EA030653B1 - Method for melting ore minerals containing iron, titanium and vanadium - Google Patents

Abstract

Proposed is a method for melting ore minerals containing iron, titanium and vanadium, initial content of each of said elements being known, in an electric melting furnace (11) provided with a containing body (12) with an inner space disposed around a central axis (X), the containing body being tiltable by rotation in a tilting plane containing the central axis (X). The method comprises the steps of feeding said ore minerals and auxiliary materials into said electric melting furnace (11) with supply of electric power until a steady-state power (Pmax) and a steady-state temperature of at least 1450°C are reached; maintaining said steady-state temperature to obtain, as products of melting of said ore minerals, liquid cast iron (G) containing vanadium, and liquid slag (S) containing titanium oxide, wherein the liquid cast iron (G) contains at least 75% of the known initial quantity of vanadium in initial ore minerals, and the liquid slag (S) contains at least 90% of the known quantity of titanium oxide in initial ore minerals, and wherein titanium oxide content of liquid slag (S) is at least 40% by weight, separate discharge of the liquid slag (S) is performed by tilting the containing body (12) in a first direction, and discharge of the liquid cast iron (G) - by tilting the containing body (12) in a second direction.

Description

The invention relates to a method for melting iron and titanium containing ore minerals, such as ore minerals such as titanomagnetites, titanohematites and others, mostly consisting of iron oxides and titanium oxides, as well as containing vanadium oxides.

The present invention can be used, in particular, in the production of ferrous metallurgy products, in which the production process begins with the mentioned ore minerals containing oxides of iron, titanium and vanadium, and liquid iron with a high content of vanadium and slag with a high content of titanium oxide.

Background of the invention

Industrial methods for extracting titanium and vanadium contained in iron-containing materials are known (see, for example, US Pat. No. 3,929,461).

It is known from practice that iron and titanium along with vanadium can be present in various ore veins as oxides. Ore minerals, consisting mainly of iron oxides and titanium oxides, as well as those containing vanadium oxides, may contain, for example, titanomagnetites, if iron is present in the form of magnetite (Fe ₃ O ₄ ), and titanohematites, if iron is present in the form of hematite (Fe ₂ O ₃ ).

It is also known that there is a need to use these containing iron, titanium and vanadium ore minerals as a raw material for the production of pig iron containing vanadium and slag containing titanium oxide.

It is also known that liquid iron produced by melting such ore minerals can be used as a source for extracting vanadium from it, and liquid slag as a source of titanium oxide extracted from it.

To this end, technologies have been developed for melting such ore minerals using blast furnaces, submerged arc electric melting furnaces or electric melting furnaces with an open liquid bath, in which the ore mineral containing iron and titanium is melted under reducing conditions with the addition of coke.

These known technologies provide for the supply of ore minerals into a smelting furnace after their extraction or preliminary reduction, usually by heating in rotary kilns.

The use of these technologies makes it possible to produce liquid iron, which contains vanadium, possibly the original ore mineral, and slag, which contains titanium oxide, which was present in the original ore mineral. Subsequent processing can be achieved obtaining vanadium from iron and titanium oxide from slag.

For example, if ilmenite is used as an initial ore mineral, which is a mineral belonging to the family of titanohematites, then using known technologies it can be used to produce slag with a high content of titanium oxide, i.e. with a titanium oxide content of over 80%.

Known methods of melting titanatematons have the disadvantage that the working conditions for their implementation do not allow maximizing the extraction of vanadium from liquid iron. In practice, if the content of titanium oxide is extremely high, when operating in moderate reduction conditions, the electrical conductivity of the slag must be limited, so that the content of iron oxide in the slag is more than 5 wt.%. Therefore, in practice, when using these methods, a useful yield of vanadium, i.e. the ratio of the amount of vanadium contained in molten iron to its content in the original ore mineral is below 75%.

As for smelting furnaces, which are usually used for this type of melting, these can be electric furnaces of the two types mentioned above, i.e. submerged arc electric melting furnaces and electric melting furnaces with an open liquid bath, usually of a fixed type, i.e. not tilted, with walls fully lined with heat-resistant material.

There are also known methods for melting titanomagnetites involving the use of blast furnaces or electric fixed-type melting furnaces, i.e. not tilted, with submerged arc or with an open liquid bath, for the production of liquid iron, which is subjected to subsequent processing in order to extract vanadium from it, and slag, which is not subjected to subsequent processing and from which titanium oxide is extracted. In practice, the purpose of these known methods is not to maximize the content of titanium oxide in the slag, which is usually below 40 wt.%, But to reduce the vanadium oxide.

To this end, the above known melting methods involve the use of additionally applied materials, such as limestone and dolomite, with which slag is diluted, lowering the content of titanium oxide in it, and, consequently, lowering its viscosity.

With this solution, sufficient liquid molten slag is obtained, which allows operation at temperatures below 1500 ° C, and, since titanium magnetites used in these methods usually contain vanadium oxide above 1 wt.%, It is possible to obtain a useful vanadium yield above 75%.

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One of the drawbacks of the known melting methods, which involve the melting of such ore minerals in non-tiltable electric melting furnaces with an open liquid bath, is that they do not provide sufficient flexibility in controlling the amount of slag contained in the melting furnace. Slag (as well as liquid iron) is released through a hole made at a given height in the furnace wall, which makes it impossible to maximize slag descent without the risk of releasing part of the liquid iron with it, given that the outlet for liquid iron must be located at a certain height from the interface of the iron and slag.

On the other hand, from the methods of smelting ore minerals containing iron, titanium and vanadium, in order to simultaneously produce slag with a high content of titanium oxide and liquid iron with a high content of vanadium, it is required that upon completion of melting the slag should be lowered as completely as possible. This need is primarily due to the fact that slag itself is a product that can be subjected to subsequent processing, and also, in addition, the aim is to prevent the formation of titanium oxide inside the furnace under reducing conditions (high temperature and high coke content in the bath), which It is necessary to produce high-vanadium iron, so that excessive formation of titanium carbides is prevented, which may cause an excessive increase in the viscosity of the slag.

It is also known that a high content of oxides in ore minerals (after iron oxides) leads to the formation of a significant amount of slag, which can be, indicatively, about 0.5 tons for each ton of liquid iron produced. And with this is connected the need to control the level of slag and its descent.

