Mineral processing of nonferrous Metals
Melik-Gaikazyan V.I., Yemelianov V.M., Yemelianova N.P., Moiseyev A.A., Yemelianov V.V., Yushina T.I.
To investigation of foam flotation process and selection of reagents on the basis of mechanism of their action. Report 2. To comparison of flotation properties of milli-, micro-, and nano-meter bubbles on the basis of capillary physics. Second part
The effect of gas capillary pressure (Р c) in micro-bubbles (MB) from 2 mm to 20 nm in size on the process of their spreading over substrate (particle) after attachment to it has been considered. A dimensionless index number Kа is derived, which characterizes the MB tendency to spreading in reducing bubble shape coefficient (b) nothing more than by 0,000001 of its initial value. Clear symbate dependence between Р c and Kа is found. The spreading tendency begins from 200 µm in MB size and then actively progresses with its reduction. It is shown that the conditions of rejection of rock slime pulp particles adherent to bubble surface are created when MB size reduces. Naturally, this improves the quality of foam products.
Key words: micro-bubbles, capillary pressure, bubble spreading tendency, micro-bubble spreading index, rock slime pulp particle rejection.
Metallurgy of nonferrous Metals
Tsogtkhangay D., Mamyachenkov S.V., Anisimova O.S., Naboichenko S.S.
Kinetic regularities of copper concentrate leaching by nitric acid
In studying the kinetic regularities of copper concentrate leaching by nitric acid, limiting stages, process rate constants, general and partial orders of reactions by components, and activation energy have been determined. The effect of reaction product films on the limiting stage of nitric acid leaching of sulfides is established. The films of elemental sulfur and ferric oxide are shown not to form at high oxidizing potential, and the process rate is limited by external diffusion.
Key words: copper concentrate, nitric acid, leaching kinetic, limiting stages, activation energy.
Malyshev V.V.
Chemical and electrode reactions with participation of chromium compounds underlain its electrodeposition from ionic melts
The information of chemistry and electrochemistry of chromium in ionic solutions are considered and generalized. The data for chemical reactions with participation of chromium compounds, electrochemical reduction of this metal and its electrolytic deposition as different forms of cathode deposits are discussed and systematized.
Key words: chromium, ionic solutions, chemical reactions, electrode reactions, electrolytic deposition.
Zhuravlev V.I.
Study of sorption treatment of lithium hydroxide solutions from aluminum by dint of ANB-11g pitch
The results of studying the basic regularities of aluminum sorption over ANB-11g grade complexing pitch from lithium hydroxide solution are given. The sorbent contains functional groups of methyl glucosylamine (N-methyl glucomine) and it is produced by amination of chloromethylated styrene- divinylbenzene copolymer by methyl glucosylamine. Tests of its chemical and thermal stability in the solutions containing 48 g/dm3 LiOH have shown that ANB-11g retain its sorption properties after 30 days of contacting it. Heating of the sorbent under study in the same solution up to 373 K results in no change of IR-spectra – they are identical to the initial ones. In plotting isotherms of aluminum sorption from solutions with 12–96 g/dm3 LiOH, it was established that the pitch capacity in aluminum rises when alkali content in the initial solution increases. The sorbent reactivation is executed by diluted alkali solution with elution heating to Т = 323¸363 K. As a result of pilot-industrial tests of sorption decontamination from aluminum, metal content in them is decreased by 1–2 order depending on the solution volume passed through pitch. Aluminum desorption degree is 99,5 %.
Key words: alkali solutions, aluminum, lithium hydroxide, sorbent, sorption, ANB-11g pitch, elution.
Shirev M.Yu., Lebedev V.A.
New process of synthetic carnallite production
The paper presents the results of investigations on production of synthetic carnallite from spent electrolyte of magnesium cells and chlorine–magnesium solution. The purpose was determination of the process parameters, which would allow producing the synthetic carnallite that meets the requirements of the magnesium industry: synthesis temperature is 100–130 °C; initial concentration of magnesium chloride in the solution is 290–400 g/l; spent electrolyte charge is 105 % of stoichiometric value; particle size is –0,315 mm. The order of process operations is established: heating chlorine–magnesium solution and spent electrolyte to 100–120 °C; their mixing in reaction vessel; dissolution of electrolyte; reactionary mass evaporation at agitation; and drying.
Key words: synthetic carnallite, chlorine-magnesium solution, spent electrolyte, classification, mixing, dissolution, synthesis.
Metallurgy of less-common and precious metals
Kudryavsky Yu.P.
Sorption concentration of thorium from solutions during complex processing and deactivation of scandium-containing technogenic raw materials
The results of selective sorption extractive investigations, over macroporous sulfocationites, of hydrolyzed thorium ions from scandium-containing solutions formed during complex processing of multicomponent polymetallic production wastes are generalized and systematized. The efficiency and selectivity process is shown to be able to essentially rise in the use of macroporous KU-23 cation-exchange resins and anion exchanger in the form of OH– for sorption as well as preliminary introduction of 50–150 g/dm3 of magnesium and calcium chlorides into the initial Sc–Th-containing solutions. Based on the earlier tests and investigations, a flow process diagram of complex processing, deactivation, and sterilization of production wastes has been developed and proposed for practical realization with localization of thorium and its decay products as well as production of various commercial products – scandium oxide, inorganic pigments, sorbents, catalysts, etc.
