JP2010111941A - Method for producing ferrovanadium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing ferrovanadium highly efficiently at a low cost without using a vanadium ore or the like. <P>SOLUTION: The method for producing ferrovanadium includes a mixing step (S1) wherein vanadium pentoxide as a vanadium precursor, an iron oxide feeding material as an iron precursor, a carbonaceous reduction agent and a slug formation agent are mixed; a melting step (S2) wherein the resultant mixture is thermally melted to obtain a melt and then ferrovanadium generated in the melt is agglutinated; and a separation step (S3) wherein slug generated by cooling the melt formed by agglutinating ferrovanadium is separated from ferrovanadium. In the melting step (S2), heating temperature is controlled at 1,350-1,650&deg;C. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for producing ferrovanadium which produces ferrovanadium from vanadium pentoxide.

Conventionally, as a method for producing ferrovanadium, there are mainly a thermite method and an electric furnace method, and the thermite method is currently used as a main production method.
Here, the raw material for producing ferrovanadium is vanadium pentoxide extracted from titanium-containing vanadium magnetite or the like. To obtain this vanadium pentoxide, first, coke and limestone are mixed into titanium-containing vanadium magnetite and preliminarily used in a rotary kiln. Reduced and reduced in an electric smelting furnace to produce pig iron containing vanadium. Thereafter, the slag containing vanadium is oxidatively refined and mixed with sodium carbonate and sodium chloride and oxidative roasted, and then water is added to obtain a sodium vanadate solution. Further, pH adjustment and ammonium chloride are added to obtain ammonium vanadate, and then dried and melted to obtain vanadium pentoxide.

  In the method for producing ferrovanadium by the thermite method, for example, a mixture of vanadium oxide, an iron source, a reducing agent (ferrosilicon powder and aluminum particles), and a solvent (iron ore, mill scale, etc.) is mixed. And ferrovanadium is produced using a thermite reactor (see Non-Patent Document 1).

  In addition, although the electric furnace method is not widely used at present, in the electric furnace method, ferrovanadium is mixed with a vanadium raw material, an iron source, a reducing agent, and a solvent, and ferrovanadium is converted using an electric furnace. To manufacture. Here, it has been proposed to use a reducing agent such as ferrosilicon or aluminum when reducing to give a slight vibration to separate the slag (see Patent Document 1).

  As another manufacturing method, a carbonaceous substance is used as a reducing agent, which is introduced into a plasma arc torch together with vanadium oxide, and the reduction proceeds in the presence of an arc between the anode and the cathode of the torch. There have been proposed a method (see Patent Document 2) and a method of mixing vanadium oxide and carbon and maintaining this mixture at a high temperature under vacuum conditions (see Patent Document 3).

  Furthermore, as a method for producing iron alloy from waste containing vanadium as a raw material, a method for recovering useful metals such as V, Mo, Ni from various wastes such as used petroleum desulfurization catalyst has been proposed. In this method, waste such as combustion ash generated from a petcoke-fired boiler is mixed with a reducing agent and an iron source, formed into briquettes or the like as necessary, and reduced at 1150 to 1350 ° C. In addition, the mixture or molded product is charged into a furnace bottomed steel electric furnace, energized and melted, and Ni and Mo in the spent catalyst or combustion ash are carbon in the combustion ash and scrap that is charged separately. Is reduced preferentially by an iron source such as Ni—Mo alloy iron. And the collect | recovered slag is reduced and Fe-V alloy iron is obtained (refer patent document 4).

JP 54-46116 A JP-A-52-145316 JP-A-60-128230 JP 2004-270036 A

Edited by Japan Iron and Steel Institute, Steel Handbook, 3rd edition, Volume 2, Issued by: Japan Iron and Steel Institute, issued July 30, 2002, Chapter 7 Section 3 Section 5

However, the above-described method for producing ferrovanadium has the following problems.
In the thermite method described in Non-Patent Document 1, it is pointed out that the cooling and crushing treatment of ferrovanadium after the thermite reaction is expensive, and there is a problem that it is inferior in economic efficiency. In addition, the rotary kiln has a large amount of dust generation, dam ring is likely to occur in the kiln, and the residence time of the raw material varies. There is also a problem that the fuel consumption increases because the surface area of the kiln increases and the amount of heat dissipation increases.

  In the manufacturing method described in Patent Literature 1, expensive ferrosilicon or aluminum is used for reduction, and the ferrovanadium to be obtained is melted. There is a problem of getting higher. In the production method described in Patent Document 2, vanadium pentoxide is decomposed using the high temperature of a plasma arc and reacted with iron to obtain ferrovanadium. Even in this method, the melting point of the mixture becomes high due to partial reduction of vanadium pentoxide, and it is necessary to treat it at a high temperature in an arc furnace.

  In the manufacturing method described in Patent Document 3, vanadium oxide is used as a target, and since processing is performed under vacuum, continuous processing cannot be performed. There is a problem that production efficiency is poor.

  In addition, due to the recent surge in vanadium ore, a method for producing ferrovanadium that does not use vanadium ore as a raw material is required, and the production method using conventional vanadium ore is inferior in economic efficiency and cannot satisfy the above requirements. is there.

  The production method described in Patent Document 4 is for producing ferrovanadium from various wastes such as a spent petroleum desulfurization catalyst. This production method is a process since it is dissolved after being reduced once. However, there is a problem that it is necessary to use a kiln, a rotary hearth furnace, and an electric furnace.

  This invention is made | formed in view of the said subject, The objective is not to use vanadium ore etc. as a raw material, but to provide the manufacturing method of ferrovanadium which manufactures ferrovanadium highly efficiently and cheaply.