Another disadvantage of the known non-tiltable smelting furnaces with discharge through the side channels is that they do not provide the ability to effectively and easily control the thickness of the slag layer inside the melting furnace. This contradicts the requirement to control the slag layer thickness in the smelting furnace so that both adequate recovery rate of vanadium oxide present in the slag is ensured under the action of coke introduced into liquid iron, as well as facilitation of melting coke supplied with ore mineral .

Therefore, a disadvantage of the methods described above is also the fact that they have low efficiency and operational flexibility, which is primarily due to the fact that the smelting furnaces used in it are stationary.

This disadvantage is particularly pronounced when the process aims to maximize the selective extraction of vanadium while simultaneously maximizing the titanium oxide content in the slag using the starting material (ore mineral as is or subjected to preliminary reduction), for which the regulation of the slag inside the smelting furnace is particularly important.

To maximize the selective extraction of vanadium oxide using reduction reactions, especially in the case of ore minerals with a low content of vanadium oxide (for example, less than 1 wt.%), It is necessary to work at temperatures above 1450 ° C and with a carburized liquid metal, i.e. with cast iron, the carbon content of which is above 3 wt.%.

In order to maximize the productivity of the smelting furnace, it is also necessary to minimize the amount of slag inside the smelting furnace, so that the ore mineral supplied (as is or subjected to preliminary reduction) to the smelting furnace easily contacts the liquid iron that contains the coke required for the reduction process. .

Minimizing the slag content inside the smelting furnace also meets the requirement of minimizing the average residence time of titanium oxide in the smelting furnace itself and therefore minimizes the formation of titanium carbides, which is due to the high content of titanium oxide and particularly intense reducing conditions. With this solution, the aim is to limit the viscosity of the slag to improve the working conditions of the smelting furnace and increase the recovery efficiency of vanadium oxide, whose recovery rate depends not only on the temperature at which the smelting process takes place, but also on the viscosity of the slag.

One of the disadvantages of melting titanomagnetites in a blast furnace is blockage due to the formation of titanium carbides.

Melting in an electric submerged arc furnace is associated with a disadvantage in that it does not provide the possibility of maximizing vanadium extraction from liquid iron, given the low processing temperature, which slows down the kinetics of chemical reduction, and does not provide sufficient slag flowability, which has a high viscosity due to high content of titanium oxide.

Melting in a non-tilting electric melting furnace with an open liquid bath raises the problem of lack of flexibility in controlling the thickness of the slag layer, in particular, the disadvantage is the impossibility of minimizing the slag from the slag inside the melting furnace. Regulation of the upper part of the slag during the reduction of titanomagnetites is necessary to maximize the reduction of vanadium oxide while minimizing the residence time of the slag inside the melting furnace.

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One of the objectives of the present invention is to improve the method of melting ore minerals containing iron, titanium and vanadium, such as titanomagnetites, so that it can simultaneously produce as liquid iron with a vanadium content above 75% of the total amount of vanadium contained in the original ore minerals, and slag containing titanium oxide above 40 wt.%.

Another objective of the invention is to create a method of melting ore minerals containing iron, titanium and vanadium, which would guarantee the flexibility of work, high productivity, efficiency and controllability of the stages of the melting process.

Another objective of the present invention is to improve the method of melting ore minerals containing iron, titanium and vanadium, so that it provides optimization of both energy consumption and time and cost while ensuring maximum recovery of vanadium oxide and the maximum content of titanium oxide in the slag, so as to make the subsequent processes for the extraction of vanadium from iron and titanium oxide from slag as efficient as possible.

The applicant has developed, tested and implemented the invention to overcome the disadvantages of the prior art and achieve the above and other objectives and advantages.

Brief description of the invention.

The invention is disclosed and characterized in the independent claims, while the dependent claims disclose other characteristics of the invention or variants of the main inventive idea.

In accordance with the aforementioned objectives of the invention, a method of melting ore minerals containing iron, titanium and vanadium is carried out in a smelting furnace having an accommodation capacity, the inner space of which is located around the central axis, and configured to tilt it by turning in a direction transverse to mentioned central axis.

In the proposed method, it is primarily intended to feed the above-mentioned ore materials into said holding capacity of the smelting furnace, to which may be added auxiliary materials, such as reducing agents and / or slagging reagents, with increasing flow rate to achieve a flow rate that ensures steady state operation. , as well as the supply of electrical energy with an increasing flow rate to achieve a flow rate that ensures steady state operation.

The feed rate in the steady state operation depends on the productivity that must be achieved, on the total time of the production cycle required to bring the production of pig iron to the end, i.e. from the time from the end of one release of iron to the end of the next release of iron, and from possible intermediate stages in which the supply of the ore mineral may be less intense than in the steady state operation.

According to the invention, the power consumption in steady-state operation should be such that the temperature maintained at or above 1450 ° C is required to maximize the useful yield of recoverable vanadium and limit the viscosity of the slag due to the high content of titanium oxide it contains.

The power in the steady state operation depends, in relation to inverse proportionality, on the intensity of the supply of the ore mineral supplied to the smelting furnace; The flow rate is calculated as the ratio of the flow to the electrical power consumed.

According to some aspects of the invention, the feed rate of the ore mineral is from about 10 to about 35 kg / (min-MW), preferably from about 15 to about 30 kg / (min-MW).

The feed rate depends on the characteristics of the ore mineral being fed, in particular on the degree of metallization, on the target mass ratio of metallic iron to total iron, on the mass content of carbon, on the supply temperature and on the total mass content of oxides, minus iron oxides.

With an increase in the degree of metallization, carbon content, temperature, as equal factors, there is a decrease in the consumed electrical power, while an increase in the content of oxides causes a corresponding increase in the demand for electrical energy.

Along with the pre-reduced ore mineral, auxiliary materials such as reducing agents and slag-forming materials are fed into the smelting furnace.

It is preferable that such a solution in which coke, used as a reducing agent, has a quality suitable for metallurgical processes, it can be, for example, metallurgical coke.

The above-mentioned slag-forming materials are used to correct the composition of the slag in order to improve its physical properties, in particular, to lower its viscosity.

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As slag-forming materials can be used, for example, limestone, dolomite and materials containing aluminum oxide (Al ₂ O ₃ ) and / or calcium fluoride (CaF ₂ ).

