which come in various sizes and are used in a multitude of applications. Large batteries are typically used in automobile and energy applications while smaller batteries are used in portable electronic devices such as computers, cell phones, power tools ...

U.S. Geological Survey news release "Going Critical". The rare earth elements (REE) are a set of seventeen metallic elements. These include the fifteen lanthanides on the periodic table plus scandium and yttrium. Rare earth elements are an essential part of many high-tech devices. The U.S. Geological Survey news release "Going Critical" explains:

The purity of rare earth products depends on the ability of the reagents used to selectively promote the precipitation of the rare earth elements (REE) from impurities present in sulfuric liquors. The present study aims at investigating the conditions required to precipitate REE, either as rare earth oxalates or carbonates, from purified rare earth …

The use of X-ray fluorescence spectroscopy (XRF) for the analysis of rare earth elements (REEs) is divided into the analysis of minors and traces in materials with natural origin and the analysis of industrial products containing REEs as main, minor or trace components.

Moreover, the residual calcium content and oxygen content are reduced to about 0.080 wt% and 0.32 wt%. As a consequence, the room-temperature magnetization of the CaH 2-recycled Nd–Fe–B powder is increased to 146.30 emu/g, ... Journal of Rare Earths, Volume 39, Issue 6, 2021, pp. 682-688. Weiqiang Liu, …, Yihui Du.

When the ion-adsorption type rare earths ore was leached by (NH 4) 2 SO 4, rare earth leaching rate was a little higher than magnesium–ammonium–calcium compound leaching agent in 15:25:60, and the rare …

In radioactive nuclear glasses, the rare earths (RE) are present as waste forms in the glass matrix. ... Compared to the base glass, the normalized release rate of calcium ions by rare earth addition decrease obviously in Fig. 2 (except Nd-doped glass). Brow [31] found that the Ca O P bond is weaker than the Fe O P bond. Leachate …

Calcium rare earth silicate oxyapatites, (Ca 2 RE 8 (SiO 4) 6 O 2 ), are of interest as components of glass–ceramic nuclear waste forms. To assess their long-term …

MATERIALS INDEX: rare earths, calcium, manganese, oxides Introduction The structure of the solid solutions of Caz_xLnxMnO4 (Ln=Pr, Nd, Sm, Eu, and Gd) at room temperature was first investigated by Daoudi and Le Flem, and was report- ed to be the tetragonal type of K2NiF4 structure for Ln=Pr and the orthorhombically dis- torted …

The rare earth fluoride (REF 3) solid wastes (such as REF 3 smelting slag, rare earth molten salt electrolytic slag, and cerium fluorocarbon tailings, etc.) are widely sourced and have high recycling value. Traditional technology for the recovering of rare earths from REF 3 solid wastes mainly includes the method of concentrated sulfuric acid …

However, some calcium-based mineral impurities (such as fluorite and apatite) still remain in mixed concentrate. 4 Generally, the grade of rare earth oxide (REO) in mixed concentrate is between 45 wt% and 65 wt%, and the calcium oxide (CaO) grade is 4 wt%–12 wt%. 5 The presence of Ca can significantly hinder the leaching and …

The recycling of rare earths is of high importance because of the possible supply risk of these elements in the near future. The method was tested for the removal of cobalt and iron from samarium and neodymium, respectively. The highest distribution ratios for cobalt and iron were found with 8.5 and 9 M HCl.

All of these are minerals related to fluorite (calcium fluoride) where the rare earths substitute for the calcium in the fluorite crystal lattice. Active drilling of the deposit, which was first done to assess potential beryllium resources, was started by Cyprus mines in the 1980s. While not all of the information was well preserved, reliable ...

Cation exchange is proposed as a possible adsorption mechanism. Doping PGA molecules into calcium alginate beads can significantly enhance the adsorption capacity and the selectivity of rare earths from non-rare earths. The maximum adsorption capacity obtained for Nd(III) was 1.65 mmol g −1.

The rare earths are a relatively abundant group of 17 elements composed of scandium, yttrium, and the lanthanides. The elements range in crustal abundance from cerium, the 25th most abundant element of the 78 common elements in the Earth's crust at 60 parts per million, to thulium and lutetium, the least abundant rare-earth elements at about 0. ...

The rare earths were eluted from the column with 4 N HCl, Analyses showed that a large part of the calcium (75 to 80%) and of the iron (85 to 95%). and also all the silica followed the fluorine on the rare earth absorption step.

The RE phosphate minerals (Table 2) are the most naturally abundant forms that are associated with fluorapatite (FAP) of chemical formula Ca 5 (PO 4) 3 F.The RE site occupancies in the FAP lattice structure are normally via the two calcium atoms, having different stereochemistries in the atomic arrangement of FAP as denoted by Ca1 and …

Rare earths have been called the vitamins of industry and are widely used in permanent magnet, phosphors, catalysts, batteries, glasses, ... (> 95%). The main reason for this is that the reaction between rare-earth fluoride and calcium oxide is a solid–solid reaction, as the melting points of NdF 3 and CaO are 1683 and 2845 K, respectively ...

Here, they used the same process to separate volatiles like magnesium and calcium from neodymium from the rare earth metal that was reduced by Terves. "The desired metals are left behind and the rest can be reused in the process," Besser said. "We used arc melting to remove other unwanted bits. This left us with pure rare earth metals."

Innovative pilot-scale process for sustainable rare earth oxide production from coal byproducts: A comprehensive environmental impact assessment. Mohsen Rabbani, Joshua Werner, Ario Fahimi, Ehsan Vahidi. In Press, Journal Pre-proof, Available online 12 April 2024. View PDF.

Harmunite may be made of common elements – calcium, iron and oxygen – but it is destroyed on contact by one of the commonest minerals of all: silica. So far it has only been found in two places.

Doping PGA molecules into calcium alginate beads can significantly enhance the adsorption capacity and the selectivity of rare earths from non-rare earths. The maximum adsorption capacity obtained ...

The Rare Earth Elements - Vital to Modern Technologies and Lifestyles (Factsheet), U.S. Geological Survey. Factsheet on the origin, …

Calciothermic reduction is one of the main processes to produce rare earth (RE) metals, such as yttrium, terbium and dysprosium. During the production process, …

Rare-earth metals, excepting samarium, europium, and ytterbium, were prepared by converting their oxides to anhydrous chlorides or fluorides and reducing the rare-earth halides with active metals such as lithium or calcium. High-purity, anhydrous rare-earth chlorides were prepared by dissolving the rare-earth oxides in hydrochloric acid to form ...

We demonstrate that rare-earth elements can structurally replace the calcium in neutral Mn 4 XO 4 clusters. All three Mn 4 XO 4 clusters with different redox …

Abstract. The charge compensation of trivalent rare earths in the divalent Ca site of calcium tungstate was studied by the determination of distribution coefficients. The behavior of neodymium was investigated in the presence of all the alkali metal ions and niobium, and all the other rare earths in the presence of sodium.

The mechanism of the uptake of rare earths by calcium oxalate was studied in detail. Yttrium-91s Eu/sup 152/, and Eu/sup 154/ were used to obtain evidence of mixed crystal formation. It was found thats out of the three hydrates of calcium oxalate claimed by earlier workers, it is calcium oxalate dihydrate which carries rare earths through mixed ...

Rare Earths Elements: Where in the World Are They? This was originally posted on Elements.Sign up to the free mailing list to get beautiful visualizations on natural resource megatrends in your email every week.. Rare earth elements are a group of metals that are critical ingredients for a greener economy, and the location of the reserves for …