Vol 46 Iss. 3

This paper proposes a method for calculating the expected classification results using the example of classification of quartz suspension in a hydrocyclone. The classification results are evaluated by the recovery of narrow size fractions in the classification products. For this purpose, feed, overflow and underflow are subjected to size analyses, on the basis of which the recoveries of narrow fractions are calculated.

The advantage of ammonia leaching of cobalt-bearing ores after reduction roasting is the possibility of almost complete separation of iron. However, the concentration of cobalt in solution after ammonia leaching of low-grade ores is very low, which causes difficulties in their further processing. Precipitation of cobalt from ammonia solution in the form of sulfide. The solubility of cobalt sulfide in ammonia solutions is negligibly small, so when sulfides Na₂S, (NH₄)₂S are introduced into the solution, cobalt ammine complexes are destroyed and metal sulfide is precipitated.

For over 40 years, cyanide technology has been used in the practice of beneficiation of polymetallic ores by flotation. However, this technology often causes significant difficulties due to its lack of perfection, which, to some extent, hinders the progress of domestic industry in the field of non-ferrous metallurgy. The present paper is devoted to the issue of development and research of a new, more effective technology.

In the practice of ore dressing for depression of sphalerite flotation, ZnSO₄ or FeSO₄ in combinations with KCN, Na₂CO₃, Ca(OH)₂ in quantities ensuring the formation of a precipitate in the pulp, consisting of one or more compounds are used. P. A. Rebinder and coworkers, in a study of the contact angle of water on polished sections of sphalerite, did not detect a depressing effect of zinc sulfate on the surface of sphalerite, whether unactivated or pre-activated with copper ions. Currently, a number of authors believe that a possible cause of depression of sphalerite flotation is the adhesion of precipitates to the surface of mineral particles.

For flotation of iron ores by fatty acids (tall oil) in the conditions of the Krivoy Rog basin, the influence of salt composition of water on flotation is of particular importance, as the technical water of enrichment plants is diverse in its composition and has a high hardness. Changing the composition of water under the action of lime, soda and caustic soda amounts to its softening. The pH required for sufficiently complete softening is determined, according to I.E. Apeltsin, depending on the initial hardness, total salinity, temperature, time, and final hardness. Fig. 1 shows that by the joint action of lime with soda and caustic soda with soda, the hardness of the technical water of CGOK is reduced.

Available recommendations on the methodology of determining the weight of samples for sieve analysis are not always justified and controversial. In theoretical studies on this issue, some methodological provisions are not convincing enough. In particular, the fundamental principle of determining the weight of the sample, which states: "It is required to determine the weight of the sample, the sieve analysis of which with a probability, however close to one, will give a result dwm, lying within (1 ± 0.02) Dwm. Since the sample is intended to determine in bulk material quantitative ratios of grains of different sizes, it is necessary that the number of grains in each class of sample material corresponds to their actual numerical proportion in the sample mass, which should be the basis for calculating the weight of the sample.

For a more detailed study of the process of processing of cinders of pyrite concentrates by chloride distillation method, the kinetics of transition to the gas phase of cobalt and iron were studied and the effect of the gas medium composition on the sublimation of metals. Experiments were carried out on the cinder with a grain size of -0.25+0.16 mm, containing 0.5% sulfur. X‑ray diffraction analysis showed that almost all the iron in the cinder is represented by oxide. The installation for chlorination experiments, described in detail by A. K. Orlov and I. N. Piskunov [1963 a, b], was supplemented only by a furnace for purification of nitrogen from oxygen with the help of hopcalite mixture and a loading device, allowing the introduction of a sample of cinders into the reaction space after reaching the operating temperature and the specified composition of the gas mixture (10‑12 min to displace air from the system after heating the reactor).

The most effective method of decomposing pyrite concentrates is known to be sulfatizing roasting. A great contribution to the understanding of sulfatizing roasting processes was made by the Soviet school of metallurgists. However, many issues of sulfatizing roasting remain unexplained to this day.

The dissociation of cobalt sulfate and its interaction with iron sulfide are important for understanding the process of sulfatizing roasting of cobalt-bearing pyrite concentrates. The dissociation of cobalt sulfate in a nitrogen atmosphere in a fixed bed begins at 730°C, in an atmosphere of air and oxygen, respectively, 15 and 30°C higher. According to A. V. Vanyukov, the beginning of thermal decomposition is observed at 692 and at 720‑770 °C, and proceeds actively. According to other data, the decomposition of cobalt sulfate at 2‑3 hour heating in a current of air occurs already at 600 °C. Information on the kinetics of dissociation of cobalt sulfate in the fluidized bed in the literature is absent.

At the nickel plant of the Republic of Cuba, at industrial and pilot plants in a number of countries, reduction roasting of oxidized nickel ore before ammonia leaching is carried out in multi-hearth furnaces with mechanical raking. The specific productivity of these furnaces is relatively low. Experience accumulated in non-ferrous metallurgy on fluidized bed roasting, as well as the results of studies of magnetizing fluidized bed roasting in ferrous metallurgy suggest that a similar process can be reduced oxidized nickel ore before ammonia leaching. The first exploratory experiments in this direction were carried out at a large laboratory installation at the Institute of Petroleum of the AS USSR.

The vacuum method is one of the new and promising ways of processing copper-zinc intermediate products. It allows increasing the recovery of valuable elements by reducing their losses during processing in hermetically sealed apparatuses. The possibility of widespread implementation of this method is provided by the modern level of development of vacuum technology.

