METALLURGY OF NONFERROUS METALS
Pupyshev A.M., Popov I.O., Ustinov S.M.
Investigation of basic regularities of iron and titanium phase distribution under the conditions of low-temperature reduction of ilmenite concentrate
The chemical and phase compositions of original and reduced at t <1150 °C ilmenite concentrate have been studied. The efficiency of the developed method through the reduction depth of iron titanates is shown. The basic regularities of the iron and titanium phase distribution in the course of reduction.
Key words: reduction, hydrocarbon, ilmenite, microstructure.
Timofeyev K.L., Naboichenko S.S., Lebed A.B., Akulich L.F.
Sorption technology of nonferrous metal extraction from mine waters
Mine waters containing harmful heavy metals constitute a significant environmental problem of the ore mining and smelting industry. The conventional treatment methods do not ensure the completeness of impurity removal. This work sets out the results of sorption researches of nonferrous metal extraction from mine waters of the copper-zinc deposit. Laboratory experiments for selection of optimum material and integrated tests of a selected sample - Lewatit TP 207 ionite have been carried out. The basic possibilities of ionite use for removal of heavy nonferrous metal ions are presented; the indexes of their capacity and selectivity in relation to the nonferrous metal sorption are given.
Key words: ion exchange, environment preservation, mine waters, ionites, extraction, copper-zinc deposit, nonferrous metal sorption.
Sitnikova O.A., Krasikov S.A., Istomin S.A., Ryabov V.V., Ponomarenko A.A.
The effect of titanium and molybdenum oxides on viscosity and electric conductivity of oxide-fluoride slag
The effect of titanium and molybdenum oxides on the viscosity and electric conductivity of Al2O3–CaO–CaF2 oxide-fluoride slag melts at temperatures of 1750–1950 K have been investigated by the oscillatory viscometry and AC bridge. Crystallization intervals with TiO2 and MoO3 concentration change in the melts from 0 to 25 % have been established. It is found that calcium and fluorine ions are basic electric current carriers. The obtained data prove the complexing nature of Ti and Mo behavior in alumocalcium oxide-fluoride melts.
Key words: viscosity, electrical conduction, oxides the titan and molybdenum, complexing properties.
Medvedev A.S., Aleksandrov P.V.
Versions of molybdenum concentrate processing including the use of preliminary mechanical activation
A review of optional versions of processing molybdenite concentrates of different grade by both pyrometallurgy and hydrometallurgy is given; the most rational versions of them are indicated. The prospectiveness of processing low-grade molybdenite raw materials by nitrogen-acid non-autoclave leaching with transfer of all molybdenum into solution as a part of sulfate complexes is shown. A version of intensification of nitrogen-acid leaching low-grade (6-17 % Ìî) concentrates, obtained by flotation of ore from the Bugdainsky deposit, by their preliminary dry mechanical activation is proposed.
Key words:molybdenite, concentrate, processing, mechanical activation, pyrometallurgical and hydrometallurgical methods, leaching.
SokolovaYu.V., Bragazina O.A.
Decomposition of LiOH·2Al(OH)3·nH2O compound above sulfocationite
Decomposition of LiOH·2Al(OH)3·nH2O compound (its technical name is lithium hydroxydialuminate) in water in a range of t = 20?90 °Ñ has been investigated. The compound was obtained by interaction of aluminate solution containing 130 g/l Al2O3, with the caustic module of 2.0 (Na2O : Al2O3 molecular ratio) and lithium chloride solution at t = 60 °Ñ. The water contained KU-2-8 sulfocationite; and full decomposition of initial compound was reached with mass ratio of mother substance : water : ionite = 20 : 1 : 4.8 at t = 80 °Ñ. Lithium desorption from KU-2-8 ionite was carried out with 1 % HCl solution at t = 70 °Ñ under the dynamic conditions.
Key words: lithium hydroxydialuminate, lithium, aluminate solution, KU-2-8 cationite, decomposition.
METALLURGY OF LESS-COMMON AND PRECIOUS METALS
Lebed A.B., Krayukhin S.A., Naboichenko S.S., Maltsev G.I.
Investigation of palladium complexing in desorption eluates from VP-1P anionite
Palladium complex forms in ammonia-nitrate solutions have been investigated during desorption of platinum-group metals (ÐGÌ) from VP-1P anionite. The possibility in principle of using VP-1P anionite for electrolyte purification from ÐGÌ in the process of silver refining is confirmed.
Key words: palladium, desorption, anionite, complex compounds.
MATERIALS SCIENCE AND HEAT TREATMENT
KucheyevYu.O., Straumal A.B., Mogilnikova I.V., Straumal B.B., Gusak A.M., Baretsky B.