As for the specific consumption of these auxiliary materials, calculated as the mass of auxiliary material supplied during the production cycle, referred to the unit mass of the ore mineral supplied during the production cycle, it depends on the chemical composition of the ore mineral used, in particular on the mass ratio of titanium oxide co all oxides minus iron oxides.

According to the present invention, in order to obtain the required degree of reduction of vanadium and in the case of slag with a mass content of titanium oxide above 40%, the specific consumption of reducing agent reagents is from about 15 to 40 kg / kg, preferably from about 20 to 35 kg / kg, and the specific consumption of slag-forming materials less than 40 kg / kg, preferably less than 35 kg / kg.

It is also possible that in the course of the entire production process - in order to ensure a more effective degree of mixing of the liquid bath and improve, thereby, the contact between the slag and the cast iron - to facilitate the recovery process - use one or more porous plates that are installed at the bottom shells and to which a neutral gas is supplied (for example, nitrogen or argon).

In the first melting stage, the steady state temperature is maintained throughout the desired melting period to melt iron, titanium and vanadium containing ore minerals and to produce liquid iron containing vanadium and liquid slag containing titanium oxide as the products of this melting.

During the period of compliance with the conditions of steady-state operation, when the correct balance between consumed electric power and the supply of ore mineral and auxiliary materials is maintained, the degree of extraction of vanadium contained in liquid iron at least 75% of the total vanadium content in the original ore mineral and the degree of extraction of titanium oxide contained in the slag, equal to 90% of the total content of titanium oxide in the original ore mineral.

In particular, the present invention provides the possibility of obtaining slag with a minimum content of titanium oxide that is greater than or equal to 40%, directly proportional to the ratio of the mass content of titanium oxide in the ore mineral supplied to the total mass content of oxides contained in the ore mineral supplied, minus iron oxides.

Such a solution seems to be preferable in which, during the period of melting, the temperature of the liquid bath and the chemical composition of liquid iron and liquid slag are periodically monitored to maintain the recovery process at an effective level.

The desired melting period continues until a certain maximum amount of liquid slag is reached.

The mentioned maximum amount of liquid slag can be defined as the maximum volume of slag that can physically be inside the melting furnace, so that if this value is exceeded, spontaneous and therefore undesirable splashing of the liquid slag from the holding capacity of the melting furnace through the side opening for slag removal occurs.

According to one embodiment of the invention, the maximum amount of liquid slag can be determined by the maximum thickness of the slag layer, so that if this value is exceeded, difficulties would arise in recovering the following quantities of feed material due to the lack of contact with the liquid iron. The maximum thickness of the slag layer depends on the required performance and on the required degree of reduction of vanadium oxide.

According to the invention, due to the size of the melting furnace, the maximum thickness of the slag layer should be less than 650 mm.

Therefore, the proposed method includes a step of determining the chemical composition of the molten iron and the resulting molten slag, to check whether the molten iron contains vanadium in an amount of at least 75% of its amount in the initially loaded ore mineral and whether the molten slag contains titanium oxide in at least 90% of its amount in the initially loaded ore mineral, as well as whether the mass content of titanium oxide in the slag is at least 40%.

If the test gave a positive result, then the method according to the invention further provides for separately lowering the liquid slag when the accommodating container is inclined in the first direction and the liquid iron is separately released when the accommodating container is inclined in the second direction opposite to the first direction.

If the result of the chemical composition check turns out to be negative, then the proposed method may include, during the processing time, the inclusion, after the first melting period, of an additional period consisting in maintaining the temperature without adding the ore mineral to complete the reduction process, and then after another chemical check.

The composition of both liquid iron and liquid slag separately lowers the liquid slag when the accommodating container is inclined in the first direction and the liquid iron is separately released when the containing container is inclined in the second direction opposite to the first direction.

According to some embodiments of the invention, during the melting period, if it is necessary to reduce the slag volume in order to obtain the desired processing conditions, the supply of the ore mineral and auxiliary materials to the holding capacity of the melting furnace is interrupted and the chemical composition of the liquid slag and liquid iron is determined. After this, and after a possible subsequent period of maintaining the temperature with the supply of electrical energy and the possible supply of only auxiliary materials to obtain the required degree of reduction, if it was not achieved during the melting period, the liquid slag is partially discharged by tilting the containing capacity in the first direction.

At the end of this possible partial slag descent, the proposed melting method involves a second melting stage, which is carried out in the same manner as the first melting stage described above, until the maximum amount of molten iron that can be contained in a melting furnace without spontaneous splashing of liquid slag is obtained. After that, the proposed method provides for checking the chemical composition of liquid iron and the resulting liquid slag, and after a possible period of maintaining the temperature without adding ore mineral to complete the recovery process separately lowering the liquid slag while inclining the containing capacity in the first direction and separately releasing liquid iron when the containing capacity is in the second direction opposite to the first direction mentioned.

In particular, liquid pig iron is released when it contains vanadium in an amount of at least 75% of its quantity in the initial loaded ore mineral, and liquid slag is drained when it contains titanium oxide in an amount of at least 90% of its amount in the original loaded ore mineral.

Due to the partial descent of the liquid slag, it is possible to control with considerable flexibility the amount of material contained in the containing capacity and to selectively control the kinetics of reactions that take place between the ore minerals, liquid slag and liquid iron, and to obtain the desired characteristics of both the products and the smelting process.

With this solution, it is possible to selectively and separately produce liquid melting products of ore minerals containing iron, titanium and vanadium, i.e. liquid slag with a high content of vanadium and liquid iron with a high content of titanium oxide.

This technology also provides the ability to control, in the process of melting, the amounts of both components present in the containing container.

According to some embodiments of the invention, before the maximum amount of liquid iron is reached, which is allowed by the geometrical parameters of the containing capacity, and during the second support period, the proposed method provides at least one additional partial descent of liquid slag to maintain the thickness of the latter at a level of less than 650 mm depending on the geometric parameters of the containing capacity and the type of ore mineral containing iron, titanium and vanadium .

A brief description of the attached graphics

These and other characteristics of the invention will become clear from the subsequent detailed description of some variants of its implementation, which are not limiting the scope of the invention, with reference to the accompanying drawings.

FIG. 1 in the top view shows a melting plant according to the invention.

FIG. 2, the melting plant shown in FIG. 1 is shown in the side view in section at different stages of the corresponding melting period.

FIG. 3 is a perspective view from below showing one part of the melting plant shown in FIG. one.

