Chalcogenide esters as reactive intermediates in selenium and tellurium purifications

1983 ◽  
Vol 61 (9) ◽  
pp. 2199-2202 ◽  
Author(s):  
Santokh S. Badesha ◽  
Paul Monczka ◽  
Steven D. Smith
Keyword(s):  
Nitric Acid ◽  
High Purity ◽  
Reactive Intermediates ◽  
Selenium Dioxide ◽  
Elemental Selenium ◽  
Organic Media ◽  
Commercial Grade ◽  
Purity Level ◽  
Selenous Acid ◽  
Source Materials

This paper describes a novel application of chalcogenide esters to purify selenium and tellurium to the 99.999% purity level. The chalcogenide esters were prepared from a variety of source materials which include: crude selenium and tellurium and commercial grade selenium dioxide, tellurium dioxide, and selenous acid. Crude selenium and tellurium were first converted to their respective oxides by treatment with concentrated nitric acid. The oxides were condensed with alcohols or diols to obtain the corresponding esters which, on reduction with hydrazine in organic media, provided high purity elemental selenium and tellurium.

Corrosion Behavior of High Purity Vanadium

CORROSION ◽  
1960 ◽  
Vol 16 (2) ◽  
pp. 70t-72t ◽  
Author(s):  
DAVID SCHLAIN ◽  
CHARLES B. KENAHAN ◽  
WALTER L. ACHERMAN
Keyword(s):  
Stainless Steel ◽  
Nitric Acid ◽  
Corrosion Behavior ◽  
High Purity ◽  
Galvanic Corrosion ◽  
Acid Solutions ◽  
Ocean Water ◽  
Nitric Acid Solutions

Abstract Chemical and galvanic corrosion experiments at 35 C show that ductile vanadium is resistant to corrosion in substitute ocean water. It is also resistant in 60 percent sulfuric and 20 percent hydrochloric acids but corrodes rapidly in nitric acid solutions. Vanadium is less noble than stainless steel and copper and more noble than aluminum, magnesium and steel (SAE 4130) in substitute ocean water. 6.3.18

Recovery of Zinc and Manganese from Spent Zn-Mn Batteries Using Solvent Extraction

2018 ◽  
Vol 775 ◽  
pp. 427-433
Author(s):  
Wei Sheng Chen ◽  
Chin Ting Liao ◽  
Chen Hsi Chang
Keyword(s):  
Solvent Extraction ◽  
Magnetic Separation ◽  
High Purity ◽  
Ph Value ◽  
Acid Leaching ◽  
Extractant Concentration ◽  
Environmental Technology ◽  
Electronic Products ◽  
Waste Plastic ◽  
Purity Level

For several decades, zinc-manganese batteries have been created to serve many forms of electronic products. However, every creative act has its destructive consequence. Plenty of waste element inside has caused the irreversible contamination to our environment.This study will focus on dealing with zinc-manganese batteries using environmental technology and hydrometallurgy methods, such as physical pretreatment, acid leaching and solvent extraction. The goal of this research will concentrate on the recovery of zinc and manganese from zinc-manganese batteries. The pretreatment processes include crushing, sieving and magnetic separation to separate the waste plastic, scraps of paper and impurity from waste zinc-manganese batteries. Before the process of the solvent extraction zinc-manganese batteries will be leached by specific acid first. In next step, the solvent extraction will be carried out and investigated. The parameters such as extractant concentration, extraction time, equilibrium pH value and organic-aqueous ratio (O/A) are analyzed in detail. Finally, the products of Zn and Mn are obtained in high-purity level and the recovery rates are about 92% for Zn and 95% for Mn.