  As a result of intensive studies on the method for efficiently and economically producing ferrovanadium, the present inventors have invented a method for producing ferrovanadium using vanadium pentoxide as a vanadium raw material.

  That is, the method for producing ferrovanadium according to claim 1 includes a mixing step of mixing vanadium pentoxide as a vanadium raw material, an iron oxide supply material, a carbonaceous reducing agent, and a slag forming agent as an iron raw material, and mixing in the mixing step. The resulting mixture is heated and melted to form a melt, and a melting step for aggregating the produced ferrovanadium in the melt, a slag produced by cooling the melt obtained by agglomerating the ferrovanadium, and ferrovanadium And a separation step of separating the two, wherein the heating temperature is controlled to 1350 to 1650 ° C. in the dissolution step. In addition, the iron oxide supply substance here refers to iron oxide itself and other oxides of Fe in addition to a substance containing iron oxide.

According to such a manufacturing method, vanadium pentoxide (V ₂ O ₅ ), an iron oxide supply substance, a carbonaceous reducing agent, and a slag forming agent are mixed in the mixing step. In the melting step, iron oxide, V ₂ O ₅ is once converted into metallic iron and metallic vanadium by carbon of the carbonaceous reducing agent, and then further reacted with carbon to produce Fe-V-C. Thereafter, ferrovanadium containing C aggregates as the temperature rises. In the separation step, the generated slag and ferrovanadium are separated to produce ferrovanadium. Further, by heating the mixture to the melting point (1350 ° C.) or higher, the mixture is melted, and the generated slag is in a molten state, and does not inhibit aggregation of ferrovanadium particles. Further, by controlling the heating temperature to 1650 ° C. or less, an increase in power consumption is prevented. Furthermore, when a carbonaceous holding container is used in the melting step, the carbon in the container reacts to prevent the holding container from being dissolved (the C concentration contained in ferrovanadium increases). Wear (melting damage) is prevented.

The method for producing ferrovanadium according to claim 2 uses a CaO supply substance, a SiO ₂ supply substance, and a MgO supply substance as the slag forming agent, and the ratio of CaO and SiO ₂ in the mixture (CaO / SiO ₂ ) is The mass ratio is 1.0 to 1.65, and the ratio of MgO to CaO (MgO / CaO) in the mixture is 0.1 to 1.5 by mass ratio.

According to such a manufacturing method, the ratio of CaO to SiO ₂ in the mixture (CaO / SiO ₂ ) is 1.0 to 1.65 by mass ratio, so that the mixture is melted and the generated slag is melted. Thus, the ferrovanadium particles tend to aggregate. Moreover, the fixing effect of S is exhibited. Furthermore, when the ratio of MgO to CaO (MgO / CaO) in the mixture is 0.1 to 1.5 in terms of mass ratio, the mixture is melted, the generated slag is in a molten state, and ferrovanadium particles are aggregated. It becomes easy to do. Note that the melting point of the slag is lowered by the MgO supply material, the slag is formed by the SiO ₂ supply material, and S is fixed to the slag. In addition, the CaO supply substance here refers to CaO itself and other oxides of Ca in addition to a substance containing CaO. The MgO supply substance here refers to a substance other than a substance containing MgO. , MgO itself and other Mg oxides. Further, the SiO ₂ feed materials, other materials containing SiO _2, SiO ₂ itself and refers to the oxides of other Si.

In the method for producing ferrovanadium according to claim 3, the slag forming agent includes a Li ₂ O supply substance, and the Li ₂ O supply substance is at least one of lithium oxide, lithium carbonate, and lithium hydroxide. Yes, Li ₂ O in the formed slag is 0.05 to 5.0 mass%.

According to such a manufacturing method, by supplying (compounding) Li ₂ O as a slag forming agent, the melting point of the slag to be generated is lowered, and sulfur distribution to the slag is improved. Thereby, S becomes easy to be fixed to the generated slag, and the S concentration in the generated ferrovanadium is reduced.

  In the method for producing ferrovanadium according to claim 4, a ratio (C / O) of the amount of carbon in the mixture and the amount of oxygen contained in iron oxide and vanadium pentoxide is 1 or more in terms of molar ratio, and the carbon The carbonaceous reducing agent is blended so that carbon contained in the carbonaceous reducing agent remains in an amount of 6% by mass or less in the ferrovanadium to be generated.

  According to such a production method, the amount of carbon necessary for reducing iron oxide and vanadium pentoxide is supplied, and when the ratio (C / O) exceeds 1 in molar ratio, When carbon is carburized into vanadium, the melting point as a metal is lowered. Further, when a carbonaceous holding container is used in the melting step, the carbon in the container reacts to prevent the holding container from being melted, and the holding container is prevented from being worn (melted).

The method for producing ferrovanadium according to claim 5 is characterized in that at least one of calcium carbonate and quicklime is used as the CaO supply substance.
According to such a manufacturing method, CaO can be efficiently supplied by using at least one of calcium carbonate and quicklime as a CaO supply substance, and economic efficiency is improved.

The method for producing ferrovanadium according to claim 6 is characterized in that at least one of magnesium carbonate and dolomite is used as the MgO supply substance.
According to such a manufacturing method, MgO can be efficiently supplied by using magnesium carbonate as the MgO supply substance, and CaO and MgO can be efficiently supplied by using dolomite as the MgO supply substance. be able to. Furthermore, economic efficiency improves by using these.

The method for producing ferrovanadium according to claim 7 is characterized in that, in the melting step, a carbonaceous material is used for a holding container for melting the mixture.
According to such a manufacturing method, it becomes easy to take out the slag from the holding container.

