Nonferrous ore concentration
Dubrovin P.V., Maltsev G.I., Naboichenko S.S. Determination of optimal conditions of flotation metal extraction out of leaching solutions
The analysis of dispersed-system coagulation kinetics under the conditions of lacking of the electrostatic repulsion barrier on the curves of particle interaction pair potential: Umi(h) = –Um(h) + Ui(h) < 1,5kT is taken as a basis of the experimental method of determining the potential barrier of solvent-adsorptive stability factor. In case of dispersion of cetyl pyridinium gallium hexametaphosphate (27 mg/dm3) stabilized by non-ionic surface active agent (OP-7) in amounts of (0,1¸ 1,0) · 10–5 mol/kg, the value of structural repulsion barrier is Ustr = 3,12÷3,7 kT. Skin flotation regime (Km) provides for increased extraction of dispersed sublate phase from solution volume into froth pulp: flotation kinetics constant for corresponding regimes are: Кs = (1,4÷2,4)∙10–2 s–1 and Кm = (2,7÷5,4) · 10–4 s–1.
Extractive metallurgy of nonferrous metals
Baimakov A.Yu., Lipin V.A. Production of iron-containing products in bauxite processing by sintering
Laboratory studies were carried out in the course of which the mixtures of reactive iron (III) oxide, sodium and calcium carbonates were heated in the presence of different reducers. In this case, the intensity of iron cation reduction to the metal state was estimated by gas amount evolved out of the reaction space per time unit. It was found that iron cation transfer to the metal state terminates mainly at T = 950÷1050 ° C. Wood charcoal is the most active reducer of used ones. Present sodium salts accelerate the reduction process. Dissociation of calcium carbonate and sintering of bauxite charge mixtures take place at lower temperatures. Iron extraction as magnetic fraction permitted increasing settling rate of slime formed after sinter leaching ~1,5 times.
Vasyunina I.P., Mikhalev Yu.G., Vasyunina N.V., Polyakov P.V. Estimation of possibility of using lithium cryolites in electrolytic aluminum production
Volatility of lithium cryolite was determined and electrolysis was carried out with using new composition electrolytes on the basis of lithium cryolite for capability assessment of their industrial application. The experiments were carried out at 840 °C. Current efficiency was determined by metal weight increment. The highest current efficiency (93,4 %) was observed in the bath on the basis of lithium cryolite with additions of (% mass): 7,4 potassium cryolite, 16,7 sodium cryoilte, 4CaF2, 3Al2O3. Hence, the most stable process in electrolytes with new composition on the base of lithium cryolite was observed in electrolyte with 7,4 mass. % K3AlF6 and 2,2 % mass. % LiF. The evaporation rate from exposed surface was 1,7487 · 10- 5 g/(cm2 · s) under free convection conditions. It was found that the electrolyte proposed evaporates as lithium tetrafluoraluminate. Consequently from the technological point of view that lithium cryolite baths have an outlook with fair promise for aluminum electrolysis.
Vorobiyov I.B., Nikolaev I.V., Kirov S.S., Zubtsova E.A. Determination of the conditions of crystallization of basic aluminum hydroxide phases in aluminate solution carbonization
Based on synthetic aluminate solutions, the crystallization regions of the main aluminum hydroxide phases (pseudoboehmite, behierite, hydrargillite) are found during aluminate solution carbonization depending on their concentration and process temperature. Pseudoboehmite is specific for the solutions of Al2O3 low content. In increasing Al2O3 concentration, crystallization of behierite takes place. Hydrargillite precipitation was found at the increased temperatures and Al2O3 contents.
Strizhko L.S., Pogosyan A.T., Kalashnikov E.A. Optimization of electronic scrap processing structure
Electronic scrap incoming to metallurgical works for extracting noble metals has been investigated. Six types of raw materials were determined and their compositions were given. The methods of possible processing of the given kinds of raw materials were analyzed and tested in part whereby nine more optimal flow sheets were proposed and the production costs of processing method for each kind of raw material were calculated.
