MINERAL PROCESSING OF NONFERROUS METALS
Solozhenkin P.M., Adamov E.V., Alekseyeva V.P.
Study of molecular structure of sulfhydryl collectors on the basis of dialkyldithiocarbamates for the purpose of criterion choosing for their selection
For the first time the computer simulation of sulfhydryl collectors and their derivatives has been executed with the use of «Chem3D» program of the specialized «ChemOffice» complex. Models (ball-and-rod-shaped and spatially filled) have been constructed for sulfhydryl collectors and dithiofragment-modified short-chain carboxylic acids. Based on the provisions of the coordination theory of floatation, effective collectors for sulfide ores are proposed. An explanation is furnished to the interaction of reagents with the surface of sulfide and oxidized minerals. The results of sulfide ore floatation with application of modified reagents are given.
Key words: flotation reagents, carboxylic acids modified by dialkyldithiocarbamate residual matter, floatation coordination theory, computer simulation.
Rakoch A.G., Nomine À., Gladkova A.A., Kovalev V.L., Bardin I.V.
Effective conditions of microarc oxidation of ML5 magnesium alloy
It has been found that for obtaining of ground layers on the surface of magnesium alloy (ML5) with microarc oxidation technique (MOT), the high efficiency of this process is developed by passing direct current between the electrodes so far as large, intensively burning microdischarges appear against rather small ones in alkaline-phosphate solution with ammonium fluoride additive. The change of the amount of effective microdischarges realized on the working electrode surface at various durations of MOÒ process is shown to be the main mechanism of the effect on growth rate of microarc coating of the AC cathode component and ammonium fluoride inducted into alkaline-phosphate solution.
Key words: magnesium alloy, microarc oxidation, working electrode, DC and AC, ammonium fluoride.
Mastyugin S.A., Naboichenko S.S.
Copper-electrolyte slurry processing: evolution of the process
The slurry formed in copper electrorefining is a valuable multicomponent product the processing techniques of which are dependent on its composition and the occurrence shape of precious metals as well as selenium and tellurium. Advantages and disadvantages of the basic utilizable techniques of copper-electrolyte slurry processing have been analyzed. The dominating trend in development of modern slurry production is improvement in hydrometallurgical technique with silver-gold alloy smelting elimination and decrease of toxic releases in the environment.
Key words: copper-electrolyte slurries, precious metals, selenium, tellurium.
Pupyshev A.M., Popov I.O., Makarov A.M., Butyrsky B.N.
Research of the phase transition at the low-temperature recovery of Khibiny titanomagnetite concentrate
Chemical and phase compositions of original and reduced at t < 1150 °C titanomagnetite concentrate have been studied. The effect of the developed reduction technique to the iron reduction depth in titanates and the iron and titanium phase distribution in the roasted product.
Key words: reduction, hydrocarbon, titanomagnetite, microstructure.
Kirichenko D.V., Tolkachyov V.A.
Investigation of magnesium extraction from serpentinite by hydrochloric acid solution
Laboratory investigations of magnesium leaching process efficiency from serpentinite by hydrochloric acid solution depending on initial material coarseness, acid strength, temperature, time, and agitation intensity have been carried out. It is determined that the most significant factor is the temperature. Its increase from 40 °C to 80 °C at time of leaching of 4 h, agitation speed of ~500 rpm, and acid strengths of 18 % raises the magnesium extraction 2,0–2,5 times. It is found that internal diffusion is a limiting stage of the magnesium leaching process from serpentinite.
Key words: serpentinite, magnesium, hydrochloric acid, leaching, extraction efficiency, magnesium chloride solution.
Doronin I.E., Svyazhin A.G.
Dusts and fine pulps as raw materials for zinc and steel production
Dusts and slurries of gas cleaning of steelmaking vessels, their element and phase compositions, and the possibility of application as raw materials for zinc and steel production have been considered. Comparison of steel-smelting dust with natural ores under the contents and the shape of extracted components is drawn. Indexes of zinc production in Russia and the world as well as alternatives of dust processing in the steelmaking vessels realized commercially are presented. The necessity of ubiquitous transfer to the metallurgical techniques close to non-waste ones from the point of view of iron and zinc is noticed. Possible ways of interacting of the steel-smelting and zinc industries are shown.
Key words: technogenic raw materials, steel-smelting dust processing, natural raw materials, steel-smelting production, zinc production, zinc returns, iron returns.
Kravtsova E.D., Frizorger V.K., Marakushina E.N., Kravtsova M.N.
