JP2010090431A - Method for producing ferro-alloy containing nickel and vanadium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a ferro-alloy containing nickel and vanadium with high efficiency and at low cost. <P>SOLUTION: The method for producing the ferro-alloy containing nickel and vanadium includes: a mixing step S1 of mixing petroleum-based combustion ash containing nickel oxide, vanadium oxide and iron oxide with a carbonaceous reducing agent and a slag-forming agent; a melting step S2 of heating and melting the mixture which has been mixed in the mixing step S1 to form a molten material, and making the produced ferro-alloy containing nickel and vanadium coagulate in the molten material; and a separating step S3 of cooling the molten material in which the ferro-alloy has been coagulated to separate the produced slag from the ferro-alloy. In the melting step S2, the heating temperature is controlled to 1,350-1,550°C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing alloy iron containing nickel and vanadium for producing alloy iron containing nickel and vanadium from petroleum combustion ash.

Conventionally, as a manufacturing method of alloy iron containing vanadium, that is, ferrovanadium, there are mainly a thermite method and an electric furnace method, and the thermite method is currently used as a main manufacturing 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 or sodium chloride and baked by oxidation, 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).

  Moreover, although it is not so much used now, in the manufacturing method of ferrovanadium by an electric furnace method, vanadium raw material, an iron source, a reducing agent, and a solvent are mixed to make a mixture, and ferrovanadium is manufactured using an electric furnace. 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).

  On the other hand, a method for producing alloy iron (Fe—Ni—V) containing nickel and vanadium from petroleum combustion ash has also been proposed. For example, a method of reducing petroleum combustion ash with ferrosilicon or aluminum in a melting furnace to obtain Fe-Ni-V (see Patent Document 2), pulverizing petroleum combustion ash and heating with a cyclone, and further ferrosilicon or There has been proposed a method of obtaining alloy iron (Fe—Ni—Mo—V) containing nickel, molybdenum and vanadium by reduction with aluminum (see Patent Document 3).

Also, petroleum-based combustion ash, reducing agent, and iron source are mixed, formed into briquettes, etc. if necessary, reduced at 1150 ° C to 1350 ° C, and the mixture or molded product is mounted in a furnace bottom steel electric furnace. A method of energizing and melting is proposed (see Patent Document 4). In this method, nickel and molybdenum contents in petroleum-based combustion ash are preferentially reduced by an iron source such as carbon in the combustion ash and separately charged scrap, and alloy iron containing nickel and molybdenum (Fe-Ni-Mo). It becomes. Then, the recovered slag can be reduced to obtain alloy iron (Fe-V, ferrovanadium) containing vanadium.
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 JP 54-46116 A JP 2001-316732 A JP 2001-98339 A JP 2004-270036 A

  However, the methods for producing alloy iron described in Non-Patent Document 1 and Patent Documents 1 to 4 have 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, rotary kilns generate a large amount of dust, and dam rings are likely to occur in the kiln, and the residence time of raw materials varies, requiring an excessive length of the processing conveyance path, and the installation area of the equipment is large. There are also problems such as an increase in the surface area of the kiln and a large amount of heat dissipation, resulting in an increase in fuel consumption.

  In the electric furnace method described in Patent Document 1, it is necessary to use expensive ferrosilicon or aluminum for reduction and to melt the ferrovanadium to be obtained. There is a problem that becomes high.

  Moreover, since the manufacturing method described in Non-Patent Document 1 and Patent Document 1 uses vanadium ore as a raw material, there is a problem that it is inferior in economic efficiency due to a recent rise in molybdenum ore.

  In the manufacturing method described in Patent Document 2, since expensive ferrosilicon or aluminum is used for reduction, there is a problem that the manufacturing cost increases.

  In the production method described in Patent Document 3, a petroleum-based combustion ash is charged into a cyclone, heated and dissolved, and then charged into a reaction furnace together with a reducing agent to obtain an iron alloy by reducing metal components. It is. Moreover, in the manufacturing method of patent document 4, after reducing petroleum combustion ash, it melt | dissolves and reduces the collect | recovered slag and obtains alloy iron. Therefore, the manufacturing methods described in Patent Document 3 and Patent Document 4 have a problem that the process becomes complicated.

