RU2097440C1 - Method of preparing ferrovanadium with low content of manganese - Google Patents

Abstract

FIELD: metallurgy. SUBSTANCE: to prepare ferrovanadium with low manganese content, charge of at least one smelting period is supplemented by sulfur-containing iron compounds, in particular, pyrite concentrate. EFFECT: reduced manganese content. 2 cl, 1 tbl

Description

 The invention relates to the field of metallurgy, and in particular to the technology of production of ferrovanadium, and can be carried out at the enterprises of ferrous metallurgy.

A known method of producing ferrovanadium in an electric furnace by the silicoaluminothermic method, in which ferrovanadium is obtained by reducing vanadium oxides entering the charge from technical vanadium pentoxide and vanadium converter slag, ferrosilicon silicon and metal aluminum. The process of reduction of vanadium oxides is carried out in two periods with downloading slag. At the final stage of production of ferrovanadium, the metal is subjected to refining with technical vanadium pentoxide — a refining period is carried out. Due to the high content of vanadium pentoxide (9-18%) in it, the slag of the refining period rafslag is returned to the furnace for the first period of the next smelting [1]
To obtain ferrovanadium with a manganese content of less than 4% (grade FVD-40-U-0.75; FVD-50-U-0.5) from vanadium materials, vanadium converter slag, which is the main source of manganese in ferrovanadium, must be completely eliminated to obtain this method. and as a source of vanadium use only technical vanadium pentoxide, which significantly increases the cost of the finished ferrovanadium. But even the complete exclusion of vanadium converter slag from the charge materials does not guarantee the mandatory receipt of the specified manganese content in the finished ferroalloy (less than 4%). About 20% of the low-manganese ferrovanadium melts is converted to a lower grade due to the high, more than 4% manganese content in the alloy, which leads to a reduction in the selling price by 300-500 rubles. for every ton of ferroalloy.

The closest technical solution is a method of producing ferrovanadium, including recovery and refining periods, the release of ferrovanadium from the furnace and its casting [2]
The disadvantage of this method is the need for additional operations on guidance, aging and downloading sulfide slag, which increases the duration of the smelting, thereby reducing the performance of the melting unit. In addition, in the process of smelting ferrovanadium, an expensive refining reagent sodium sulfide is used.

 The purpose of the invention is to reduce the duration of the smelting period of ferrovanadium with a low content of manganese and reduce the cost of its production.

 The problem is solved in that in the method of producing ferrovanadium with a low manganese content, including recovery and refining periods, the release of ferrovanadium from the furnace and its casting, sulfur-containing iron compounds are additionally fed into the charge of at least one melting period.

 In this case, a pyrite concentrate is used as a sulfur-containing iron compound.

The presence of sulfur-containing iron compounds in the charge materials of ferrovanadium smelting leads to the following chemical reactions:
2 [Mn] + (FeS ₂ ) = 2 (MnS) + Fe (1)
[Mn] + (FeS) = (MnS) + Fe (2)
Due to the stronger chemical affinity of manganese for sulfur than that of vanadium and iron, the equilibrium of reactions (1) and (2) under conditions of smelting of ferrovanadium is biased towards the formation of manganese sulfide. The manganese sulfides that form are associated with the slag phase and are removed from the system under consideration with drain slags. Thus, the presence of sulfur-containing iron compounds in the charge materials of at least one of the periods of smelting of ferrovanadium allows selective sulfidization of manganese in the Fe-Mn-V system, which can significantly increase the amount of manganese carried away with waste slag and does not lead to vanadium losses.

 The supply of sulfur-containing iron compounds directly with charge materials does not increase the duration of ferrovanadium melting. In addition, the cost of pyrite concentrate is 30-40 times less than the cost of sodium sulfide, which will reduce the cost of smelted low manganese ferrovanadium.

 The proposed method for producing low-manganese ferrovanadium was carried out in a three-ton arc furnace DSP-3A with magnesite lining in the conditions of the electrometallurgical department of the ferroalloy production of OA of the Chusovsky Metallurgical Plant.

 First, the charge of the first recovery period is loaded and melted into the furnace, to which pyrite concentrate is additionally added. Pyrite concentrate is fed through the filling funnel using a rotary hopper mixed with lime supplied. After downloading the slag of the first period, the charge is loaded and subsequently melted in the second recovery period, to which, if necessary, pyrite concentrate is also additionally supplied. After the charge of the second recovery period is melted, drain slag is downloaded and the charge of the refining period is loaded, to which, if necessary, pyrite concentrate is fed. After melting the charge of the refining period, the refining slag is drained, the ferrovanadium is released and cast.

 The amount of pyrite concentrate supplied during each melting period is determined depending on the lost wax grade of ferrovanadium, the consumption of vanadium converter slag and raf slag in the charge.

 The composition of the blends by periods, the consumption of pyrite concentrate, as well as the results of melting by the known and proposed methods are shown in the table.

 As can be seen from the table, the additional supply of pyrite concentrate to the charge of at least one ferrovanadium melting period allows one to obtain low manganese (containing less than 4% Mn) ferrovanadium grades with a shorter melting time and lower cost of smelted ferroalloy.

Claims (2)

 1. The method of producing ferrovanadium with a low manganese content, including recovery and refining periods, the release of ferrovanadium from the furnace and its casting, characterized in that sulfur-containing iron compounds are additionally fed into the charge of at least one melting period.  2. The method according to p. 1, characterized in that the pyrite concentrate is used as a sulfur-containing iron compound.

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