Grain boundary wetting in Nd–Fe–B hard-magnetic materials
Samples of Nd–Fe–B alloys, which from the end of 1980th are the basic hard-magnetic materials with the highest magnetic energy, have been examined. Magnets on their base are produced by liquid-phase sintering method or quenching from the liquid state. The given work considers Nd2Fe14B grain boundary wetting by the second liquid phase enriched by neodymium is considered. The microstructure of Fe–12,3 at.% Nd–7,6 at.% B alloy quenched after annealing at t = 700?1100 °C above the alloy being rich with neodymium has been studied. The obtained data show that the transition from insufficient to full grain boundary wetting is followed by the temperature rise. The results are compared with the literary data for the Nd–Fe–B system alloys produced by liquid-phase sintering method. In addition, the relation between phase transition of grain boundary wetting and the magnetic properties is considered.
Key words: grain boundaries, wetting, Nd–Fe–B alloys, hard-magnetic alloys.
Mikhailovskaya A.V., Kotov A.D., ChuryumovA.Yu., Portnoy V.K.
Analysis of the Al–Ni system alloy softening, which contain particles of different dispersivity
The regularities of mechanical hardening and softening of aluminum alloys containing Al3Ni second phase particles of 0,3 to 2,2 µm in size with volume fraction of 0,03 to 0,1 have been examined in the course of cold strain and subsequent annealing at temperature of 0,6Tm. The maximum increase of hardness is shown to take place in the alloys with the maximum portion of dispersed particles (d = 0,3 µm) after rolling strain, which is more than 0,4. Small particles effectively constrain the softening process inhibiting from the development of recrystallization at the true strain value to 2.3. The increase of the particles to 1,2–2,2 µm in size promotes the nucleation at the recrystallization accelerating appreciably its processes. So, if d = 2,2 µm, 0,4 degree cold strain is sufficient for passing the recrystallization uniformly in the whole volume of a sheet.
Key words: recrystallization, grain structure, particles, degree of strain, softening.
Nosov V.K., Nesterov P.A., ShchugorevYu.Yu.,Polyakov O.A., Grachyov N.A.
The effect of initial hydrogen concentration and vacuum annealing modes on the structure, phase composition, and mechanical properties of VT6 alloy sheet billets. Part 2. The effect of phase composition and grain size on the mechanical properties of VT6 alloy sheet billets
The effect of ?-grain value and phase structure on the mechanical properties of VT6 alloy sheet billets after warm rolling with the use of reversible alloying by hydrogen has been examined. Hall-Petchrelation ?ò = ?i + kyd–1/2 was used for estimating the contribution of various hardening mechanisms into total hardening. The possibility of its use for estimation of intragranular and grain-boundary hardenings of VT6 (?+?)-alloy in comparison with Ti-6Al ?-alloy and technical titanium is shown.
Key words: phase composition, hardening mechanisms, Hall-Petch relation, VT6 titanium alloy, reversible alloying by hydrogen.
POWDER MATERIALS AND COATINGS
Laptev A.I., Nozhkina A.V., Zaitsev A.K., Yermolayev A.A.
Peculiar properties of “carbonado” diamond polycrystalline composite material structure
The thermodynamic analysis of graphite?diamond transformation has been carried out in synthesizing diamond polycrystals. It is established that the size of critical nuclei decreases with pressure increase and makes up 2,3 nm for p = 12,0 GPa. In studying the crystal structure of diamond polycrystals, it is established that the size of their blocks doesn’t depend on the synthesis pressure and exceeds the size of initial graphite material blocks. The characteristic features for martensite transformation in metals and alloys are shown not to be observed during the synthesis of diamond polycrystals.
Key words: synthesis, high pressure, martensite transformation
Artyukhova N.V., YasenchukYu.F., Gyunter V.E.
Shape memory effect in porous alloys produced by reaction sintering of the Ti–Ni system
Temperature and time intervals of liquid-phase sintering occurrence have been determined and qualitative change of TiNi phase in sintered reactionary Ti-Ni system has been found as a result of carried-out examinations. It is caused by the change of the TiNi phase nature in the solid-phase to liquid-phase transition of sintering stage, in this case not only the phase morphology but also its properties change. Two process models are proposed: one describes the phase interaction in the material structure and another – the sequence of phase transformations. It is found that the change of the properties and parameters of material forming correlates with the qualitative increase in connectivity and a fraction of TiNi phase itself during sintering.
Key words: porous titanium nickelide alloy, Ti-Ni system, reactionary sintering, solid-phase sintering, shape memory, TiNi phase, scanning electron microscopy, micro X-ray spectral analysis.
ENERGY SAVING AND ENVIRONMENT PROTECTION
Shakhrai S.G., Korostovenko V.V., Kaplichenko N.M.
Reduction in resinous substance ejections in the electrolytic aluminum production
An analysis is given of the effect of new technical solutions in the electrolytic aluminum production processes on the quantitative indexes of contaminants in the anode gas ejections. The methods of reducing resinous substance ejections are described. The problem of entrapping the ejections in cooling the rods to be extracted from anodes is described. A version is suggested to solve the problem by means of cooling the anode rods in the aspirated cassette, thus reducing the ejection of resinous substances on the average of 5 %.
Key words: aluminum production, anode rod, ejections, reduction in resinous substance ejections.