  This invention is made | formed in view of the said subject, The objective is to provide the manufacturing method of the alloy iron containing nickel and vanadium which manufactures the alloy iron containing nickel and vanadium highly efficiently and cheaply. is there.

  As a result of earnest research on the method of efficiently and economically producing alloy iron containing nickel and vanadium, the present inventors have added a carbonaceous reducing agent to petroleum-based combustion ash, and heated and melted it. As a result, the inventors have invented a production method for producing alloy iron containing nickel and vanadium.

  That is, the method for producing alloy iron containing nickel and vanadium according to claim 1 comprises mixing a petroleum combustion ash containing nickel oxide, vanadium oxide and iron oxide, a carbonaceous reducing agent, and a slag forming agent, The mixture mixed in the mixing step is heated and melted to form a melt, and a melting step for aggregating the produced iron alloy containing nickel and vanadium in the melt, and cooling the melt obtained by agglomerating the alloy iron And a separation step of separating the slag produced from the alloy iron, and the heating temperature is controlled to 1350 to 1550 ° C. in the melting step.

  According to such a production method, the petroleum combustion ash, the carbonaceous reducing agent, and the slag forming agent are mixed in the mixing step. In the melting step, nickel oxide, vanadium oxide and iron oxide contained in petroleum-based combustion ash are once converted into metallic nickel, metallic vanadium and metallic iron by carbon of the carbonaceous reducing agent, and then further react with carbon. To produce Fe—Ni—V—C, and then the Fe—Ni—V containing C agglomerates as the temperature rises. In the separation step, the generated slag and Fe—Ni—V are separated, and alloy iron containing nickel and vanadium is manufactured. In addition, 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 without inhibiting the aggregation of Fe—Ni—V. Further, by controlling the heating temperature to 1550 ° C. or less, an increase in the amount of power used can be prevented. Furthermore, when a carbonaceous holding container is used in the melting step, the holding container is prevented from dissolving due to the reaction of the carbon in the container (the concentration of C contained in Fe-Ni-V is increased) and held. The wear and tear of the container is prevented.

The method for producing alloy iron containing nickel and vanadium according to claim 2 uses at least one of a CaO supply substance and a SiO ₂ supply substance as the slag forming agent, and a ratio of CaO and SiO ₂ in the mixture ( wherein the CaO / SiO ₂₎ is 0.2 to 1.65 in mass ratio.

According to such a manufacturing method, the ratio of CaO to SiO ₂ in the mixture (CaO / SiO ₂ ) is 0.2 to 1.65 by mass ratio, so that the mixture melts and the generated slag melts. It becomes a state and Fe-Ni-V tends to aggregate. Moreover, it becomes easy to fix S contained in the petroleum-based combustion ash to the slag. Here, the CaO supply substance refers to CaO itself and other Ca oxides in addition to substances containing CaO. Further, the SiO ₂ feed materials, other materials containing SiO _2, SiO ₂ itself and refers to the oxides of other Si.

  The method for producing an alloy iron containing nickel and vanadium according to claim 3 is a ratio of the amount of carbon in the mixture and the amount of oxygen contained in the iron oxide, nickel oxide and vanadium oxide in the petroleum combustion ash (C / O) is 1 or more in molar ratio, and the carbonaceous reducing agent is blended so that the carbon contained in the carbonaceous reducing agent remains 6 mass% or less in the produced alloy iron. Features.

  According to such a manufacturing method, the amount of carbon necessary for reducing nickel oxide, vanadium oxide and iron oxide contained in petroleum-based combustion ash is supplied, and the ratio (C / O) is 1 in molar ratio. When the carbon content exceeds 1, the carburization of the produced ferrovanadium lowers the melting point as a metal. In addition, when a carbonaceous holding container is used in the melting step, the holding container is prevented from dissolving due to the reaction of carbon in the container, and wear (melting damage) of the holding container is prevented.

