Fundamental Investigation for Processing of Pb-Cu-S-Bearing Materials

The processing of polymetallic materials provides some challenges to every flowsheet. Within Aurubis Cu-Pb-metallurgical flowsheet, a broad range of raw materials and intermediates are processed. Continuous improvements are required to adapt the flowsheet according to the changing material quantity and quality. Therefore, thermodynamic modeling is the desired and most efficient way to conduct scenario analysis. Hence, databases and software are becoming better and better as the acceptance of this method increased. Further understanding is promoted by conducting experimental test work to validate the calculated results. In this research work, the impact of various oxygen potential on the formation of the condensed phases’ slag, matte, speiss and crude lead were investigated. A frequent check of slag metallurgy, in particular, the iron and lead concentration, provide feedback if the metallurgical process is operating at the right oxygen potential. Following, the calculated distribution coefficients for Cu, Pb, As, Sb, Sn and Ni between matte/speiss and speiss/lead are discussed.

The interphase distribution of light REE Ce(III) and La(III) in system based on PEG-1500 – NaNO3 – H2O with the quaternary ammonium base addition

The problem of e-waste processing and recovery of valuable metals from such waste for the second use is attracting more and more scientists’ attention. Liquid extraction as one of hydrometallurgy steps is a traditional method for the metal recovery. However, application of solvent extraction is not meet the green chemistry principles due to organic solvents. Aqueous two-phase systems based on water-soluble polymers are promising alternative for hazardous organic solvents. In this work the dependencies of Ce(III) and La(III) distribution coefficients from process time and the initial quaternary ammonium base concentration have been achieved. Also, based on the Ce(III) and La(III) extraction isotherms it has been shown that the metals initial concentrations are highly affects the distribution coefficients of studied metals. The possibility of aqueous two-phase system application as a solvent for quaternary ammonium salt for light REE (Ce(III) and La(III)) extraction from water solution has been shown.

Vanadium(IV) ions extraction in the aqueous two-phase system based on poly(ethylene glycol)

Vanadium has found wide applications in various industries: metallurgy, electronics, batteries, and others. This element, being dispersed, does not form its minerals and, therefore, is mined along the way. An alternative approach of vanadium extraction is to separate it from heavy oil, by flushing the oil with strong acids solutions and further hydrometallurgical processing. The existing methods of oil dehydration solutions processing for the vanadium extraction are not perfect - they do not meet the “green” chemistry principles. Thus, we investigated V(IV) ions extraction in the aqueous two-phase system (ATPS) based on poly(ethylene glycol) 1500 (16.3wt%) – NaNO3 (36wt%) – H2O. The dependences of V(IV) extraction efficiency on phases time contact, and dependences V(IV) distribution coefficients on salt phase acidity have been obtained. This system is shown to be a prospective solution for the vanadium(IV) recovery from acidic waste steams problem as it is possible to extract vanadium with an efficiency of more than 81.6% per one extraction step (the distribution coefficient of vanadium (IV) was 4.84).

The possibility of using DES based on polypropylene glycol 425 and tetrabuthylammonium bromide in the extraction processes of transition metals

Traditionally, the method of liquid extraction is used to extract metals from aqueous. This work is devoted to the combination of perspective alternative for hazardous solvents (aqueous two-phase systems based on water-soluble polymers) and the novel deep eutectic solvents in the non-ferrous metals extraction processes. In this work, the synthesis of deep eutectic solvent based on a water-soluble polymer (PPG-425) and tetrabutylammonium bromide (TBAB) by stirring for 10 minutes at 80° C has been shown. The obtained results showed not only the possibility of using DES in the metal extraction process, but the selectivity to the Fe(III) and Zn(III), the distribution coefficients were 71.64 and 25.17 respectively. The metal concentrations were determined spectrophotometrically using 4-(2-pyridylazo)resorcinol. This work shows the perspectives of using DESs in the metal extraction processes.