The method for producing ferrovanadium according to claim 8 is characterized in that, in the melting step, a rotary hearth furnace is used to melt the mixture.
According to such a manufacturing method, generation | occurrence | production of dust etc. can be suppressed and an installation cost and an installation area can be reduced, Therefore Ferrovanadium can be manufactured more efficiently.

The method for producing ferrovanadium according to claim 9 is characterized in that, in the melting step, carbonaceous powder is spread on the hearth before charging the mixture onto the hearth of the rotary hearth furnace. To do.
According to such a manufacturing method, by laying the carbonaceous powder on the hearth, the refractory material used for the hearth is prevented from being melted, and the inside of the furnace is maintained at a high reduction potential, and the metallization is performed. The rate will increase further.

The method for producing ferrovanadium according to claim 10 is characterized in that the carbonaceous powder is laid on the hearth with a thickness of 2 mm or more.
According to such a manufacturing method, the effect | action by laying carbonaceous powder on a hearth improves more.

  According to the method for producing ferrovanadium according to claim 1 of the present invention, ferrovanadium having a high V concentration can be produced stably, efficiently and economically (cheaply). Further, the production can be performed without causing melting of the holding container. According to the method for producing ferrovanadium according to claim 2, since the S concentration in ferrovanadium can be suppressed and the mixture is easily melted, ferrovanadium is easily aggregated, and ferrovanadium is highly efficient. Can be manufactured.

  According to the method for producing ferrovanadium according to claim 3, the S concentration in ferrovanadium can be suppressed, and the ferrovanadium aggregation effect is enhanced. According to the method for producing ferrovanadium according to claim 4, ferrovanadium can be produced with high efficiency by supplying the amount of carbon necessary to reduce iron oxide and vanadium pentoxide. Further, by adding extra carbon, the melting point as a metal is lowered, and ferrovanadium having a high molybdenum concentration can be produced at a low temperature. Furthermore, the melting loss of the holding container is less likely to occur.

  According to the method for producing ferrovanadium according to claim 5, CaO can be supplied efficiently and economically. According to the ferrovanadium production method of claim 6, MgO can be supplied efficiently and economically. According to the ferrovanadium manufacturing method of the seventh aspect, the slag can be easily taken out from the holding container.

  According to the method for producing ferrovanadium according to claim 8, ferrovanadium can be produced efficiently and economically. According to the method for producing ferrovanadium according to the ninth aspect, the refractory material used for the hearth can be prevented from being melted and the metallization rate can be improved. According to the method for producing ferrovanadium according to the tenth aspect, the effect of preventing the refractory material from being melted and the metallization rate can be further improved.

(A) is a figure which shows the flow of the manufacturing method of ferrovanadium, (b) is a figure which shows the flow of the substance in each process. It is a schematic diagram which shows a rotary hearth type heating reduction furnace typically.

  Next, a ferrovanadium production method according to the present invention and ferrovanadium produced by this production method will be described in detail with reference to the drawings.

≪Method for producing ferrovanadium≫
As shown in FIG. 1 (a), the method for producing ferrovanadium includes a mixing step (S1), a melting step (S2), and a separation step (S3).
Hereinafter, each step will be described.

<Mixing process>
As shown in FIG. 1B, the mixing step (S1) includes vanadium pentoxide as a vanadium raw material, an iron oxide supply material, a carbonaceous reducing agent, and a slag forming agent (hereinafter also referred to as “raw material” as appropriate). ).

[Vanadium pentoxide]
Vanadium pentoxide is a vanadium raw material contained in ferrovanadium to be produced. Examples of the vanadium pentoxide raw material (vanadium raw material) include industrially produced pure vanadium pentoxide and oil coke. Vanadium pentoxide contained in the ash generated when this heavy oil fuel is burned can be used.

[Iron oxide supply material]
The iron oxide in the iron oxide supply substance (iron oxide-containing substance) is for use as an iron source, and as the iron oxide supply substance, any substance that can supply (compound) iron oxide into a mixture is particularly useful. It is not limited, Iron ore (iron ore powder), a scale (mill scale), etc. can be used.
The amount of iron oxide supply material is determined based on the iron oxide supplied (blended) with respect to the ratio of vanadium to iron in the vanadium pentoxide calculated from the desired vanadium concentration (target V concentration). Here, when iron ore is used, target V concentration = vanadium amount in vanadium pentoxide × amount of vanadium pentoxide / (amount of vanadium in vanadium pentoxide × amount of vanadium pentoxide + in iron ore The amount of iron contained × the amount of iron ore blended).

[Carbonaceous reducing agent]
The carbonaceous reducing agent reduces iron oxide and vanadium pentoxide. The carbonaceous reducing agent only needs to contain fixed carbon, such as coal, coke, charcoal, waste toner, biomass carbide, etc. These may be used, and these may be mixed as appropriate.
The compounding ratio of the carbonaceous reducing agent in the mixture is the reduction of iron oxide blended with respect to the vanadium pentoxide ratio calculated from the desired vanadium concentration (target V concentration) in the heating furnace. Decide to be more than the amount of carbon needed to do.

  The amount of carbonaceous reducing agent (fixed carbonaceous) to be blended may be blended in consideration of the mass of fixed carbon contained in the substance (coal etc.), but the amount of carbon in the mixture and iron oxide and The ratio (C / O) of the amount of oxygen contained in vanadium pentoxide is 1 or more in terms of molar ratio, and the carbon contained in the carbonaceous reducing agent is 6% by mass or less (0 The carbonaceous reducing agent is preferably blended so as to remain at 0.2% by mass or less. When the ratio (C / O) is 1 in terms of molar ratio and 0% by mass of carbon remains, no carbon remains in the produced ferrovanadium.

