The paper studies the patterns of copper slag mineral phase separation by flotation depending on the modification of the additional BTF series collecting agent (dialkyldithiophosphate derivatives) and the ratio of main and additional collecting agent consumptions. The results of open and locked-cycle laboratory flotation tests are presented, and the effect of pulp pH on copper extraction is observed. The reasons for the copper extraction gain during grinding and subsequent flotation in acidic medium are analyzed. The aggregates of copper and iron sulfides are identified in slags thus proving decoppering effectiveness with a decrease in pH to slightly acidic values due to the active flotation of intergrown pieces of copper-containing phases with iron sulfide (pyrite, pyrrhotine). It is shown that the additional BTF series collecting agent added to the main collecting agent – potassium butyl xanthate – makes it possible to reduce the total consumption of the combined collecting agents while maintaining copper extraction and concentrate quality as compared to the consumption of only xanthate necessary to achieve the same parameters. The best results were achieved with the use of the BTF 1614 reagent in combination with potassium butyl xanthate at the BCC : BTF = 3 : 1 ratio. At an optimum pH = 5,5÷6,8, the increase in copper extraction to the concentrate was 11.13%, and gold and silver extraction increased by 9.68% and 9.93%, respectively.

The article considers possibility of using inorganic sorbent – iron oxyhydrate (IOH) – to remove F– ions from process solutions of zinc production. The method of IOH synthesis is chosen. The results of scanning electron microscopy and X-ray phase analysis are presented. The principal possibility of using ion-exchange resins as IOH-modified carriers is considered. The paper studies active substance formation on anion and cation exchange resins. It is shown that the most durable composite sorbents are obtained using strongly acidic cation exchange resins with SO3– groups. A method for introducing IOH into the structure of carrier materials and obtaining composite sorbents is described. The KU-2×8 strongly acidic cation exchanger is recommended as a composite base. Cation exchangers saturated with iron were held in a sodium chloride solution with a concentration of 2,5 g/dm3 for 24 hours at 85 °C to ensure formation of β-modification IOH crystals distributed over the ion exchanger grain volume. Anion exchangers were held in an iron(III) sulfate solution with added sodium chloride for 24 hours at 85 °C. At the same time, iron oxyhydrate films formed on the surface of sorbent grains were observed. Fluorine sorption was carried out in a static mode from a standardized test solution with a concentration of F– = 100 mg/dm3 at 60 °C. Sorption on the AB-17×8 anionite was carried out at 20 °C. Absorbed fluorine was desorbed by the NaOH (0,1 M) solution at 60 °C for 2 hours. The synthesized KU-2×8-IOH composite sorbent has a fluorine capacity of 0,7–1,1 mg/g, and can be regenerated with resulting easily utilizable fluorine-containing eluate.

The paper presents a theoretical study conducted to investigate the effect that the chemical composition of electrolyte and its overheating have on the size of sideledge formed in an aluminum smelting bath. Three electrolyte compositions were chosen: (1) sodium cryolite with the cryolite ratio CR = 2,7; (2) cryolite CR = 2,7 + 5 wt.% CaF2; (3) cryolite CR = 2,7 + 5 wt.% CaF2 + 5 wt.% Al2О3. The electrolyte liquidus overheating temperatures were 5, 10, 15 and 20 °C. Calculations were performed using the finite element method. A simplified design of an aluminum cell was used with a prebaked anode. The temperature field was calculated using a mathematical model based on the Boussinesq approximation, which contains the Navier–Stokes equation as well as thermal conductivity and incompressibility equations. The key role of electrolyte overheating in sideledge formation was established. The resulting sideledge profile depends on the heat transfer coefficients and thermophysical properties of materials. The smallest sideledge thickness with the same electrolyte overheating was observed in cryolite composition 3, and the profiles of the formed sideledge for samples 1 and 2 were nearly the same. The thickness of the sideledge formed with a 5 degree overheating exceeded 7 cm and the difference in temperature between the sideledge in contact with electrolyte and the side block wall was 20–25 degrees. It was found that the virtually total disappearance of the sideledge occurs at electrolyte liquidus overheating by 20 degrees.

The paper presents a review of some trends observed on the world market of rare-earth elements (REE). This review takes into account actual changes in the commercial and industrial policy of China and the current trends of REE consumption. Main characteristics of the modern REE markets are considered. The paper provides an assessment of world production volumes, world trade and prices. The article describes the REE market behavior in 2000–2020 and provides a forecast of main indicators and prices up to 2020. It contains a description of current world REE resources, production and trade over the main countries. In addition, the prices and the main buyers of REE are specified indicating the forecast of consumption. The prospects of the Russian REE market are estimated taking into account the «Development of the Rare and Rare-Earth Elements Industry» subprogram implemented as part of the State Program of the Russian Federation «Industry Development and Competitiveness Improvement». The purpose of the subprogram is to create a competitive rare-earth industry of an integrated production cycle in the Russian Federation in order to satisfy the needs of the domestic defense industry complex, civil industries and enter the foreign markets. It is noted that this subprogram should be upgraded with regard to changes in the market conditions and development of rare-earth elements production in the Russian Federation including by means of statutory, non-tariff and technical regulation. Loparite and apatite will remain the main sources of rare-earth elements as raw materials for industrial processing in Russia in the near future, while REE production from apatite will increase. It is emphasized that the prospects of REE development in Russia consist not so much in increasing the primary production as in establishing new plants consuming rare-earth products.