Quantum-chemical investigation of interactions in supramolecular systems: cholesterol - bile acids - silica in aqueous solutions

Hypercholesterolemia significantly increases the risk of myocardial infarction associated with COVID-19. Along with pharmacological treatment, the possibility of the excretion of excess cholesterol from an organism by adsorption is also of great interest. The interaction of cholesterol with the surface of partially hydrophobized silica in aqueous solutions of bile acids was investigated by the PM7 method using the COSMO (COnductor-like Screening MOdel) solvation model. The distribution of electrostatic and hydrophobic potentials of molecules and complexes was calculated. The values of free Gibbs energy adsorption of bile acids on the surface of silica correlate with the distribution coefficients in the n-octanol-water system. The energy of interaction of cholesterol with bile acids affects its adsorption on silica. The stronger the bond of cholesterol with the molecules of bile acids, the less it is released from the primary micelles in solution and adsorbed on the surface.

A NEW METHOD OF THE STOICHIOMETRY INCREASE OF THE LITHIUM NIOBATE NONLINEAR-OPTICAL CRYSTAL

Experimental and theoretical data on the influence of В2О3 flux on the crystal-melt system, the structural features, and the optical properties of a crystal of lithium niobate are summarized. The Gibbs energies of the borate impurities formation (Al4B2O9, CaB2O4, CaB4O7, Ca2B2O5, Ca3B2O6, PbB2O4) in a congruent composition charge of lithium niobate are calculated. It was found that the element boron, as an active complexing agent, in the composition of the В2О3 flux aligns the distribution coefficients of lithium (KLi) and niobium (KNb). Also, the element boron is able to prevent the transition of trace amounts of impurity metals into the structure of a lithium niobate crystal. Boron increases the ordering of structural units of the cation sublattice and distorts the anionic framework of the crystal. This is due to the fact that boron is embedded in the tetrahedral voids faces of the crystal structure in trace amounts (4∙10-4 mol.%). This leads to changes in bond lengths O-O of the oxygen octahedra O6, thereby changing polarizability oxygen-octahedral cluster NbO6, determining nonlinear optical and ferroelectric properties of the crystal.

Overview of Stochastic Model Updating in Aerospace Application Under Uncertainty Treatment

This chapter presents the technique route of model updating in the presence of imprecise probabilities. The emphasis is put on the inevitable uncertainties, in both numerical simulations and experimental measurements, leading the updating methodology to be significantly extended from deterministic sense to stochastic sense. This extension requires that the model parameters are not regarded as unknown-but-fixed values, but random variables with uncertain distributions, i.e. the imprecise probabilities. The final objective of stochastic model updating is no longer a single model prediction with maximal fidelity to a single experiment, but rather the calibrated distribution coefficients allowing the model predictions to fit with the experimental measurements in a probabilistic point of view. The involvement of uncertainty within a Bayesian updating framework is achieved by developing a novel uncertainty quantification metric, i.e. the Bhattacharyya distance, instead of the typical Euclidian distance. The overall approach is demonstrated by solving the model updating sub-problem of the NASA uncertainty quantification challenge. The demonstration provides a clear comparison between performances of the Euclidian distance and the Bhattacharyya distance, and thus promotes a better understanding of the principle of stochastic model updating, as no longer to determine the unknown-but-fixed parameters, but rather to reduce the uncertainty bounds of the model prediction and meanwhile to guarantee the existing experimental data to be still enveloped within the updated uncertainty space.

Ion Flotation of Ytterbium Water-Salt Systems—An Innovative Aspect of the Modern Industry

