First, 4N grade tellurium was prepared as shown in Table 1.The major impurities in the tellurium (4N grade) were bismuth (Bi), antimony (Sb), tin (Sn), and selenium (Se) due to the characteristics of the source material, as we used thermoelectric devices recycled by pretreatment methods such as mechanical crushing, tumbling, and …

First, the states of impurities in selenium sludge were characterized in detail. Second, hydrogen peroxide (H 2 O 2) was employed for converting the impurity phases in the selenium sludge slurry, thereby decreasing the volatilization of impurities in the later distillation process. Third, a vacuum distillation process was carried out to ...

Selenium (Se) was identified in 1818 by Berzelius as an elemental residue during the oxidation of sulfur dioxide from copper pyrites in the production of sulfuric acid. It is similar in properties to tellurium (discovered some 35 years earlier) and was named for the moon (selene in Greek) while tellurium had been named for the earth (tellus in Latin). Little …

The microscopic impurity elemental distribution was analyzed using an electron probe microanalyzer (EPMA), and it shows that the impurities were relatively concentrated and gathered in crude selenium.

Because of the high content of Se among impurities, its removal is a major objective of this study. However, once zone refining has been conducted for the purification of tellurium, selenium (Se) is known to be very difficult to remove by zone refining under normal conditions because of its k of 0.44–0.5 [13].

Abstract. Theoretical research on the separation of tellurium by vacuum distillation from crude selenium could provide further key data support for industrial …

Selenium (Se, atomic number 34, atomic weight 78.96) lies between arsenic and bromine and between sulfur and tellurium (Te, atomic number 52, atomic weight 127.61) in Group 6A (chalcogens) in the periodic table. It was discovered in 1817 by a Swedish chemist as a contaminant in sulfuric acid. Its name was derived from the Greek selene, meaning ...

To minimize tellurium loss during reduction and facilitate tellurium–selenium separation, this study employed hydroxylamine hydrochloride for the selective reduction of tetravalent selenium. ... maintaining the pH below the threshold for tellurium hydrolysis throughout this process effectively minimizes tellurium impurities …

In the electrolytic refining of copper, the anode mud contains antimony, selenium, tellurium, silver gold and platinum. These are impurities in blister copper. They are less reactive and unaffected by C u S O 4 − H 2 S O 4 solution and hence, settle down under anode as anode mud.

method, concentration of impurities in the anodes, and the electrorening conditions. However, common components of the slimes are copper, silver, gold, selenium, tellurium, arsenic, bismuth, antimony, lead, barium, and platinum-group metals (PGMs) [5 –8]. Tellurium is a rare metalloid that is majorly produced from copper anode slime [8].

where (omega ) is the evaporation rate in g·cm −2 ·s, which represents the mass change ((Delta m), g) of selenium at a certain time ((Delta t), s) and evaporation area (A, cm 2) during the distillation process.. Therefore, the evaporation rate of elemental selenium can be obtained only by experimentally measuring mass changes during the …

As the temperature increases, the selenium and tellurium content in the copper and matte phases decreases. The introduction of CaO flux, and typical impurities of Pb and Si, had significant influence on Se and Te distribution. The results revealed that CaO addition and Si impurity accelerated the removal of Se and Te from the copper and …

During the experiment, tellurium's higher saturation vapor pressure than copper and lead [16] can evaporate tellurium from the alloy system during vacuum distillation, leaving impurity elements in the liquid phase. Therefore, high-purity Te can be obtained by condensing vapor phase substances.

Deep oxidation of selenium was carried out to remove the impurity tellurium. Finally, high purity selenium with a purity of more than 6N was prepared by vacuum distillation. Dutton et al [ 26 ] purified selenium by multiple oxidation method, studied the process of selenium vapor oxidation to SeO 2, and carried out complete or …

The major impurities in the tellurium (4N grade) were bismuth (Bi), antimony (Sb), tin (Sn), and selenium (Se) due to the characteristics of the source material, as we used thermoelectric devices recycled by pretreatment methods such as …

However, the accompanying increase in impurity ion scattering usually results in an undesirable loss in hall mobility, negatively impacting the electrical transport properties. In this work, a tellurium-selenium (Te-Se) solid solution with trace antimony (Sb) doping was synthesized via the high pressure and high temperature method.

Forming solid solutions is one of the most effective strategies to suppress the thermal conductivity of thermoelectric materials. However, the accompanying increase in impurity ion scattering usually results in an undesirable loss in hall mobility, negatively impacting the electrical transport properties. In this work, a tellurium–selenium (Te-Se) …

The main sources of tellurium in the lead smelting process are copper dross (mass of solid impurities floating on a molten metal), alkaline skimming and rich sliver dross intermediate products ... where slimes were roasted at 530–650 °C to convert all of the tellurium and selenium to hexavalent state without volatilization (Fig. 5). The ...