Troshkin A.M., Mel’nikov Yu.T., Abdrashitova E.A. Kinetics of antimony reduction out of acidic fluoride-sulfate solutions
Kinetic laws of antimony cementation process from acidic fluoride-sulfate solutions by aluminum and iron are investigated. It is established that the order of reaction by antimony is equal to 1 in both cases for the given process depending on Sb concentration in the solution. Apparent activation energies being equal to 38 and 18 kJ/mole are found from the temperature dependences of the rate of antimony reduction by aluminum and iron respectively. The process of antimony reduction by aluminum is shown to proceed in the kinetic mode and that by iron is limited by diffusion of reagents through the layer of iron fluoride formed. It is revealed that the cementation process of antimony by aluminum in the presence of sulfuric acid proceeds in the kinetic mode, and the increase of sulfuric acid concentration in fluoride-sulfate solution results in reducing the share of aluminum required for antimony reduction.
Extractive metallurgy of less-common and precious metals
Petrov G.V., Greiver T.N., Belen’ky A.M., Boduen A.Ya., Kovalev V.N. Study of behavior of sulfate iridium complexes in sorption by ion-exchange resins
The regularities of polynuclear iridium sulfate complexes were studied during sorption from sulfuring solutions. A non-monotonic dependence of Ir sorption degree over high-basic anion-exchange resins AV-16 and EDE-10P on acid intensity of the solution was found. Three maxima of Ir extraction into sorbent were determined at 30, 150 and 250 g/l in H2SО4 concentration. A tendency of the complex iridium anion charge change from –2 to –8 was established in increasing the acid intensity of solution to 250 g/l H2SО4. A possibility in principle of the effective application of anion-exchange sorption was shown in extraction platinum-group metals out of saturated sulfuric solutions produced during sulfating processing of different-type platinum-metal raw materials.
Mineev G.G., Zhuchkov I.A. Investigation of gold dissolution kinetics in chloride-hypochlotite solutions
Assisted by physical-chemical and electrochemical methods, the gold dissolution process in neutral and weak-acid low-toxic chloride-hypochlotite solutions was investigated. Indicating the diffusion control of the process studied, the dependencies of gold dissolution rate on disc rate speed, ligand and oxidizer concentration, medium acidity, and temperature were investigated using the “rotating disc” procedure. A combination of kinetic data as well as the results of electrochemical investigations (potentiodynamic curves, stationary potentials, electrolytic metal dissolution under different conditions) permit assuming a complex multi-stage gold dissolution process in the chloride-hypochlotite solvent comprising the formation of intermediate solid product: monovalent gold chloride (AuCl).
Materials science and heat treatment
Bokshtein B.S., Dolgopolov N.A., Petelin A.L., Rakov S.V. Formation morphology and growth kinetics of liquid-metal etching grooves in the Al- Sn system (experiment)
Grooving during liquid-metal etching was studied in the Al–Sn system in a range of T = 520÷600 ° C. Three primary morphological species: Mullins, wedge-type, and finger-shaped were found. Characteristic parameters and growth kinetics were determined for each of them. Wetting phase transition temperature was determined for wedge-type grooves by measuring the angles in the groove apex.
Rusin N.M. Variation in structure of cast AM60 alloy in annealing
Used in the work, AM60 standard alloy being unaffected by age hardening was produced by secondary remelting in inert-reducing atmosphere and subsequent pouring into solid molds heated to T = 200 ° C. Its structure is of globular type with precipitations of g -phase predominantly along the grains of solid solution the average size of which is ~70 m m. Microhardness of the alloy is 49,8 ± 0,8 HV. Annealing of the samples cut by a thin abrasive disc with continuous water cooling was carried out in a muffle furnace at T = 420 ° C for 1–72 h. Polished sections were prepared by diamond paste polishing of the surface followed by chemical etching. The investigations showed that the change in average grain during the annealing is of non-monotone character: the grains grow at the stage of g -phase particle dissolution and alloy composition homogenization, then the small new grain nucleation and increasing stage (i.e. decreasing of average grain size in the alloy) is observed, which is replaced by the period of static growth of new grains at the cost of recrystallization. Previously, the grain refining stage during annealing in unstrained magnesium alloys has not been observed yet, and its detection can be of practical importance.
