Mineral processing of nonferrous metals

Melik-Gaikazyan V.I., Yemelianova N.P., Kozlov P.S., Trufanov M.I., Frolov N.S., Yushina T.I., Lipnaya E.N. Relaxation curves, their meaning for foam flotation process understanding and control, and curve recording procedure
Originating on the pulled bubble surface, nonequilibrium is shown to be the only possibility of necessary reinforcement of contact in the particle–bubble system under the dynamical foam flotation conditions. The nonequilibrium is estimated by the relaxation curve parameters characterizing the reagent activity and its residual concentration in solution. Detailed description of the curve recording technique illustrating with diagrams and microphotographs of used bubbles is given. Application of the digital technology and computer enables to use the technique described for prompt control of the process and replenishment of consumable reagents.

Yevdokimov S.I., Panshin A.M., Kanashvili M.Zh. Magnetic liquid: new technique
A decision of the problem to synthesize magnetic fluid is offered for application in magneticfluid separators in finishing rich goldcontaining primary concentrates as a result of development and investigation of new methods of colloidal magnetite production and stabilization

Metallurgy of nonferrous metals

Karelov S.V., Anisimova O.S., Mamyachenkov S.V., Sergeev V.A. Leaching of lead cake from zinc production in complex-forming solvent
Using the mathematical design approach, the leaching process of lead cakes from the zinc production in complexing reagent (Trilon B) has been investigated for selective extraction of lead into solution. Its optimum conditions: pH, liquidtosolid ratio in slurry, and temperature are determined. The process flow diagram for cake processing allows us to produce lead as a separate product, return zinc into the main production process, and reduce the current charges at the cost of solvent recovery.

Tatarchuk V.V., Druzhinina I.A., Vyazovoi O.N., Mamonov S.N., Mikhnev A.D., Ryumin A.I. Study of nonferrous metal occurrence forms in oxy hydroxides of chloride solution "nitration" process
Forms of nonferrous metals being contained in oxyhydroxide precipitates of ‘nitration’ process of rhodium, iridium, and ruthenium refining are studied by Xray photoelectron spectroscopy (XPS), Xrayphase analysis, gammaresonance (Mossbauer) spectroscopy, thermogravimetry (for solid samples) and atomic absorption, atomic emission spectrometry (for solutions). According to the XPS results, nitration hydroxides (NH) are composed of oxidized and unoxidized (selenium) transition metals: Fe(III) , Sn(II), Te(IV), Cu(I), Cu(II), Ni(II), Pb(II), As(III), Se(0), and Se(IV) as well as nonmetals: O, Cl, and C. All the nitration hydroxides (NH) are based on Xrayamorphous phase (>90 %). When heating nitration hydroxides to 900 °C in inert atmosphere, hydroxides dehydration and some phases crystallization occur, though Xrayamorphous phase is about 50 %, purely oxide or combined oxide phases Fe₃O₄, SnO₂, Cu^IFe^IIIO₂, Pb₂O₃ (NH1); Ni_0,4 Fe_2,6O₄, Cu^IFe^IIIO₂, CuNiSnO₄ (NH2); Fe₃O₄, SnO₂ (NH3) being formed.

Abikenova G.K., Kovzalenko V.A., Ambarnikova G.A., Ibragimov A.T. Study of the effect and behavior of sulfur compounds on process cycle of alumina production
Physical and chemical characteristics of Krasnogorski offgrade bauxite used in Pavlodar Aluminum Works have been studied. Its quantitative and qualitative composition is presented. The evaporation unit is shown to be the point of maximum oxidation of all lowest valence sulfur species into sulfates in the alumina process system. Basic desulfurization processes in the alumina production cycle: iron sand removal, increase of reducer quantity in charge sintering, and periodic removal of sodasulfate mixture are shown.