Variation of Vanadium Incorporation in Semi-Insulating SiC Single Crystals Grown by PVT Method

2019 ◽  
Vol 963 ◽  
pp. 30-33
Author(s):  
Chae Young Lee ◽  
Jeong Min Choi ◽  
Dae Sung Kim ◽  
Mi Seon Park ◽  
Yeon Suk Jang ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Single Crystals ◽  
High Purity ◽  
Growth Direction ◽  
Source Materials ◽  
Better Than

Two SiC crystals were grown using SiC source powder with different level of purity and then the effect of the purity of SiC source materials on the final electrical properties has been systematically observed. Furthermore, the variation of vanadium amount according to the growth direction of vanadium doped semi-insulated SiC single crystals has been investigated. The quality of SiC crystal grown using SiC source powder with higher purity was definitely better than SiC crystal with lower purity. SiC crystals having an average resistivity value of about 1×1010 Ωcm were successfully obtained. In the result of COREMA measurement, the use of high purity SiC powder was revealed to obtain wafers with better uniformity in resistivity value.

Mutual Separation of Uranium, Plutonium and Fission Products by Gradient Multistage Extraction

1962 ◽  
Vol 1 (1) ◽  
Author(s):  
Tomitaro Ishimori ◽  
Johkun Akatsu
Keyword(s):  
Nitric Acid ◽  
Aqueous Solutions ◽  
High Purity ◽  
Active Material ◽  
Fission Products ◽  
Mutual Separation ◽  
Uranium Plutonium ◽  
Organic Solutions

SummaryUranium, plutonium and fission products are separated by means of a simple multistage extraction of 20% TBP-carbontetrachloride vs. nitric acid series. In order to enhance the mutual separation, the acidity of the aqueous portions is lowered stepwise. All fission products, plutonium and uranium are obtained in aqueous solutions in the sequence mentioned, leaving no active material in the organic solutions of the extractor. The plutonium fractions contain some fission products and a small amount of uranium. However, uranium is obtained with a fairly high purity. The same organic solutions can be used several times giving more or less the same separated products.

Studies on the interaction of selenite and selenium with sulphur donors. Part 2. A kinetic study of the reaction with 2-mercaptoethanol

1994 ◽  
Vol 72 (12) ◽  
pp. 2506-2515 ◽  
Author(s):  
Wimal Amaratunga ◽  
John Milne
Keyword(s):  
Reaction Mechanism ◽  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Nucleophilic Attack ◽  
Elemental Selenium ◽  
Sulfinic Acid ◽  
Reaction Stage ◽  
Second Stage ◽  
Selenous Acid ◽  
Two Stages

Selenous acid is reduced by 2-mercaptoethanol in water to elemental selenium in two stages.[Formula: see text]The reactions have been followed by spectrophotometry and by proton and 77Se NMR spectroscopy. The mechanism of the first stage parallels that proposed for butyl thiols in 60% dioxane but nucleophilic attack by RS− rather than RSH on the Se(IV) intermediate, RSSeO2−, is of greater significance for 2-mercaptoethanol than for n-butylthiol. The signals of three intermediates are observed in the Se-77 NMR spectra of a mixture undergoing the first reaction stage. These arise from, HOC2H4SSeO2−, (HOC2H4S)2SeO, and an asymmetric intermediate that chemical shift evidence suggests is the sulfinic acid ester, HOC2H4S(O)SeSC2H4OH. The second stage involves coordination of the bis(thio)selenide by thiolate followed by decomposition to disulfide and selenium. Evidence is presented to support a reaction mechanism involving nucleophilic attack exclusively at Se(II) and not at S(II) as suggested in previous work. This stage is strongly accelerated at basic pH and, at pH 8.3 and above, both the first and second stages can take place simultaneously.

Studies on the interaction of selenite and selenium with sulfur donors. Part 3. Sulfite

1995 ◽  
Vol 73 (5) ◽  
pp. 716-724 ◽  
Author(s):  
Sheila Ball ◽  
John Milne
Keyword(s):  
Raman Spectroscopy ◽  
Aqueous Solutions ◽  
Nmr Spectra ◽  
Formation Constants ◽  
The Other ◽  
Elemental Selenium ◽  
Ambient Temperatures ◽  
Selenous Acid ◽  
First Time ◽  
Sulfite Solution