Opportunities of mechanical activator application for improvement of rheological properties of cake-dust compositions
The viscosity of the compositions containing 55 % of pitch and cake dust with particle size less than 0,212 mm obtained in mechanical activator has been examined and comparison of the obtained results with the data for identical cake-dust compositions prepared by usual blending has been carried out. It is confirmed for three coking charge mixtures containing 25, 50, and 75 % of coke fraction of –0,063 mm (the remaining fraction: –0,212+0,063 mm) that within a temperature range from 428 to 498 °Ñ (all other things being equal) the viscosity of the mixtures exposing to mechanical activation is always less than the mixtures obtained by standard agitation.
Key words: pitch, coke, viscosity, mechanical activation, anode mass.
Kirichenko A.G., Nasekan Yu.P., Kolesnik N.F.
The effect of sulfur compounds in gas on carbon monoxide decomposition process over red mud
The process of red mud recovering by carburization of its iron component by CO-containing gases from ferroalloy furnaces has been investigated. The experiments showed that red mud of alumina production and waste gases from ferroalloy furnaces after the relevant preparations are well suited for the carbon monoxide decomposition reaction. It is determined that hydrogen sulfide has the toxic effect on the catalytic ability of iron oxides as catalysts for the reaction of CO thermocatalytic decomposition. The mechanism of the effect of sodium hydroaluminosilicates included in red mud on the ferroalloy gas purification degree from sulfur-containing compounds is revealed. Ferroalloy gas purification allows us to increase the carbon content 5–10 times in the end product.
Key words: red mud, recovering, ferroalloy gas, thermocatalytic decomposition, carbon monoxide, hydrogen sulfide, sodium hydroaluminosilicate.
MATERIALS SCIENCE AND HEAT TREATMENT
Terentiev Yu.A., Bokshtein B.S., Pomadchik A.L., Popova D.E., Rodin A.O.
Grain boundary diffusion of germanium in copper and Cu–Ge and Cu–Fe alloys
Grain boundary diffusion (GBD) of Ge in Cu and Cu-based alloys (Cu–2 % Ge and Cu–0,5 % Fe) has been investigated with the help of X-ray microprobe analysis at temperatures in a range from 500 °C to 590 °C. Values of GBD parameters – triple product P = s?DÃÇ and effective activation energy E – were obtained. The temperature dependence of GBD triple product of Ge in pure copper can be described with the following equation P = 3·10–15exp[–80 kJ·mol–1/(RT)] m3·s–1. Germanium addition is shown to have no effect on the germanium GBD parameters in copper, and iron doping results in a significant decrease of the triple product.
Key words: grain boundary diffusion, grain boundaries, copper, germanium, iron, X-ray microprobe analysis, concentration dependence.
Mikhailovskaya A.V., Portnoy V.K.
Analysis of softening processes in hetero-phase aluminum alloys containing eutectic component
The effect of inter-particle size, volume fraction of particles and mean eutectic particle size in cold rolled sheets of aluminium alloys of the Al–Ni, Al–Mg–Si, Al–Ni–Ce and Al–Cu–Ce systems on the softening and structural variations during heating at (0,6?0,8)Òm temperatures have been investigated. The dependence between particle parameters and hardness decrease are found. The ability of the particles to retard or accelerate recrystallization has been analyzed.
Key words: aluminum alloys, eutectic particles, recrystallization, nucleation on particles.
Zolotorevsky V.S., Pozdnyakov A.V., Kanakidy Ya.Yu.
On relation of complete and effective crystallization ranges with hot-brittleness of aluminum based multicomponent alloys
A relation of calculated complete and effective crystallization ranges (CCR & ECR) with experimentally determined hot-brittleness index (HI) in standard industrial and experimental foundry aluminum alloys of various systems has been analyzed. It is established that a good correlation of ECR with HI is observed only for the alloys, which are falling into one alloying system; a conclusion is drawn on the above basis that ECR value is not the only factor and, possibly, not the most important factor determining HI. Correlation between CCR and HI in the examined multicomponent alloys is lacking practically in full.
Key words: aluminum alloys, complete crystallization range, effective crystallization range, hot-brittleness.
ENERGY SAVING AND ENVIRONMENT PROTECTION
Isayev A.S., Levitsky I.A., Sborshchikov G.S.
Numerical investigation of thermal stabilization process of acrylic fiber bundles in VULON furnace
A mathematical model of radiation-convective heat-exchange in the working space of VULON furnace designed for thermal stabilization of raw materials in the production of carbon fibers has been developed. From the results of a numerical experiment with the use of the above model, the basic possibility of automatic control of the thermal stabilization process by temperature regulation of electric heaters installed in the furnace channels is shown. The temperature conditions of the heaters, thus eliminating bundle fusing, for specific bundle samples of acrylic fibers with application of experimentally obtained physicochemical constants of the reactions proceeding in the course of thermal stabilization of the fibers have been calculated. Recommendations on optimization of the raw material preparation to thermal stabilization and the air supply system to the working channels of the furnace are presented.
Key words: acrylic fibers, carbon fibers, exothermic effect, thermal stabilization.