  This provides the amount of carbon necessary to reduce iron oxide and vanadium pentoxide. Furthermore, since carbon is carburized into the produced ferrovanadium, the melting point as a metal is lowered, so it is preferable to add extra carbon so that a certain amount of carbon can be carburized. Thereby, ferrovanadium with a high vanadium concentration can be produced at a low temperature by transferring carbon to the obtained ferrovanadium and lowering the melting point as a metal. In addition, since carbon already exists in ferrovanadium, even if a carbonaceous holding container is used, carbon in the holding container does not react with ferrovanadium, and it is possible to prevent melting of the holding container. Become.

  When the molar ratio (C / O) of the oxygen amount is less than 1, iron oxide and vanadium pentoxide are difficult to be reduced, and carbon contained in the carbonaceous reducing agent does not migrate to ferrovanadium. On the other hand, when heating and melting at 1350 to 1650 ° C., even if a carbonaceous reducing agent is blended in the produced ferrovanadium so that the carbon exceeds 6% by mass, the carbon is further contained in the ferrovanadium. Since it cannot be dissolved (carburized), it is not necessary to add more than 6% by mass.

[Slag forming agent]
The slag forming agent is for forming slag, and is compounded to immobilize S in the slag, and includes a CaO supply substance (CaO-containing substance), a SiO ₂ supply substance (SiO ₂ -containing substance). ) And a MgO supply substance (MgO-containing substance) are preferably used. Furthermore, it is preferable to include a predetermined amount of a Li ₂ O supply substance (Li ₂ O-containing substance).

(CaO supply substance)
The CaO supply substance is not particularly limited as long as it is a substance capable of supplying (compounding) CaO in the mixture, but at least one of calcium carbonate (lime) and quicklime from the viewpoint of efficiency and economy. It is preferable to use seeds, and slaked lime or the like may be used. Moreover, SiO ₂ and MgO may be included as impurities. Furthermore, if it contains impurities other than SiO ₂ and MgO, the blending amount is determined in consideration of the CaO content. In addition, you may use these, mixing. In addition, although it is preferable to use calcium carbonate and quicklime as a CaO supply substance, these are equivalent as a CaO supply substance.

  In addition, when determining the amount, the amount included as an impurity in the carbonaceous reducing agent (carbon supply substance), and when using dolomite described later, the amount of CaO included in dolomite is also taken into consideration. decide.

(SiO ₂ supply substance)
The SiO ₂ supply substance is not particularly limited as long as it is a substance capable of supplying (compounding) SiO _{2 in the} mixture, and silica stone, silica sand, or the like can be used. Moreover, CaO and MgO may be included as impurities. In addition, in these uses, it is necessary to grind | pulverize to about 100 micrometers or less.
Wollastite can also be used as a mineral containing CaO and SiO ₂ at the same time. Incidentally, SiO _2, by reaction with CaO, is intended to be blended in order to melt the mixture as a slug at a heating temperature in the melting step (S2).

The vanadium pentoxide, the iron oxide supply substance, the carbonaceous reducing agent, and the like contain SiO ₂ as an impurity. As described below, the ratio of CaO to SiO ₂ in the mixture (CaO / SiO _2). ) In a mass ratio of 1.0 to 1.65, it is preferable to further mix a SiO ₂ supply substance in addition to SiO ₂ contained as an impurity.

(MgO supply material)
The MgO supply material is not particularly limited as long as it is a material that can supply (formulate) MgO in the mixture, but at least one of magnesium carbonate and dolomite is used from the viewpoint of efficiency and economy. It is preferable. Further, SiO ₂ may be contained or CaO as an impurity. As the MgO supply substance, it is preferable to use magnesium carbonate or dolomite, but these are the same as the MgO supply substance.
In addition, since MgO has a lower reaction capacity than CaO, usually, a part of the blend of the CaO supply substance is replaced with the MgO supply substance. However, by replacing MgO with CaO, the melting point of the slag is lowered, so that the entire melting is likely to proceed at a lower temperature.

Here, when the CaO supply material, the MgO supply material and the SiO ₂ supply material are added to the vanadium pentoxide, the iron oxide supply material and the carbonaceous reducing agent, the ratio of CaO and SiO ₂ in the mixture (CaO / SiO ₂ ) Is blended so that the mass ratio is 1.0 to 1.65. If the mass ratio is less than 1.0, it is difficult to fix S in the slag, and the melting point of the slag increases, and the mixture is difficult to melt (dissolve). On the other hand, the larger the ratio of CaO to SiO ₂ (CaO / SiO ₂ ), the larger the ability to fix S, so it is preferable to blend so as to have a large value. As in the case of less than this, the melting point of the slag rises and the mixture becomes difficult to melt (dissolve).

  Moreover, it is preferable to adjust the compounding quantity of a CaO supply substance and a MgO supply substance so that the mass ratio (MgO / CaO) of MgO and CaO in a mixture may be 0.1-1.5. By containing MgO in a predetermined amount, the melting point of the slag is lowered, but when the mass ratio (MgO / CaO) exceeds 1.5, the melting point of the slag is increased and the slag is hardly melted. If (MgO / CaO) is less than 0.1, the effect of using MgO is small.

Furthermore, and CaO and MgO in the mixture, when containing only a small amount of SiO ₂ is, CaO and MgO or one of SiO _2,, or blended with CaO and MgO, both the SiO _2, the resulting ferrovanadium It is preferable that the slag is by-produced so that the mass of the slag is 0.1 times or more with respect to the mass of the amount, and the S content contained in the raw material is fixed. The amount of ferrovanadium obtained is the total amount of iron contained in the iron ore and the like mixed with the amount of vanadium in the compounded vanadium pentoxide.

