Vol 54 Iss. 3

Hydroxamic acids have been recommended for wide use as reagents for quantitative and qualitative analysis of metals, their extraction separation, and as collectors in the processes of flotation beneficiation of ores of rare and non-ferrous metals. Owing to the simple technology of synthesis of alkylhydroxamic acids using aqueous solutions of hydroxylamine sulfate, the reagent IM-50, consisting of hydroxamic acids of the C₇–C₉ fraction or their sodium salts, has found application in concentration plants of the USSR. Studies of the effect of hydroxamic acids during flotation have shown that their interaction with iron ions present in the pulp volume and on the surface of minerals has a substantial and sometimes decisive effect on the results of beneficiation.

Carboxymethylcellulose (CMC) is a highly effective high-molecular-weight flotation depressant. The features of the depressing and coagulating effect on flotation-active silicates have ensured the use of CMC at all copper-nickel concentration plants in the Northwest of the USSR.

Zincate technology attracts the attention of researchers in the beneficiation of polymetallic ores. Using zincate, positive results have been obtained in the beneficiation of lead-zinc ores. However, sometimes experimenters fail to synthesize the reagent correctly, with all the resulting consequences. To avoid such cases, additional information on the synthesis and use of zincate is advisable.

It is advisable to perform a thermodynamic assessment of sulfatizing roasting of sulfide materials on the basis of an analysis of the equilibria in the Me-S-O system. The basic roasting reactions of simple sulfides may generally be represented by the following equations. …

Sulfatization of zinc, copper, and cobalt oxides was performed on a fluidized bed unit at a conventional normal gas mixture velocity (air and SO₂) of 0.15 nm/s. The process was controlled by analysis of the residue. In special experiments, before the gas mixture entered the reactor, part of the sulfur dioxide was oxidized to sulfur trioxide on a vanadium catalyst. The object of the study was zinc and copper oxides of reagent grade (KhCh) and cobaltosic oxide obtained by calcining cobalt oxide of reagent grade at 700°C. The particle-size class of the material was 0.17 + 0.14 mm. The solid products of the process were analyzed by infrared spectroscopy and X-ray diffraction.

Double sulfates of non-ferrous metals are formed during sulfatizing roasting of sulfide materials in the presence of sodium sulfate. The thermochemical stability of double sulfates has not been studied.

Despite significant advances achieved in the development of methods for selective chlorination and chloride volatilization of materials containing nickel, cobalt and copper, iron chlorides remain an indispensable component of both the gas phase and the condensate. This indicates the possibility of interaction of gaseous ferric chloride with oxides of non-ferrous metals in the chlorination zone and with oxygen in the condensation system. As a result of the latter process, iron is converted from gaseous chloride to solid oxide, which improves the selectivity of the condensate, and the released chlorine can be returned to the chloride volatilization process. The present work is devoted to the study of some regularities of these processes.

Laboratory and enlarged-laboratory studies of the process of chloride volatilization of cinders from pyrite concentrates have shown the effectiveness of this method for processing this type of raw material. One of the unresolved problems associated with the industrial implementation of this process is the issue of furnace heating.

The continuous conversion process being developed by the Leningrad Mining Institute together with the Gipronickel Institute is based on top blowing of matte melts in a stationary unit.

The process of continuous conversion of mattes with top blast supply provides for the presence of a slag depletion chamber in the unit, in which the primary slag formed in the blowing part of the continuous converter is treated for depletion.

Heat transfer in a converter bath is a complex and still insufficiently studied process. A spherical sensor can be used to study heat transfer in the converter bath. A methodology for investigating the heat transfer process between a spherical sensor and the melt of a converter bath using an analog computer (AVM) is proposed below.

Top blowing of a liquid or melt with various gaseous agents is associated in most cases with both physical and chemical interaction of the phases. In recent years, a number of papers have appeared dealing with the physical interaction of phases. There are relatively few studies on the chemical interaction of phases under top-blowing conditions. However, they are of interest for a number of non-ferrous metallurgy processes (conversion, refining of melts, etc.).

Melts containing titanium and zirconium chlorides are used in the production of refractory metals and their alloys. In particular, the electrolytic process for producing titanium-zirconium powders was investigated. An equimolecular melt of NaCl and KCl salts containing di- and trivalent titanium chlorides and zirconium tetrachloride was used as the electrolyte. The content of dissolved zirconium in the electrolyte did not exceed 0.8%.

The article presents the results of laboratory studies of the process for producing unalloyed titanium powders by sodium-thermal reduction of lower titanium chlorides from melts.

Melts containing chlorides of certain metals have found wide application in chemistry and metallurgy. The production and refining of titanium, zirconium, vanadium and other metals is based on the use of the properties of such melts. In many cases, melts are used under conditions of dynamic interaction with the structural materials of process equipment.

