Vol 50 Iss. 3

The general principles of selecting selectively acting solvents, setting up tests and interpreting their results for the technical and economic assessment of mineral leaching processes have long been known and described in detail in many hydrometallurgy courses. With regard to the specific problems of selectivity of dissolution in phase chemical analysis, these issues are also covered quite fully ...

The kinetics of oximation of substituted 1-phenyl — 1, 2-propanediones of the general formula CH3COC6H4P, where R=H, p —CH3, p—OSN3, p—Cl, p—Vg, m—Cl, m—CH3 was studied at 278, 288, 298° C and pH = 6.5 ...

Hydrochloric and nitric acids, which are commonly used to separate oxidized and sulfide bismuth compounds, do not allow quantitative separation of oxidized and sulfide bismuth minerals ...

A gushing layer can serve as one of the intensive methods of contacting a solid material with a liquid. While a significant number of works have been devoted to its hydrodynamic patterns in the G—S system, there is practically no work on the hydrodynamics and mass transfer of the gushing layer in the G—S system. The lack of a complete analogy in the behavior of these two heterogeneous systems, caused by a significant difference in the viscosity and density of the light phases of L and G, urgently requires independent hydrodynamic studies of the gushing layer in the L—S system...

The method of mercury porometry is widely used to determine the geometric structure of solid porous bodies. The porous structure of granular materials with a granule size of at least 1-2 mm is usually determined. However, in a number of fields (flotation enrichment processes, powder metallurgy), the objects of research are powders in which the minimum particle size is reduced to several tens of microns. The method of mercury porometry is of interest in studying the structure of powders...

Studies on the autoclave oxidation of nickel sulfides mainly consider the behavior of fused nickel sulfide, which is similar in composition to heatherwood Ni3S2. Only a few have highlighted the kinetics of dissolution of nickel monosulfide NiS, one of the main components of various intermediates of nickel production: anode sludge, nickel sulfide concentrate obtained by precipitation with hydrogen sulfide, intermediate phase of autoclave dissolution of nickel concentrate flotation of copper-nickel feinstein...

When determining the specific surface area of solids by the gas chromatographic method of thermal desorption, the areas of desorption calibration peaks are compared. The catharometer is usually calibrated by introducing an adsorbate gas into the main stream. Another gas, such as air, can also be used for this purpose...

The dependences linking the degree of decomposition of a solid substance with the initial amount and concentration of a solvent through an equilibrium constant are described more simply if the equation of the chemical dissolution reaction, accompanied by the formation of complex or difficult-to-dissolve products, is attributed to one mole of solvent. The equilibrium constant of such a reaction ...

The complexity of calculating the porosity characteristics prevents the widespread use of the mercury porometry method in factory and research laboratories. It is possible to reduce the calculation time by standardizing measurements on a high-pressure foam meter, using pre-prepared tables, simplifying the calculation scheme, and reducing the number of measurements. Simplification is allowed, however, only for materials that are thinly porous and with a strongly developed porosity...

The kinetics of dissolution and methods of phase analysis of antimony compounds have been studied repeatedly. To study the kinetics of Sb2S3 and Sb2O3 dissolution in KOH solutions, polydisperse samples of these antimony compounds (a.g.) were taken in order to use them for phase analysis....

Hydroxamic acids have been used as effective flotation reagents and are promising in the extraction of metals. The analysis of hydroxamic acids was studied by K. E. Istomina and L. A. Ionina. The quantitative determination of small concentrations of hsptylhydroxamic acid in aqueous solutions was carried out as follows...

Studies on the kinetics of apatite dissolution in sulfuric acid have shown that the formation of films of insoluble compounds on the surface of the solid phase makes it difficult for solvent to access it and leads to a slowdown and even complete cessation of the dissolution process. In the concentration range of 16-25 n. H2SO4, the dissolution reaction slows down sharply. At concentrations above 25 n., apatite dissolves quickly. This is due to the different physical structure of the calcium sulfate film, which depends on the concentration of the solvent...

Very small amounts of sulfides have to be determined in natural waters, wastewater from processing plants and other enterprises. Evaporation of such solutions often changes their chemical composition and requires a long time...

One of the ways to extract tin from tinplate waste is to dissolve tin in alkaline solutions containing methanitrobenzoic acid, followed by electrolysis. The technological solution is a complex multicomponent system. In addition to free alkali and methanitrobenzoic acid, it may contain stannates and stannites of tin, as well as various nitrobenzoic acid reduction products (azoxy-, azo-, hydrazo- and other compounds). The formation of carbonates is inevitable due to the absorption of carbon dioxide from the air ...

During extraction of non-ferrous metals from dilute solutions with naphthenic acids, salts are formed that are soluble in the organic phase and poorly soluble in water. The solubility of naphthenates in the organic phase is determined both by the nature of the solvent and by the composition of the extracted compound, which usually contains a certain amount of hydrated water ...

The effect of temperature on the distribution of substances in extraction processes has been repeatedly considered. The distribution of coordination-solvated compounds is usually placed in a greater dependence on temperature than the distribution of hydrate-solvates...