(Li ₂ O supply material)
The Li ₂ O supply substance may be any substance that generates Li ₂ O by heating, and is at least one of lithium oxide (Li ₂ O), lithium carbonate (Li ₂ CO ₃ ), and lithium hydroxide (LiOH). One type can be used. When blending the Li ₂ O feed materials, Li ₂ O content in the slag (formed slag) by-product is formulated to be 0.05 to 5.0 mass%. By the content of Li 2 _O is formulated to be 0.05 mass% or more, the melting point of the resulting slag is lowered, thereby improving the sulfur distribution to the slag. This makes it possible to fix S in the slag and reduce the S concentration in the ferrovanadium to be generated. Furthermore, since the melting point of the generated slag is lowered, it is possible to enhance the aggregation effect of the generated ferrovanadium. In addition, even if it mix | blends so that it may exceed 5.0 mass%, since it will evaporate at the time of a heating, it is not necessary to mix | blend so that it may exceed 5.0 mass%. As the Li ₂ O feed _materials, Li ₂ O, but using _Li 2 CO 3, LiOH, as the Li ₂ O feed materials, which are equally.

Here, as shown in FIG. 1B, a mixer (for example, a screw-type mixer) is used to mix the vanadium pentoxide, the iron oxide supply substance, the carbonaceous reducing agent, and the slag forming agent. Moreover, it is preferable to agglomerate the mixed mixture with a granulator. By agglomerating the mixture, the amount of dust generated from the heating furnace is reduced, and the CO gas generated as a result of the reaction inside the mixture (agglomerate) in the heating furnace becomes easy to move. It is because it can prevent that becomes dust. As the granulator, in addition to a compression molding machine such as a briquette press and a rolling granulator such as a pan pelletizer, an extrusion molding machine may be used.
In addition, when a raw material contains much water | moisture content, it is preferable to dry beforehand. The degree of drying is determined in consideration of the mixing means in the mixing step (mixer in the present embodiment), and the water content in the raw material is preferably 10% by mass or less. Moreover, when the water | moisture content of the mixture (aggregate) after granulation is high, you may dry before charging to a heating furnace.

<Melting process>
The melting step (S2) is a step in which the mixture mixed in the mixing step (S1) is heated and melted to form a melt, and the produced ferrovanadium is agglomerated in the melt and a reduction reaction is caused. But there is.
As shown in FIG.1 (b), the mixture mixed with the mixer or the agglomerate granulated with the granulator is charged into a heating furnace and heated and melted. As a heating furnace, a furnace equipped with a crucible such as a resistance heating furnace or an induction heating furnace can be used. As other heating furnaces, rotary hearth furnaces (RHF), linear furnaces, multi-stage furnaces, etc. can be used. In these moving hearth furnaces, the mixture (agglomerate) to be heated is on the hearth. Therefore, all the furnaces are compact and can save equipment costs and installation area compared to rotary kilns.

Next, as an example of the reduction reaction in the melting step (S2), a case where the oxidized form of iron oxide in the iron oxide supply substance is Fe ₂ O ₃ will be described. The reaction of the present invention is represented by the following formula.
xFe ₂ O ₃ + yV ₂ O ₅ + (3x + 5y) C → x2Fe + y2V + (x + y) CO

It should be noted that CaO, MgO, SiO ₂ , Li ₂ O, and the like used as the slag forming agent are difficult to be reduced by carbon, and therefore remain in the form of oxides even during heating and exist as slag.

Here, V ₂ O ₅ is vanadium pentoxide as a vanadium raw material, Fe ₂ O ₃ is iron oxide as an iron raw material, and C is a carbonaceous reducing agent.

In this reaction process, Fe ₂ O ₃ and V ₂ O ₅ contained in the raw material are once converted into metal iron and metal vanadium by carbon, and then further reacted with carbon to become Fe—V—C. Ferrovanadium containing carbon is produced without reducing the yield by the treatment.

Moreover, in order to melt a mixture (agglomerated material), it is necessary to heat more than melting | fusing point. For this reason, the heating temperature (maximum heating temperature) needs to be 1350 ° C. or higher. However, in the case of using an electric furnace or the like that requires an object to be held for heating when melting the mixture, it is difficult to take out the melt from the holding container after melting unless a carbonaceous molded body is used. . From the viewpoint of preventing an increase in the amount of power used or as described later, when heated in a carbonaceous material holding container, when the temperature is raised, the generated ferrovanadium reacts with the carbon in the container to react with ferro Since the concentration of C contained in vanadium increases (the container melts), heating is performed at 1650 ° C. or lower. Further, when the slag forming agent contains SiO ₂ , if the heating temperature is high, SiO ₂ contained in the slag coexisting with ferrovanadium is reduced with carbon in the holding container. As a result, Si yields in ferrovanadium, and the Si concentration of ferrovanadium increases. Therefore, it heats at 1650 degrees C or less.

  The ferrovanadium produced in the present invention is produced as ferrovanadium particles in the molten slag, and in the range of the heating temperature, the ferrovanadium particles are solid or liquid. For this reason, while being held at the heating temperature, the ferrovanadium particles coagulate while coexisting with the molten slag, and the ferrovanadium is agglomerated and the slag and ferrovanadium are physically separated. That is, when using a holding vessel, let the melt flow in the holding vessel for a predetermined time, and when using a moving hearth furnace, move the hearth to remove the generated ferrovanadium. Aggregate. In addition, when using a holding | maintenance container, it is usually preferable to hold | maintain at the said heating temperature for 30 minutes to 1 hour. In addition, if the slag to be produced is not melted at the processing temperature, the slag inhibits aggregation of the generated ferrovanadium particles, and the slag and ferrovanadium cannot be separated.