The method for producing alloy iron containing nickel and vanadium according to claim 4 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 alloy iron containing nickel and vanadium according to claim 5 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.

A method for producing an alloy iron containing nickel and vanadium according to claim 6 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 of dust and the like can be suppressed, and equipment costs and equipment area can be reduced. Therefore, alloy iron containing nickel and vanadium (Fe-Ni-V) is more efficiently manufactured. be able to.

The method for producing an iron alloy containing nickel and vanadium according to claim 7 is characterized in that, in the melting step, before charging the mixture onto the hearth of the rotary hearth furnace, carbonaceous powder is spread on the hearth. It is characterized by leaving.
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 alloy iron containing nickel and vanadium according to claim 8 is characterized in that the carbonaceous powder is spread 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.

According to the manufacturing method according to claim 1 of the present invention, it is possible to stably manufacture high-efficiency and economically (cheaply) alloy iron having high nickel concentration and vanadium concentration. Further, the production can be performed without causing melting of the holding container.
According to the manufacturing method which concerns on Claim 2, S concentration in alloy iron can be suppressed and a mixture becomes easy to melt | dissolve. Thereby, the iron alloy is easily aggregated, and the iron alloy containing nickel and vanadium can be manufactured with high efficiency.
According to the manufacturing method which concerns on Claim 3, alloy iron containing nickel and vanadium can be manufactured with high efficiency by supplying the carbon amount required for reducing nickel oxide, vanadium oxide, and iron oxide. Further, by adding excess carbon, the melting point as a metal is lowered, and an alloy iron having a high nickel concentration and a high vanadium concentration can be produced at a low temperature. In addition, the holding container is less likely to melt.
According to the manufacturing method which concerns on Claim 4, CaO can be supplied efficiently and economically.

According to the manufacturing method of the fifth aspect, the slag can be easily taken out from the holding container.
According to the manufacturing method according to the sixth aspect, alloy iron containing nickel and vanadium can be manufactured efficiently and economically.
According to the manufacturing method according to the seventh aspect, the refractory material used for the hearth can be prevented from being melted and the metallization rate can be improved.
According to the manufacturing method according to the eighth aspect, the effect of preventing the refractory material from melting and the metallization rate can be further improved.

  Next, a method for producing alloy iron containing nickel and vanadium according to the present invention (hereinafter also referred to as “alloy iron” as appropriate) and an alloy iron produced by this production method will be described in detail with reference to the drawings. In the drawings to be referred to, FIG. 1 (a) is a diagram showing a flow of a manufacturing method of alloy iron, and (b) is a diagram showing a flow of a substance in each step.

≪Method for producing alloy iron≫
As shown to Fig.1 (a), the manufacturing method of alloy iron includes a mixing process (S1), a fusion | melting process (S2), and a isolation | separation process (S3).
Hereinafter, each step will be described.

<Mixing process>
The mixing step (S1) is a step of mixing petroleum combustion ash, a carbonaceous reducing agent, and a slag forming agent as shown in FIG. 1 (b). Hereinafter, the mixture is also referred to as “raw material” as appropriate.

[Petroleum combustion ash]
Petroleum combustion ash is EP ash, in-furnace ash, in-furnace ash, etc., and ash containing nickel oxide, vanadium oxide and iron oxide is used. The petroleum-based combustion ash is preferably a residue after EP ash granulation in which ash recovered from a boiler using oil coke is carbonized by wet granulation. In addition, when petroleum combustion ash contains much moisture, it is preferable to dry beforehand. At this time, the water content in the petroleum combustion ash is preferably 10% by mass or less.

[Carbonaceous reducing agent]
A carbonaceous reducing agent reduces nickel oxide, vanadium oxide, and iron oxide in petroleum combustion ash. Any carbonaceous reducing agent may be used as long as it contains fixed carbon, and coal, coke, charcoal, waste toner, biomass carbide, and the like may be used as appropriate.

