Abstraсt: This work presents a method of an extraction of pcwder components, containing a trivalent nitrogen or atoms of other elements with an undivided electron pair, by the aqueous solutions of complexing extragents. The aqueous solution of aluminium chloride was used as an example. The method is based on the reagents’ interaction according to a donor-acceptor mechanism, in which a nitrogen atom with the undivided electron pair of a diphenylamine molecule acts as a donor of the electrons and an aluminium ion Al3+ with free p- and d-orbitals acts as an acceptor. A formation of complex compounds according to this mechanism promotes an increase in a solubility of DPA in water and a strengthening in its extraction from a powder composition. This fact was applied for an extraction of this component from powders with trying out of the technological conditions for a treatment of powders with the aqueous solution of aluminium chloride. The porous pyroxylin powders were used as an example.
Keywords: complex compounds, diphenylamine, aluminium chloride, undivided electron pair, donor, acceptor, complexing extragent, pyroxylin powder.
Abstraсt: The requirements of state-of-the-art technologies in respect of liquid-solid separation quality in suspensions are getting stricter and result in increased specific flow rates and failure of manufacturing equipment to meet the set requirements. Based on the existing practice of medium-concentrated process suspension dewatering, it is proposed, depending on the clarified solution requirements, to retrofit the existing equipment with filtering units for control operations or to design intensive dewatering modules with a view to ensure zones of comfortable operation of filtering equipment with various operating principles, to reduce specific flow rates. Adoption of the dynamic filtration technology for treatment of solutions with a high initial solids content makes it possible to exclude clarification and settling operations at the required filtration volumes from 1 to 100 m3/h, and when combined with a vacuum filter or press filter will result in liquid-solid separation with filtrate clarity of up to 5 mg/l and the final cake moisture of less than 8% [1,2]. High suspension separation quality requirements are set by the hydromet-allurgical and food industries, since the filtration process quality determine subsequent separation products processing costs and in-process losses of valuable components.
Keywords: module, suspension, dynamic filter thickener, press filter, concentrate, filtrate, cake, filtration, food industry, nuclear industry, hydrometallurgy, chemical industry, public utilities.
Abstraсt: In the two-phase system «aqueous solution of boric acid-solution of H3BO3 in tributyl phosphate» at various concentrations of H3BO3, temperature and ratio of phase volumes, the phase and isotopic equilibrium was studied. It was shown that the equilibrium concentration of H3BO3 in TBP is equal to 1/5 of the acid concentration in the aqueous phase, and the value of the single stage separation factor of boron isotopes is equal 1.005-1.007, which exceeds- at the rectification of BCI3 and is comparable with the isotope effect in the low-temperature rectification of BF3.
Keywords: boric acid, tributyl phosphate, distribution coefficient, degree of extraction, boron isotopes, single stage separation factor of boron isotopes, phase isotope effect.
Abstraсt: Mathematical models have been developed to estimate the time of reduction of the concentration of harmful chemicals released from wood materials, taking into account the single-phase and two-phase emission process. Mathematical model is developed for studying the non-stationary diffusion of harmful chemicals from a sample of wood material with boundary condition of the 2nd and 3rd genera, taking into account the convective mass transfer. The model is presented in a dimensionless form and includes diffusive criteria for nonstationary mass transfer processes, such as the Nusselt, Prandtl, Fourier and Biot criteria.
Keywords: mathematical modeling, harmful chemical substance, boundary value problem, initial condition, boundary condition.
Abstraсt: The КLa(SO4)2·H2O – SrSO4·0.5H2O system was studied by X-ray phase and thermogravimetric analysis. The existence of wide regions of solid solutions based on the hexagonal modification of SrSO4·0.1H2O, stabilized by the heterovalent substitution of two Sr2+ ions for La3+ and K+ ions, is established. For the first time, it was found that the compound Sr0,5K0,25La0,25SO4·0.5H2O, which belongs to the structural type of the hexagonal modification SrSO4·0.5H2O, is dehydrated to the composition Sr0,5K0,25La0,25SO4·0.1H2O, which belongs to the new structural type of the monoclinic modification SrSO4·0.1H2O at a temperature of 250°C. At temperatures above 350°C, the compound Sr0,5K0,25LA0,25SO4·0.1H2O breaks down into a highly soluble КLA(SO4)2 and insoluble SrSO4, which may be important in the development of technology for the isolation and separation of lanthanides and actinoids in the crystallization of strontium sulfate, as well as in the manufacture materials, including for medicine.
Keywords: strontium, lanthanum and potassium sulfates.
Abstraсt: This paper investigates the interaction of azo dyes with the isomeric arrangement of the carboxyl group to the azo group with the oxirane group of the epoxy resin. It is noted that the reaction of the azo dye proceeds completely only with the ortho-arrangement of the carboxyl group to the azo group, which makes it possible to purposefully synthesize oligomeric azo dyes based on the oligo epoxy ester. The possibility of dyeing with the obtained PVC dyes in bulk is shown.
Keywords: modification of axo dyes, oligomeric axo dyes based on oligoepoxyester, coloring of polymers in the mass.