Considering the ever-increasing role of rare-earth elements (REE) in the modern hi-tech field, their effective use has tremendous significance, although the production process is inevitably linked to the large volumes of industrial ammonia effluents and heavy metal wastes. In the process of metallurgical separation of metals, the emission of large volumes of noxious gases and radioactive substances is inevitable. Lean technogenic raw material processing is sensible under the condition of the development of non-waste technology. The lack of competent regulations governing the disposal of waste containing REE has an impact on adjacent territories, accumulating in water bodies and, as a result, in the human body. Such an impact cannot pass without a trace, however, the ambiguity of opinions in the scientific community regarding the toxic effects of REE on living organisms determines the relevance of a more detailed study of this issue. The study of ytterbium ions removal from aqueous standard test solutions by the adsorptive bubble method—ion flotation—was conducted. The experiments showed that by using the ion flotation method, the maximum removal of ytterbium (III) was achieved at pH = 8.30. It was shown that ytterbium (+3) distribution coefficients as a function of aqueous phase pH value in the process of ion flotation with sodium dodecyl sulphate were derived. The comparison of values of removal pH with those of hydrate formation pH allowed to conclude that ytterbium floate as basic dihydroxoytterbium dodecyl sulphate Yb(OH)2(C12H25OSO3).

OPTIMIZATION EXTRACTION OF COFFEINE AND THEOBROMINE FROM VARIOUS VARIETIES OF TEA WITH PLURONIC BLOCK COPOLYMER

Контроль содержания алкалоидов в пищевых продуктах и напитках в соответствии с нормируемыми показателями – актуальная задача для биотехнологии. Рассмотрена экстракция кофеина и теобромина из растительного сырья – чая черного и зеленого с использованием в качестве экстрагента блок-сополимера плюроник, представляющего собой чередующиеся фрагменты этиленоксида (20 мономерных звеньев) и пропиленоксида (70 мономерных звеньев). Экстракционные системы на основе водорастворимых полимеров отвечают всем требованиям «зеленой» экстракции и могут применяться в технологических процессах, связанных с контролем качества исходного сырья. Исследованы условия процесса извлечения пуриновых алкалоидов, установлены его оптимальные параметры: концентрация экстрагента 0,25 г/см3, температура процесса 95°С, степень измельчения для черного и зеленого чая 0,4 и 0,8 мм соответственно, соотношение водной и органической фаз 10 : 1 соответственно. По результатам экстракции рассчитаны коэффициенты распределения и степень извлечения кофеина и теобромина, которая составляет 95–99% в зависимости от сорта чая. Содержание кофеина и теобромина в фазе органического растворителя после экстракции определяли методом капиллярного электрофореза по электрофореграммам образцов черного и зеленого чая. На основании разработанной экстракционно-электрофоретической методики определения кофеина и теобромина в различных сортах чая предложен механизм взаимодействия пуриновых алкалоидов с экстрагентом плюроник. Наличие в цепи полимера концевых НО-групп, а также в основной цепи атомов кислорода способствует взаимодействию полимера с аналитами с образованием водородных связей. Представленные схемы образования Н-связей подтверждают эффективность применения блок-сополимера плюроник в качестве экстрагента пуриновых алкалоидов. Monitoring the content of alkaloids in food and beverages in accordance with the normalized indicators is an urgent task for biotechnology. The extraction of caffeine and theobromine from vegetable raw materials – black and green tea using the pluronic block copolymer as an extractant is considered. The pluronic block copolymer consists of alternating fragments of ethylene oxide (20 monomer units) and propylene oxide (70 monomer units). Extraction systems based on water-soluble polymers meet all the requirements of «green» extraction and can be used in technological processes related to quality control of feedstock. The conditions of the purine alkaloid extraction process have been investigated, its optimal parameters have been established: the extractant concentration is 0,25 g/cm3, the process temperature is 95°C, the degree of grinding for black and green tea is 0,4 and 0,8 mm respectively, the ratio of aqueous and organic phases is 10 : 1 respectively. According to the extraction results, the distribution coefficients and the degree of extraction of caffeine and theobromine, which is 95–99%, depending on the tea variety, are calculated. The content of caffeine and theobromine in the organic solvent phase after extraction was determined by capillary electrophoresis from electrophoregrams of black and green tea samples. The presence of terminal HO-groups in the polymer chain, as well as in the main chain of oxygen atoms, promotes the interaction of the polymer with analytes with the formation of hydrogen bonds. The presented schemes for the formation of H-bonds confirm the effectiveness of using the pluronic block copolymer as an extractant of purine alkaloids.