Key words: polymetallic waste, scandium-containing technogenic raw materials, sorption, macroporous cation exchange resin, thorium hydrocomplexes, ion-exchange extraction.
Materials science and heat treatment
Cheverikin V.V., Khvan A.V., Zolotorevsky V.S., Levchenko V.S., Ernandes Lara T.
Analysis of multicomponent alloys based on aluminum with a great portion of three-phase eutectics
An analysis of some fragments of the phase diagrams of the Al–Zn–Mg + (Ni, Fe, Mn, Cr) system has been carried out. The researches were executed both by experimental methods and calculations using TermoCalc program. The structure of ternary eutectics was examined in as-cast state and after annealing. The alloy with a great number of eutectics, which have dispersed structure achieved at average cooling rates. It was shown that intermetallic phases in the eutectics are shown to be fragmented and spheroidized in the process of homogenizing annealing before quenching.
Key words: eutectic, aluminum alloys, phase diagrams.
Casting production
Pashkov A.I., Gerasimov S.P., Pashkov I.N.
Investigation of melting and filling of gap clearances by mechanically and casting Cu–Mn–Ni soldering alloys
Investigations of the Cu–Mn–Ni system alloys produced by different methods have been carried out and a special procedure has been developed for estimation of their behavior in melting and filling capillary gap clearances. The given procedure allows choosing optimum modes for the alloy production process, estimating its purity and the effect on capillary gap clearance filling process.
Key words: mechanical alloying, manganese, nickel, Cu–Mn–Ni system, melting, capillary gap clearance.
Nesterov N.V., Yermilov A.G.
Low-frequency pulsations of melt during lost foam casting process. Part 1
The process of initiation of low-frequency pulsations in liquid metal in mold has been studied on the basis of the mathematical model of mold filling in carrying out the lost foam casting process. Mold filling is shown to take place with somewhat delaying when gaseous gap between material of the model to be gasified and liquid metal that gets a mechanical impulse resulting in oscillations of its level in the riser pipe and pressure in gas space. The own frequency of oscillations in the gas space is shown to decrease first drastically and then slowly in the course of filling the mold with metal. Thus, it slightly depends on gas permeability of mold while slowly decreases and then stabilizing in increasing the speed of liquid metal supply into the mold and decreases in increasing the reduced pressure in the mold box.
Key words: lost foam casting process, thermal destruction, low-frequency pressure pulsations, stability of mold.
Powder materials and coatings
Rusin N.M., Ivanov K.V.
Characteristic properties of plastic flow of powder Al–40Sn alloy during extrusion
The characteristic properties of compaction with Al–40Sn alloy powder extrusion have been investigated. The compaction was carried out in a temperature range of 25–230 °C with reduction ratio of 4,5 (e = 1,5). The investigation of the structure along the specimen length including remainder of billet showed its change to take place at the blank forming stage and in being in the working channel of extrusion compression mold. At that time, new composite material consisting of aluminum particles, which are dispersed into continuous soft tin matrix, is formed under the effect of current pressures. In pressing such material through a drawing die, tin intermediate layers act as inter-particle grease facilitating mutual displacement of aluminum particles, which consequently are poorly deformed. As a consequence, oxide particles on aluminum particles remain unchanged and prevent the formation of strong interface boundaries. The extruded material contains cracks along the phase boundaries and shows low ductility.
Key words: powder Al–Sn alloy, antifriction materials, extrusion, structure of compact.
Process control and automation
Salikhov Z.G., Rutkovsky A.L., Dyunova D.N.
Management object parameter identification in closed systems
The questions of application of the correlation approach to the decision of a problem of management object identification in closed regulation systems have been considered. It is established that the identifiability in a closed system is defined by a kind of auto- and cross-correlation functions of stochastic processes at the object inlet and outlet as well as a delay value on the operating influence transfer channel and the transfer function of a regulator. The opportunity of using the identification criteria in the form of equalities of mutually correlating functions of a target variable and disturbance as well as the operating influence is substantiated. Comparison of the correlation method of the object parameter identification in the closed systems and the least-squares method has shown the applicability of the last approach to the limited class of closed systems.
Key words: closed regulation systems, object parameter identification, correlation method, criterion of identification in closed systems.
Economics and management
Rubinshtein T.B.
To question of M&A effect determination in metallurgy
The article gives the results of the investigation concerning the determination of the economic effect due to M&A of companies in the nonferrous metallurgy. The questions of synergic effect and decomposition: efficiency criterion, features of transactions connected with the corporate restructurings are considered. The algorithms of the M&A effect calculation of transactors on mergers and acquisitions are proposed.
Key words: M&A, economic effect, investment transaction, generating company, synergic effect, decomposition.
Chronicle
- To 100-year birthday of A.N. Zelikman