FIG. 4 is a sectional side view of the melting plant component shown in FIG. one.

FIG. 5 shows an example of a graph of the stages of the method according to the invention.

In the following description, the same reference numerals are used for identical parts of the smelting plant for melting iron, titanium and vanadium containing ore minerals, according to the present invention, also in different embodiments. It should be understood that the elements and characteristics of one embodiment of the invention may be introduced into other variants without further explanation.

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Detailed description of the invention

The following is a detailed description of various embodiments of the invention, of which one or more variants are illustrated in the accompanying drawings. Each of the presented embodiments of the invention is illustrative and cannot be understood as limiting its scope. For example, features depicted or described as belonging to one embodiment of the invention may be used in other embodiments of the invention to obtain other forms of its implementation. It should be clear that the scope of the invention should include all such modifications and variations.

FIG. 1 and 2 show a smelting plant 10 according to the invention, used for smelting ore minerals containing iron, titanium and vanadium, to produce liquid iron G and liquid slag S.

In particular, ore minerals may contain vanadium oxide V ₂ O5 in an amount of more than 0.5 wt.% And have a mass ratio of titanium oxides to other oxides — less iron oxides — more than 50%.

In the following description, as an example, not limiting the scope of the invention, as ore minerals containing iron, titanium and vanadium, are considered ore minerals belonging to the family of titanomagnetites.

The smelter 10 contains at least a smelting furnace 11, which may contain an enclosing container 12, perimetric walls 13, defining the smelting chamber 14.

In some embodiments of the invention, said perimetric walls 13 of the enclosing container 12 may be provided with a protective coating 15, which may be made in the form of one or more covering layers for the purpose of insulating or removing heat, for example layers of heat-resistant coating 15a inside the melting chamber to protect the perimeter walls 13 from the heat developed inside the melting chamber 14.

In some embodiments of the invention, which can be combined with all the embodiments of the invention described herein, a protective coating 15 can be provided which can be made in the form of one or more layers of cooling panels with sets of tubes 15b allowing the perimetric walls 13 to be cooled by removing heat using a fluid coolant, and possibly also from layers of heat-resistant coating 15a.

The space of the containing container 12 is located around the central axis X, and this containing container may have, for example, a substantially cylindrical shape or the shape of a body of revolution.

The accommodating container 12 may have a first hole 17 intended for lowering slag and made with the possibility of lowering liquid slag S through it, which is formed as a melting product of titanium magnetites, and a second hole 18 intended for producing iron and made with the possibility of producing liquid iron G formed as a result of the same process.

Mentioned intended for the discharge of liquid slag first hole 17 and intended for the release of liquid iron, the second hole 18 is made on the opposite relative to the Central axis X sides of the containing container 12.

A solution is possible in which the second hole 18 intended for the release of molten iron is made on one side of the containing container 12 and in which accordingly the melting furnace 11 contains an outlet chute 19 used as a channel for diverting the liquid iron G from the melting chamber 14 in the direction to the first container 20, which is located below the containing capacity 12.

It is also possible such a solution, in which the second hole 18 intended for the release of liquid iron is made in the bottom part of the containing container 12, and with this solution the presence of the discharge chute is not provided.

Under the first opening 17 intended for the discharge of liquid slag, a second container 21 may be located, configured to receive liquid slag S from a smelting furnace.

FIG. 1 and 2 illustrate such embodiments of the present invention, in which an ac melting furnace 11 is used which has three electrodes 16 located symmetrically in the central region of the melting chamber 14.

However, the present invention can equally be applied also to smelting furnaces operating on direct current with one or more pairs of electrodes.

The melting furnace 11 may have a support structure 22, which can be seen in FIG. 1 and 3, providing support for the containing container 12. The said supporting structure 22 may have an annular portion 22a (circular in FIG. 1 and rectangular or square in FIG. 2), which is limited to the housing 22b, within which at least partially is located holding capacity 12.

In addition, the support structure 22 can be provided in its lower part with at least one pair of curved runners 23, made with the ability to act as guide elements and set the swing axis B, which is oriented in the transverse direction, for the containing capacitance 12.

for example, at right angles to the central axis X.

These curved runners 23 provide for the containing container 12 the opportunity to perform a rotational movement around the axis of swing B when the supporting structure 22 is tilted in a known manner by means of driving means (not shown in the drawings). Linear actuators can be installed between the mentioned drive means, which can be pushed up or pulled down the side of the support structure 22 located near the first hole 17 used for draining the liquid slag, or the second hole 18 for releasing liquid iron, or electric or hydraulic motors or screw or pinion actuators acting directly on curved runners 23.

The inclination of the containment vessel 12, both in the first direction towards the first opening 17, which is intended for slag descent, and in the second direction towards the second opening 18, which is intended for the production of cast iron, can be carried out in a vertical plane in which the said central axis lies X.

Such embodiments of the invention are possible in which the said vertical plane, in which the inclination of the containing container 12 is carried out, passes through the center line of the first hole 17, which is intended for slag descent, and / or through the center line of the second hole 18, which is intended for cast iron production .

The inclination of the containment container 12 may be both symmetrical and asymmetrical with respect to the position in which the central axis X passes essentially vertically.

The inclination of the containing container 12 in the first direction is determined by the angle of slag descent α, measured between the inclined position, which the central axis X takes every time when the accommodating container 12 is inclined in this direction, and the vertical position it takes.

The inclination of the containing container 12 in the second direction is determined by the angle of release of the cast iron β, measured between the inclined position, which the central axis X takes every time when the accommodating container 12 is inclined in this direction, and the vertical position it takes.

Such embodiments of the invention are possible in which the aforementioned slag discharge angle α is from 0 to 15 °.

In some embodiments of the invention, which can be combined with all the embodiments of the invention described here, the angle of production of cast iron β, which depends on the type of furnace 11 and on the geometric parameters of the containing container 12, can be from 0 to 40 °.

For example, when casting iron from an enclosing container, the angle of cast iron β is from 0 to 25 °, and when casting iron through the discharge chute 19, this angle can be from 0 to 40 °.

The method of melting titanomagnetites is carried out using the installation 10 in the smelting furnace 11, if the slag has a high electrical conductivity, it seems to provide the advantage of such a solution in which an open-type electric arc is used, in which, as can be seen in FIG. 2, the electrodes 16 are raised above the liquid slag S and therefore they provide an electric arc outside the liquid bath consisting of the liquid slag S and the liquid iron G below it.

