RU2368689C2 - Method of receiving of vanadium-bearing alloys and ligatures - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: in method in the capacity of charge it is used vanadium-bearing wastes and lime, herewith in oxidising area it is implemented separation of metal from vanadium-bearing melted slag with periodic or continuous discharge of it from furnace. It is implemented reduction of vanadium oxides from melted slag in reducing zone by introduction into melt of silicon-bearing alloy with acceptable content of aluminium 2-15%, taken in amount for 2-50% more than stoichiometrically necessary for reduction vanadium oxides.

EFFECT: invention provides increasing of vanadium concentration in alloy, reducing of power inputs, improving of ecological situation.

2 ex, 2 tbl

Description

The invention relates to the field of ferrous and non-ferrous metallurgy, and more particularly to the production of vanadium-containing alloys and alloys from slags, sludges, dusts and other vanadium compounds.

Due to the low content of vanadium in ores, the technology of their processing is a complex technological process, consisting of a combination of a number of metallurgical and chemical processes.

A known method of producing ferrovanadium, consisting of the preparation of a mixture, which includes vanadium oxides, lime, ferrosilicon and slag, melting, recovery, refining, the release of finished smelting products from the furnace and casting into molds (Ryss M.A. Production of ferroalloys. - M .: Metallurgy, 1975, p. 281-292).

A feature of the known method for producing ferrovanadium is that the melting consists of two periods: recovery and refining. In the first period, vanadium is reduced from vanadium oxides under conditions of a significant excess of a reducing agent — ferrosilicon and high slag basicity. As a result, we obtain an alloy with a vanadium content of 25-30%, silicon - 21-23%, carbon - 0.3-0.5% and slag with a vanadium content of less than 0.35%, the slag is released, cooled and sent to the dump. In the second period, the alloy is enriched with vanadium by refining it from silicon with vanadium oxides, which are loaded into the furnace with lime. When the silicon concentration in ferrovanadium reaches 9-12%, the slag is discharged and dumped, and a new portion containing a mixture of vanadium oxides and lime is loaded onto liquid ferrovanadium, and the metal continues to be refined to a silicon content of 1.5-2%. The resulting alloys contain 40-45% vanadium, 1.2-1.4% manganese, 0.08% phosphorus and refining slag with a vanadium content of 6-12%. It is returned to the electric furnace on the next heat during the first period. For one basic ton of ferrovanadium (40% vanadium), 710 kg of V ₂ O ₅ (100%), 425 kg of ferrosilicon, 75 kg of aluminum, 1350 kg of lime, 300 kg of iron trimmings and about 1500-1800 kWh of electricity are consumed.

The disadvantages of this method is:

- high power consumption;

- the difficulty of obtaining a stable alloy composition;

- low productivity of the furnace unit due to the need for recovery and refining processes in one unit.

It is known that in recent years, converter slag is used directly for smelting ferrovanadium, bypassing the stage of chemical isolation of pure vanadium oxide from it.

Vanadium slag is a slag metal conglomerate with a ratio of metal and slag phases of 30-80% and 20-70%, respectively.

The composition of the slag phase: 17-24% V ₂ O ₅ ; 2.5-3.0 Cr ₂ O ₃ ; 17-20% SiO ₂ ; 7-11% MnO; 8-12% Al ₂ O ₃ ; 6-9% TiO ₂ ; 0.5-2% CaO; 5-8% MgO; 35-49% Fe _total

The composition of the metal phase: 3% C; 0.02-0.06% V; traces of other elements, the base is Fe.

A known method of producing a ferroalloy, including filling the mixture, melting the vanadium-containing mixture together with a reducing agent in an electric furnace and releasing the melts into the ladle. In order to reduce harmful impurities in the alloy, sulfates of alkali and alkaline earth metals are introduced into an electric furnace heated to 1200-1700 ° C before filling the charge, then they are coated with coke at a certain weight ratio (Author's certificate of the USSR No. 589273, class C22C 33/04, priority from 09.09.1976, publ. 01/18/78).

The disadvantages of the method are:

- low productivity of the electric furnace unit;

- high power consumption;

- significant losses of vanadium with slag;

- environmental degradation.

A known method of producing ferrovanadium, consisting of preparing a vanadium-containing melt in an electric furnace, releasing it into a ladle at a temperature of 1400-1550 C and feeding lime, iron and liquid ferrosilicon to the ladle (Author's certificate of the USSR No. 258348, class C22C 38/12, stated 07.16.76, publ. 25.12.77).

