The extraction of cobalt with amines has been studied in the most detail. The article presents experimental data obtained in the study of cobalt extraction from leaching solutions of cobalt ores with a mixture of tributylamine (TBA) in toluene and hexane. The dependence of the extraction degree and distribution coefficient of cobalt on pH, time, and the ratio of aqueous and organic phases have been studied. It has been shown that cobalt is maximally extracted with TBA in toluene in the pH range of 3-5 for no more than 5-10 minutes; in this case, 98% of cobalt extraction is achieved. The developed method of cobalt extraction with organic extractants can be widely used in non-ferrous metallurgy

Aminomethylation of trifunctional 2.5-dihydroxyacetophenone (2.5-DHA) and 2.4-dihydro¬xy¬aceto-phenone (2.4-DHA) by free primary and secondary amines in the presence of formaldehyde has been conducted for the first time. It has been established that 2.5-DHA is aminomethylated with secondary heterocyclic amines - piperidine and morpholine and with aqueous formaldehyde solution in alcohol medium at 500C. The reaction proceeds simultaneously via all three functions forming stable C,O-substitution products − β-amino-2-aminomethoxy-4-aminomethyl-5-hydroxypropiophenones. The aminomethylation reaction of 2.4-DHA proceeds by phenolic function only under the action of methylene bis-amines piperidine and morpholine in absolute alcohol at 200C with the formation of 2.4-dihydroxy-3-aminomethylacetophenones. Aminomethylation of 2.4-DHA with primary aromatic amines - n-to¬luidine and n-anisidine proceeds in absolute alcohol under the action of formaldehyde in the form of paraform in the presence of catalytic amounts of KOH at 500C. The reaction products are 3.4-dihydro-2H-1.3-benzoxazines. 2.5-DHA does not react with primary aromatic amines and formaldehyde. The composition and structure of compounds synthesized have been established according to the data of ele¬mental and spectral methods of analysis

The complexation of tungsten (VI) with an azo compound synthesized from para-tret-butylphenol (2-hydroxy-5-Tr-butylphenol-4-nitro-asobenzene) has been studied spectrophoto¬metrically. The optimum pH values of the solution are 2.0-3.0. The maximum light absorption of the complexes in n-butanol is in the range 460-470nm, and that of the reagent at 360-370; complex formation is accompanied by a bathochromic shift. The spectrophotometric characteristics of the complex have been calculated and the composition of the complex was determined by various methods. Using the equilibrium shift and isomolar series methods it has been found that the W:R ratio is 1:2. By the Sommer method it has been found that during complex formation one proton is released from each reagent molecule. The complex stability constant βk = 9.04·108 and the complex formation reaction equilibrium constant (4.2·104) have been calculated by the method of Komar. The molar absorption coefficient is (3.44.2).104. The graduation diagram is linear at a tungsten concentration of 1.0-10 µg/ml, n-butanol has been used as an extractant. A single extraction with n-butanol 97% of tungsten as a complex is extracted. Methods of extraction-atomic-absorption and extraction-photometric determination of tungsten have been developed and the influence of a number of extraneous ions on the determination of tungsten has been revealed. The correctness of the results obtained has been controlled by analysing the State Standard Alloy Reference Materials

It is shown that in the near-surface region of the solar cells (SCs) the concentration of nickel atoms is higher than in the bulk by 2–3 orders of magnitude, therefore, the gettering rate in the near-surface region is higher. Optimal modes of gettering by nickel clusters (i.e., nickel diffusion – Т = 800–850 °С, additional thermal annealing – Т = 750–800 °С) and the structure of a silicon SC were experimentally determined, which makes it possible to increase the efficiency of silicon SCs by 25–30% relative to the control. The physical mechanisms of the influence of the processes of diffusion of impurity nickel atoms and additional thermal annealing on the state of nickel atoms in the near-surface region and the SCs base and, accordingly, on the parameters of the SC are revealed. Physical models of the structure of a cluster of nickel atoms in silicon and the process of fast diffusing impurities gettering by clusters of nickel atoms are created. The binding energy of fast dissusing impurities atoms with a nickel cluster is estimated to be ~ 1.39 eV. The calculation shows that doping with nickel can increase the lifetime of minority charge carriers by 2–4 times, and the collection coefficient by 1.4–2 times. The experiment showed an increase in the minority charge carriers lifetime up to 2 times and an increase in efficiency by 25–30%.