Rimkevich V.S., Malovitsky Yu.N., Bogidaev S.A., Pushkin A.A., Demianova L.P., Eranskaya T.Yu. Efficient processes in complex processing of non-bauxite ores
The chemicalmetallurgical conditions of the contrast distribution of aluminum, silicon and their compounds between coexisting phases have been found as a result of the researches of nonbauxite ore complex processing by segregation, extraction, and electrolysis. Effective processes of aluminum and alumina production as well as nonbauxite ore complex processing technique with production of amorphous silica, silicon and other useful components have been developed.

Metallurgy of less-common and precious metals

Neta V., Strizhko L.S. Development of technique to process gold-containing sulfide concentrate
Flotation goldcontaining concentrate smelting with application of copper collector and slag of fourcomponent SiO₂–FeO–Na₂O–CaO system has been studied. The optimum parameters of preliminary concentrate roasting (t = 750800 °С, t = 4560 min) and its smelting (t = 12001250 °С, t = 5060 min, metalslag layering time is 45 min, concentrate : carbon ratio is 10:1) have been found. In decreasing the last index (lower than 10 : 1), hematite and magnetite can be reduced to iron metal, which then goes into copper. With fourfold return of the collector, the gold extraction was 99,5 % and silver 77,7 %.

Metal forming

Polyakov A.P. Calculation of deformation non-uniformity during extrusion of porous material
A mathematical model of porous rough part extrusion is considered. The model takes account of strain nonuniformity in the transverse section of a rough part. An arrangement of rigid blocks is used while supposing the use of the conditions on the surfaces of violent rupture in plastically compressed medium. The strain nonuniformity in the course of extrusion is essentially to depend on matrix taper angle. As a result of calculations, the straining conditions have been determined to ensure the most uniform deformation of material particles within the zone close to the extrusion axis and the area adjacent to the forming part of the matrix. The optimum taper angle to ensure the most uniform material deformation varies from 30 to 40° depending on the reduction ratio.

Physical metallurgy and heat treatment

Kolachev B.A., Yegorova Yu.B. The effect of hydrogen on oxidation of VT6Ch titanium alloy
The effect of hydrogen alloying of VT6Ch titanium alloy on the structure and hardness of gassaturated surface layers during the air heating in a temperature range of 800–1050 °C has been investigated. Related to hydrogen, two effects were observed: a) decrease of the +/ transition temperature due to hydrogen that results in interaction of the alloy with oxygen in the range at lower temperatures; b) hydrogen changes the kinetic interaction parameters.

Powder materials and coatings

Zaitsev A.A., Kurbatkina V.V., Levashov E.A. Special features of the effect of nanosized additives on sintering process and properties powder cobalt alloys
Some questions of creation of nanoparticle dispersionhardened cobaltbased composite material by methods of powder metallurgy. Powders WC, ZrO₂, Al₂O₃ were used as nanoparticles to harden the Comatrix. Mixing of nanoparticles with cobalt powder of Co extra fine grade was carried out in planetarymotion centrifugal mixer. Processing according to the proposed mode is shown to ensure uniform distribution of nanoparticles in the Copowder volume, as remains unchanged after hot compression as well. Such dispersionhardened Coalloy has high indices of mechanical and tribological properties: wearresistance of the specimens of optimal composition increases 6 times and ultimate bending strength increases by 25 %.

Structural macrokinetics. SHS

Braverman B.Sh., Lepakova O.K., Maksimov Yu.M. Special features of nitride layer growth during self-propagating high-temperature synthesis of chromium nitrides
Product layer formation has been studied in combusting chromium powder in atmosphere of nitrogen under pressure from 1 до 10 MPa. Cr₂N is shown to form continuous protective layers, and partial destruction of the product layer occurs in forming CrN. Strength characteristics of chromium nitrides were determined by indentation method using diamond indenter. CrN phase has lower strength and higher brittleness than Cr₂N. It can explain the phenomenon observed.

Chronicle

In memory of Kolachev Boris Aleksandrovich