The paper provides the results of studies into the interaction between Aerophine 3418A, Aerophine 3416, Aerophine 3406 collectors containing diisobutyldithiophosphinate (DIP) and butyl xanthate with pyrrhotite, pentlandite, platinum black and cooperite by measuring the electrode potential and determination of DIP adsorption forms using extractive spectrophotometry. It was shown that butyl xanthate reduces the electrode potential to a greater extent compared to DIP-containing collectors. The value of electrode potential shift in the presence of collectors decreases in the series: platinum black — pentlandite — pyrrhotite. Pentlandite and pyrrhotite interaction with butyl xanthate and DIP mainly results in the molecular form - disulfide - formed on the surface with the order of magnitude less compounds of collectors with metal. After interaction with butyl xanthate, the sorption layer on cooperite contained disulfide only, and both disulfide and the complex compound of Pt with DIP in case of DIP. It was demonstrated that DIP containing collectors have a greater collecting and hydrophobic ability than butyl xanthate to pentlandite and pyrrhotite. The maximum hydrophobic effect is achieved using a composition of butyl xanthate and DIP-containing collectors with a ratio of 1:1 to 1:3. The effectiveness of Aerophine 3416 and butyl xanthate compositions in bulk flotation of platinum-copper-nickel ores is shown.

X-ray diffraction, optical microscopy and X-ray microanalysis were used to determine the composition and distribution of elements in the main mineral constituents of oxidized nickel ore at the Sakhalin deposit (goethite, hematite, serpentine, talc and chlorite). The main fraction of nickel is concentrated in iron oxides, where its content reaches 2,4 %, while in magnesium silicates it does not exceed 0,4 %. The sequence and temperature intervals of transformations were established when heating ore in inert and reducing media by means of thermal analysis methods combined with mass-spectrometric analysis of gases and subsequent X-ray phase analysis of products. The temperature regimes of ore roasting for the reduction of nickel and iron from their minerals were justified. The temperature regimes of sample heating are assumed to be close to the conditions implemented in industrial units (electric furnaces) where the rate of charge heating varies within 5—15 degrees/min, up to the melting point (1450 °С) of ferronickel and slag. It is proposed to use information on material composition, thermal properties and metal forms in ore to select regimes and technologies for their pyro-or hydrometallurgical processing. Nickel and iron recovery from oxides in CO environment occurs above 800 °С, while serpentines remain stable up to 1200 °С. The use of coke as a reducing agent allows reducing iron and nickel from serpentines at temperatures above 1250 °С. The obtained data were used to substantiate the operating conditions of roaster and electric furnaces during ferronickel smelting from oxidized ores. When roasting, resulting ferronickel particles will contain 2—4 % Ni. Completing recovery processes in the electric furnace will ensure metal recovery from magnesium silicates, which will slightly increase the nickel content in ferro-nickel.

The results of a study on the disposal of waste discharge at the iron and steel works using centrifugation and vacuum sublimation methods are presented. The object of the study was industrial effluents of titanium-magnesium production. The influence of centrifuge rotation speed, duration, temperature and fraction of solid phase on the process of industrial effluent separation into liquid (fugate) and solid (sediment) phases is studied. A complex of studies based on the multifactor experiment design was carried out to evaluate the effect of each of these factors. Optimum centrifugation parameters were established: rotor speed — 3000 rpm and duration — 30 min. The obtained solution (fugate) contained 195 mg/dm³ of suspended matter, 26500 mg/dm³ of chlorides, 39750 mg/dm³ of dry residue, which indicates its high mineralization and the need for further purification. The expediency of a thermal method of fugate demineralization using a rotary vacuum evaporator was demonstrated in laboratory conditions. Optimum process parameters were determined: temperature 70 °С, residual pressure — less than 50 mbar, duration — 30 min. Residue yield after vacuum sublimation was 6 % of the fugate weight. No suspended substances were found in the obtained condensate, and chloride content was 50 mg/dm³. The proposed technology for the disposal of industrial effluents at titanium-magnesium production will facilitate forming a closed water supply cycle at the enterprise. Residue obtained after the fugate vacuum sublimation containing mainly chlorides of alkali and alkaline earth metals can be recommended to use as an additive for the preparation of anti-ice materials, as well as drilling fluids and kill mud.

Corrosion tests of SCh15 cast iron, Steel 3 and Steel 3 with aluminized coating in some compositions of 10%MgCl₂-KCl-NaCl and 10%MgCl₂-KCl-Naa-Caa₂ salt melts with 10 %, 25 % and 40 % CaCl₂ concentrations, and also in 10MgCl₂-45%KCl-20%NaCl-25%NaBr melt, and in the gas phase above these melts at 700 °C. A gravimetric method was used to determine corrosion rates of metal samples. Chemical analysis of absorption solutions was used to determine concentrations of halide and hydrogen halide impurities in air blown through the reactor with melts and samples. It was shown that carbon steel aluminizing can reduce the corrosion rate in the gas phase over the salt melt by a factor of 5 to 70. The formation mechanism of gases aggressive in relation to carbon steel and cast iron in atmospheric air in contact with salt chloride melt was considered. Accelerated hydrogen chloride and chlorine formation during the salt melt interaction with atmospheric air under the influence of iron corrosion products was found.