Next, as an example of melting (dissolving) a mixture (agglomerate) in a heating furnace, a case where a rotary hearth type heating reduction furnace (rotary hearth furnace) is used will be described.
FIG. 2 is a schematic diagram schematically showing a rotary hearth-type heat reduction furnace. As shown in FIG. 2, in the rotary hearth type heating reduction furnace 10, first, the mixture mixed in the mixing step is continuously charged onto the rotary hearth 2 through the raw material charging hopper 1. Prior to the charging of the mixture, a granular carbonaceous material may be charged and spread on the rotary hearth 2 from the raw material charging hopper 1 and the mixture may be charged thereon. When a holding vessel is not used as in the rotary hearth type heating reduction furnace 10, a refractory material is used for the rotary hearth 2, a carbon-containing substance on the powder is laminated thereon, and a mixture is placed on the material and heated. By doing so, the refractory material can be prevented from melting. Further, the inside of the furnace can be maintained at a high reduction potential by the action of the carbonaceous powder, and the metallization rate is further increased. In this case, the carbonaceous powder is preferably laid on the hearth with a thickness of 2 mm or more. By setting the thickness to 2 mm or more, the above effect is easily exhibited. On the other hand, if it is too thick, it becomes difficult to enclose the mixture on the rotary hearth 2 and the effect is saturated. Therefore, the upper limit is preferably set to 7.5 mm or less.

  Then, the rotary hearth 2 rotates counterclockwise and normally makes one turn in about 8 to 16 minutes, depending on the operating conditions. A plurality of combustion burners 3 are provided on the upper side wall and / or the ceiling of the rotary hearth 2, and heat is supplied to the hearth by the combustion heat of the combustion burner burned by supplying fuel or its radiant heat. Is done.

  The mixture charged on the rotary hearth 2 made of the refractory material is heated by the combustion heat and radiant heat from the combustion burner 3 when moving in the reduction furnace 10 on the rotary hearth 2 in the circumferential direction. While passing through the heating zone in the reduction furnace 10, the vanadium pentoxide and iron oxide in the mixture are solid-reduced, and coexist with the by-product molten slag, and by the remaining carbonaceous reducing agent. While being carburized and softened, the particles aggregate and become ferrovanadium particles, and the ferrovanadium lump and the slag lump 4 become a metal lump (reduced solidified product) 4 in close contact with each other. In addition, the operating temperature of the reduction furnace 10 shall be the range of 1350-1650 degreeC. And after this metal lump 4 is cooled and solidified in the downstream zone of the reduction furnace 10, it is scraped off from the rotary hearth 2 by a discharge device 5 such as a screw arranged at the upper part of the rotary hearth 2. Then, it is discharged to the discharge hopper 6. In addition, you may cool after discharging | emitting from the rotary hearth 2 to the discharge hopper 6. FIG. The metal block 4 made of slag and ferrovanadium thus produced is separated into slag and ferrovanadium in the separation step (S3), as will be described later. The exhaust gas generated in the reduction furnace 10 is discharged from the exhaust gas duct 7.

<Separation process>
The separation step (S3) is a step of separating slag (formation slag) generated by cooling the melt obtained by agglomerating ferrovanadium and ferrovanadium.
As shown in FIG. 1 (b), the molten mixture (reduced mixture), which is a melt that has been melted and reduced in the heating furnace, is cooled after the heating, and discharged from the crucible (holding container) or the hearth. In addition, when using a holding vessel, the cooling is performed by allowing the melt to elapse in the holding vessel for a predetermined time. When using a moving hearth furnace, the cooling may be performed by a cooling mechanism provided in the furnace. Good. Moreover, you may cool after discharging | emitting from a holding container or a hearth (cooling means). The reduced solidified product, which is a cooled reduction mixture, is crushed by a crusher and sieved to ferrovanadium (metal) and slag by a sieve (separation means). This separation by crushing and sieving can be performed using a screen in addition to being performed manually. The obtained slag can be used for aggregates for concrete. In addition, the ferrovanadium content can be further recovered from the separated slag by means such as magnetic separation and flotation as necessary.

  The present invention is as described above, but in carrying out the present invention, within a range that does not adversely affect the respective steps, for example, a raw material pulverizing step of pulverizing the respective raw materials between or before and after the respective steps, Other processes such as an unnecessary object removing process for removing unnecessary substances such as garbage and an accommodating process for accommodating the obtained ferrovanadium may be included.

≪Ferovanadium≫
According to the production method described above, for example, the V content is 29.1% by mass or more and 79.6% by mass or less, the S content is 0.031% by mass or more and 0.159% by mass or less, and the C content Ferrovanadium that is 0.31 mass% or more and 6.15 mass% or less with the balance being Fe and inevitable impurities can be obtained.

Further, by blending the Li ₂ O feed material to the slag forming agent, and the S content is further reduced, eg, V content is not more than 48.1 mass% or more 48.9 wt%, S content Is 0.005 mass% or more and 0.052 mass% or less, C content is 3.19 mass% or more and 3.50 mass% or less, and ferrovanadium with the balance being Fe and inevitable impurities can be obtained. .

  Next, the method for producing ferrovanadium according to the present invention will be specifically described by comparing an example satisfying the requirements of the present invention with a comparative example not satisfying the requirements of the present invention.

[First embodiment]
In order to grasp the reduction state of the mixed raw material of the present invention, the following reduction experiment was performed using a small-scale laboratory heating furnace.