The disadvantages of the method are:

- the need to have another electric furnace to obtain liquid ferrosilicon;

- unstable heat balance of the heat;

- the difficulty of regulating the composition of ferrovanadium in the bucket.

The closest in technical essence, methods and achieved effect is a method of processing raw materials containing non-ferrous metals and iron (RF Patent No. 2194781, priority dated November 28, 2000, publ. December 20, 2002, bulletin No. 35). It is accepted by us as a prototype.

The method includes feeding a mixture consisting of feed ore, fluxes, carbon-containing material and oxygen-containing blast into the oxidizing zone of a two-zone furnace to a slag melt, melting the mixture to produce a melt, which enters the reduction zone, which additionally contains carbon-containing material in an oxygen-containing blast, and the amount carbon-containing material and oxygen-containing blast in the oxidation zone give exactly so much that the carbon carbon burned completely, and its amount in the reduction zone is supported in order to completely transfer vanadium oxides to the metal phase and compensate for heat loss. In this case, the ratio of the specific consumption of carbon-containing material per ton of recoverable metal in the oxidation and reduction zones is maintained within the range of 0.3-2.5, and the ratio of the specific consumption of oxygen in these zones is within the range of 0.7-3.0.

The disadvantages of this method are:

- the impossibility of its use for raw materials containing a large quantity of a metal phase, for example, converter slags;

- low productivity of the unit;

- high concentration of iron (oxide and metal) in the melt.

The aim of the present invention are:

- increasing the concentration of vanadium in the alloy upon receipt of it from vanadium slags;

- reduction of energy costs;

- productivity increase;

- improvement of the environmental situation.

The goal is achieved in that:

- metal inclusions present in vanadium slag are melted in the oxidation zone of the furnace and are separated from the slag melt;

- metal is periodically or continuously released from the oxidation zone;

- a silicon-containing material is used as a reducing agent, the composition of which may include: aluminum in an amount of 2-15% and impurities - magnesium, calcium and other metals, the thermodynamic strength of which is higher than that of silicon dioxide;

- silicon-containing alloy is taken in an amount of 2-50% more stoichiometrically necessary for the reduction of vanadium oxides

The basis of the proposed method are the following processes:

- in the oxidation zone: C + 2O ₂ = 2CO ₂ + Q; V ₂ O ₃ + O ₂ = V ₂ O ₅ ;

- in the reduction zone: 2 / 4V ₂ O ₅ + Si = 4 / 5V + SiO ₂ .

In the presence of calcium oxide, the last reaction takes the form: 2 / 5V ₂ O ₅ + Si + 2CaO = 4 / 5V + 2CaO * SiO ₂ .

Coals are used as carbon-containing material, oxygen-containing blast is oxygen-enriched air, and ferrosilicon with a silicon content of at least 65% is used as a reducing agent.

The amount of silicon-containing material is taken from the calculation to ensure the complete reduction of vanadium oxides from the melt and some of its final content in ferrovanadium (at the request of the Customer). When its content in the charge is less than 2%, vanadium extraction is reduced, and when it is introduced in the range of 2 to 50%, not only complete reduction of vanadium oxides is achieved, but also the production of silicon-vanadium alloys, a higher concentration of silicon-containing material (more than 50%) is not economically justified .

The introduction of a certain amount of aluminum into the mixture provides an improvement in the kinetic and thermodynamic conditions for the reduction of oxides and the production of slag with a reduced viscosity.

The following are examples of the invention, not excluding others in the scope of the claims.

Example 1

The mixture, consisting of 1000 kg of converter slag and 400 kg of lime, was thoroughly mixed and portioned loaded into a furnace heated to 1350 ° C (oxidation zone). The mixture was further heated by burning coal in a stream of oxygen enriched air. Upon reaching a temperature in the oxidation zone of 1650 ° C, without interrupting the charge loading, the pulmonary opening was opened and the metal accumulated on the bottom of the furnace was released. After closing the notch, the accumulated melt began to go into the reduction zone, where FS75 grade ferrosilicon (170 kg) and lime (400 kg) were continuously charged at a certain speed. The furnace worked for 3 hours. Smelted 1000 kg of converter slag, 170 kg of ferrosilicon and 800 kg of lime. Received pig iron 155 kg (from the oxidation zone) and ferrovanadium 320-350 (from the reduction zone). Table 1 presents the results of a chemical analysis of metal samples from the reduction zone taken during the experiments.