A comparative study on the effect of methods for obtaining AlTi4 modifying master alloys on the sizes of Al3Ti intermetallics is made. It is found that increasing cooling rates at solidification from 10–15 °C/s (crystallization in a hot cast iron mold, a plate 30 mm in thickness) to 60–65 °C/s (crystallization in a cold cast iron chill mold, a rod 20 mm in diameter, 170 mm in length) reduces the length and thickness of needle-shaped intermetallics almost twice (397×23 to 215×13 μm). At the same time, lower electrical conductivity and higher alloy density in a solid state are observed. Melt modification with 0,5 wt.% magnesium addition causes the formation of homogeneous 98×3 μm fine-needle intermetallics. The addition of magnesium slightly reduces electrical conductivity and density compared with the AlTi4 master alloy crystallized at the same cooling rate (60–65 °C/s). Modification of A97 grade aluminum and AK9ch alloy (Al–Si–Mg system) with the specified master alloys at the same amount of titanium added (0,01 wt.%) exerts hereditary influence on the density and electrical conductivity, and macrograin (A97) and dendrites of aluminium (AK9ch). The maximum modifying effect is provided by the AlTi4 master alloy containing 0,5 wt.% magnesium. When introduced into the alloy, it contributes to the formation of 10 μm aluminum dendrites 1427 pcs/mm2 in total in the alloy structure. When the AK9ch alloy is modified with the master alloy crystallized at cooling rates of 10–15 °C/s, 28 μm dendrites 672 pcs/mm2 in total are formed in the alloy structure. It is suggested to use density and electrical conductivity determination methods for express evaluation of master alloy modifying effectiveness.

It is known that casting long ingots of small sections (∅8–12 mm) of 01417 alloy into an electromagnetic crystallizer makes it possible to obtain a dispersed structure with insignificant intradendritic segregation. Diffusion annealing of ingots (550 °C, 4–5 h holding time) eliminates intracrystalline segregation and reduces the level of internal stresses in metal thus providing the conditions for subsequent wire drawing. The paper demonstrates that high plastic deformation of ingots without diffusion annealing can be achieved by Conform continuous extrusion, which ensures high quality and geometrical accuracy of products. The analysis of various Conform units revealed an inherent weakness – the absence of connection between the system securing the fixed part of the detachable container (shoe) and the drive wheel shaft, which leads to an increased load in the operating mode. The purpose of the work was to upgrade the Conform unit by creating a connection between the shoe and the impeller shaft to obtain a high-quality billet for subsequent wire drawing of the ∅12 mm ingot cast into the electromagnetic crystallizer. An optimal temperature of ingot extrusion (300 °С) was found to eliminate the intense adhesion of wrought metal on the tool surface. The experimental ∅5 mm rod made of 01417 alloy obtained from the ∅12 mm ingot at the Conform unit features high processing ductility. This is indicated by an increase in its yield point and relative elongation. Metallographic studies demonstrated a fine-grained structure achieved in the extruded rod, which provides the conditions for subsequent wire drawing without annealing. The results of the study provide a basis for refining the process conditions of calibrated billet production on the Conform unit followed by wire drawing with required properties.

Aluminum-based metallic glasses are the new promising family of materials. However, the effect of heat treatment on the structure and properties of Al–Y–Ni–Co amorphous alloys has not been widely studied so far. In this paper, Al85Y8Ni5Co2 amorphous alloy strips were obtained by hardening on a rotary copper wheel. The effect of vacuum annealing at temperatures ranging from 100 to 500 °C for 30 minutes on the structure and hardness of these strips was investigated. Transmission electron microscopy, X-ray diffraction analysis, and differential scanning calorimetry were used to study changes in the structure of strips after heat treatment. Vickers microhardness was measured to investigate the effect of annealing on the mechanical properties of strips. The results obtained allowed for the conclusions made about changes in hardness depending on the Al85Y8Ni5Co2 alloy strip structure. It was found that as the temperature rises, strip microhardness increases reaching a maximum value of 575±7 HV after annealing at 350 °C, then it decreases with a further increase in the annealing temperature. It was shown that the Al85Y8Ni5Co2 alloy strips remain completely amorphous and no crystalline phases are detected in their structures after annealing at temperatures up to 250 °C for 30 minutes. A sharp increase in hardness after annealing at 350 °C is associated with 10–30 nm nanocrystals of an aluminum solid solution formed in the amorphous matrix and surrounded by a residual amorphous matrix, while further hardness decrease is associated with the increasing sizes of these crystals and Al3Y and Al19Ni5Y3 intermetallics formed in the structure.

The paper studies the group of composite bronzes, BrFNCA 9-4-1-1, BrFNA 12-7-1 and others where brittle Cu3Sn intermetallics are «replaced» by steel dendrites. The mass transfer of Fe, Ni, Co, Al between the matrix and dendrites in these bronzes is investigated. Dendrite dispersion depending on the methods used to produce these bronzes can be increased by a factor of 10, for example, in the vacuum casting process. The mechanical properties of BrFNCA samples (σв = 372 МPа, δ = 25 %, ψ = 42 %) are higher as compared with the BrO10 prototype: by 50 % in terms of σв hardness, and by 4–5 times in terms of δ and ψ plasticity. The coefficient of friction is lower than that of BrO10 by 20–30 %, and wear resistance is higher by an order of magnitude. The fact of a significant effect of the dendritic component dispersion on the BrFNA bronze wear rate is found. Thus, the wear rate for 1 μm and 10 μm dendrite cross sections is 0,002 and 0,025, respectively, and the coefficient of friction remains unchanged, i.e. it does not depend on dendrite dispersion. The whole set of mechanical, processing and service properties makes it possible to consider that the semicommercial tests of this new class of BrFNCA composite bronzes reinforced with H12C7A maraging dendrites for sliding friction units are justified and promising.