Elemental selenium dissolves in sulfite solution to form selenosulfate ion: Se + SO32− = SeSO32−.The formation constants for this equilibrium at temperatures from 0 to 35 °C are reported for the first time. The isomeric thioselenate anion, SSeO32−, is not, however, produced by the reaction of sulfur with selenite nor is the selenoselenate ion, Se2O32−, formed from selenium and selenite. Selenotrithionate is formed rapidly from the reaction of selenous acid with sulfite and hydrogen sulfite according to: HSeO3− + 3 HSO3− = Se(SO3)22− + SO42− + 2H2O.Two isomers of the selenotrithionate ion are observed by Se-77 NMR and Raman spectroscopy, one with O-bonded Se, Se(OSO2)22−, and the other with S-bonded Se, Se(SO3)22−. Both isomers are formed in reactions with hydrogen sulfite but only the O-bonded isomer is formed in sulfite solutions at ambient temperatures. The Raman and Se-77 NMR spectra of the various sulphur–selenium anions formed are given and the parallel with the reactions of selenous acid and thiols is discussed. Keywords: selenium, sulfite, selenosulfate, selenotrithionate, Se-77 NMR, Raman spectroscopy, equilibria, aqueous solutions.

Superconductivity in Y-Ba-Cu-Ag-O and Y-Ba-Cu-Pt-O Systems

1987 ◽  
Vol 99 ◽  
Author(s):  
V. T. Kovachev ◽  
M. M. Gospodinov ◽  
E. S. Vlachov ◽  
V. A. Lovchinov ◽  
P. K. Svestarov ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Transition Temperature ◽  
Solid State ◽  
Superconducting State ◽  
High Purity ◽  
Solid State Synthesis ◽  
Pure Oxygen ◽  
Ac Magnetic Susceptibility ◽  
Source Materials

A STUDY OF THE Y-Ba-Cu-Ag-O SYSTEM: The specimens studied were produced using the standard ceramic technique. High purity source materials Y2O3, BaCO3CuO, and Ag2O were used. Solid state synthesis was carried out at 900 C for six hours in oxygen ambient. Pressed samples of 16 mm diameter and 2 mm thick were processed in an atmosphere of pure oxygen at 950 C for 12 hours. The transition temperature to the superconducting state was measured by the four point probe resistance technique. The ac magnetic susceptibility was determined by the method outlined in [1].

scholarly journals Resource Recovery of Waste Nd–Fe–B Scrap: Effective Separation of Fe as High-Purity Hematite Nanoparticles

2020 ◽  
Vol 12 (7) ◽  
pp. 2624
Author(s):  
Suiyi Zhu ◽  
Ting Su ◽  
Yu Chen ◽  
Zhan Qu ◽  
Xue Lin ◽  
...  
Keyword(s):  
Rare Earth ◽  
Nitric Acid ◽  
Rare Earth Elements ◽  
High Purity ◽  
Hydrothermal Route ◽  
Acid Dissolution ◽  
Hematite Nanoparticles ◽  
Pharmaceutical Ingredients ◽  
Effective Separation ◽  
Fe Impurity

Recycling rare-earth elements from Nd magnet scrap (Nd–Fe–B scrap) is a highly economical process; however, its efficiency is low due to large portions of Fe impurity. In this study, the effective separation of Fe impurity from scrap was performed through an integrated nitric acid dissolution and hydrothermal route with the addition of fructose. Results showed that more than 99% of the scrap was dissolved in nitric acid, and after three dilutions that the Nd, Pr, Dy and Fe concentrations in the diluted acid were 9.01, 2.11, 0.37 and 10.53 g/L, respectively. After the acid was hydrothermally treated in the absence of fructose, only 81.8% Fe was removed as irregular hematite aggregates, whilst more than 98% rare-earth elements were retained. By adding fructose at an Mfructose/Mnitrate ratio of 0.2, 99.94% Fe was precipitated as hematite nanoparticles, and the loss of rare-earth elements was <2%. In the treated acid, the residual Fe was 6.3 mg/L, whilst Nd, Pr and Dy were 8.84, 2.07 and 0.36 g/L, respectively. Such composition was conducive for further recycling of high-purity rare-earth products with low Fe impurity. The generated hematite nanoparticles contained 67.92% Fe with a rare-earth element content of <1%. This value meets the general standard for commercial hematite active pharmaceutical ingredients. In this manner, a green process was developed for separating Fe from Nd–Fe–B scrap without producing secondary waste.

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