Behavior of copper chalcogenides during vacuum-thermal processing

In this work, thermodynamic functions of evaporation of copper chalcogenides (Cu2S, Cu2Se, and Cu2Te) are determined via previously published data and thermodynamic values obtained by the authors of the work. The obtained results indicate a very low probability of separation of compounds into copper and chalcogen by dissociation under vacuum-thermal processing conditions. Liquid-vapor phase transitions in binary systems Cu2S – Cu2Se, Cu2S – Cu2Te, and Cu2Se – Cu2Te at low pressures of 15 and 0,7 kPa are constructed based on the vapor pressure of copper chalcogenides. It is shown that the pressure eases over the liquid bath impairs the separation of chalcogens, therefore separation in one stage by thermo-vacuum treatment at a pressure of 0,7 – 15 kPa is not possible

Behavior of copper chalcogenides during vacuum-thermal processing

In this work, thermodynamic functions of evaporation of copper chalcogenides (Cu2S, Cu2Se, and Cu2Te) are determined via previously published data and thermodynamic values obtained by the authors of the work. The obtained results indicate a very low probability of separation of compounds into copper and chalcogen by dissociation under vacuum-thermal processing conditions. Liquid-vapor phase transitions in binary systems Cu2S – Cu2Se, Cu2S – Cu2Te, and Cu2Se – Cu2Te at low pressures of 15 and 0,7 kPa are constructed based on the vapor pressure of copper chalcogenides. It is shown that the pressure eases over the liquid bath impairs the separation of chalcogens, therefore separation in one stage by thermo-vacuum treatment at a pressure of 0,7 – 15 kPa is not possible

Achievements in the titanium production development

Titanium sponge process flowchart includes the following main operations: concentrates reduction melting (example for concentrate from the Obukhovskoe field, the Republic of Kazakhstan), chlorination of obtained titanium slug, refining of industrial tetrachloride and ma gnesium-thermic reduction of titanium tetrachloride purified from any impurities. This paper presents the results of material flows balance studies and quality analysis of the technological products. It is shown that stillage bottoms pulp feed on the melt mirror of potassium chloride electrolyte with a speed less than 2,5 t/h excludes the temperature overshoot within 570 - 620 °C of titanium tetrachloride vapors sublimation. Chlorinator melt bubbling in the process initial period with dried air (nitrogen) can significantly improve the quality of titanium products

Graphene oxide deposition on neodymium doped zinc borotellurite glass surface: optical and polarizability study for future fiber optics

Neodymium oxide doped tellurite-based glass has been widely documented for potential uses in optoelectronics, but graphene oxide (GO)-coated tellurite-based glass has rarely been reported. In this work, we compare two sets of glass series which were GO-coated and uncoated tellurite-based glass series denoted as ZBTNd-GO and ZBTNd, respectively. The two sets of glasses were fabricated via melt-quenched process. A set of glass was coated with GO using low-cost spray coating method. The structural and morphological properties of the glass samples were investigated to confirm the type of structure in glass and formation of graphene oxide on glass surface. The X-ray diffraction (XRD) pattern confirmed the amorphous structural arrangement in both sets of glass series. The morphological study proved the existence of GO layers on top of the ZBTNd-GO surface. The optical bandgap energy of ZBTNd-GO glass was found in the range of 3.253 eV–3.381 eV which was higher than ZBTNd glass. Meanwhile, the refractive index of ZBTNd-GO glass varies from 2.301 to 2.332 which was higher than ZBTNd glass due to the presence of functionalized oxygenated groups in GO structure. The oxide ion polarizability of ZBTNd-GO glass was found decreased due to the shift of optical band gap when coated with GO. This work offers a new form of glass that could be used as a new strategy to upgrade the current photonic materials

Decomposition of a Synthetic Copper Sulfoarsenide

We have studied the thermal behavior of synthetic lautite, a copper sulfoarsenide widespread in nature. The material was characterized by thermogravimetric analysis under nonisothermal and isothermal conditions. Using the data thus obtained, equations of nonisothermal formal kinetics, and the Kazeev-Erofeev-Kolmogorov equation with the Sakovich correction, we assessed kinetic parameters. Lautite decomposition to copper sulfides has been shown to be accompanied by the formation of tennantite as an intermediate phase. The sublimates consist of an alloy of arsenic sulfides. The E (a) values obtained under nonisothermal conditions suggest that synthetic CuAsS dissociation is a kinetically controlled process. The E (a) values obtained under isothermal conditions suggest that, at a temperature of 500A degrees C, the lautite decomposition process switches from intermediate to diffusion control

Vacuum-Distillation Extraction of Selenium from Selenium-Containing Preliminary Products and Materials