Powder materials and coatings
Panov V.S., Serdyuchenko K.Yu. Investigation of regularities in compacting hard-alloy mixtures with different cold binders
The effect of different amount (1–5 wt %) of cold binders (PVA, PEG, PEG + PVA and, for comparison, solution of synthetic gum in gasoline) on the main properties of VK and TK group alloy mixture compacts was investigated. The effect of chemical structure of cold binders on the behavior of hard-alloy mixtures during compaction was found.
Structural macrokinetics. Self-propagating high-temperature synthesis
Levashov E.A., Zamulayeva E.I., Kudryashov A.E., Vakaev P.V., Sviridova T.A., Petrzhik M.I. Formation processes and properties of electrospark coatings on nickel substrate, which are produced with using nanostructural and microcrystalline WC–Co electrodes
The processes of coating formation on nickel are studied in using nanostructural and microcrystalline (conventional VK8) electrode materials of WC–8%Co composition in varying the energy of pulsed discharges in the range of 0,01–1,2 J. The secondary structure of electrodes and the physicochemical processes that take place in them were investigated. It was found that the mass transfer of conventional VK8 proceeds predominantly through the liquid and gas phases owing to different erosion stability of electrode materials and that of nanostructural electrode materials does with significant fraction of solid-phase component because of low strength of intergranular and interphase boundaries. High surface energy of nanodispersed WC grains facilitates their active sintering and growth according to the coalescence and coagulation mechanism. A possibility of carbide grain controlling in electrode and coating by varying the energy of pulsed discharges is shown. W2C and WC are the main phases in the coating applied by nanostructural electrode in the high-energy mode (E = 1,20 J). It represents the carbide crystallites distributed in Ni–Co-matrix. Coating of conventional VK8 alloy in this mode consists of interstratified layers of roentgenoamorphous phase and nickel based FCC-solid solution. Use of nanostructural electrodes facilitates increasing thickness, hardness, and elastic modulus of coatings.
Process control and automation
Ishmetiev E.N., Salikhov Z.G. Engineering fundamentals of calculation of quick information transfer in networks of different configuration
An urgent problem of selection and development of engineering calculation of quick information transfer in the networks of different configuration used predominantly in creating the automatic process control system and CAM system where signals from the data sources are formed and transferred by different sources and received in a similar way. The problem solving is limited by consideration of three groups of data sources and transfer. On the basis of the multiyear experience of designing and operation of communication systems in the automatic process control system and trunk information systems of the Magnitogorsk Integrated Iron-and-Steel Works, the transparent engineering design formulae for choosing design information transfer rate in the communication networks of different configuration are recommended. Five schemes of realizing the methods developed for various groups of telecommunications configuration are given.
Economics and management
Andreev A.M., Kelchevskaya N.R. Problem of cost management and price level for magnesium exported
The AVISMA and the Solikamsk Magnesium Plant, metallurgical enterprises of Russia producing magnesium, are subjects of the investigation. The problem was put to develop the mechanism of cost management and price level for magnesium exported. Its actuality is related to the loss of the sales markets in the USA by domestic companies because of introduction of the antidumping duty established after investigations and study of the C&MA and price setting system at the RF enterprises. Based on the results of these measures in the USA in regard to the Russian producers of magnesium, an analysis of existing C&MA and price setting systems for exported magnesium was carried out with determining their disadvantages. Separate C&MA systems are compared and the basic concepts attributable to dumping are defined. As a result, the problems are put the decision of which permits avoiding establishment of high antidumping duties in the future and making provision of keeping the sales markets and the efficiency of interaction with consumers.
Standarts
Karetnikova N.V. How voluntary the application of standards may be?
