METALLURGYOF NONFERROUS METALS
Medvedev A.S., So Tu.
Features of electrochemical reactions accompanying the chloridizingroasting of copper sulfide concentrates
A mechanism of the reactions accompanying low-temperature roastingof copper sulfide concentrate with potassium and sodium chlorides withoutformation of sulfur dioxide gases and their evolution to the environment isproposed. The cake produced is leached by water with рНcorrection near to 6. Water-soluble sulfates pass into the solution and copperand iron hydroxides remain in the cake. The subsequent cake leaching by sulfateaqueous solution at final рН = 2,5?3,0 allowstransferring the whole of copper into the solution and leaving the whole ofiron as solid phase. Under the optimum conditions of roasting (t = 450 °С, ? = 1 h) and the above conditions of double leaching, copperextraction into the solution makes up no less than 95 %. Chloridizing roastingat temperatures lower and above 450 °C results in lowering of copper extractionin the finished product – copper vitriol. The detected maximum is explained.
Key words: chloridizing roasting,sulfide copper concentrate, roasting mechanism, copper vitriol production.
Kniss S.V., Naboichenko S.S.,Zhukov V.P.
Kinetic modeling of autoclave dissolution of iron sulfide in nickelore with oxygen present
Mathematical description of specific stages of autoclave oxidizingdissolution of iron in nickeliferous sulfide ore has been carried out. It issupposed that the process kinetics is determined by the regularities ofexternal diffusion, and oxygen absorption by fine pulp is the most probablelimiting stage of the process.
Key words: diffusion, paraboloid ofrotation, mass transfer.
Samoilova O.V.,Makrovets L.A., Mikhailov G.G.,Trofimov E.A.
Thermodynamicanalysis of the Cu–Si–Ni–O system
The liquidus surface for the Cu2O–SiO2–NiOternary equilibrium diagram is plotted. It is shown that there are peritecticreactions in the ternary diagram and, thanks to the reactions, Ni2SiO4nickel olivine existence domain with oxide melt emerges. The surface ofcomponent solubility in metal melt of the Cu-Si-Ni-O system is plotted fortemperature 1200 °C.
Key words: copper, refining, ternaryequilibrium diagram, surface of component solubility in metal, non-metalliccompounds, silicon, nickel, oxygen.
Lebed A.B., Krayukin S.A., Naboichenko S.S., Maltsev G.I.
Palladium and platinum desorption out of VP-1P anionite
Complex palladium and platinum forms raised in ammoniac-nitratesolutions in desorbing platinum-group metals (PGM) from VP-1P anion exchangerhave been investigated. The possibility in principle of applying VP-1P anionexchanger for purification of electrolytes from PGM in the silver refiningprocess is confirmed.
Key words: palladium, platinum,desorption, anion exchanger, complex compounds.
Tanutrov I.N.,Sviridova M.N., Kashin V.V., Savenya A.N.
Joint waterleaching of red mud and oily oxide scale
A new approach to the process of waste recovery of two technogenicwaste kinds: red mud from bauxite processing (including the Ural plants) andoily oxide scale from the rolling production has been developed. The processconsists in joint processing of the two waste kinds with producing a product,which is applicable for extraction of principal components with the use ofblast-furnace smelting to iron and aluminous slag. In carrying out theinvestigations, the technological simulation method for the leaching,filtration, and drying processes was used. The optimum leaching parametersensuring high speed of mud filtration applicable for treatment of industrial anddomestic sewages and production of 52–56 % of iron in calcine are established.
Key words: red mud, oily oxide scale ofrolling production, joint processing, water leaching.
Vershinina E.P., Ghildebrandt E.M., Frizorger V.K.