Результаты многолетних исследований коллектива лаборатории вакуумных процессов АО «Институт металлургии и обогащения» легли в основу разработки экологически безопасной вакуум-дистилляционной технологии извлечения селена из различных селенсодержащих промпродуктов и материалов с последующим его рафинированием до марочного состояния в соответствии с ГОСТ 10298-79. Технология и аппаратура апробированы на многих видах материалов, в том числе на техническом и черновом селене, производимом ТОО «Казцинк» и ТОО «Корпорация Казахмыс», селенсодержащих пылях рукавных фильтров аффинажного производства и шламах сернокислотного производства ТОО «Корпорация Казахмыс», шламах никелевого производства ГМК «Кольская», селенсодержащих концентратах ОАО «Красцветмет». В данной работе на примере нескольких видов материалов показана эффективность разработанной вакуум-дистилляционной технологии и аппаратуры, позволяющих получать в одну стадию дешёвым безреагентным способом марочный селен с содержанием более 99,5 % основного компонентаThe results of long standing studies by collective of the laboratory of vacuum processes JSC “Institute of Metallurgy and Ore Benefication” provided the basis for the development of environmentally friendly vacuum-distillation technology of selenium extract from the various selenium-containing middling products and materials with further refinement to the slate condition in accordance with GOST 10298-79. The technology and equipment has been tested on different raw materials, including: technical and crude selenium produced by Kazzink LLP and Kazakhmys Corporation LLP, selenium-containing bag filter fumes of refinery production and drilling cutting of sulfuric production produced by Kazakhmys Corporation LLP, sludge of nickel production produced by Kolsky MMC, selenium-containing concentrates Krastsvetmet JSC. Potential of developed vacuum-distillation technology and equipment, allowing to receiving the selenium containing more than 99.5 % of the main component within one step by cheap reagentless method, is shown in this article an example of several form of material

ПАРОЖИДКОСТНОЕ РАВНОВЕСИЕ В СИСТЕМЕ ОЛОВО–СВИНЕЦ В ФОРВАКУУМЕ

The boiling point method (isothermal version) was used to determine the partial pressure of saturated lead vapor over lead-tin solutions with the following lead content (the rest is tin), wt.%: 96.43, 93.02, 89.55, 80.73, 64.18, and 43.80 (93.93, 88.42, 83.08, 70.59, 50.65, and 30.87 at.%, respectively). The partial pressures of tin were calculated by the numerical integration of the Duhem–Margules equation using the auxiliary function proposed by Darken. The tin and lead partial pressure values over their melts were approximated by temperatureconcentration dependences. The total determination error was calculated as a sum of independent measurement errors: temperature, mass, pressure, approximation of experimental data, equal to 7.78 %. Based on the values of saturated lead and tin vapor partial pressures, the boundaries of liquid and vapor coexistence fields in the tin-lead system in a primary vacuum of 100 and 1 Pa were calculated and specified: boiling temperature – as a temperature at which the sum of metal partial pressures is equal to 100 and 1 Pa, vapor composition – as the ratio of metal vapor partial pressures at this temperature. It was found that the reason for the increased content of tin in lead condensate during the distillation of alloys with a lead content of less than 5 at.% (8.41 wt.%) and tin accumulation in the distillation residue is partial pressure values of tin vapor comparable to that of lead. Tin accumulation in the distillation residue should not exceed a concentration of ~ 50 wt.% during the distillation separation of lead-tin melts by lead evaporation in a real process under non-equilibrium conditions. If the specified concentration is exceeded, the condensate obtained will require repeating the evaporation-condensation process.Методом точек кипения (изотермический вариант) определены значения парциального давления насыщенного пара свинца над свинцово-оловянными растворами, содержание свинца в которых (остальное – олово) составило 96,43; 93,02; 89,55; 80,73; 64,18 и 43,80 мас.% (93,93; 88,42; 83,08; 70,59; 50,65 и 30,87 ат.% соответственно). Величины парциального давления олова рассчитаны численным интегрированием уравнения Дюгема–Маргулеса с использованием вспомогательной функции, предложенной Даркеном. Показатели парциальных давлений олова и свинца над их расплавами аппроксимированы температурно-концентрационными зависимостями. Общая погрешность определений вычислена как сумма погрешностей независимых измерений: температуры, массы, давления, аппроксимации экспериментальных данных, и равна 7,78 %. На основании данных о парциальном давлении насыщенного пара свинца и олова рассчитаны и уточнены границы полей сосуществования жидкости и пара в системе олово–свинец в форвакууме 100 и 1 Па: температура кипения – как температура, при которой сумма парциальных давлений металлов равна 100 и 1 Па; состав пара – как соотношение величин парциального давления паров металлов при этой температуре кипения. Установлено, что причиной повышенного содержания олова в свинцовом конденсате при дистилляции сплавов с содержанием свинца менее 5 ат.% (8,41 мас.%) и накоплением олова в остатке от дистилляции являются сопоставимые со свинцом значения парциального давления пара олова. При дистилляционном разделении свинцово-оловянных расплавов испарением свинца в реальном процессе в неравновесных условиях накопление олова в кубовом остатке не должно превышать значение ~50 мас.%. Превышение указанной концентрации будет сопровождаться получением конденсата, для которого необходимо повторение процесса «испарение–конденсация»