According to the invention, it is possible to load the melting furnace 11 with pre-reduced titanomagnetites with a metallization degree of more than 90% in order to limit the specific consumption of electrical energy in the melting process.

The method according to the invention provides the ability to simultaneously obtain as a result of melting liquid iron G, which can be used to extract vanadium, which can be contained in it, for example, in quantities of more than 0.5 wt.%, And liquid slag S, which can be used to extract titanium, as it may contain titanium oxide (TiO ₂ ), for example, in the amount of more than 40 wt.%.

The above are only approximate values of the content of vanadium and titanium oxide, which may occur in the case of melting titanomagnetites, carried out according to the invention.

In particular, with the proposed method, it is possible to produce liquid iron G containing 75%, preferably 80% vanadium contained in the original ore mineral containing iron, titanium and vanadium, and liquid slag L containing at least 90%, preferably at least 95% of titanium oxide contained in the original ore mineral.

Let XTiO ₂ _s be the minimum content of titanium oxide that can be obtained in the slag, let XTiO ₂ _m be the mass content of titanium oxide contained in the loaded ore mineral, and let Xox_m be the total mass content of oxides - minus the iron oxides contained in the loaded ore mineral, then the minimum mass content of titanium oxide XTiO ₂ can be calculated by the following formula:

where q is a coefficient that essentially depends on the amount of slag materials to be loaded.

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First of all, the melting process should be carried out at a high temperature, at least 1450 ° C, maintained throughout the entire process, with the exception of the initial and final periods, as well as possible intermediate transition periods. The duration of the process can be from 60 to 130 minutes, for example, it can be 94 minutes, depending on the specific requirements associated with the composition of the titanomagnetites to be melted and the required productivity.

High temperature is required to prevent too high viscosity of the slag, which, therefore, must be maintained in a liquid state (liquid slag S). The high viscosity of the liquid slag makes its descent from the smelting furnace 11 problematic, and also slows down the kinetics of the recovery process of vanadium oxide.

The high viscosity of the liquid slag may be due to the high content of titanium oxide in it. The reason for the high content of titanium oxide in the liquid slag may be the insufficient introduction of slagging materials (limestone, dolomite), which are required to produce liquid slag S with a high content of titanium oxide (TiO ₂ ).

In addition, the high temperature allows to obtain an adequate content of vanadium in the liquid iron G, especially in cases when the content of vanadium oxide (V ₂ O ₅ ) in the initial titanomagnetite is low, i.e. usually lower than 1% by weight.

However, there is the problem of thermal shock experienced by the perimetric walls 13 of the enclosing container 12 upon contact with materials having a high temperature.

Additional thermal shock may be due to the simultaneous presence inside the melting chamber 14 as an electric arc, which may be outside of the liquid bath, i.e. over the liquid slag S, and liquid slag S with a high content of titanium oxide and therefore has a high electrical conductivity.

For this solution, this problem may require that the proposed melting method include a preparatory stage, which consists in preparing the melting furnace 11 and in which the containing container 12 is provided with a protective coating 15.

FIG. 4 illustrates such embodiments of the invention, in which the protective coating 15 can be made in the form of a known heat-resistant coating 15a 'at the bottom of the containing capacitance 12 and a heat-conducting coating 15a "on the lateral perimetric walls 13 of the containing capacitance 12.

Solutions are possible in which said known heat-resistant coating 15a 'and possibly heat-conducting coating 15a "can be replaced with a heat-resistant coating properly examined to meet specific requirements associated with the smelting process of iron, titanium and vanadium containing ore minerals, in particular requirements of corrosion resistance, which is associated with a high content of titanium oxide in the slag.

Heat-conducting coating 15a "may be partial and not affect the upper part of the perimetric walls 13 of the containing container 12, where one or more cooling panels can be installed with sets of tubes 15b located inside the perimetric walls 13 themselves.

Possible solutions are those in which the said sets of tubes 15b or another type of cooling or air conditioning device are located outside the containing container 12, surrounding its peripheral walls 13, in accordance with the zone of separation of the surfaces of liquid iron G and liquid slag S.

The thermally conductive coating 15a "and the sets of tubes 15b may cause some part of the liquid slag S located at the periphery to transition to a solid state, which transition to the solid state protects the thermally conductive coating 15a" from wear.

At temperatures (above 1450 ° C) of titanomagnetite melting by the method according to the invention, the kinetics of formation of titanium carbides is high, since it increases with increasing temperature. Titanium carbides, if their content in the slag composition is above a certain value, can impart excessive viscosity to the liquid slag, neutralizing, thereby, the effect of high temperature and causing the same disadvantages associated with viscosity as described above.

According to the present invention for the implementation of the process, which simultaneously provides effective recovery of vanadium in liquid iron G and high content of titanium oxide (TiO ₂ ) in liquid slag S, it is necessary to apply temperatures above 1450 ° C, which creates favorable conditions for the formation of titanium carbides. Therefore, in order to limit the problems mentioned above, it is necessary in accordance with the required kinetics of the process to minimize the time during which the slag remains inside the melting furnace.

For this, the melting method according to the invention provides for the use of a tilting melting furnace 11, as described above, and its inclination around the swing axis B.

In the method according to the invention, before a fixed-type electric melting furnace, the melting furnace 11 is an advantage, since the process carried out using a tilting melting furnace 11 at the same time ensures the production of liquid slag S with a high content of titanium oxide and effective reduction of vanadium in liquid iron G,

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if necessary, with intervention in liquid slag S.

Being properly inclined, the inclined melting furnace 11 (see FIG. 2) allows the desired amount of liquid slag S to be lowered without the risk of producing liquid iron G with it and providing general control over the head of liquid slag S by adjusting the duration and inclination modes smelting furnace 11.

Considering the above, after the preparatory stage, in which the holding tank provides 12 with a protective coating, the proposed method of melting titanomagnetites provides that if there is no liquid bottom H in the holding tank 12, then a preliminary stage in which a limited amount is introduced into the melting chamber 14, for example several tons of a solid metallic material, such as ferrous scrap.

Then pre-melting of the metallic material in the solid state is performed using an electric arc to obtain a liquid bottom H consisting of at least a liquid metal.

If the melting furnace 11 is already in a state after performing at least one working cycle, then a liquid bottom H, consisting of liquid iron G and liquid slag S, remaining from the previous melting cycle and properly supported inside the melting chamber 14 can be present.

