Extractive metallurgy of nonferrous metals

Trofimov E.A., Mikhailov G.G. Phase equilibria realizing in the Cu–As(Sb,Bi)–O systems under the conditions of existing copper melt
Based on the thermodynamic calculations, the surfaces of component solubility in metal melt for the Cu–As–O, Cu–Sb–O, and Cu–Bi–O systems in a range of t = 1100ч1300 °C as well as the high-temperature fragments of the structural diagrams of the Cu₂O–R₂O₃ oxidic systems (where R is the As, Sb, and Bi) are plotted. Experimental researches of the phase equilibriums being realized in the Cu-Sb-O and Cu-Bi-O systems are carried out. The results of the work can be used for analyzing the processes of production of copper and copper-based alloys.
Key words: copper melt, arsenic, stibium, bismuth, oxygen, thermodynamic calculations.

Tsogtkhangai D., Mamyachenkov S.V., Anisimova О.S., Naboichenko S.S. Thermodynamics of reactions in the course of nitric-acid leaching of copper concentrate minerals
Using the “potential – рН” thermodynamic diagrams in the Cu–Fe–S–N–O–H system at 20 and 100 °C, the conditions of effective dissolution of sulfides without precipitation of elemental sulfur and iron oxides have been determined. The obtained thermodynamic characteristics of copper concentrate leaching by nitric acid can be used in selecting the copper concentrate processing variables.
Key words: sulfide concentrates, nitric-acid leaching, thermodynamic characteristics, process variables.

Aleksandrov P.V., Medvedev A.S., Kamkin R.I. Absorption of nitrous gases evolving at nitric-acid decomposition of sulfide materials
The article gives a review of the methods of nitrous gas (NO_x) recovery evolving during nitric-acid decomposition of sulfide minerals. Advantages and disadvantages of each method are described. The results of experiments on NO_x absorption by water are given. The dependences of NO_x recovery degree on various factors (water temperature, height of water column, dispersion of gases, oxidizing agent (air oxygen) consumption) are determined. It is found that for the purpose of increasing the efficiency of nitrous gas recovery, the obtained solutions after termination of their barbotage through water should be held for 2–3 days in tight containers at small excessive air pressure. NO_x absorption by water is shown to take place on the phase boundary, not inside the volume.
Key words: absorption, nitrous gases, sulfide minerals, nitric acid.

Bazhenov A.A., Kulifeev V.K., Vatulin I.I., Kropachev A.N., Podrezov S.V. Investigation of solid and liquid aluminum behavior during lithium carbonate dissociation in vacuum
In the context of the aluminothermic process being developed to produce lithium metal, the process of oxidizability of aluminum powder by carbon dioxide – product of lithium carbonate dissociation – has been investigated theoretically and experimentally. The thermodynamic estimation of hard and liquid aluminum interaction with CO₂ as well as (for comparison) with oxygen has shown that aluminum both in hard and in liquid state should be oxidized by both gases. The experience has shown that during lithium carbonate dissociation the oxide film protects aluminum against oxidation by carbon dioxide. The assumption has been proved experimentally that the protective Al₂O₃ layer on aluminum powder surface interacts with Li₂CO₃ in the course of dissociation with formation of a new compacter layer – lithium monoaluminate, which protects aluminum better than Al₂O₃ against oxidation by CO₂.
Key words: lithium carbonate, aluminum, Pilling-Bedwords criterion, aluminum oxide, lithium monoaluminate, X-ray analysis, change of Gibbs energy.

Nikolaev I.V., Kirov S.S., Vorobiyov I.B., Zakharovа V.I., Bogatyryov B.A., Magazina L.O. Application of hydrogarnet process for complex processing of Indian khondalites
The results according to one of alternatives of high-silicon aluminum raw material processing – Indian khondalites are presented. The possibility is established to extract the primary impurity (silicon dioxide) in the successive version of Bayer-hydrochemistry with red mud processing in high-modulus solutions according to the hydrogarnet process. The conditions have been determined to form ferrous hydrogarnet of the 3CaO · Fe₂O₃ · 2SiO₂ composition as a monomineral phase: temperature of 230–250 °С, alkali concentration no lower than 200 g/l, and introduction of active iron oxide form.
Key words: Indian khondalites, red mud, sodium hydroaluminosilicate, ferrous hydrogarnet, losses of sodium and aluminum oxides.