  As raw materials, vanadium pentoxide, iron oxide as raw material, hematite iron ore as iron oxide supply substance, carbonaceous reducing agent as coke powder (fixed carbon content 86.3 mass%) (manufactured by Kansai Thermal Chemical Co., Ltd.) ), And calcium carbonate (limestone), silica sand, and dolomite were mixed in order to adjust the composition of by-product slag as a slag forming agent. Moreover, about some, lithium carbonate was mix | blended. Table 1 shows the components of the vanadium pentoxide, the iron oxide supply material, the carbonaceous reducing agent, and the slag forming agent used.

  The formulation was such that the ratio of iron content (target V concentration) contained in the iron ore to the amount of V contained in vanadium pentoxide was the values shown in Tables 2 and 3. That is, the amount of vanadium in vanadium pentoxide × the amount of vanadium pentoxide / (the concentration of vanadium in vanadium pentoxide × the amount of vanadium pentoxide + the concentration of iron contained in iron ore × the amount of iron ore) = This is the target V concentration shown in Tables 2 and 3.

Coke powder has a molar ratio (C / O) of the amount of carbon in the mixture to the amount of oxygen contained in iron oxide and vanadium pentoxide of 1 or more, and the carbon mass remaining in the ferrovanadium produced is In the calculation, they were blended so as to have the values shown in Tables 2 and 3 (target C concentration). However, when it is -5.0 or more and less than 0.0, it is the compounding quantity with the ratio with the oxygen contained in iron oxide and vanadium pentoxide being less than equivalent by molar ratio. Calcium carbonate, silica sand and dolomite have a mass ratio of the ratio of CaO to SiO ₂ in the mixture (CaO / SiO ₂ ) and the ratio of MgO to CaO in the mixture (MgO / CaO) as shown in Tables 2 and 3. It mix | blended so that it might become a value. Lithium carbonate was blended so that the Li ₂ O content (concentration) in the slag (formed slag) was the value shown in Table 3.

  For mixing, an appropriate amount of water was added and granulated with a small pan pelletizer with a diameter of 600 mm to produce pellets with a diameter of about 13 mm. After 1000 grams of the pellets dried at 105 ° C. for 24 hours are charged into a small induction furnace equipped with a carbonaceous crucible having an inner diameter of 130 mm and a depth of 150 mm, the holding time is maintained at a constant ambient temperature. The mixture was heated for 30 minutes, reduced and melted, cooled, and the slag and ferrovanadium were separated. The obtained ferrovanadium was chemically analyzed to determine the content (concentration) of V, C, and S. The atmosphere was a nitrogen atmosphere, and the heating temperature (maximum heating temperature) was 7 levels shown in Tables 2 and 3. Heating was started and the temperature was maintained for 30 minutes after reaching the maximum heating temperature (firing). Tables 2 and 3 show the results obtained in this heating experiment.

In Tables 2 and 3, the target C concentration is the mass of carbon remaining in the generated ferrovanadium, and CaO / SiO ₂ is the ratio of the contained CaO mass to SiO ₂ mass, and MgO / CaO Is the ratio of the contained MgO mass to CaO mass, and the ferrovanadium recovery rate is recovered ferrovanadium amount × V concentration / charge V amount. The amount of charge V is V concentration contained in vanadium pentoxide × mixing ratio × treatment amount.

As an evaluation, the ferrovanadium recovery rate was determined, and those having a ferrovanadium recovery rate of 80% or more were determined to be excellent, those having 50% or more and less than 80% were good, and those having less than 50% were determined to be poor. Moreover, the molten state of the sample after baking was investigated. The melted state is ○ (excellent) when the sample is in a melted state after firing, △ (good) when the slag and ferrovanadium are not easily separated but is not melted, and × (Defect). In addition, ◎ (excellent) for the case where no erosion of the carbonaceous container was observed, ○ (excellent) for the case where the wall surface of the container after use was eroded 5 mm or less, and eroded 10 mm or less exceeding 5 mm △ (good), and eroded over 10 mm was evaluated as x (defect).
In Tables 1 to 3, those that do not contain components, or those that could not be measured because the mixture did not melt and ferrovanadium and slag could not be separated, are indicated by “−”. Moreover, about what does not satisfy | fill the structure of this invention, it shows by underlining a numerical value.

  From the results in Tables 2 and 3, the implementation No. Examples 1 to 70 satisfy the requirements of the present invention, and the recovery rate of ferrovanadium was excellent or good. Moreover, the molten state of the sample after firing was excellent or good. Furthermore, no. 1 to 61, the amount of carbonaceous compound is equal to or greater than the molar ratio of oxygen contained in iron oxide and vanadium pentoxide. Even though it was not recognized at all, it was eroded by 5 mm or less, and it was possible to prevent melting of the holding container.

Implementation No. 56-58, since the value of (MgO / CaO) exceeded the upper limit, the melting point of slag was high and the mixture was in a molten state, but slag and ferrovanadium were not easily separated, and ferrovanadium The recovery was not good but good.
No. No. 59 has a CaO / SiO ₂ value of less than the lower limit. In Nos. 60 and 61, since the CaO / SiO ₂ value exceeded the upper limit, the melting point of the slag was high, and the mixture was in a molten state, but the slag and ferrovanadium were not easily separated, and ferrovanadium was recovered. The rate was not good but good.

  No. Nos. 62 to 64 are carbonaceous containers, although the amount of carbonaceous compound is less than an equivalent amount in terms of molar ratio to oxygen contained in iron oxide and vanadium pentoxide, so that the recovery rate of ferrovanadium was excellent. As for the occurrence of melting damage of the container, the wall surface of the container after use exceeds 5 mm and erodes by 10 mm or less. It was larger than 1-61.

