Acid Dissolution of Neodymium Magnet Nd-Fe-B in Different Conditions

The separation of rare earth metals (REM) from a neodymium magnet has been widely studied in the last year. We have shown that the waste of computer hard disk contains 25.41 % neodymium, 64.09 % iron, and &lt;&lt;1 % boron. To further isolate rare-earth metals, the magnet was acidically dissolved in open and closed systems. In both methods of dissolution was used concentrated nitric acid. The difference between these methods are the conditions of dissolution of magnet. The magnet was dissolved in a microwave sample preparation system at different temperatures and pressures in a closed system. In the open system, the acid dissolution of the magnet conducted at room temperature. 0.2 g of the neodymium magnet sample was taken under two conditions, and the dissolution process in the closed system lasted 1 hour, and in the open system-30-40 minutes. The open system is a non-laborious, simple and cheap method of dissolving the magnet by comparing both systems. Therefore, an open sample preparation system is used for further work. To remove the iron in the magnet, oxalic acid was used and precipitated as oxalates under both conditions. According to the result of the ICP-MS method, it is shown that the neodymium and iron contents in the precipitate are 24.66 % and 0.06 %, respectively. This shows that the iron has almost completely passed to the filtrate. Thus, it is possible to remove the iron from the sample.

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Acid dissolution of neodymium magnet Nd-Fe-B in different conditions

Bulletin of the Karaganda University Chemistry series ◽

10.31489/2021ch4/79-86 ◽

2021 ◽

Vol 104 (4) ◽

pp. 79-86

Author(s):

A.G. Ismailova ◽

◽

G.Zh. Akanova ◽

D.Kh. Kamysbayev ◽

◽

...

Keyword(s):

Rare Earth ◽

Sample Preparation ◽

Open System ◽

Closed System ◽

Inductively Coupled Plasma ◽

Acid Dissolution ◽

Inductively Coupled ◽

Microwave Sample Preparation ◽

Neodymium Magnet ◽

The Difference

The separation of rare-earth elements (REE) from a neodymium magnet has been widely studied last year. During the research it was identified that the waste of computer hard disk contains 25.41 % neodymium, 64.09 % iron, and <<1 % boron. To further isolate rare-earth metals, the magnet was acidically dissolved in open and closed systems. In both methods of dissolution, concentrated nitric acid was used. The difference between these methods is the conditions of dissolution of magnet. The magnet was dissolved in a microwave sample preparation system at different temperatures and pressures in a closed system. In the open system, the acid dissolution of the magnet is conducted at room temperature. 0.2 g of the neodymium magnet sample was taken under two conditions, and the dissolution process in the closed system lasted 1 hour, and in the open system 30-40 minutes. The open system is a non-laborious, simple, and cheap method of dissolving the magnet by comparing both systems. Therefore, an open sample preparation system is used for further work. To remove the iron in the magnet, oxalic acid was used and REEs are precipitated as oxalates under both conditions. According to the result of the Inductively coupled plasma mass spectrometry (ICP-MS) method, it was identified that the neodymium and iron contents in the precipitate are 24.66 % and 0.06 %, respectively. This shows that the iron has almost completely passed to the filtrate

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Impact of flavours, device, nicotine levels and price on adult e-cigarette users’ tobacco and nicotine product choices

Tobacco Control ◽

10.1136/tobaccocontrol-2021-056599 ◽

2021 ◽

pp. tobaccocontrol-2021-056599

Author(s):

Yong Yang ◽

Eric N. Lindblom ◽

Ramzi G. Salloum ◽

Kenneth D. Ward

Keyword(s):

Open System ◽

Closed System ◽

Smoking Status ◽

Discrete Choice Experiments ◽

User Characteristics ◽

Product Attributes ◽

Product Choices ◽

Nicotine Level ◽

The Difference ◽

The Impact

IntroductionTo understand the impact of e-cigarette devices, flavours, nicotine levels and prices on adult e-cigarette users’ choices among closed-system and open-system e-cigarettes, cigarettes and heated tobacco products (HTPs).MethodsOnline discrete choice experiments were conducted among adult (≥18 years) e-cigarette users (n=2642) in August 2020. Conditional logit regressions were used to assess the relative impact of product attributes and the interactions between product attributes and user characteristics, with stratified analyses to examine differences by smoking status and primarily used e-cigarette device and flavour.ResultsOn average, participants preferred non-tobacco and non-menthol flavours most, preferred open-system over closed-system e-cigarettes and preferred regular nicotine level over low nicotine level. However, the preference varied by demographics, smoking status and the primarily used e-cigarette device and flavour. The differences in preference among products/devices were larger than the difference among flavours or nicotine levels. Participants who primarily used closed-system e-cigarettes exhibited similar preferences for closed-system and open-system e-cigarettes, but those who primarily used open-system e-cigarettes preferred much more open-system over closed-system e-cigarettes. HTP was the least preferred product, much lower than cigarettes in general, but participants living in states where IQOS is being sold had similar preferences to cigarettes and HTPs.ConclusionsPeople are unlikely to switch to another product/device because of the restriction of flavour or nicotine level. If non-tobacco and non-menthol flavours were banned from open-system e-cigarettes, users may switch to menthol flavour e-cigarettes. Intervention strategies should be tailored to specific groups.

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Ordnung und Fehlordnung der Anionen in tetragonalen Boridcarbiden der Seltenerdmetalle / Order and Disorder of Anions in Tetragonal Boride Carbides of Rare Earth Metals

Zeitschrift für Naturforschung B ◽

10.1515/znb-2004-11-1228 ◽

2004 ◽

Vol 59 (11-12) ◽

pp. 1551-1562 ◽

Cited By ~ 10

Author(s):

Oliver Oeckler ◽

Hansjürgen Mattausch ◽

Josef Bauer ◽

Arndt Simon

Keyword(s):

Rare Earth ◽

Metal Atom ◽

Rare Earth Metals ◽

Stability Range ◽

Positional Disorder ◽

Order And Disorder ◽

Structure Determinations ◽

Distorted Octahedra ◽

Single Well ◽

The Difference

Compounds that feature the metal atom substructure of “La5B2C6” are known for most rare earth metals (Ln). They are characterized by two types of voids surrounded by large bicapped tetragonal antiprisms and smaller distorted octahedra, respectively. For many rare earth elements, a huge variation of lattice parameters has been observed for the corresponding compounds. A series of structure determinations has beed performed in order to elucidate the reasons for this remarkable stability range. The compounds of the earlier lanthanoids (La-Nd) exhibit broad ranges of homogeneity that are due to varying occupancy of octahedral voids which can be empty or filled by varying amounts of C atoms or C2 groups. However, the larger voids are fully occupied with disordered C3B groups. In most cases the disorder is completely statistical with only a few exceptions. In contrast, two different phases have been observed in the case of late rare earth metals (starting from Gd). Their ranges of homogeneity are moderate, and the larger voids are fully occupied by ordered CBC entities. The difference between these two types of phases concerns the octahedral voids which contain C atoms in the case of compounds with the idealized composition Ln5B2C5 and C2 groups for Ln5B2C6, respectively. Positional disorder is possible for both C atoms and C2 groups. Therefore, no single well-defined compound is known that possesses the metal atom arrangement of “La5B2C6”.

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