The study covers the possibility to improve the quality of copper-zinc ore prior to its enriching using screens for hydraulic fine screening in closed grinding cycles. The paper presents the results obtained when studying the products of copper-zinc ore separation in the RWS 75 hydrocyclone and in the Kroosh ULS 1,5×0,6 screen. It was found that the use of screens (in contrast to hydrocyclones) for hydraulic fine screening in closed cycles for copper-zinc ore grinding will: 1) reduce the circulating load in closed grinding cycles and the circulation of fine size grades with the oversize product; 2) decrease potential overgrinding of ore minerals; 3) enhance the «quality» of enriched raw materials by increasing the mass fraction of size grades optimal for subsequent flotation, as well as by lowering the content of coarse size grades in the final product of the cycle and reducing the transition of copper into fine size grades. 

The Outotec’s Chemical Reaction and Equilibrium Software HSC Chemistry software was used to make balance calculations for multicomponent equilibrium compounds in a heterophase gas-liquid-solid system under oxidizing fusion of the decoppered anode slime with sulfur, selenium and tellurium dioxides entering the gas phase, while the compounds of lead, copper, antimony, iron, and aluminum are concentrated in silicate slag. The study findings are as follows: under optimal conditions for the oxidizing fusion of the mixture (100 kg) of the anode slime (O2 » 0,9 kg; SiO2 ³ 6 %; CaO ~ 3 %; t = 1200 °C), lead, antimony and arsenic almost completely pass into silicate slag, while copper and silver (over 91 %) pass into matte. Selenium is distributed between the gas phase (49,8 %), matte (24,1 %), and metal phase (26,1 %); while tellurium is distributed between the fumes (14,4 %), silicate slag (8,4 %), and matte (77,2 %). 

Here we present the results of studying thermodynamic principles and kinetics of thermal dissociation of dolomites in the Urals deposits. Dolomite samples vary by fractions and grain size of calcite inclusions that determines the differences in their dissociation kinetics. It was found that dolomite dissociation occurs based on the two-stage model limited at the first stage by the reaction on a three-dimensional surface and at the second stage – by the kinetic equation with a degree close to 0,3 and 0,6. 

Tin bronzes are widely used in various industries to produce parts running under friction conditions. Thus, eutectoid component distribution is specified for BrO10S2N3 bronze used for critical part manufacturing. The paper studies the effect of casting and ingot solidification conditions on the distribution and amount of eutectoid in the alloy structure. Several ways of bronze die casting were tested, including ones with water cooling and without it; using ultrasonic waves and without them. As a result, we developed the method of BrO10S2N3 tin bronze casting into a combined mold subjected to ultrasonic waves. The mold is a steel casting form placed in graphite filler with an insulating insert at the top of the mold. The results showed that the new technology allows producing ingots that fully meet the requirements of regulatory documents and have a high yield exceeding 70 %. 

Computer modeling was used to simulate main force factors of aluminum melt processing by pulsed magnetic fields both in the radial and axial impact pattern. It was found that a shock wave arising after a single pulse propagates throughout the melt volume within 40 μs in the radial impact pattern, and within 416 μs in the axial pattern. Experimental studies of Al–Si–Cu and Al–Si–Cu–Ni industrial silumins confirmed a sustainable modifying effect resulting from the magnetic-pulse treatment (MPT): α-Al dendrites and eutectic silicon crystals are reduced in size, while density and electrical conductivity of as-cast alloys increase along with their mechanical properties and ductility. Based on the experimental studies it was concluded that the best MPT performance is obtained with the axial impact pattern. 

LC16K4 silicon brass is widely used in ornamental casting because of its good processing characteristics, beautiful golden color and the possibility to apply various decorative coatings. The paper studies the possibility to increase fluidity of LC16K4 silicon brass by varying its chemical composition according to GOST 17711-93. A vacuum suction method used for fluidity measurement revealed that this parameter changes when adding 0,1 wt.% of the alloying element (Zn, Si, Al) and that measurements show high repeatability. The experimental data were subjected to regression analysis. The effect of zinc and silicon on the silicon brass fluidity was quantitatively assessed, and an adequate mathematical model was built with a response surface of the fluidity function. The optimum melt overheating temperature was found that ensures the highest alloy fluidity with a minimum zinc loss. The results of this study may be useful in ornamental and industrial casting of LC16K4 silicon brass, as well as in other metallurgy and foundry areas. 

The study covers extrusion of preheated aluminum-alloy billets at hydraulic presses within the «heating – metal forming» production complex. Billets are preheated in a multi-section induction heater ensuring a predetermined temperature difference along the billet length. To provide the most favorable conditions for isothermal extrusion, a special task of parametric optimization of the forming process was formulated and solved to a maximum accuracy for the die temperature approaching its maximum permissible value specified by process requirements. The billet state as regards its temperature after loading into the press container was considered as a control parameter at the forming stage. The study used a special alternance method designed to optimize distributed parameter systems. This method is based on mathematical models developed for billet temperature fields at the heating and forming stages. 

Following I.L. Perlin’s technique based on active and reactive forces balance, the formula was suggested to calculate extrusion force for spiral-finned drill pipes. The spiral pipe cross section was regarded as a smooth tube with a screw arrangement of metal fibers and external spiral fins. A component introducing energy spent for the screw motion of metal was added to the formula. It was shown that the extrusion force obtained by the modified formula is 28 % higher than the same for a smooth pipe of equal area. It was discovered that the increase of fin helix angle leads to the increase of force compared to that of longitudinally finned pipes. 

The microstructure of polycrystalline titanium alloys with added chromium (2, 4, and 5,5 wt.%), cobalt (2 and 4 wt.%) and copper (2 and 3 wt.%) was studied. A series of long isothermal annealing cycles (under vacuum) was performed for these materials within the temperature range from 600 to 850 °C. The annealing temperatures were in the α(Ti,Me) + β(Ti,Me) two-phase regions of the Ti–Cr, Ti–Co and Ti–Cu phase diagrams. The temperature dependence plots were built for the β(Ti,Me)/β(Ti,Me) portion of grain boundaries completely «wetted» by layers of the α(Ti, Me) second solid phase and the average contact angle. The results of microscopic investigation showed that the type and content of the second component in the alloy greatly affect formation of equilibrium grain boundary layers. We were the first to discover a non-monotonic temperature dependence of the portion of grain boundaries completely «wetted» by layers of the second solid phase in the absence of bulk «ferromagnetic–paramagnetic» phase transitions. 

Eutectic silumin was processed with a high-intensity pulsed electron beam, and a multi-fold increase in the material fatigue life was discovered. Scanning electron microscopy was used to study the modified layer structure and the fracture surface of silumin subjected to high-cycle fatigue breakdown tests. The factors responsible for the increase in fatigue life of silumin were identified and analyzed.