Preparation of copper-nickel concentrates for electric smelting by means of their agglomerative roasting and oxidative roasting of pyrrhotite concentrates - the main operation of segregation technology of their processing - is insufficiently studied and causes great difficulties ...

The mechanism of converter slag depletion includes the process of enlargement and sedimentation of matte droplets, the efficiency of which depends on the extraction of valuable components ...

In metallurgical and chemical industries reactors with circulation of reactants are widely spread. Application of circulation allows to regulate quite precisely the degree of transformation of reacting substances, to carry out the process with an excessive amount of one of the reagents, which is introduced with the recirculant and reduces the yield of reaction by-products ...

The main directions of technical progress in non-ferrous metallurgy, stipulated by the Directives of the XXIV Congress of the CPSU on the ninth five-year plan for the development of the national economy of the USSR, are: increasing the extraction of metals from ores, improving the comprehensiveness of the use of raw materials, widespread introduction of closed technological schemes with full processing of semi-products.

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.

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.

Metal-oxide electrodes are used to determine the pH of solutions in various technological processes, but the mechanism of their action has not been sufficiently studied to date.

Pyrite concentrates are one of the promising types of raw materials for cobalt production. Sulfatizing roasting is the most widespread in processing of such concentrates. It is established that three periods can be distinguished in the sulfatizing roasting of pyrite concentrate: 1) oxidative; 2) intensive sulfatization; 3) slow sulfatization of metals. The present work aims to determine the main factors affecting the processes in these periods of pyrite concentrate roasting.