The melting furnace 11, containing the liquid bottom H, is ready for subsequent melting, which provides for the initial stage, which is carried out in the melting chamber of the melting furnace 11 and during which electric energy of reduced power, ranging from 50 to 80% of the power supplied at the subsequent stage, is supplied melting, and loading are in the solid state titanomagnetites.

During this initial stage, one or more reducing agents, such as coke, can be introduced with or into the melting furnace 11 together with titanomagnetites.

According to the present invention, it seems to be an advantageous solution in which restoration conditions are maintained inside the melting chamber 14, for which specific strategies can be used to prevent air from entering the melting chamber 14. For this, for example, a thorough and hermetic clogging of possible gaps between the components of the smelting furnace can be carried out with the help of a heat-resistant sealing material.

Such embodiments of the invention are possible in which simultaneously with or after titanium magnetites, slagging agents, such as limestone and / or dolomite, and / or materials containing oxides such as aluminum oxide (Al ₂ O ₃ ) and fluoride are loaded into the melting chamber 14. calcium (CaF ₂ ).

Prior to introduction into the smelting furnace 11, titanomagnetites are subjected to chemical analysis in order to identify each relevant component (iron, vanadium, titanium oxide) in the composition of the ore mineral, determining their initial content.

At the subsequent intermediate stage, the supply of electrical energy is increased until the steady state of operation is achieved, the value of which depends on the required plant capacity and the type of ore mineral, as will be clear from the further detailed description; feeding solid material into the smelting furnace 11, i.e. titanomagnetites and / or reducing agents and / or slagging reagents are also increased until a steady state temperature of more than 1,450 ° C is reached.

The steady-state operating temperature is maintained for a melting period of at least about 30 minutes, for example, for a period of from 30 to 130 minutes.

Temporary profiles for the supply of electrical energy and the load of the smelting furnace 11 with ore mineral, subjected to preliminary recovery, depend on the chemical composition of the latter, which determines the need for electricity for melting. These profiles have already been previously studied for a specific type of ore mineral and in relation to the specific performance required.

After the mentioned melting period, the proposed melting method may include an intermediate stage during which samples of liquid slag S and liquid iron G are taken, and then the chemical composition of liquid slag S and liquid iron G is determined.

In addition, at the end of the melting period, the supply of titanomagnetites and auxiliary materials, such as reducing agents and / or slagging reagents, if used, may be interrupted.

In some cases, the melting period can determine the time required to obtain the maximum amount of liquid iron with given geometrical parameters of the holding capacity 12.

According to other embodiments of the invention, the melting period can be followed by a period of maintaining the maximum temperature for about 5 minutes, for example, from 2 to 10 minutes, during this period, electrical energy is supplied without loading the ore mineral.

After determining the chemical composition or in connection with it, the intermediate stage may also

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provide for the partial descent of part of the liquid slag S, considered excessive. This descent can be carried out through the first hole 17 intended for the descent of the slag, for which the enclosing container 12 is inclined at the desired angle of descent of the slag α.

The purpose of this partial descent of slag is to limit the thickness of the liquid slag S inside the melting furnace 11 and to reduce its volume to ensure the desired conditions of the process. Depending on the specific needs or conditions that may occur in each case, a partial descent of the slag can ensure removal of essentially any amount of liquid slag S, even up to 90% of the total amount of liquid slag S present in the smelting chamber 14.

One of the embodiments of the present invention provides that the inclination of the enclosing container 12 both at the angle of slag descent α and at the angle of production of cast iron β is performed with an accuracy of less than 0.5 °, while ensuring the advantage - with an accuracy of 0.1 °.

Thanks to the aforementioned accuracy of inclination of the containing capacity 12, it is possible to accurately lower the liquid slag S, even with an accuracy of several tens of kilograms, which gives the proposed method of melting extreme flexibility and accuracy of operation.

It seems obvious that ensuring a constant optimal level of liquid slag S ensures the best result.

After the above operation of the partial descent of the slag by the proposed melting method, a second melting stage can be provided, lasting for its melting period, the minimum value of which is approximately 30 minutes, this period can be, for example, from 30 to 70 minutes.

According to one embodiment of the invention, the melting method provides for the possibility of more than two melting stages, each of which has its own duration (melting period), while the melting stages mentioned are separated by a series of partial descents of liquid slag S carried out in different volumes.

At any time during the production cycle, it is possible to control the temperature and determine the chemical composition of liquid iron G and liquid slag S.

Based on the results obtained, when the amount of vanadium in liquid iron G is at least 75%, for example 80% of the previously defined amount of vanadium in the original ore mineral, and the amount of titanium oxide (TiO ₂ ) in liquid slag S is at least 80% for example, 90-95% of a previously determined amount of titanium oxide (TiO ₂ ) in the original ore mineral, and, in particular, the mass content of titanium oxide (TiO ₂ ) in liquid slag S is at least 40%, the supply of electrical energy is interrupted and separate the liquid slag S and separately about let out liquid cast iron G.

Such a separate descent of liquid slag and a separate release of liquid iron is possible due to the first gradual inclination of the containing capacity 12 of the melting furnace 11 in the appropriate direction until the desired angle of descent of the slag α, which can be, for example, 8 °, and the subsequent second gradual inclination of the containing melting capacity 12 the furnace 11 in the opposite direction to achieve the desired angle of release of iron β.

For example, in the case of casting iron through the bottom of the containing container 12, the casting angle β can be about 14 °, while in the case of casting iron through the discharge chute 19, the casting angle β can be about 35 °.

The following describes an applied example of the method according to the invention.

In this example, a production target is considered that requires, during a production cycle (i.e., the time from the beginning of one melting cycle to the beginning of the next) for about 120 minutes, the ore mineral loading rate to be approximately 73 t / h. Assuming that during the production cycle, the time spent on the introduction of material into the smelting furnace is approximately 94 minutes, the average feed rate of the ore mineral will be 93 t / h. Taking into account the initial transitional stage in which the feed rate of the ore mineral is lower than in the steady state operation, the maximum feed rate Qmax in the steady state operation may be approximately 96 t / h.