Table 1 Experience number The composition of the charge of the oxidation zone, kg The composition of the charge recovery zone, kg The composition of the metal recovery zone, wt.% Note slag lime FS75 lime vanadium manganese chromium silicon one one hundred 40 fifteen thirty 23.5 10.7 2.0 0.5 In experiment 1, the content of FS75 in the charge is less than 2% stoichiometry 2 one hundred fifty 17 thirty 24.1 9.9 1.9 2.0 3 one hundred fifty 17 thirty 24.0 9.6 1.9 1.9 four one hundred fifty twenty thirty 24.4 9.0 1.7 3,5 5 one hundred 60 22 thirty 24.0 8.3 1.4 5,6 6 one hundred 60 24 thirty 23.6 7.7 1,2 8.3 7 one hundred 70 26 thirty 22.6 7.1 0.9 9.8

Ferrovanadium obtained by a known technology using the same slag had the composition,%: vanadium - 18-18.6, manganese - 5-6.4, silicon - 7.5-8.6, chromium - 2.9, titanium - 0.14-0.65, aluminum - 0.3-0.5.

The composition of the metal released from the oxidation zone,%: vanadium - 0.02, carbon - 2.73, manganese - 0.34, chromium - 0.13, iron - the rest.

The experiments showed that the proposed technology allows to increase the concentration of vanadium in ferrovanadium by 5-7%, while the extraction of vanadium in the alloy was 85-89%.

Example 2

The experiments were carried out according to the same procedure; in the charge, ferrosilicon was partially replaced by aluminum; in some experiments, in order to obtain manganese-vanadium ligatures, dump slag of metallic manganese composition was introduced into the charge,%: MnO - 22.6; CaO - 42.1; SiO2 33.6; MgO - 4.4; Al ₂ O ₃ - 2.2.

The results of the experiments are presented in table 2.

table 2 Experience number The composition of the charge of the oxidation zone, kg The composition of the charge recovery zone, kg The composition of the metal recovery zone, wt.% Note slag lime FS 75 lime Al Mn slag vanadium manganese chromium silicon 8 one hundred fifty 16 thirty 3 - 24.6 9.8 1.8 1.8 9 one hundred fifty fourteen thirty 5 25.1 9.8 1.8 1.4 10 one hundred fifty 5 thirty eighteen 25.3 9.3 1.7 0.9 eleven one hundred fifty 17 thirty - twenty 20,2 15,2 1,1 0.9 12 one hundred fifty 17 thirty - thirty 18.6 20,4 0.9 1,0 13 one hundred fifty twenty thirty - thirty 18,4 25.7 0.6 1,2 fourteen one hundred fifty twenty thirty - 40 15.3 32,4 0.4 1.4

The metal composition of the oxidation zone has not changed. An analysis of the experiments showed that the introduction of waste slag, in particular slag metal manganese, allows to obtain manganese-vanadium alloys of a given composition with almost complete recovery of manganese and vanadium.

The present invention can be implemented at metallurgical enterprises where converter vanadium-containing slags are produced, there is waste in the form of dust from furnaces and converters, for example, the Nizhny Tagil Metallurgical Plant.

The proposed technology for the redistribution of vanadium-containing slag is characterized by the absence of toxic substances in the exhaust gases, a high level of mechanization and automation; carried out using high-performance equipment and instrumentation.

The invention can also be used for processing other metal-containing wastes, in particular, from the production of nickel, chromium, manganese, added to the main charge of the oxidative and / or recovery period of the smelting.

The economic effect of the implementation of the invention consists of saving energy resources, increasing furnace productivity and simplifying technology and reducing costs for environmentally harmful emissions.

Claims (1)

A method of producing vanadium-containing alloys and ligatures, including preparing the charge, continuously feeding it into the oxidizing zone of the furnace, melting with a mixture of carbon-containing material in an oxygen-containing blast, taken in a ratio that ensures complete combustion of carbon in the oxidizing zone, obtaining slag metal, reducing its oxides in the reduction zone, characterized in that vanadium-containing waste and lime are used as a charge, while metal is separated from the van in the oxidation zone of di-containing slag melt with periodic or continuous discharge from the furnace, vanadium oxides are reduced from the slag melt in the reduction zone by introducing into the melt a silicon-containing alloy with an allowable aluminum content of 2-15%, taken in an amount 2-50% more stoichiometrically necessary for oxide reduction vanadium.