Nonferrous ore concentration
Samokhvalov N.M. Gas dedusting using granular-bed filters
Gas dedusting during the processing of ore and mineral raw materials using granular-bed filters is discussed. A new method for dust removal by grain layer, which provides effective uninterrupted purification, is offered. The idea of the method is that the filtration cycle duration is determined by the time during which the dusted gas flow passes through the granular layer. The layer is then regenerated. Two types of granular-bed filters of continuous action employing this technique were designed: one with recirculation of grain material and another, drum-type with rotating grain material phase. Intensive air blowing during pouring of filter grains is used to regenerate the filtering material. The drum-type filter provides over 98 % efficiency in dust removal under hydraulic resistance of up to 300 Pa.
Extractive metallurgy of nonferrous metals
Khrennikov A.A., Lebed A.B., Naboichenko S.S. Regularities of interaction of zinc sulfide with arsenate ion in sulfuric solutions
Regularities of the reaction of zinc sulfide with arsenate ion in sulfate medium were studied. The rate of zinc sulfide dissolution and arsenic precipitation raises proportionally as sulfuric acid concentration increases but upon reaching a critical value of the latter (~0,1 mol), further changes are insignificant. Experimental activation energies of zinc sulfide dissolution and arsenic precipitation were found to be 9,7 and 16,5 kJ/mol respectively. Based on the results obtained, a conclusion was made that the limiting step of the reaction is the reactant and product diffusion through the gas film consisting of hydrogen sulfide bubbles formed on the surface of zinc sulfide.
Efremov A.N., Arkhipov P.A., Zaikov Yu.P. Distribution of direct current over surface of liquid-metal anode and in the volume of PbCl2–KCl electrolyte
Distribution of direct current in an electrolysis unit of cylindrical shape across the surface of liquid metal anode and in electrolyte volume (PbCl2–KCl) (using electrical field build-up methods and direct investigations of metal distribution over the electrode surface at t = 550 °C) was studied. The true current density value was found to change by more than 2 times upon moving across the surface of lead anode in an electrochemical cell of complex configuration. A graphical representation of current concentration distribution is presented.
Extractive metallurgy of less-common and precious metals
Malyshev V.V. Electrochemical synthesis of protective coatings by heat-resistant compounds of IV–VIА group metals of the Periodic system from ionic melts
The paper contains information on manufacturing the protective coatings by heat-resistant compounds of IV–VIА group metals using the technique of high-temperature electrochemical synthesis from ionic melts.
Rychkov V.N., Norkina L.V. Tantalum sorption from chloride-fluoride solutions by anion exchangers
Calculated and experimental data on the sorption of tantalum ions from chloride-fluoride solutions by various class/structure anion exchangers are reviewed and discussed. Based on the calculations, tantalum was shown to form a number of complex ions (chloride, fluoride, hydroxo-, and mixed chloride-fluoride and hydroxochloride) in chloride-fluoride solutions. Equilibrium of tantalum ions in their sorption from chloride solutions was studied. Behavior of tantalum ions in the sorption from hydrochloric acid solutions in a wide range of concentrations was explained by a concept of ionic state of metal in solution taking into account structure and functional features of ion exchangers. The conclusions regarding the sorption chemistry are supported by IR spectroscopy investigations.
Kudryavtsev I.V., Rychkov V.N., Skorokhodov V.I., Radionov B.K., Naboichenko S.S. Sorption behavior of cobalt in sulfate solutions
The interaction of cobalt (II) ions with functional sorbent groups based on amines, additionally containing carboxylic (ANKB-35) and hydroxylic (SB-1, AN-31) moieties was studied. The sorbent state was shown to have little effect on the absorption of cobalt by the ampholyte ANKB-35. In contrast, anion exchangers AN-31 and SB-1 show substantial activity in cobalt sorption only in deprotonated form (OH–). Analysis of cobalt sorption results under equilibrium conditions and IR spectroscopy data made it possible to get a better understanding the process. The cobalt absorption was found to occur through the complex formation with nitrogen atoms of amino groups of sorbents and additional bonding with carboxylic (ANKB-35) and hydroxylic (AN-31, SB-1) moieties. Apart from that, the process is complicated by precipitate formation in sorbent phase according to the scheme: Co2+ → Co(OH)2 → Co(OH)3, which is especially characteristic of anion exchanger SB-1, containing substantial amount of hydroxylic groups. Based on data obtained one can choose ion exchanger type and its application conditions for concentrating Co2+ from sulfate solutions obtained from sulfuric acid treatment of various cobalt-containing raw materials.
Petukhov M.A., Rakova N.N., Chub A.V. Investigation of tantalite/columbite concentrate chlorinating process
Chemical, phase and grain metrical composition and radioactivity of tantalite/columbite ore concentrate was studied. Thermodynamics of chlorination of concentrate components in the range T= 400÷1273 K was calculated. A technique for laboratory chlorination was developed and experiments carried out at t = 750 and 800 °C. Analysis of the products obtained was done. Total concentrate chlorination degree and its values for tantalum and niobium at different temperatures were determined.