  The compounding ratio of the carbonaceous reducing agent in the mixture is calculated from the desired nickel concentration and vanadium concentration (target Ni concentration and target V concentration). And it determines so that it may become more than the amount of carbon required in order to reduce nickel oxide, vanadium oxide, and iron oxide in petroleum combustion ash in a heating furnace.

  Moreover, the amount of carbonaceous reducing agent (fixed carbon) 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 the petroleum type Alloy iron in which the ratio (C / O) to the amount of oxygen contained in nickel oxide, vanadium oxide and iron oxide in combustion ash is 1 or more in terms of molar ratio, and carbon contained in the carbonaceous reducing agent is generated It is preferable to blend a carbonaceous reducing agent so that it remains 6 mass% or less (including 0 mass%), preferably 0.2 mass% or less. In addition, when the ratio of carbon amount to oxygen amount (C / O) is 1 in molar ratio and carbon is 0% by mass, no carbon remains in the produced alloy iron.

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

  When the ratio (C / O) of the amount of carbon in the mixture to the amount of oxygen in the petroleum-based combustion ash is less than 1, the nickel oxide, vanadium oxide and iron oxide are difficult to be reduced, and the carbonaceous reducing agent Carbon contained in does not migrate to alloy iron. On the other hand, when heating and melting at 1350 to 1550 ° C., even if a carbonaceous reducing agent is blended in the produced alloy iron so that the carbon exceeds 6% by mass, the carbon is further contained in the alloy iron. Since it cannot be dissolved (carburized), it is not necessary to add more than 6 mass%.

[Slag forming agent]
The slag forming agent is for forming slag, and is added for immobilizing S in the slag. As the slag forming agent, it is preferable to use at least one of a CaO supply substance (CaO-containing substance) and a SiO ₂ supply substance (SiO ₂ -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. Further, SiO ₂ may be contained as an impurity. Furthermore, if it contains impurities other than SiO ₂ , the blending amount is determined in consideration of the content of CaO. In addition, you may use these, mixing. Further, when determining the blending amount, the blending amount is determined in consideration of the amount contained as impurities in the petroleum combustion ash and the carbonaceous reducing agent (carbon supply substance).

(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. Further, CaO may be included as an impurity. In addition, in using these, it is desirable 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).

Note that the petroleum-based combustion ash and the carbonaceous reducing agent described above contain CaO and SiO ₂ as impurities. Thus, as CaO and SiO ₂ ratio in the mixture (CaO / SiO ₂₎ is 0.2 to 1.65 in mass ratio, CaO contained as impurities, in addition to SiO _2, further CaO feed material or It is preferable to mix a SiO ₂ supply substance.

Here, when adding (mixing) at least one of the CaO supply substance and the SiO ₂ supply substance to the petroleum combustion ash and the carbonaceous reducing agent, the ratio of CaO and SiO ₂ in the mixture (CaO / SiO 2). ₂ ) is blended so that the mass ratio is 0.2 to 1.65, thereby determining the overall blending ratio. If the mass ratio is less than 0.2, it becomes difficult to fix S in the petroleum-based combustion ash in the slag, the melting point of the slag rises, and the mixture becomes difficult to melt (dissolve). On the other hand, the larger the ratio of CaO and 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, but when the mass ratio exceeds 1.65, As in the case of less than 0.2, the melting point of the slag rises and the mixture becomes difficult to melt (dissolve).

Furthermore, when the mixture contains only a small amount of CaO and SiO ₂ , slag is by-produced so that the mass of the slag is 0.1 times or more of the mass of the obtained iron alloy, and the raw material It is preferable to immobilize the S content contained therein. The amount of alloy iron obtained is the total amount of nickel, vanadium and iron in the blended petroleum-based combustion ash.

Here, as shown in FIG. 1B, a mixer (for example, a screw-type mixer) is used to mix the petroleum-based combustion ash, 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 (mixer in the present embodiment) in the mixing step, 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 alloy iron is aggregated 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), the oxidation form of iron oxide in petroleum combustion ash is Fe ₂ O ₃ , the oxidation form of nickel oxide is NiO, and the oxidation form of vanadium oxide is V ₂ O _5. The case will be described. The reaction of the present invention is represented by the following formula. Here, C is a carbonaceous reducing agent.
Fe ₂ O ₃ + V ₂ O ₅ + NiO + 9C → 2Fe + 2V + Ni + 9CO

Incidentally, CaO used as slag forming agent, the SiO ₂ and the like, because it is difficult to reduce the carbon has kept the form as an oxide even when heated, it is present as a slag.

