Nanoreactors were created by entrapping homogeneous catalysts in hollow nanocapsules with 200 nm diameter and semipermeable nanometer-thin shells. The capsules were produced by the polymerization of hydrophobic monomers in the hydrophobic interior of the bilayers of self-assembled surfactant vesicles. Controlled nanopores in the shells of nanocapsules ensured long-term retention of the catalysts coupled with the rapid flow of substrates and products in and out of nanocapsules. The study evaluated the effect of encapsulation on the catalytic activity and stability of five different catalysts. Comparison of kinetics of five diverse reactions performed in five different solvents revealed the same reaction rates for free and encapsulated catalysts. Identical reaction kinetics confirmed that placement of catalysts in the homogeneous interior of polymer nanocapsules did not compromise catalytic efficiency. Encapsulated organometallic catalysts showed no loss of metal ions from nanocapsules suggesting stabilization of the complexes was provided by nanocapsules. Controlled permeability of the shells of nanocapsules enabled size-selective catalytic reactions.

The purpose of this investigation was studying the process of an acid leaching of vanadium and other valuable components from black shales of Big Karatau of the Republic of Kazakhstan. The maintenance of principal components in ore of 0,8% V2O5, 67,7% of SiO2, 3,1% of Al2O3, 0,3% of Mo, 0,2% of U3O8 and 0,05% of rare-earth metals. To provide this process was used low-temperature sintering and leaching of this type of raw material for the subsequent extraction of vanadium, uranium, molybdenum and rare earth metal concentrates. Moreover, it was established that with increasing concentration of sulfuric acid to 40 g/l, the degree of leaching of uranium, vanadium, molybdenum and rare earth metals (REM) increases noticeably. The degree of extraction of vanadium includes 81.7 %; uranium – 93,3%; molybdenum – 82.2 % and REM – 78.3%. Besides, it was determined the optimal leaching time, which takes 2 hours long, and the chemical composition of the cakes after leaching.

This work studies the removal of uranium ions from chemically leached solutions by sorption using two weak and two strong base anionites. Batch sorption experiments were performed to evaluate the optimum conditions at pH 1.2–2.2, 1.0 g resin dose for 1–12 h contact time at room temperature. These experiments addressed sorption kinetics and sorption isotherm. The maximum sorption capacity reached 55.8 mg/g at room temperature. The kinetics data are well described by the pseudo-second-order kinetic model at initial uranium concentration of 0.62 mg·L−1. To describe sorption kinetics pseudo-first-order, pseudo-second-order and intraparticle diffusion models were proposed. Studies indicated that the sorption of uranium can be fitted by a pseudo-second-order kinetic model very well. Equilibria were described by Langmuir, Freundlich, and Dubinin–Radushkevich equations. The experimental sorption isotherm is successfully described by the Langmuir model.

This article presents the technology of niobium recovery by processing of chloride residues generated during the chlorination of titanium slags. For waste processing, a two-stage leaching technology is proposed. Water is used at the first stage of leaching and hydrochloric acid 4.0 M is used at the second stage. For the purpose of sorption of niobium from the solution composition obtained during leaching, cation-exchange sorbents Purolite-C104 and KU-2-8 H were used. By the usage of Purolite-C104 ion exchange resin the sorption efficiency of niobium from a solution with a concentration of 2 g/l was about 71.0 % (0.071 g/g) in 3.5 hours, while for KU-2-8 H ion exchange resin, sorption efficiency was about 89.0 % (0.089 g/g).

We investigated the potential of tailings generated from chrysotile asbestos fiber production as a source of iron, nonferrous metals, and gold. We proposed the use of granulometric separation and systematically examined different enrichment processes, namely magnetic separation, gravity concentration, and enrichment using a Knelson concentrator, to extract the valuable components. The characterization of the initial tailing samples revealed that it comprises primarily of serpentine, brucite, antigorite, hematite, vustite, sillimanite, and magnesium oxide. Using the suggested enrichment process, we isolated gold, chromite, and nickel-cobalt concentrates as valuable products in addition to magnetite. The new approach exhibited high separation efficiency for iron, nonferrous metals, and gold, allowing their satisfactory extraction.