Implementation No. 65 to 70 as Li ₂ O feed material is obtained by blending a lithium carbonate, performed No. 41 to that of, Li ₂ O content in the slag (formation slag) is what was blended so that 0.05 to 5.0. Therefore, the effect of fixing S in the slag was further exhibited, and the S concentration in ferrovanadium further decreased. Also in this case, there was no erosion of the holding container, and the recovery rate of ferrovanadium was improved.

  On the other hand, the implementation No. Nos. 71 to 76 are comparative examples that do not satisfy the requirements of the present invention. In Nos. 71 to 73, since the heating temperature was less than the lower limit, the mixture did not melt and ferrovanadium could not be separated into slag, so ferrovanadium could not be recovered, and the ferrovanadium recovery rate was poor. Implementation No. Since 71-73 could not isolate | separate ferrovanadium, the component could not be measured. No. In 74 to 76, since the heating temperature exceeds the upper limit value, carbon in the carbonaceous container reacts with ferrovanadium, and erosion exceeding 10 mm is recognized on the wall surface of the container, and the carbonaceous container can be prevented from being damaged. There wasn't. In addition, the amount of power used increased and the economy was inferior.

[Second Embodiment]
Next, the following experiment was conducted using the rotary hearth type heating reduction furnace shown in FIG.
The same raw materials as in the first example were used. However, lithium carbonate is not blended.
The blending was performed so that the ratio of iron contained in iron ore (target V concentration) was equal to the amount of V contained in vanadium pentoxide, and the vanadium concentration in the ferrovanadium to be produced was 50% by mass. Further, the ratio of CaO to SiO ₂ in the mixture (CaO / SiO ₂ ) is 1.5 by mass ratio, and the ratio of MgO to CaO in the mixture (MgO / CaO) is 0.2 by mass ratio. As such, calcium carbonate, silica sand, and dolomite were blended.

  For mixing, an appropriate amount of water was added and granulated with a small pan pelletizer with a diameter of 600 mm to produce pellets with a diameter of about 13 mm. 1000 g of the pellets dried at 105 ° C. for 24 hours were used. In the rotary hearth heating and reducing furnace, before charging the pellets, powdery coal is laid on the hearth to a thickness of 2 mm, and then the pellets are charged. The maximum temperature in the furnace is 1450 ° C. After heat treatment for 12 minutes, it was discharged outside the furnace and cooled, and slag and ferrovanadium were separated and recovered by a screen. As a result, the recovery rate of ferrovanadium was 98%.

  As mentioned above, although the best embodiment and the Example were shown and demonstrated in detail about the manufacturing method of the ferrovanadium which concerns on this invention, the meaning of this invention is not limited to an above-described content. Needless to say, the contents of the present invention can be widely modified and changed based on the above description.

1 Raw material charging hopper 2 Rotary hearth 3 Combustion burner 4 Metal lump (reduced solidified product)
5 Discharge device 6 Discharge hopper 7 Exhaust gas duct 10 Rotary hearth heating reduction furnace (reduction furnace)
S1 mixing process S2 melting process S3 separation process

Claims (10)

A mixing step of mixing vanadium pentoxide as a vanadium raw material, an iron oxide supply substance, a carbonaceous reducing agent, and a slag forming agent as an iron raw material;
The mixture mixed in the mixing step is heated and melted to form a melt, and in the melt, a melting step of aggregating the produced ferrovanadium,
A slag produced by cooling the melt obtained by agglomerating the ferrovanadium, and a separation step of separating the ferrovanadium,
In the melting step, the heating temperature is controlled to 1350 to 1650 ° C., A method for producing ferrovanadium. A CaO supply substance, a SiO ₂ supply substance, and a MgO supply substance are used as the slag forming agent, and the ratio of CaO to SiO ₂ (CaO / SiO ₂ ) in the mixture is 1.0 to 1.65 by mass ratio, and 2. The method for producing ferrovanadium according to claim 1, wherein the ratio of MgO to CaO (MgO / CaO) in the mixture is 0.1 to 1.5 in terms of mass ratio. The slag forming agent includes a Li ₂ O supply substance, and the Li ₂ O supply substance is at least one of lithium oxide, lithium carbonate, and lithium hydroxide, and Li ₂ O in the formed slag includes: It is 0.05-5.0 mass%, The manufacturing method of the ferrovanadium of Claim 1 or Claim 2 characterized by the above-mentioned.   The ratio of the amount of carbon in the mixture to the amount of oxygen contained in iron oxide and vanadium pentoxide (C / O) is 1 or more in terms of molar ratio, and the carbon contained in the carbonaceous reducing agent produces ferro The method for producing ferrovanadium according to any one of claims 1 to 3, wherein the carbonaceous reducing agent is blended so as to remain in vanadium at 6 mass% or less.   The method for producing ferrovanadium according to claim 2, wherein at least one of calcium carbonate and quicklime is used as the CaO supply substance.   The method for producing ferrovanadium according to claim 2, wherein at least one of magnesium carbonate and dolomite is used as the MgO supply substance.   The method for producing ferrovanadium according to any one of claims 1 to 6, wherein a carbonaceous material is used for a holding container for melting the mixture in the melting step.   The method for producing ferrovanadium according to any one of claims 1 to 6, wherein in the melting step, a rotary hearth furnace is used to melt the mixture.   9. The method for producing ferrovanadium according to claim 8, wherein, in the melting step, carbonaceous powder is spread on the hearth before charging the mixture onto the hearth of the rotary hearth furnace. .   The method for producing ferrovanadium according to claim 9, wherein the carbonaceous powder is laid on the hearth with a thickness of 2 mm or more.

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