Sulfide-alkaline electrolytes were studied for the cathodic deposition of tin, antimony, mercury, indium, and tellurium. Electrolysis of sulfide-alkaline solutions of antimony has found industrial application, and a large number of works have been devoted to its study. There is insufficient information in the literature on changes in the ionic composition of the electrolyte during the electrolysis of thio-salt solutions and its relationship to current efficiency. An attempt to study this issue with reference to tellurium solutions is described in this report. The electrolysis of such solutions was first considered earlier.

One of the stages in the tellurium production scheme at the Pyshma Copper Electrolysis Plant is the electrolytic deposition of tellurium concentrate from solutions from aqueous leaching of soda-tellurium slag. Stainless steel grade 1X18N9T is used as anodes, which have proven themselves in alkaline media. However, during industrial operation of the electrolytic unit, corrosion of the anodes was revealed, which led to a violation of the electrolysis regime.

Electrolytic deposition of tin from alkaline solutions is widely used in industry in the processing of secondary raw materials. However, the cathodic reactions occurring in this process have not been sufficiently studied, which excludes clear recommendations on the parameters of electrolysis (electrolyte composition, current density, and the relationship between these indicators). The present work aims to fill this gap.

Heterogeneous equilibria involving metal carboxylates have been studied in sufficient detail. Based on the results of these studies, an extraction series of elements has been compiled, which makes it possible to predict the direction of possible ion-exchange reactions. At the same time, the kinetics of heterogeneous processes of this kind have not been studied, which hinders the elucidation of the mechanism of the reactions and the correct choice of equipment for carrying out the process.

The presence of large amounts of iron in ores of non-ferrous metals, and consequently in the solutions obtained during their processing, complicates the technological process of extraction of these metals with naphthenic acids. Thus, the presence of ferrous iron naphthenate in the extract hinders the stripping of nickel and cobalt from the organic phase. In this regard, it is of interest to study the composition and properties of this salt.

Ion exchange is widely used in hydrometallurgy, especially in the extraction of rare earth or ferrous elements from solutions. The field of application of ion exchangers in non-ferrous metallurgy can be significantly expanded, firstly, if sufficiently cheap and high-capacity domestic ion exchangers are available, and secondly, if the mechanism of the ion exchange process is known, which makes it possible to obtain, analyze and use appropriate kinetic equations. For a number of cations (copper, zinc, etc.), the domestic cation exchanger KU-2 can be confidently attributed to the number of ion exchangers meeting the first requirement. Not having selectivity with respect to ions of a certain type in the combined presence of several ions, the KU-2 cation exchanger turns out to be quite high-capacity with respect to each of the cations individually.

When selenium is extracted from copper electrolysis slimes, soda-alkaline selenium-containing solutions are usually obtained. In addition to the main component, selenium, they contain impurities: tellurium, various heavy metals, silver, iron, arsenic, mercury, etc. The main impurity is tellurium, which is precipitated from the solution as hydrated dioxide by neutralization to pH = 5–6. At the same time, it is very important to remove other impurities, the ingress of which into selenium reduces its quality.

The distribution of the extracted substance between the aqueous and organic phases depends, among other factors, on the diluent chosen. It has already been noted in many studies that dilution with alkanes usually increases the extraction capacity of TBP.

For hydrometallurgical processes occurring in alkaline media, the solubility, determined by the instability constants of the corresponding hydroxo complexes, is essential.

Tellurium in the tetravalent state in hydrochloric acid solutions forms moderately strong complexes absorbing in the ultraviolet region. The spectrum consists of a number of bands characterizing various tellurium-containing particles. Solutions with a high HCl content (5–10 mol/L) and a low tellurium content (10⁻⁶–10⁻³ mol/L) possess buffering properties. The proportion of different forms of tellurium-containing particles depends little on the total concentration of tellurium and is determined by the concentration of hydrochloric acid.

The OP-4 reagent is an oxyethylated alkylphenol with an average degree of oxyethylation equal to 4, and is used in ore flotation. Various methods have been proposed for the quantitative determination of such surfactants. However, almost all of them were used for the analysis of either pure surfactants or relatively concentrated solutions. In this case, surfactants such as OP-7 and OP-10, which are well soluble in water and have a greater degree of oxyethylation, were usually determined, unlike OP-4.

The widespread use of various substances in the flotation of minerals pollutes wastewater, which, poisoning water bodies, poses a threat to the normal existence of wildlife.

In theoretical studies of various processes in the metallurgical and beneficiation industries (sintering, leaching, grinding, flotation, etc.), in some cases, important information about the patterns of the phenomena occurring is provided by the values of the specific surface area of the corresponding solid phases (sinters, slurries, charges, pure minerals, etc.).