Non-volatile impurities in molten tellurium, particularly carbon, that may have a concentration as high as 5 × 10 14 molecules/m 3, have the chance to occupy a certain number of positions at the ...

Abstract. The paper reports the effect of silver impurity on photoconductive properties of selenium- tellurium glassy system. Steady state and transient photoconductivity is reported in Se-Te ...

Tellurium is recognized as one of the critical elements[9,10,11,12] with an approximate production rate of 480 tons per year (2019), and about 90 pct of it comes from copper anode slime.[2,7] Major components of copper anode slime are copper, sulfur, silver, selenium, arsenic, lead, gold, nickel, antimony, and tellurium.Apart from copper anode …

In this study, we developed a concise and efficient chemical method that does not require expensive reagents or equipment, enabling the separation and …

Selenium and tellurium metals were being recovered as allied products at Ghatsila Copper Smelter of HCL in Jharkhand, where the annual installed capacity to produce selenium was 14,600 kg. HCL has not reported production of selenium since 2006-07 and that of tellurium since 2004-05. HCL has developed its own Precious Metal Recovery Plant at …

Most of the impurities in metallic tellurium can be removed relatively well by zone refining method. The impurity selenium in tellurium is an exception, the impurity Se has similar properties to tellurium and its equilibrium partition coefficient k 0 (0.44) is close to 1.0, so the conventional zone refining method is less effective in removing the …

The presence of impurities, in particular selenium and tellurium, in ZnO-based clusters can affect their structural and spectroscopic properties. Some of these doped …

Tellurium and selenium belong to the chalcogen group (Group VI of the periodic table). All the chalcogens have six valence electrons, and their most common oxidation states are 2, + 2, + 4, and + 6. There is a substantial similarity between the properties of Te, Se, and S. Because of the close chemical similarities, tellurium, and selenium ...

The papers explore the physics of selenium and tellurium, with emphasis on band structure, crystal growth and characterization, optical properties, and electrical properties. This book consists of 33 chapters and opens with a review of progress in the physics of selenium and tellurium, particularly with respect to the mechanical and thermal ...

Selenium and tellurium are typical trace elements, also called rare metals. They are necessarily associated with many sulfide ores or heavy non-ferrous metals. ... TeO 2 is purified by repeated dissolution and reprecipitation of the TeO 2, which eliminates the majority of heavy metal impurities. The final TeO 2 precipitate, contaminated ...

The removal of Te and Cu was the key point during the selenium purification process. Experimental results found that the volatile decomposition and volatilization behavior of Cu–Se compounds and Te would result in a high content of Cu and Te in selenium. Based on Eh-pH of the Se–Te–Cu–H2O system, a removal route of …

Since then, Vale has used cuprous sulfate to remove selenium and tellurium impurities from copper sulfate-sulfuric acid electrolyte prior to electrowinning (Stewart et al., 1985). In this plant, selenium and tellurium are dissolved during high pressure oxidative leaching of a copper sulfide residue to give Se IV/VI and Te IV/VI species into …

Selenium is also recovered from the sludge accumulating in sulfuric acid plants and from electrostatic precipitator dust collected during the processing of copper and lead. Detailed procedures for isolation and purification depend on the relative concentrations of selenium, tellurium, and other impurities, but a typical sequence involves ...

It has been reported that the impurities like Se, As, Na, K, Mg and S are more difficult to remove using vacuum distillation [7]. Out of the various purification techniques for tellurium, multi-pass zone refining is the ultimate purification process [7,8] as majority of impurities in tellurium matrix have segregation coefficient far from unity.

Abstract. Selenium and tellurium are both energy critical elements as defined by the American Physical Society and the Materials Research Society. When mixed together, both elements form an alloy.

In this work, based on the Eh-pH diagrams of the Pb–Se–H 2 O and Pb–Te–H 2 O system, an efficient process of controlling potential oxidation and vacuum distillation for removing impurity Pb from crude selenium was proposed. The occurrence state and the removal behavior of impurity Pb in crude selenium were deeply investigated and ...

The Behaviour of Selenium Impurities During the Addition of Se-Containing Manganese to Steel Melt. M. Reza Aboutalebi, ... Given that selenium and its compounds are potentially toxic and damaging to the work place and environment, effluents have to be treated in a controlled manner. In order to determine how selenium typically distributes ...