As an example, used in the smelting process according to the invention, the ore mineral that has undergone preliminary reduction, contains iron, titanium and vanadium, and may have the following chemical composition (in wt.%):

iron (Fe) - 63,

ferrous oxide (FeO) - 6.1 (metallization degree 93%), carbon (C) - 2.5, calcium oxide (CaO) - 1,

magnesium oxide (MgO) - 2.7%, silicon dioxide (SiO ₂ ) - 4.2%, aluminum oxide (Al ₂ O ₃ ) - 4.0%, titanium dioxide (TiO ₂ ) - 15.1,

vanadium oxide (V ₂ O ₅ ) - 0.7.

Ore mineral, titanomagnetite, is served at ambient temperature, which is usually

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below 40 ° C.

The production target is such that the melting furnace must be loaded with an average titanomagnetite feed rate of 73 t / h (relative to the average melting cycle time, which also includes the time during which the material is not fed).

As follows from the foregoing, it may be preferable to choose a melting furnace 11 in which the internal diameter of the containment container 12 is sufficient to provide a large contact area between the liquid iron G and the liquid slag S. It is therefore proposed to use the melting furnace 11 with an internal diameter capacity of 12, approximately 7 m. In addition, the capacity of 12 must be such that during each melting cycle it can produce and contain liquid iron G, the total amount of which It is 100 tons.

The chemical composition specified for titanomagnetite in the above example is such that from each ton of material fed to the smelting furnace, liquid iron G is obtained in an amount of approximately 0.69 tons and liquid slag S in an amount of approximately 0.30 tons.

Therefore, during the melting cycle, approximately 145 tons of titanomagnetite must be supplied, and the duration of the melting cycle is approximately 120 minutes.

Assuming that the density of the liquid slag is approximately 2.2 t / m ³ , the volume of the liquid slag produced during one melting cycle is 13.6 m ³ .

The diameter of the liquid bath, i.e. parts of the melting chamber 14 capable of holding liquid iron G and liquid slag S, which is given by the internal diameter of the containing container 12 minus the thickness of the protective coating 15 of a layer of solid slag adhering to this protective coating 15.

Said solid slag layer is assumed to be present if a heat-conducting heat-resistant coating 15a and cooling the containing container 12 from an external source are used with a set of tubes 15b.

If we assume that the thickness of the protective coating 15 is approximately 0.55 m, and the thickness of the layer of solid slag adhering to this protective coating is approximately 0.33 m, then with an [inner] diameter of the holding capacity 12 equal to 7 m, the diameter of the liquid bath will be approximately 5.3 m, and the surface of the liquid bath 22 is 2 m (sic!).

The cap of the liquid slag S formed during the production cycle is estimated to be approximately 620 mm.

Therefore, if it is assumed that all the molten slag S formed during melting remained in the furnace and at the beginning of melting in order to immerse the electric arc as much as possible, the slag thickness should be at least 200 mm, then the final slag thickness would be approximately 820 mm. With such a thickness, the recovery process would be extremely difficult, especially at the stage of steady state operation. For this reason, taking into account the chemical composition of the feed material and the size of the smelting furnace 11, it is advisable to choose a process that at the end of the melting period provides for an intermediate descent of the liquid slag S.

A single-phase process that does not involve the partial descent of the liquid slag would be possible with an increase in the diameter of the smelting furnace 11, which would limit the cap of the liquid slag S; However, this would lead to an increase in heat dissipation and a decrease in the energy efficiency of the process; moreover, this would entail a higher cost of the smelter.

Therefore, if it is decided to carry out the smelting process with an intermediate descent of part of the liquid slag S, then, as established, this descent should be done after half of the total material supplied in this melting cycle has been fed. Therefore, the thickness of the liquid slag layer S, expected at the beginning of this partial descent of the liquid slag S, is approximately 510 mm.

As can be seen in FIG. 5, considered as an example, the melting cycle has the following stages.

Minutes 0-7: initial stage of preparation of the smelting furnace 11 (testing the operability of devices and components of the smelting furnace 11).

Minutes 7-15: initial transition stage with simultaneous supply of material with reduced speed (50-70 t / h) and supply of electric energy with reduced power (35-55 MW) to bring the temperature of the liquid bath to the required value (more than 1450 ° C ). Together with the ore mineral or in another mode (through alternative entry points), a reducing agent and slag-forming materials can be supplied.

For example, in the case of the ore mineral described above, and assuming that it has a mass ratio of titanium oxide to the total amount of oxides (excluding iron oxides), it is 0.53, the specific consumption (ratio of the mass of material fed during one melting cycle , to the mass of the ore mineral supplied during one melting cycle) required to obtain the desired degree of reduction of vanadium and to obtain slag with a high content of titanium oxide (more than 40%) is in the following range: coke - 20-34 kg / kg, slag-forming materials - less than 35 kg / kg.

Minutes 15-54: melting stage, power supply with maximum power (65-75 MW)

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and the supply of ore mineral with a maximum speed (85-105 t / h).

For example, in the case of smelting ore mineral, subjected to a preliminary reduction, characterized by a degree of metallization of 93%, carbon content 2%, total oxide content (minus iron oxides) 28%, at an ambient temperature from 5 to 40 ° C, specific feed Msp ore the mineral supplied to the smelter during the melting stage is in the range of 20-25 kg / (min-MW). This range determines the maximum electric power supplied at the melting stage in the steady state operation. The electrical power supplied to the melting stage, denoted as Pmax, can be determined by the following formula:

Mouth = k * Qmax / Msp.

For example, with the values of Qmax and Msp indicated above, Pmax will be approximately 70 MW.

In the case of an ore mineral with a different chemical composition and / or in the case of a different temperature value, the ratio between the electrical power and the feed of the ore mineral at the maintenance stage will change. For other values of these characteristics, the magnitude of the specific supply Msp of the ore mineral determined above can be adjusted by multiplying it by a factor k, the value of which depends on the degree of metallization of the ore mineral, carbon content, oxide content (minus iron oxides) and temperature of ore mineral supply.

In the process of melting, the reducing agent and slag-forming materials can be supplied simultaneously with the ore mineral or through alternative entry points. A few minutes before the ore mineral supply is stopped, chemical analysis of slag and molten iron is performed.

Minutes 54-57: maintenance stage at which it is possible to maintain or increase the temperature when applying electrical energy without feeding the ore mineral (but adding reagent-reducing agent and / or slag-forming materials is not excluded) to complete (based on chemical analysis of two stages) recovery vanadium before the descent of liquid slag S.