Properties of coke-carbon loam composition of Soderberg anode
Samples from the zone of coke-carbon loam compositions (CCC) of«dry» and «colloid» Soderberg anodes with carbon loam content of 28,2 and 24,0% respectively have been drawn. Coefficient of elongation and viscosity of thesamples were measured. The grain-size composition of coke charge wasdetermined. It is noted that the properties connected with the compositionfluidity ensure uniform filling-up of the anode shell even with low content ofcarbon loam. Coke particle redistribution in the CCC zone of operatingelectrolyzer in the course of their sedimentation is representative for the«dry» anode. Such a phenomenon is not observed for «colloid» anode CCC. Itexcludes the possibility of anode mass layering and creates more favorableecological service conditions of the electrolyzer.
Key words: aluminum electrolyzer, «dry»and «colloid» Soderberg anodes, coke-carbon loam composition, coefficient ofelongation, viscosity, grain-size and gravimetric compositions of coke charge,sedimentation.
METALLURGY OF LESS-COMMON AND PRECIOUS METALS
Gostishchev V.V., Teslina M.A.
Magnesium-thermic synthesis of molybdenum carbide in ionic melts
Physicochemical aspects of molybdenum carbide powder synthesis bymagnesium-thermic reduction of its oxide in lithium, sodium, and potassiumcarbonate melts are considered. A thermodynamic estimation of the synthesisunderlying reactions is given. The effect of the melt temperature on the sizedistribution of carbides produced is found. Powders of the greatest specificsurface are formed in lithium carbonate melt (Mo2C – 7,96 m2/g)at 750 °C.
Key words: metallothermy, molybdenumcarbide, powders, ion melts, grain-size distributions.
MATERIALS SCIENCE AND HEAT TREATMENT
Psaryov V.I., Parkhomenko L.A.
On technique of identified analysis of disperse precipitations inalloys
Formulas, analytical and cumulative probability distributions areproposed for the system analysis of disperse precipitations in alloys and othermaterials. For this purpose, a method is developed for revealing thesimilarities and differences (identification) between the characteristics ofexperimental histogram and theoretical particle-size distribution. Such amethod of the identification of distributions makes it possible to establishthe correlation between the specific features of the transformation of theexperimental distributions and endogenous processes.
Key words: identifiable analysis,analytical and cumulative functions of distribution, disperse precipitations,critical size, activated state, endogenous processes.
METALFORMING
Ganieva V.R., Lyubimov A.S., Kutluyeva A.I.,Yenikeyev F.U.
Unbiased estimate of superplastic material speed sensitivity
A procedure of determination of rheological parameters K and m ofsuperplasticity, which enter the standard power relation ? = K?m,is proposed. The dependence of flow stress ? on strain rate ? is used as inputdata into the procedure proposed. The procedure is based on the minimization ofdeviation of calculated values ? from the correspondent experimental data. Ascompared with the known techniques, the procedure proposed contains no materialmodel linearization ? = K?m. Practical approbation ofthe procedure developed is effected by using the experimental data on Al–12Si,Al–33Cu, Al–Cu–0,4Zr and SUPRAL alloys known in the literature. It is foundthat the linearization of non-linear model ? = K?m canresult in bias of estimators in m parameter by 5–10 %. This, in turn, resultsin overestimation of superplastic forming by 10–30 %.
Key words: superplasticity, strain ratesensitivity index, determination of material properties.
CASTINGPRODUCTION
Koltygin A.V., Bazhenov V.E., Gordievskaya M.V.
Search of substitutes of binding and refractory materials used inindustrial three-dimensional printing plants in obtaining molds for producingiron, aluminum and magnesium alloy castings
Possible substitutes of binders and refractory materials applied inthe «ProMetal» (Germany) S-15 installation of three-dimensional printing havebeen found. The properties of domestic and import binding materials having theanalogous hardening chemistry have been studied. Available and inexpensiveenough «Resifix 0448» resin (Germany) in density, viscosity, and ultimatetensile strength of samples on its basis is shown to be very close to the firmresin. It is established that 2К1О3016 brand sand (Russia) after corresponding treatment can be usedin S-15 three-dimensional printing installation since its grain composition andmorphology are similar to the firm one.
Key words: furan resins,three-dimensional printing installations, ProMetal, binding substances,fireproof fillers, molding materials, S-15 installation.