In this reaction process, Fe ₂ O ₃ , NiO and V ₂ O ₅ contained in the raw material are once converted into metallic iron, metallic nickel and metallic vanadium by carbon, and then further reacted with carbon to form Fe—Ni—V. -C, alloy iron containing carbon (alloy iron containing nickel and vanadium, Fe-Ni-V) is produced without lowering the yield by one-step heat 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. . Also, 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 increased, the generated iron alloy reacts with the carbon in the container, and the alloy Since the concentration of C contained in iron increases (the container melts), heating is performed at 1550 ° C. or lower. Further, when the slag forming agent contains SiO ₂ , when the heating temperature is high, SiO ₂ contained in the slag coexisting with the alloy iron is reduced by carbon in the holding container. As a result, Si yields in the alloy iron and the Si concentration of the alloy iron increases. Therefore, it heats at 1550 degrees C or less.

  In addition, although the alloy iron manufactured by this invention produces | generates as an alloy iron particle in the molten slag, in the range of the said heating temperature, this alloy iron particle is a solid or a liquid. For this reason, while being held at the heating temperature, the alloy iron particles aggregate while coexisting with the molten slag, and the alloy iron becomes a lump and the slag and the alloy iron are physically separated. . That is, when a holding vessel is used, the molten iron is allowed to pass through the holding vessel for a predetermined time, and when a moving hearth furnace is used, the generated iron alloy is removed by moving the hearth. Aggregate. In addition, when carrying out multilayer charging using a holding | maintenance container and heating, it is preferable to hold | maintain for 30 minutes-1 hour at the said heating temperature. Further, if the slag to be by-produced is not melted at the processing temperature, the slag inhibits the generated alloy iron particles from aggregating, and the slag and the alloy iron 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 nickel oxide, vanadium oxide and iron oxide in the mixture are solid-reduced and then coexist with the by-product molten slag and the remaining carbonaceous reduction. The alloy iron particles are agglomerated into particles while being softened by receiving the carburizing by the agent, and become a metal lump (reduced solidified product) 4 in a state where the lump of alloy iron and the lump of slag are in close contact with each other. The operating temperature of the reduction furnace 10 is in the range of 1350 ° C to 1550 ° C. And after this metal lump 4 is cooled and solidified in the downstream zone of the reduction furnace 10, it is discharged from the rotary hearth 2 to the discharge hopper 6 by a discharge device 5 such as a screw. In addition, you may cool after discharging | emitting from the rotary hearth 2 to the discharge hopper 6. FIG. The metal lump 4 made of slag and alloy iron thus produced is separated into slag and alloy iron 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 the slag produced by cooling the melt obtained by agglomerating the alloy iron and the alloy iron.
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 the cooled reduction mixture, is crushed by a crusher and sieved to iron alloy (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, from the separated slag, the iron alloy content can be further recovered 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 dust and a housing process for housing the obtained iron alloy may be included.

«Alloy iron (alloy iron containing nickel and vanadium)»
According to the production method described above, for example, the Ni content is 17.95 to 28.78% by mass, the V content is 16.55 to 28.38% by mass, and the Si content is 0.21 to 5.21% by mass. The C content is 1.09 to 6.23 mass%, the S content is 0.041 to 0.159 mass%, and the balance is Fe and alloy iron containing inevitable impurities can be obtained.

  Next, the method for producing iron alloy and the iron alloy 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.