Extractive metallurgy of less-common and precious metals

Gostishchev V.V., Boiko V.F., Komkov V.G. Gold leaching by low-temperature salt melts from concentrates
Reactive capability of the NH₄NO₃–MeCl, NH₄Cl–MeNO₃, NH₄Cl–NH₄NO₃, (NH₄)₂SO₄–NaNO₃ (Me – Na, K) salt systems has been experimentally investigated in relation to gold at temperature of 260–320 °С. It is found that the gold solubility in the mentioned salt systems at t = 320 °С is high. The heat treatment of Au containing concentrate with salt mixtures is shown to provide ecologically safe gold extraction of ~90 %.
Key words: gold containing concentrate, salt melts, gold solubility, extraction.

Kunty O.I., Bukliv R.L., Korny S.A. Morphology and composition of deposit obtained from [Ag(S₂O₃)₂]^3––S₂O₃^2– solutions by magnesium scrap carburizing
The morphology and composition of the deposit obtained in the course of carburizing by magnesian scrap from the 0,0025-0,01М [Ag (S₂O₃)₂]^3– + 0,5М S₂O₃^2– solutions have been studied at t = 2040 °С. Dispersed deposit of silver and sulphur is shown to form in a wide range of densities, the deposit being released easily from magnesium surface. The sulfur content in it is reduced with [Ag (S₂O₃)₂]^3– ion concentration increase in the solution and temperature growth. It is established that the final product of the [Ag(S₂O₃)₂]^3– –S₂O₃^2– solution carburizing corresponds to Ag₂S in composition.
Key words: silver carburizing, magnesium, thiosulphate solutions, morphology.

Casting production

Dubrovin B.K., Zaslavskaya O.M., Karpinsky A.V. Casting production from non-ferrous alloys in bulk molds of consumable patterns
The theoretical aspects and practical results are presented for development and industrial application of new processes concerning manufacture of art nonferrous castings from 0,1 to 100 kg in weight and as great as 1,5 m in size in three-dimensional molds of consumable patterns with gypseous and cement binders under the conditions of individual and batch production.
Key words: investment casting, bulk crystallohydrate molds, gypseous binders, cement binders, calcium silicate and aluminate.

Metal forming

Maksimov E.A. Experimental investigation of kinematic criterion of flatness and conditions of defect creation in strips during cold rolling
The existing and new kinematic flatness criteria have been experimentally investigated. The effect of roll circumferential-speed mismatch factor on change in the geometrical form, non-uniformity of friction conditions across the width of a strip has been found.
Key words: cold rolling, flatness, kinematic flatness criterion, non-uniformity of friction conditions.

Zagirov T.M., Kruglov A.A., Yenikeev F.U. Manufacture of cylindrical shells from welded sheet blanks by superplastic molding
Two alternative process flow diagrams to manufacture cylindrical shells of titanium alloys in the superplastic state are considered: sheet molding into a rectangular die and free molding of a stack consisting of two sheets welded along the outline by diffusion welding. A comparative analysis shows that for the case of superplastic free molding of a stack of sheets the damaging parameter and the process duration are approximately three times less in value as compared with standard molding diagram into a rectangular die under the same gas pressure. A conclusion is made that the free superplastic molding of rectangular stacks can be used to manufacture cylindrical articles from materials with low plasticity.
Key words: superplastic molding, cylindrical shell, welded sheet blank.

Materials science and heat treatment

Belov N.A., Belov V.D., Cheverikin V.V., Mishurov S.S. Sparingly alloyed high-strength wrought nickalines – aluminum alloys of new generation
An analysis of phase composition of the Al–Zn–Mg–Cu–Cr–Mn–Zr–Fe–Si–Ni system has been carried out with reference to high-tensile V96 type aluminium alloys. It is found that in lacking copper, manganese, and chrome, the amount of possible phases is reduced more than threefold. The data of calculation by means of Thermo-Calc program testify the Al–Zn–Mg–Ni–Fe system to be the most perspective for development of a new group of high-tensile wrought alloys being sparingly alloyed nickalines on the basis of (Al) + Al₉FeNi eutectic. By the example of АЦ7НЖ (ATs7NZh) nickaline, containing more then 10 % (Zn + Mg), a high level of mechanical characteristics: s_m > 670 MPa, s_0,2 > 640 MPa, d > 6 % is shown to be reached in rods.
Key words: high-tensile aluminium alloys, phase composition, structure, nickalines.

Process control and automation

Spesivtsev A.V., Dudorova M.L. Multimodel approach of material balance calculation for enterprise in the environment of intellectual information and measuring systems
By the example of a gold-processing plant, a comparison of two conceptually various design procedures of mass balan-ces – graph and neuro-indistinct ones has been carried out. The preferable application of the multimodel approach to the enterprise activity analysis within the limits of the informational and measuring system is shown.
Key words: graph and neuro-indistinct models, material balance of enterprise, informational and measuring system.

Chronicle

• Michail Iosifovich Alkatsev is 85 years old
• Vladimir Aleksandrovich Arutyunov is 75 years old