POWDERMATERIALS AND COATINGS
Volkhonsky A.O., Blinkov I.V.
The sputtering effect of multilayered nanostructuralTi–Al–N/Zr–Nb–N/Cr–N coatings produced with arc-PVD technique on theirphysical-mechanical, tribological, and operation properties
Physical-mechanical, tribological, and service properties of theTi–Al–N/Zr–Nb–N/Cr–N multilayer coatings obtained by the arc-PVD method havebeen studied. The dependences have been established between controlledsedimentation variables (displacement potential on substrate and speed ofsample rotation relative to the cathodes to be sputtered) and thecharacteristics of produced coatings having hardness as high as 37 GPa and adhesivestrength more than 100 N. Comparative investigations of tribological propertiesof different-composition multilayer coatings show the developed coatings to becharacterized by the least friction coefficient. The cutting tools with suchcoatings possess high durability under the conditions of intermittent andcontinuous cutting of grey iron (SCh30) and steels (Steel 45, Kb8N10T).
Key words: coatings for milling andturning instruments, hardness, viscosity, adhesive strength, tribologicalproperties, durability.
ENERGY SAVING AND ENVIRONMENT PROTECTION
Yachikov I.M., Sergienko S.N.
Distribution of heat flow over the surface of intermediate tank incase of electron-beam melting
Operation of ELP-30 furnace intermediate-container affectsessentially the processes defining the quality of produced titanium ingots. Theprocedure of calculation of average-density heat-flux distribution, which dropsonto the right-angled surface, depending on the electronic beam power;prescribed periodic functions of its parametric sweep; and focal spot diameterhas been developed. The linear-harmonic sweep of electronic beam, not uniformsweep, is shown to be the most interesting for practice.
Key words: electron beam, focal spot,ray sweep, local heat flux, axial electronic gun.
Levitsky I.A., Tikhomirova N.V.
Comparison of different methods of geometrical angularemission-value matrix correction
Various methods of correcting the matrix of geometrical angularradiation coefficients, which are found by approximate methods and consequentlynot complying with the properties, are considered. It is obtained that neitherthe method of fixed consecutive correction nor the method based on applicationof Lagrange undetermined multipliers allows obtaining physically reasonablematrix with ideal execution of the named properties for the matrix with a greatnumber of zero elements. The proposed method of selective correction also givesno reasonable result; we have succeeded in obtaining the reasonable inaccuracyby means of two-stage procedure: selective correction with application ofLagrange multipliers with subsequent fixed correction of the obtained matrix.
Key words: geometrical angular radiationcoefficients, closability and reciprocity properties, angular coefficientmatrix correction, Lagrange multiplier method, principle of maximum likelihood.
PROCESSCONTROL AND AUTOMATION
Lisienko V.G., Malikov G.K., Morozov M.V.,Belyaev V.V., Kirsanov A.V.
Simulation of heat-and-mass exchange processes in Vanyukov furnacein special functioning conditions
The mathematical model of Vanyukov melting furnace has beendeveloped. It allows to predict the behavior of furnace at the emergencyoperation mode – if oxygen is off – and to construct an effective heatingsystem, which dampens the harm of the emergency mode and reduces the costs offurnace reactivation. The efficiency of the dynamic zone-node method ofcalculation (DZN or two-grid method) is proved. Adaptation of the mathematicalmodel for the existing process conditions, which are weakly defined, isperformed. Simulation delivers the detailed pictures of complex gas-dynamic andtemperature processes in all the points of the furnace space. A system of theoff-design heating process quality criteria for emergency is developed. Usingthe model the heating system structure and parameters have been selected. Theheating system keeps the surface of a quiet bath in the molten state for morethan four days, and thereby it is quite economical.
Key words: mathematical simulation,mathematical model, grid model, DZN-method, Vanyukov melting furnace,oxygen-off, emergency operation mode.
INFORMATION
Kurdyumov G.M., Bragazina O.A.
Cross-tests are a new method of chemical knowledge monitoring formetallurgical students