  The blended raw materials are petroleum-based combustion ash, ash recovered from a boiler using oil coke, and the residue after EP ash granulation in which carbon content is separated by wet granulation, coke powder (fixed carbon as a carbonaceous reducing agent) Calcium carbonate (limestone) was mixed in order to adjust the composition of slag by-produced as a slag forming agent. In addition, Table 1 shows the components of the used post-EP ash granulation residue, coke powder, and calcium carbonate. Tables 2 and 3 show the blending ratios of the residue after EP ash granulation, coke powder, and calcium carbonate.

  Coke powder is the ratio of the amount of carbon in the mixture (residue after EP ash granulation and the amount of carbon contained in coke powder) to the amount of oxygen contained in nickel oxide, vandium oxide and iron oxide in petroleum-based combustion ash ( C / O) was a molar ratio of 1 or more, and the carbon remaining in the produced alloy iron was calculated so as to satisfy (target C concentration) in Tables 2 and 3 in calculation.

  In Tables 2 and 3, (target Ni concentration) is the nickel concentration in the residue after EP ash granulation × the blending ratio of the residue after EP ash granulation / (the iron concentration in the residue after EP ash granulation × EP Mixing ratio of residue after ash granulation + Nickel concentration in residue after EP ash granulation × Composition ratio of residue after EP ash granulation + Vanadium concentration in residue after EP ash granulation × Blending ratio of residue after EP ash granulation), (Target V concentration) is the vanadium concentration in the residue after EP ash granulation × the blending ratio of the residue after EP ash granulation / (the iron concentration of the residue after EP ash granulation × the blending ratio of the residue after EP ash granulation + EP ash The nickel concentration in the post-granulation residue x the blending ratio of the residue after EP ash granulation + the vanadium concentration in the post-EP ash granulation residue x the blending ratio of the residue after EP ash granulation).

  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. Heating was performed for 30 minutes, and after reductive melting, cooling was performed to separate a slag portion and an iron alloy portion. The obtained alloy iron was chemically analyzed to determine the contents of Ni, V, Si, C, and S (Ni concentration, V concentration, Si concentration, C concentration, and S concentration). The atmosphere is a nitrogen atmosphere, and the heating temperature (maximum heating temperature) is 5 levels of 1300 ° C, 1350 ° C, 1450 ° C, 1550 ° C, 1650 ° C, and heating is started, and the temperature is maintained for 30 minutes after reaching the maximum heating temperature. (Fired). Tables 2 and 3 show the results obtained in this heating experiment.

  In Tables 2 and 3, the recovery rate of alloy iron (Ni) is alloy iron amount × Ni concentration / charge Ni amount. Further, the recovery rate of alloy iron (V) is alloy iron amount × V concentration / charge V amount. Here, the amount of charged Ni is the amount of nickel calculated from the concentration of nickel contained in the residue after EP ash granulation × the mixing ratio × the amount of treatment, and the amount of charged V is the residue in the residue after EP ash granulation. It is the amount of V calculated from the concentration of vanadium contained x blending ratio x throughput.

As an evaluation, an alloy iron (Ni) recovery rate and an alloy iron (V) recovery rate are obtained, and those with a recovery rate of 80% or more are excellent, those with a recovery rate of 50% or more and less than 80% are good, and less than 50% The thing was considered bad. Moreover, the molten state of the sample after baking was investigated. The melted state is ◯ (excellent) when the sample is in a molten state after firing, △ (good) when the molten state is present but the slag and the iron alloy are not easily separated, and is not melted X (defect). Furthermore, ◎ (excellent) in which the occurrence of melting damage of the carbonaceous container was not recognized at all, ○ (good) that the wall surface of the container after use was eroded 10 mm or less × (good) × ( Bad).
In Table 1, Table 2, and Table 3, "-" indicates that the component is not contained or the mixture is not melted and the alloy iron and slag cannot be separated and the component cannot be measured. . 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 24 and 28 to 33 satisfy the requirements of the present invention. Implementation No. In Nos. 1 to 24, the recovery rates of alloy iron (alloy iron (Ni) recovery rate and alloy iron (V) recovery rate) were excellent, and the molten state of the sample after firing was also excellent. Implementation No. Nos. 28 to 31 have a CaO / SiO ₂ value less than the lower limit of the preferred range. 32-33, since the value of CaO / SiO ₂ exceeds the upper limit of the preferred range, the melting point of the slag is increased, the mixture has the shape of a molten state, ferroalloys was not easily separated from the slag. Therefore, the recovery rate of the alloy iron (alloy iron (Ni) recovery rate and alloy iron (V) recovery rate) is No. Although it decreased compared with 1-24, it was favorable. Implementation No. No. 1 to 24 and 28 to 33 were not recognized at all for the occurrence of erosion of the carbonaceous container, or even when erosion was observed, the erosion of 10 mm or less was able to be prevented.