Neta V., Strizhko L.S. Gold-containing concentrate processing using copper collector
Melting of gold-containing gravitation concentrates using a copper collector and SiO2–FeO–Na2O–CaO system slag was studied. The optimal concentrate : collector ratio was found to be 100 : (14÷20). Increasing of reducing agent (coal) content ratio relative to the concentrate from 1 : 30 to 1 : 5, was shown to decrease the weight fraction of Fe2O3 in the slag (from 34,7 to 27,2 %) and increase that of FeO by 6,3 % (from 1,4 to 7,7 %). The slag viscosity (η) drops rapidly as the temperature increases. For slags with sodium borate content of 25 % (mass) at T= 1423 K, the η value of 3,611 Pa · s drops to 0,917 Pa · s at T = 1523 K. For a slag containing 20 % (mass) of iron oxide at T = 1423 and 1523 K, the viscosity is 0,675 and 0,276 Pa · s, respectively. After four-fold copper collector cycling, the concentrations of gold, silver, platinum and palladium in it increased to 19,8, 2,16 %, 1,08 %, and 0,9 %, respectively. The total sorption of Au, Ag, Pt and Pd under these conditions was 96, 92, 93, and 93 %, correspondingly.
Materials science and heat treatment
Churyumov A.Yu., Zolotоrevsky N.Yu., Solonin A.N., Zolotоrevsky V.S. Flow stress simulation of quenched-after-founding single-phase Al–Mg alloys
Based on the physical strengthening factors analysis, a mathematical model of the dependence of flow stress of single-phase alloys of the Al–Mg system (quenched after molding) in a concentration range of 1,5–9,0 % of Mg on the combination of major structure characteristics (dislocation density, alloying element content in the solid solution, and grain size), has been developed. The mathematical model parameters were corrected using experimental dependencies of flow stress of Al–Mg system alloys with various grain sizes. The model allows one to predict the flow stress with an error not exceeding 13 %.
Powder materials and coatings
Antsiferov V.N., Trusov P.V., Nyashina N.D., Smetkin A.A. Origins of wavelike variation of cross section and rupture of fibers produced by melt extraction from drop suspended
The causes of wave variations in cross section values of metal fibers obtained by pendant drop melt extraction method on crystallization disk under vacuum are analyzed. Theoretical results are supported by experimental data for aluminum and titanium alloy VT1 fibers. It has been shown that diameter changes and fiber breakage are caused by capillary waves (Rayleigh waves) on the surface of melt drop, ignited by the rotation of crystallization disk. The waves on the fiber surface are likely to occur due to vibrations with frequencies 3000-3500 times higher than disk rotation frequency, or due to defects of disk surface located approximately 0,2÷0,3 mm from each other.
Narva V.K., Shugaev V.A., Vin T., Monina L.V. Technology and properties of aluminum based powder porous materials produced by sintering of free power loading in the air and in presence of flux and additives
A method for the preparation of porous powder material based on aluminum by baking in the free backfilled state in air using silumin and KAlF4 flux is offered. The effect of source powder dispersion degree and source mixture composition on the porosity and properties of baked powder material was studied. It has been shown that during the baking in air in the presence of a small amount of flux and a low-melting component (silumin), no significant aluminium oxidation takes place and it is possible to obtain materials with 30-35 % porosity possessing satisfactory physical and mechanical properties.
Rudneva V.V., Galevsky G.V. Investigation of corrosion resistance of nanopowders of high-melting borides and carbides in electrolyte solutions
The solubility of nanopowders of vanadium, titanium, chromium and zirconium borides and carbides (and silicon carbide) in standard nickel plating electrolytes was studied. Nanopowders with the main phase content of 92,6-95,3 % and average particle size of 35-62 nm were used. Corrosion resistance of the samples was assessed relative to the electrolyte acidity, temperature and duration of the interaction. Within the same compound groups, boride and carbide nanopowders were found to have similar corrosion resistance in electrolyte solutions and unlimited induction period in alkaline media. An exception is the nanopowder of silicon carbide, which is stable in solutions of any acidity.
Radyuk A.G., Titlyanov A.E., Samedov E.M. Properties of surface layer on copper after application and heat treatment of aluminum gas-thermal coating
The deposition process and properties of surface layers formed on copper after deposition and thermal treatment of aluminium gas thermal coating were studied. The process results in the formation of protective diffusion layer possessing good physical, mechanical and operational characteristics.
Process control and automation
Zurabov A.T., Meshkov E.I., Gerasimenko T.E. Investigation of anthracite calcining process in new technological complex
The paper presents results of a calculation experiment on calcining anthracite in a tube-type rotating furnace and criteria for optimal process performance. It has been shown that the calcining method in a combined technological complex consisting of a tube-type rotating furnace and a drum heater allows reducing the production costs as compared to the procedure without preliminary material heating.
Chronicle
Antsiferov V.N., Vakutin A.P. Review of “Metallic powders and powder materials” handbook edited by Yu.V. Levinsky
