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Methods of determination of cobalt and nickel in copper concentrates currently used in factory laboratories are very labor intensive and time consuming. The limiting stage of the analysis is preliminary chemical sample preparation. Carrying out the decomposition process of industrial samples with concentrated mineral acids in open systems does not allow to improve the metrological characteristics of the methods, for this reason improvement the methods of sample preparation is quite relevant and has a practical interest. The work was dedicated to the determination of the optimal conditions of preliminary chemical preparation of copper concentrate samples for the subsequent determination of cobalt and tellurium in the obtained solution using tellurium-spectrophotometric method. Decomposition of the samples was carried out by acid dissolving in individual mineral acids and their mixtures by heating in an open system as well as by using ultrasonification and microwave radiation in a closed system. In order to select the optimal conditions for the decomposition of the samples in a closed system the phase contact time and ultrasonic generator’s power were varied. Intensification of the processes of decomposition of copper concentrates with nitric acid (1:1), ultrasound and microwave radiation allowed to transfer quantitatively cobalt and tellurium into solution spending 20 and 30 min respectively. This reduced the amount of reactants used and improved the accuracy of determination by running the process in strictly identical conditions.

Цель настоящего исследования – разработка методики определения примесей в оксиде скандия методом масс-спектрометрии с индуктивно связанной плазмой (ИСП-МС). Методология работы включала: анализ нормативной документации, регламентирующей номенклатуру и содержание примесей в оксиде скандия, а также методы их определения; проведение предварительного полуколичественного анализа Sc2O3 методом ИСП-МС и выбор элементов-примесей для дальнейших исследований; выбор изотопов элементов и условий работы масс-спектрометра; исследование влияния матричного элемента (скандия) на результаты прямого определения элементов-примесей; оценка правильности и воспроизводимости определений. Выбран 31 элемент: Na, K, щелочноземельные металлы, Al, 3d-элементы, Pb, 15 редкоземельных элементов, торий. Исследовано влияние матричного элемента – скандия на прямое определение примесей. Учет спектральных и неспектральных влияний на определение примесей в оксиде скандия проведён с помощью метода добавок и метода внутреннего стандарта. В качестве внутреннего стандарта применяли раствор индия. Рассчитаны метрологические характеристики разработанной методики: пределы воспроизводимости, пределы правильности, расширенная неопределённость.

The aim of this work is to investigate the possibility of extraction separation of scandium and rare earth metals accompanying impurities trioctylphosphineoxide solution in kerosene. Extraction of scandium by TOPO - kerosene solution depending on the concentration of mineral acids was investigated. Extraction of scandium from HCl solution proceeds quantitatively in the range of 0.5 - 7 M, increasing of HNO 3 concentration leads to extraction of scandium decrease. Based on the obtained extraction isotherm capacitance of 0.001M TOPO in a kerosene solution by scandium was determined, which is 7.7 mg/l, the number of theoretical extraction stages was calculated. The conditions for extraction separation of scandium and rare earth metals-impurities by TOPO - kerosene solution were determined. When the concentration of nitric acid is 0.5 M selective extraction of scandium is possible, when the concentration of HNO 3 is 5 M, earth metals-impurities pass into the organic phase.

The extractive separation of scandium and rare earth metals (REM) was studied. The extractants used are trialkylbenzylammonium di-2-ethylhexylphosphate (TABAC-D2EHPA, binary extractant) and trioctylphosphine oxide (TOPO). The effect of concentration and nature of mineral acids on the scandium recovery was studied. Changing the HNO3 concentration in the range of 0.01 – 2.0 mol/L does not affect the extraction of metals by binary extractant, extraction corresponds to the following row: La, Eu, Gd < Tb

Цель настоящей работы - исследование возможности экстракционного разделения скандия и сопутствующих ему редкоземельных металлов-примесей раствором триоктилфосфиноксида в керосине. Исследована экстракция скандия раствором ТОФО-керосин в зависимости от концентрации минеральных кислот. Извлечение скандия из растворов HCl протекает количественно в интервале 0,5 – 7 М, повышение концентрации HNO3 приводит к уменьшению извлечения скандия. На основании полученной изотермы экстракции определена ёмкость 0,001М раствора ТОФО в керосине по скандию, которая составляет 7,7 мг/л, рассчитано число теоретических ступеней экстракции. Определены условия экстракционного разделения скандия и редкоземельных металлов-примесей раствором ТОФО-керосин. При концентрации азотной кислоты 0,5 М возможно селективное выделение скандия, при концентрации HNO3 5 М редкоземельные металлы-примеси переходят в органическую фазу.

Regularities of extraction of rhenium (VII) melt tetraoctyl-ammonium bromide in a mixture of higher alcohols and paraffin were determined. Quantitative extraction of measurements obtained in the range of pH of the aqueous phase 1.5–2.0 was carried out. It was shown that the degree of extraction of rhenium is reduced during the transition from sulfuric to nitric acid. The introduction of extracting 20% of higher alcohols improved the solubility of the extracted complex in paraffin. The composition of the complex, calculated, was 3.37±0.4.

Extraction concentration of rhenium by a melt of tetraoctylammonium bromide in paraffin was used with the aim of preparation of calibration samples for roentgen fluorescent analysis. The calibration characteristics of the roentgen fluorescent analysis of rhenium is established, its linearity is evaluated, a limit of detection and a limit of quantification (determination) of rhenium are calculated. The maximal value of the relative total standard uncertainty of the calibration characteristic does not exceed 1.45%. ristic does not exceed 1.45%.

The method including microwave acidic dissolution of samples and atomic-emission analysis of rhenium for determination of rhenium in cupper-molybdenum and lead-cupper wares is proposed. The range of determination concentration of metal is 0.05 – 0.5 mass percent, standard deviation of repeatability is 0.002 – 0.01 %.