In the process of fuming zinc, lead, tin and rare metals contained in molten slag are extracted into fumes. The process was first carried out in 1927 and has not changed significantly since then. There are currently about 10 fuming plants in operation around the world. All of them consist of a caissonized shaft furnace in which a suspension of coal dust in the air is blown through a layer of molten slag. The coal dust is the fuel by combustion of which the required temperature of the slag is maintained. As a rule, the excess air to coal dust ratio in the blast is about 0.7. Partial combustion of coal creates a reducing atmosphere in the furnace. By varying the air-to-coal ratio, the process is controlled, the amount of heat generated and the degree of slag reduction are varied.

The essence of metallurgical furnace operation. Modern metallurgical furnaces are most properly regarded as complex physicochemical units, in which a whole complex of processes diverse in nature occur. If we combine these processes into their most characteristic varieties, we can distinguish the following: technological, heat exchange, energy, movement of gases, movement of materials and products. All of them proceed in the working space in close mutual connection and interdependence and often coincide in their purpose and nature. For example, the technological process of oxidation of sulfides is simultaneously an energetic process, providing the heat release necessary for the furnace operation. The movement of molten slag in ore-thermal electric furnaces is simultaneously a process of convective heat exchange in the bath. The main process among these, of course, is technological, so the basic parameters of metallurgical furnaces and the development of all processes in them should provide optimal flow conditions for the technological process with the best qualitative and quantitative indicators.

The use of material balance equations is the basis of numerous methods of analyzing and calculating metallurgical processes. However, such equations are quite insufficiently applied in the preparation of experimental balances. The present paper deals with the method of obtaining indicators of material distribution in the metallurgical process on the basis of their compositions obtained experimentally. It involves the preparation of balance equations of several chemical elements in the form linking the compositions and quantities of materials, and solving the system of such equations by the usual algebraic methods. A partial variation of such a method was used, for example, by V. A. Bogolyubov. In this case, the task of obtaining a more general formulation is set.

One of the most important tasks of beneficiation engineers and metallurgists is to find better methods of complex utilization of polymetallic ores: lead-copper-zinc and copper-zinc ores containing, in addition to base metals Cu, Pb, Zn, a number of other associated metals – Au, Ag, V, Cd, Se, Te, Sn, Tl, Ge, In, Ni, Co, As, Sb, Hg and others. The value of base metals, including noble metals, contained in the ores is often no more than 50‑70% of the value of all metals in the ores. Conventional methods of beneficiation of most polymetallic ores do not provide rich and pure selective concentrates with sufficiently high recovery of the corresponding metals. The recovery of lead in lead concentrate is 75‑88%, zinc in zinc concentrate 78‑85%, copper in copper concentrate 68‑78%.

The possibility of using naphthenic acids for the extraction of some non-ferrous metals has long been established, but more detailed studies of this extractant have been published only in recent years. Thus, A. Fletcher and his co-workers established the dependence of metal extraction by naphthenic acid solution in kerosene on pH value and showed the possibility of separation of some metals by this method. The research resulted in several patents for the practical separation of metals. This process was applied for the separation of copper and zinc from solutions obtained by leaching of pyrite cinders. The possibility of using naphthenic acids for the extraction of rare and rare earth metals has been investigated.

Naphthenic acids are good extractants for heavy non-ferrous metal ions, with each metal ion being extracted in a specific region of pH values. It has been shown that Cu2+ copper ions begin to be extracted at a pH of 3.2-3.7, depending on the concentration of copper in the aqueous phase, the concentration of naphthenic acid in the organic phase, and the ratio.

The method of separation of zinc and nickel with the help of ionites is based on the different strength of complex ions of these metals in aqueous solution. Thus, at a chlorine ion concentration of 1.5‑2.0 g‑ion/l, zinc forms complex anions, while nickel remains in the form of cations. The different charge sign of nickel and zinc ions in chloride solution can be used for the separation of these metals by sorption of nickel cations by cationites or complex zinc anions by anionites. In this work both variants were investigated. Weakly acidic KB‑4‑P2 in Na‑form and strongly acidic KU‑2 in H‑form served as cationites, strongly basic AB‑17 in chloride form served as anionites.

The issues of electrolytic precipitation of cobalt from concentrated hydrochloric acid solutions (100 g/l of metal and above) are the subject of a considerable amount of research.In the literature there is information about the possibility of obtaining electrolytic cobalt from dilute (20-30 g/l of metal) solutions. However, the data on the technological mode of the process under these conditions are extremely limited, and the quality of the resulting metal is not specified.

In recent years, much research has been carried out on the chromatographic separation of a number of metals based on their ability to form complex compounds in concentrated hydrochloric acid solutions with varying degrees of stability. The process of complexation in the liquid phase is extremely important in the practice of separation of metals close in their properties.

As is known, many objects (sites) of automatic control can be experimentally investigated by applying step or pulse inputs to the object, obtaining respectively the step or pulse response at the output. Determining the dynamic parameters of the object from its pulse response is preferable to the step response, because, firstly, it gives more accurate results and, secondly, conducting an experiment with the impact in the form of a pulse is less disruptive to the normal course of the technological process. When taking the dynamic characteristics by this method, the following is assumed: 1) all disturbing influences during the experiment can be stabilized within certain limits so that their influence on the output parameter can be neglected; 2) the pulse disturbance does not entail significant nonlinear distortions of the transient process.

In the light of the decisions of the September (1965) Plenum of the Central Committee of the CPSU, the establishment of the optimal level of current assets both for the industry as a whole and for individual enterprises of the nickel-cobalt industry is of great importance. In turn, this necessitates the correct determination of the true values of individual categories of current assets, the evaluation of the existing methodology of their accounting and the impact of accounting errors on the economic performance of enterprises. This article is limited to the consideration of these issues with respect to one of the categories of current assets – work in progress.