It is known that commercial aluminum with a high content of iron, silicon and other impurities has no industrial application because of low performance. Hence, the development of new alloy compositions based on such a metal is a very urgent task. Promising compositions in the Al—Fe diagram are the (a-Al + A₃Fe) eutectic and hypereutectic compositions that correspond to an iron content of 2—5 wt.% due to a minimum range of crystallization temperature. An alloy with the composition Al + 4,5 % Fe (AlFe4,5) was taken as a model alloy and subjected to modification with tin. The paper experimentally determined the dependence of specific heat of the Al + 4,5 % Fe alloy doped with tin with the calculation of changes in its thermodynamic functions. Studies were carried out in a «cooling» mode using computer equipment and the Sigma Plot program. The polynomials of the temperature dependence of the specific heat and changes in thermodynamic functions (enthalpy, entropy, and Gibbs energies) were determined for Al + 4,5 % Fe alloys doped with tin and basic reference standard (Cu) defined by the correlation coefficient R_corr = 0,999. It was found that the heat capacity of the initial alloy decreases with an increasing tin content and increases as temperature rises. The enthalpy and entropy of the Al + 4,5 % Fe alloy increase with rising tin content and temperature, while the Gibbs energy decreases.

Deformation patterns of rolling, equal-channel angular pressing and non-equal-channel angular pressing were evaluated. It is noted that when rolling, it is difficult to transfer a circular section preform into a rectangular section with a small thickness. This problem cannot be solved using equal-channel angular pressing. In connection with this, it is proposed to use a non-equal-channel angular pressing pattern to study the cast structure of magnesium. An experimental procedure based on cold extrusion of cylinders with a diameter of 42 mm and a height of 40 mm is described. The strip at the outlet was 40 mm in width and 1 mm in thickness. The percentage reduction of the preform material determined by the ratio of areas was 96 % with a draw ratio of 17. The specific pressures on the punch at the beginning ofthe extrusion process were 1200—1300 MPa, and extrusion force was 1670—1800 kN. The preform was cut into lengths that were rolled at a room temperature into 50 and 10 pm thick foils without intermediate annealing. Rolling was carried out on the Duo mill with a percentage reduction of 12—20 % at an average speed of 0,1 m/s. 20 passes were performed with a total relative reduction of 95 % to make the 50 pm thick foil. The results of computer simulation by the finite element method demonstrated that the constant value of the deformation degree is achieved at a rather considerable distance from the front end estimated as 50 times the thickness of the strip. The deformation rate field was calculated to determine the configuration of the deformation center. Energy costs were estimated. As a result of the completed set of calculated and experimental work, it was possible to establish the following — it is possible to produce a thin sheet preform from a cylindrical cast magnesium blank in one operation at a room temperature. The sheet blank has a level of ductility sufficient for subsequent sheet rolling. The sheet blank obtained in the proposed process has a high level of plastic deformation elaboration created due to the forming pattern with the high level of elongation and shear deformation. Despite the high level of pressure that must be applied to create a comprehensive compression scheme taking into account the lack of the need to heat the preform, energy costs are no higher than in traditional treatment processes.

The paper states the results of obtaining Fe—Ag and Fe—Cu dense nanocomposites from composite powders consolidated by cold sintering in the high pressure gradient, as well as from nanosize powders of silver (Ag), iron (Fe) and copper (Cu). The results of mechanical tests conducted on Fe—Ag and Fe—Cu nanocomposites are provided. Nanocomposite powders were obtained by high energy attrition milling of carbonyl iron (Fe) micron scale powder and nanosize silver oxide powder (Ag₂O), as well as iron and cuprous oxide (Cu₂O) nanopowders. High resolution scanning electron microscopy was used to study the microstructure. Compacts featuring approximately 70 % of full density were annealed in hydrogen atmosphere to reduce silver and cuprous oxides to metals and to remove oxide layers from the surface of iron powder particles. This was followed by cold sintering — consolidation under high pressure at a room temperature. The data on specimen density dependence on pressure in the range of 0,25 —3,0 GPa were obtained. Densities were above 95 % of the full density for all nanocomposites, and close to 100 % of the full density under 3,0 GPa for Ag and Cu powders. High mechanical properties in three-point bending and compression were observed for all nanocomposites. It was found that mechanical properties of nanocomposites are substantially higher as compared with composites obtained from micron scale powders. Higher ductility was observed in Fe—Ag and Fe—Cu nanocomposites as compared with specimens obtained from nanostructured Fe.

The paper considers the potential practical application of an electrochemical membrane method in the process of copper sulfate and trisodium phosphate removal from industrial water. The research objects were process solutions containing copper sulfate and trisodium phosphate and semipermeable polymeric membranes with various selective permeability characteristics. The study covers the effect that the transmembrane parameters of electromembrane separation have on the main kinetic characteristics of MGA-95P and OPM-K membranes in the process of copper smelting production water treatment. Approximation expressions were obtained to calculate membrane rejection rate depending on the physicochemical basis of the semipermeable membrane polymer, transmembrane pressure as well as process solution concentration and temperature. Empirical coefficients were determined to calculate and predict rejection rate values that can be used in the design of laboratory, pilot and industrial units used in the separation, treatment and concentration of industrial and waste water. The mathematical model of mass transfer was developed for electrochemical membrane separation taking into account assumptions made based on the solutions of the Nernst—Planck and Poisson—Boltzmann equations. This model allows for process physical description and calculations of concentration fields in the intermembrane channel and concentration changes in permeate and retentate lines. The mathematical model was checked for adequacy by comparing experimental data on retention rate with theoretical values where discrepancies between the experimental and theoretical data were within the limits of the experimental error and the error of calculated values.