Using reference materials of blast furnace slag, steelmaking slag, converter slag and fused fluxes when developing a procedure for analysis of slag-forming mixtures using inductively coupled plasma atomic emission spectrometry

Introduction. Slag-forming mixtures play an important role in obtaining metal without non-metallic inclusions. Required properties of slag-forming mixtures (SFMs) directly depend on their chemical composition, that is why control of individual component content in a mixture is an important stage in the technological chain of metallurgical production. At the present time, it is a common practice to use inductively coupled plasma atomic emission spectrometry (ICP-AES for analyzing SFMs, requiring sample preparation by alloying with alkali fluxes, which makes it impossible to determine potassium and sodium oxides in a sample. That is why it is necessary to work out a procedure for simultaneous determination of calcium, silicon, magnesium, aluminium, potassium, and sodium oxides by the method of ICP-AES, which would include quantitative transferring of all components into a solution. For that purpose, it is suggested to use microwave digestion of samples in autoclaves.The purpose was to develop a procedure for simultaneous determination of specified components of SFMs using ICP-AES after transferring the sample into a solution in an autoclave under conditions of microwave heating, and to certify it reference materials of slag and fluxes.Materials and methods. Compositional analysis of slag-forming mixtures was conducted using an atomic emission spectrometer with inductively coupled plasma «iCAP 6500 Duo»; sample digestion was conducted with the use of the microwave system «ETHOS PLUS». The following brands of SFMs were chosen as research objects: Melubir 9563 and Accutherm ST-SP/235AL4D; AlsifluxGS-C7; SRCP015, SRCP173P. For calibrating the spectrometer and controlling correctness of determining the specified components, the following reference materials were used: reference materials of blast furnace slag, steelmaking slag, converter slag, and fused fluxes, which have close chemical composition.Research results. An ICP-AES analysis procedure has been developed for calibrating the spectrometer and controlling correctness of determining CaO, SiO2 , MgO, Al2 O3 , K2 O, Na2 O in reference materials of blast furnace slag, steelmaking slag, converter slag and fused fluxes, which allows to establish target components of SFMs quickly and reliably

Применение стандартных образцов доменных, сталеплавильных, конвертерных шлаков и сварочных плавленых флюсов при разработке методики анализа шлакообразующих смесей методом атомно-эмиссионной спектрометрии с индуктивно связанной плазмой

Introduction. Slag-forming mixtures play an important role in obtaining metal without non-metallic inclusions. Required properties of slag-forming mixtures (SFMs) directly depend on their chemical composition, that is why control of individual component content in a mixture is an important stage in the technological chain of metallurgical production. At the present time, it is a common practice to use inductively coupled plasma atomic emission spectrometry (ICP-AES for analyzing SFMs, requiring sample preparation by alloying with alkali fluxes, which makes it impossible to determine potassium and sodium oxides in a sample. That is why it is necessary to work out a procedure for simultaneous determination of calcium, silicon, magnesium, aluminium, potassium, and sodium oxides by the method of ICP-AES, which would include quantitative transferring of all components into a solution. For that purpose, it is suggested to use microwave digestion of samples in autoclaves.The purpose was to develop a procedure for simultaneous determination of specified components of SFMs using ICP-AES after transferring the sample into a solution in an autoclave under conditions of microwave heating, and to certify it reference materials of slag and fluxes.Materials and methods. Compositional analysis of slag-forming mixtures was conducted using an atomic emission spectrometer with inductively coupled plasma «iCAP 6500 Duo»; sample digestion was conducted with the use of the microwave system «ETHOS PLUS». The following brands of SFMs were chosen as research objects: Melubir 9563 and Accutherm ST-SP/235AL4D; AlsifluxGS-C7; SRCP015, SRCP173P. For calibrating the spectrometer and controlling correctness of determining the specified components, the following reference materials were used: reference materials of blast furnace slag, steelmaking slag, converter slag, and fused fluxes, which have close chemical composition.Research results. An ICP-AES analysis procedure has been developed for calibrating the spectrometer and controlling correctness of determining CaO, SiO2 , MgO, Al2 O3 , K2 O, Na2 O in reference materials of blast furnace slag, steelmaking slag, converter slag and fused fluxes, which allows to establish target components of SFMs quickly and reliably. Введение. Шлакообразующие смеси играют важную роль для получения «чистого» от неметаллических включений металла. Необходимые свойства шлакообразующих смесей (ШОС) напрямую зависят от химического состава, поэтому контроль содержания индивидуальных компонентов смесей является важным этапом в технологической цепи металлургического производства. В настоящее время для анализа шлакообразующей смеси практикуется метод атомно-эмиссионной спектрометрии с индуктивно связанной плазмой (АЭС ИСП), требующий пробоподготовки путем сплавления с щелочными плавнями, что делает невозможным определение оксидов калия и натрия в пробе. Поэтому существует необходимость разработки методики одновременного определения оксидов кальция, кремния, магния, алюминия, калия и натрия методом АЭС ИСП, включающей количественное переведение всех компонентов в раствор. Для этих целей предложено использовать микроволновое разложение проб в автоклавах.Цель работы. Разработка методики одновременного определения нормируемых компонентов ШОС методом АЭС ИСП после переведения пробы в раствор в автоклаве в условиях микроволнового нагрева, ее аттестация с применением стандартных образцов шлаков и флюсов.Материалы и методы. Определение компонентного состава ШОС осуществлялось с помощью атомно-эмиссионного спектрометра с индуктивно связанной плазмой «iCAP 6500 Duo»; разложение проб осуществлялось с помощью микроволновой системы «ETHOS PLUS». В качестве объектов исследования выбраны шлакообразующие смеси марок Melubir 9563 и Accutherm ST-SP/235AL4D; AlsifluxGS-C7; SRCP015, SRCP173P. Для градуировки спектрометра и контроля правильности определения нормируемых компонентов использованы СО шлаков доменных, сталеплавильных, конвертерных, а также флюсов сварочных плавленых, имеющих близкий химический состав.Результаты исследования. Разработана методика АЭС ИСП анализа, предназначенная для градуировки спектрометра и контроля правильности определения CaO, SiO2 , MgO, Al2 O3 , K2 O, Na2 O стандартных образцов шлаков доменных, сталеплавильных, конвертерных и флюсов сварочных плавленых, которая позволяет быстро и надежно определить целевые компоненты ШОС