  On the other hand, the implementation No. 25 to 27 and 34 are comparative examples that do not satisfy the requirements of the present invention. Implementation No. Since the heating temperature of Nos. 25 to 27 was less than the lower limit, the mixture did not melt, and the alloy iron (alloy iron containing nickel and vanadium) did not separate from the slag. Therefore, the alloy iron could not be recovered, and the alloy iron recovery rate (alloy iron (Ni) recovery rate and alloy iron (V) recovery rate) was poor. Implementation No. In No. 34, since the heating temperature exceeded the upper limit value, carbon in the carbonaceous container reacted with the alloyed iron, and erosion exceeding 10 mm was observed on the wall surface of the container, and it was not possible to prevent melting of the carbonaceous container. . 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. The formulation is No. 3 was used.

  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 out of the furnace and cooled, and slag and iron alloy were separated and recovered with a screen. As a result, the alloy iron (Ni) recovery rate was 96%, and the alloy iron (V) recovery rate was 85%.

  As mentioned above, although the best embodiment and the Example were shown and demonstrated in detail about the manufacturing method of the alloy iron 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.

(A) is a figure which shows the flow of the manufacturing method of the alloy iron containing nickel and vanadium, (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.

Explanation of symbols

S1 mixing process S2 melting process S3 separation process

Claims (8)

A mixing step of mixing petroleum-based combustion ash containing nickel oxide, vanadium oxide and iron oxide, a carbonaceous reducing agent, and a slag forming agent;
The mixture mixed in the mixing step is heated and melted to form a melt, and in the melt, the melting step of agglomerating the alloy iron containing nickel and vanadium,
A slag produced by cooling the melt obtained by agglomerating the iron alloy, and a separation step of separating the iron alloy,
In the melting step, a heating temperature is controlled to 1350 to 1550 ° C., and a method for producing alloy iron containing nickel and vanadium. As the slag forming agent, at least one of a CaO supply substance and a SiO ₂ supply substance is used, and a ratio of CaO to SiO ₂ (CaO / SiO ₂ ) in the mixture is 0.2 to 1.65 by mass ratio. The method for producing an alloy iron containing nickel and vanadium according to claim 1.   The ratio of carbon in the mixture to the amount of oxygen contained in iron oxide, nickel oxide and vanadium oxide in the petroleum-based combustion ash (C / O) is 1 or more in molar ratio, and the carbonaceous reduction The nickel and vanadium according to claim 1 or 2, wherein the carbonaceous reducing agent is blended so that carbon contained in the agent remains in an amount of 6% by mass or less in the produced alloy iron. A manufacturing method of iron alloy containing.   The method for producing alloy iron containing nickel and vanadium according to claim 2, wherein at least one of calcium carbonate and quicklime is used as the CaO supply substance.   5. The method for producing an iron alloy containing nickel and vanadium according to claim 1, wherein a carbonaceous material is used in a holding container for melting the mixture in the melting step. .   5. The method for producing alloy iron containing nickel and vanadium according to claim 1, wherein in the melting step, a rotary hearth furnace is used to melt the mixture.   In the melting step, before charging the mixture onto the hearth of the rotary hearth furnace, carbonaceous powder is spread on the hearth, containing nickel and vanadium according to claim 6. A method for producing iron alloy.   The said carbonaceous powder is spread | laid by the thickness of 2 mm or more on the said hearth, The manufacturing method of the alloy iron containing nickel and vanadium of Claim 7 characterized by the above-mentioned.

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