The article presents the results of thermodynamic calculations and analysis of the CuFeS2–H2O–O2–CO2–C4H9OCSS–– CrO42–system characterizing chalcopyrite surface condition under the conditions of selective floatation of copper-lead concentrates according to potassium dichromate technics in alkaline medium. Electrolytic potentials of chalcopyrite are measured experimentally in the solutions of potassium bichromate and potassium butyl xanthate of alkaline pH. As a result of the investigations, the mechanism of formation of sorption collecting agent layer under the conditions of galena depression by chromates-ions is considered. It is sown theoretically that sulfide sulfur oxidation degree should not affect the process of competitive reactions of butyl xanthate formation over chalcopyrite surfaces. It is established from the results of chalcopyrite electrode potential measurement that chromates-ions in a wide range of their concentrations are not potential-determining ones for chalcopyrite. Its surface in alkali solutions of butyl xanthate and potassium bichromate should mainly be hydrophobizated at the expense of copper butyl xanthate formation, and a sorption collecting agent layer of mixed composition as copper (I) butyl xanthate and dixantogen can be formed only in a narrow range of redox potential and pH.

A hydrometallurgical method of copper-smelting slag processing by means of ammonium chloride is proposed.  A basic processing diagram has been developed. Investigations of slag decomposition by ammonium chloride are conducted and the recommendations concerning the process implementation are given. Minerals, which form copper-smelting slag, are Fe2SiO4, Zn2SiO4, CuFe2O4 and Ca2SiO4. The decomposition should be carried out at temperature of 280 °C for 4 hours with continuous agitation and at slag/ammonium chloride ratio of 1 : 2.

The method of EMF measurement of a galvanic cell with solid electrolyte (EMF method) has been used for examination of the equilibrium conditions of wustite and spinel solutions in the Fe-Ge-O system in the temperature range of Т = 1100÷1300 K. X-ray diffraction and micro X-ray spectral methods were used for determination of phase composition. It is found that magnetite and iron germanate are restrictedly dissolved in each other. Isothermal sections of the phase diagram of the Fe–Fe3O4–Fe2GeO4 system are plotted at Т = 1273 and 1173 K.

The structure and phase composition of nis matte sulfate-chloridizing roasting processing products have been studied. Distribution of non-ferrous metals in the phase components at the stages of nis matte oxidizing in «fluidized bed» and calcine roasting with sylvinite is estimated. The data of optical spectrometry as well as X-ray phase, micro X-ray spectral and chemical analyses are used in the work. Based on the phase composition being formed in the course of sulfate-chloridizing roasting and the data of thermodynamic simulation, the sequence of reactions proceeding during the roasting is presented.

Investigations concerning nitric acid leaching of polymetallic middlings for the purpose of maximum copper and zinc recoveryinto solution have been carried out. The optimal process parameters: L : S = 5, nitric acid consumption of 80 cm3 per 20 g weightedquantity, and process duration of 120 min were determined using the methods of mathematical design of the experiment.

The kinetic regularities of oxidizing autoclave dissolution of iron, copper and nickel sulfides in the course of the «Shanuch» deposit ore leaching have been examined in the controllable conditions of experiment. The sulfide dissolution rate is shown to be limited by oxygen absorption. 

Niobium and tantalum are rare refractory metals of industrial significant importance. Their stores are reckoned to the «critical» raw materials that results in the necessity of estimating the risks connected to the availability of fundamental and technogenic raw sources of niobium and tantalum and the effect of these factors on the offers and demand for these metals and their compounds taking into account the traditional and new areas of their application. The article gives an analysis of the world’s reserves of niobium and tantalum; the dynamics of structural change of the raw-material base and the technological solutions realized and offered for their processing is considered. The modern market of materials based on niobium and tantalum is described; basic players in this market are determined; the tendencies in structural change in the consumption of functional materials on the basis of these metals are considered.

The effect of mechanical activation of M2O3 (La2O3, Ce2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Yb2O3, Lu2O3) oxides on the electrical conductivity (æ) of the B2O3–M2O3 molten systems has been studied. It is supposed that protons can be the major current carriers in the melts, which enters the melt because of B2O3 hydration. The æ value change of borate melts for various M2O3 content is explained by the corresponding structure variation of the structural units as a result of dissociation of boron-oxygen groups consisting of OH groups. When temperature grows, the activation energy of electrical conductivity in the B2O3–M2O3 melts increases due to decomposition of superstructural units: [B3O4,5] and B3O3O3/2OH. The dependence of æ value against the serial number of lanthanide in series of B2O3–La2O3 → B2O3–Lu2O3 melts have been found to be subject to the intranuclear periodic sequence, which depends on the stabilization energy of the basic terms of rare earth ions.

A method of mathematical simulation of tube-drawing tool for draw of many-sided tubes made of non-ferrous metals and alloys with the use of the vector-matrix tools, which can be applied for analytical description of the volume deformation region, is given. Reducing dies with various geometry of the squeezing zone are considered. As a result of the simulation of the deformation region arising in the course of producing section-shaped many-sided tubes by the mandrel drawing method with the use of all types of considered reducing dies, it is found that the best result with the least spherical radiuses is reached with reducing dies with the pyramidal input into the squeezing zone.

A design procedure of energy-power characteristics is proposed for the trimetallic raw part drawing process. Stresses in separate layers of trimetallic raw parts and total stresses of drawing are determined. The optimum geometry of drawing tool including key parameters of the process is found.

In designing the regular polygonal section shape drawing process, it is convenient to use analytical expressions allowing us to estimate effectively the effect of different process factors. A design procedure of stress calculation for this process is proposed. The ratios for calculation of drawing stress, optimum angle of the drawing tool hole, limit value of deformation degree in using the standard tool and index of stress state in the axial part of the deformation zone are obtained. The use of drawing tools with optimum angles reduces the accumulation rate in the metal structure and in case of repeated drawing allows us to cut down the number of intermediate heat treatments.

Formation and movement of gas bubbles in the melt affect the heat interchange and the kinetics of chemical transformations in the course of copper fire refining in a ladle-furnace. The present mathematical model considers changing the bubble speed and volume and surface of moving gas bubble through the melt height.