Minutes 57-61: partial descent of liquid slag S by tilting the holding capacity 12 of the smelting furnace 11. The amount of liquid slag S can be controlled by visually observing the head of the liquid slag S inside the holding capacity 12, or by measuring the amount of liquid slag S going into suitable container, or using the weighing system of the smelting furnace 11. The goal is to bring the size of the cap of the liquid slag S in the holding tank 12 to a value from 150 to 250 mm.

Minutes 61-66: as in the period of minutes 7-15.

Minutes 66-107: as in the period of 15-54 minutes.

Minutes 107-113: as in the period of minutes 54-57.

Minutes 113-120: the final descent of the liquid slag by tilting the melting furnace in the corresponding direction and the subsequent release of the molten iron by tilting the melting furnace in the opposite direction.

It should be understood that the above-described smelter 10 and the method of melting an ore mineral containing iron, titanium and vanadium can be rolled up to modifications and additions can be made to them without disturbing the scope and spirit of the invention.

It should also be understood that, although the present invention has been described with specific examples, a specialist in this branch of technology will be able to easily obtain other equivalent embodiments of the proposed melting plant and melting method, the characteristics of which are set forth in the claims, and therefore fall within the scope of protection, defined by this claims.

Claims (8)

CLAIM 1. The method of melting ore minerals containing iron, titanium and vanadium, the initial content of each of which is known in an electric melting furnace (11), which includes a holding capacity (12) with an internal space located around the central axis (X), made with its inclination by turning in the inclination plane, in which said central axis (X) is located, characterized in that it includes the following operations: The above-mentioned ore minerals and auxiliary materials containing reductants and / or slagging reagents with increasing feed rate and with increasing power are supplied to the above-mentioned melting furnace (11) to the above-mentioned electric smelting furnace (11), until the power will be achieved in steady state operation (Pmax) and the temperature of steady state operation is at least 1450 ° C, while the said power in steady state operation (Pmax) is directly proportional to the speed and the supply of the mentioned ore minerals in steady state operation (Qmax) and inversely proportional to the specific feed (Msp) of the ore minerals supplied to the holding capacity (12), while the said specific feed (Msp) depends on the degree of metallization of the ore minerals used, on the mass content carbon, from the temperature at which the said ore minerals are supplied, and of the total mass content of oxides minus iron oxides; - 12 030653 the temperature of the steady state operation is maintained during the desired period of melting sufficient to achieve complete melting of the ore minerals mentioned and to obtain liquid iron (G) containing vanadium and liquid slag (S) containing titanium oxide as the products of this melting; the melting period is prolonged until the maximum amount of liquid slag (S) is obtained, which is chosen from considerations of the volumetric quantity due to the geometric pairs meters accommodating vessel (12), and the maximum permissible layer thickness of the liquid slag (S), above which would prevent recovery of vanadium contained in the ore minerals used; upon completion of the said melting period and / or during this melting period, the chemical composition of the molten iron (G) and molten slag (S), including sampling, is determined to determine if the amount of vanadium in the molten iron (G) is at least at least 75% of the known amount of vanadium in the original ore minerals, and whether the amount of titanium oxide in the liquid slag (S) is at least 90% of the known amount of titanium oxide in the original ore minerals, and does the content of the said titanium oxide in the liquid slag (S) at least 40 wt.%; at the completion of the chemical composition determination stage, the liquid slag (S) is descended separately by tilting the containing container (12) in the first direction and discharging the liquid iron (G) by tilting the containing container (12) in the second direction. 2. The method according to claim 1, characterized in that after the mentioned period of melting and before the operation of separate descent of liquid slag (S) and release of liquid iron (G) depending on the results of determining the chemical composition of liquid slag (S) and liquid iron (G ) interrupt the supply of the mentioned ore minerals containing iron, titanium and vanadium, with the possible continuation of the supply of the above-mentioned auxiliary materials and the continuation of the supply of electric power less than the mentioned power in the steady state (Pmax) or equal to it, with the aim of dderzhaniya temperature of said steady state operation during the maintenance period, the duration of which is sufficient to ensure that in the liquid iron (G) the amount of vanadium has been achieved, of at least 75% of the known amount of vanadium in the starting ore minerals. 3. The method according to any one of claims 1 or 2, characterized in that, after a period of melting, the level of liquid slag (S) is maintained in each case within a certain amount, for which partial liquid slag (S) is lowered, tilting the containing capacity (12 ) in the first direction, so that the desired amount of liquid slag (S) is lowered through the hole (17) intended for the descent of the slag, made in the containing container (12). 4. The method according to claim 3, characterized by the fact that in the process of the said operation of partial descent of the liquid slag (S) the accommodating capacity (12) is inclined in the said first direction by the angle of descent of the slag (α) less than or equal to 15 °. 5. A method according to any one of claims 3 or 4, characterized in that in the process of the said partial liquid slag operation (S), a part of the liquid slag present in the holding capacity (S) is lowered to keep the liquid slag layer (S) less than 650 mm, preferably between 100 and 300 mm, more preferably between 150 and 250 mm. 6. The method according to any one of claims 1 to 5, characterized in that the liquid iron (G) is produced by tilting the containing capacity (12) in said second direction by an angle of iron (β) which is less than or equal to 40 °. 7. A method according to any one of claims 3 to 6, characterized in that after said operation of partial descent of liquid slag (S) and before the operation of separate descent of liquid slag (S) and the release of liquid iron (G) by tilting the holding capacity (12) in the said first direction and second direction, respectively, a sequence of operations is performed at least once, consisting of supplying ore minerals to the containing capacity (12) with increasing feed rate and supplying electric power with increasing power, until crucible in steady state operation (Pmax) and steady state operating temperature exceeding 1450 ° C to melt the ore minerals at said steady state temperature during the desired second melting period until the maximum amount of liquid slag is reached ( S) to check the chemical composition of the above-mentioned liquid slag (S) and the above-mentioned liquid iron (G) and the possible performance of the operation of the partial descent of the liquid slag (S). 8. The method according to claim 7, characterized in that, before reaching said maximum amount of liquid slag (S), the supply of ore minerals to the containing capacity (12) is interrupted, and the supporting electric power is supplied below the mentioned power in steady state (Pmax) or equal to it during a maintenance period sufficient to ensure that, at least in liquid iron (G), a quantity of vanadium is reached in excess of 75% of the amount of vanadium in the original ore minerals. - 13 030653