Methods of phase chemical analysis of iron ores have not been sufficiently developed. Methods for the separate determination of iron oxides, hydroxides, and silicates have been particularly poorly studied. When studying them, it is possible to apply sample treatment with gaseous hydrogen chloride. Unlike chlorine, a common and well-studied chlorinating agent, hydrogen chloride is not an oxidizer and does not change the iron valence of the initial compounds when they are converted to chlorides...

Due to the success of vacuum metallurgy in the post-war years, the assessment of the applicability of this method to non-ferrous metal sulfides is of undoubted interest. The kinetics of lead and zinc sulfide distillation in vacuum at (10-2) - (10-3) mmHg were studied at the facility and according to the procedure described earlier [4]. Experiments have shown that lead and zinc sulfides are distilled at constant speeds under isothermal conditions...

Extensive experimental material on the kinetics of the pyrrhotite firing process has made it possible to establish the influence of temperature, oxygen concentration, and particle size on the rate of the oxidation process. Oxidative firing of pyrrhotides is a complex physicochemical heterogeneous process accompanied by the formation of gaseous and solid reaction products, which leads to additional resistance to mass transfer caused by the diffusion of oxygen through a porous layer of solid oxides...

When sulfatizing roasting of copper-zinc concentrates and industrial products, it is most difficult to achieve a high degree of zinc sulfatization. When studying the causes of this phenomenon, the main attention should be paid to the kinetics of the zinc sulfate formation reaction...

The possibility of successfully using naphthenic acids for extractive extraction of non-ferrous and rare metals has been established by numerous studies. The widespread industrial use of this extractant from non-ferrous metallurgy is hindered by the unavoidable presence of ferric ions in the initial solutions. To remove these ions, it is proposed to use other extractants (for example, fatty acids) or hydrolytic precipitation, which undoubtedly complicates the technological process...

The distribution of the extracted substance between the aqueous and organic phases depends on the nature of the diluent used. If kerosene or individual alkanes are used as a diluent, i.e. compounds that are slightly polar and do not have the ability to form donor-acceptor bonds, then their interaction with tributyl phosphate (TBP) and solvate is apparently limited by the occurrence of dispersion forces without the formation of molecular compounds with dissolved substances. In such systems, limited solubility of solvates of extracted compounds is very often observed...

Molybdenum and tungsten can be extracted with alkylamines from acidic solutions obtained during the chemical refinement of scheelite concentrate at the Tyrnyauz Processing Plant. These solutions contain 5-8 g/l of molybdenum and tungsten. Each is present in both oxidized and reduced forms. The solution also contains significant amounts of phosphorus and silicon. Apparently, molybdenum and tungsten are found in these solutions in the form of phosphoric and silicic heteropoly acids, since these metals are excellently extracted by solutions of amines in nonpolar diluents. To determine the state of molybdenum and tungsten in these solutions, the behavior of metals during extraction by their amines from hydrochloric acid solutions in the presence of phosphorus and silicon in a wide range of hydrochloric acid concentrations was studied...

Magnesium ions, along with other unavoidable impurities, are usually contained in solutions obtained during the hydro-metallurgical conversion of ore raw materials and in the aqueous part of the flotation pulp. It is of interest to clarify the composition and properties of compounds formed by magnesium ions with naphthenic acid, the possibility of using it for extraction of non-ferrous metals from solutions and flotation of some non-sulfide minerals has been established by many studies...

The flotation capacity of a mineral is influenced by the electrical characteristic of the boundary layer in the mineral-solution system. Therefore, it is important to correctly determine the zero charge point, which characterizes the absence of a double electric layer. It can be found by measuring the capacity of this layer ...

Currently, methods of precipitation of dissolved substances by various precipitators are most widely used for wastewater treatment of mining and metallurgical enterprises, with the associated extraction of metals contained in them. However, bulky equipment for settling, filtration, or centrifugation limits the use of these time-consuming methods. The use of ion-exchange resins, taking into account the solid phase in wastewater, is also not always economically justified. The method of liquid extraction from very dilute solutions is associated with significant losses of extractant per unit of extracted metal caused by the solubility of the extractant in the aqueous phase...

The harmful effect of fine powders on the flotation of mineral grains is due to the absorption of some reagents, slurry coatings on the surfaces of minerals and air bubbles, changes in the viscosity of the pulp, increased foam stability, etc.

In copper-nickel ores, some of the nickel isomorphically bound to some silicates floats very poorly. At the same time, the easy acid decomposition of nickel silicates indicates the possibility of using the Mostovich method for certain difficult-to-enrich intermediate enrichment products or substandard concentrates with a high content of nickel silicate. In order to judge the possibility of practical and economically advantageous application of the proposed combined method of processing nickel industrial products, it was necessary to establish the conditions for flotation of cement nickel, ensuring high results in this operation...

Upper purging of metallurgical melts with gaseous agents is currently being successfully used in ferrous metallurgy and is beginning to gain recognition in non-ferrous metallurgy, where the nozzle arrangement inclined to the surface of the bath is most promising for such units...