Thermosinus carboxydivorans gen. nov., sp. nov., a new anaerobic, thermophilic, carbon-monoxide-oxidizing, hydrogenogenic bacterium from a hot pool of Yellowstone National Park

A new anaerobic, thermophilic, facultatively carboxydotrophic bacterium, strain Nor1T, was isolated from a hot spring at Norris Basin, Yellowstone National Park. Cells of strain Nor1T were curved motile rods with a length of 2.6-3 μm, a width of about 0.5 μm and lateral flagellation. The cell wall structure was of the Gram-negative type. Strain Nor1T was thermophilic (temperature range for growth was 40-68 °C, with an optimum at 60 °C) and neutrophilic (pH range for growth was 6.5-7.6, with an optimum at 6.8-7.0). It grew chemolithotrophically on CO (generation time, 1.15 h), producing equimolar quantities of H2 and CO2 according to the equation CO+H2O → CO2 + H2. During growth on CO in the presence of ferric citrate or amorphous ferric iron oxide, strain Nor1T reduced ferric iron but produced H2 and CO2 at a ratio close to 1:1, and growth stimulation was slight. Growth on CO in the presence of sodium selenite was accompanied by precipitation of elemental selenium. Elemental sulfur, thiosulfate, sulfate and nitrate did not stimulate growth of strain Nor1T on CO and none of these chemicals was reduced. Strain Nor1T was able to grow on glucose, sucrose, lactose, arabinose, maltose, fructose, xylose and pyruvate, but not on cellobiose, galactose, peptone, yeast extract, lactate, acetate, formate, ethanol, methanol or sodium citrate. During glucose fermentation, acetate, H2 and CO2 were produced. Thiosulfate was found to enhance the growth rate and cell yield of strain Nor1T when it was grown on glucose, sucrose or lactose; in this case, acetate, H2S and CO2 were produced. In the presence of thiosulfate or ferric iron, strain Nor1T was also able to grow on yeast extract. Lactate, acetate, formate and H2 were not utilized either in the absence or in the presence of ferric iron, thiosulfate, sulfate, sulfite, elemental sulfur or nitrate. Growth was completely inhibited by penicillin, ampicillin, streptomycin, kanamycin and neomycin. The DNA G+C content of the strain was 51.7 ± 1 mol%. Analysis of the 16S rRNA gene sequence revealed that strain Nor1T belongs to the Bacillus-Clostridium phylum of the Gram-positive bacteria. On the basis of the studied phenotypic and phylogenetic features, we propose that strain Nor1T be assigned to a new genus, Thermosinus gen. nov. The type species is Thermosinus carboxydivorans sp. nov. (type strain, Nor1T = DSM 14886T = VKM B-2281T).This work was supported by the NATO LST.CLG. 978269 grant, the CRDF RB2-2379- MO-02 grant and the Program ‘Molecular and Cell Biology’ of the Russian Academy of Sciences. J. M. G. acknowledges support from the Spanish Ministry of Science and Technology through a Ramón y Cajal contract and grant REN2002-00041.Peer Reviewe