JP5561155B2 - Melting method of vanadium pentoxide - Google Patents

Description

  The present invention relates to a method for melting vanadium pentoxide. More specifically, the present invention relates to a melting method that is required in the previous step in order to make vanadium pentoxide into a product form that is a solidified product.

Vanadium, when added to steel and alloys, has the property of increasing its tensile strength and heat resistance, and is used for building structures, bridges, tools, aircraft, and rockets. It is also used as a catalyst for petroleum desulfurization, alcohol oxidation, sulfuric acid production, propylene resin synthesis, and the like.
Japan imports the entire amount of vanadium mainly in the form of V ₂ O ₅ and ferrovanadium, but because vanadium is subject to national stockpiling, recycling technology has been developed, and vanadium is converted into petroleum. Production in the form of recovery from used catalysts for purification is also performed.

Conventional methods for treating spent catalysts for petroleum refining and recovering vanadium include soda roasting and solvent extraction, but the obtained vanadium is in the form of V ₂ O _{5 and} is separated into solid and liquid. It is a solid deposit (hereinafter referred to as a cake) peeled off from the filter material after being formed, or a granulated product obtained by drying, granulating and molding the solid deposit. By the way, vanadium pentoxide is a harmful substance, and when it is inhaled or attached to the skin, it has a great adverse effect on the human body. Therefore, dust generation such as fine powder is very dangerous for the human body.

Therefore, considering the safety in the manufacturing process of the product that uses vanadium at the time of transportation, a commercialization process such as flaking is required, and it is necessary to melt vanadium pentoxide as a pre-process for flaking.
However, vanadium pentoxide is highly osmotic and corrosive when melted. When the molten metal comes into contact with the furnace wall in the melting furnace, the vanadium pentoxide penetrates and damages the furnace wall. And there is a problem that the purity of vanadium pentoxide falls when impurities from the damaged furnace wall are mixed.

As a technique for commercializing vanadium pentoxide, there are conventional techniques disclosed in Patent Documents 1 and 2.
The conventional technology of Patent Document 1 is a technology for producing high-purity V ₂ O ₅ using an inexpensive low-purity vanadium raw material. As a product form, it is in a powder form or put in a molding machine and molded. It is intended for the body.
Therefore, if the powder remains as it is, there is a high possibility of dust generation, and the molded body will lose its shape during handling, and dust generation will remain. Therefore, the problem of human body damage cannot be prevented.

Moreover, although the prior art of patent document 2 is a technique which obtains vanadium oxide with a solution, as a commercialization form, drying vanadium oxide solution and solidifying is demonstrated.
However, there is no specific description of the form of the solidified material in this way, there is no mention of prevention of dust generation due to the collapse of the shape of the solid material, and it is not considered to consider the prevention of human damage .

As described above, Patent Documents 1 and 2 do not teach even problems regarding prevention of human damage caused by vanadium pentoxide dusting.
Moreover, about the process of melt | dissolving a vanadium pentoxide solid substance and making it flakes, what mentions not only patent document 1, 2 but another well-known literature is found. Therefore, the present situation is that there is no presentation of a problem with respect to the technology for preventing damage to the melting furnace due to the penetration corrosion property when melting vanadium pentoxide.
Thus, at present, no practical melting technique for vanadium pentoxide has been established.

Japanese Patent Laid-Open No. 10-114525 JP 2006-169025 A

  In view of the above circumstances, the present invention has an object to provide a melting method capable of maintaining high purity of vanadium pentoxide without suppressing dust generation and adversely affecting the human body, without damaging the furnace wall of the melting furnace. And

The method for melting vanadium pentoxide according to the first aspect of the present invention is that only a limited range of the surface of the vanadium pentoxide deposit accommodated in the surface melting furnace of the vanadium pentoxide deposit accommodated in the melting furnace is obtained. Battering is performed by direct heating with a flame or hot air so that the temperature is equal to or higher than the melting point of vanadium oxide, and the furnace wall of the melting furnace is not directly heated so as to be maintained at a temperature lower than the melting point of vanadium pentoxide. It is characterized by.
The melting method of vanadium pentoxide according to a second aspect of the present invention is the method according to the first aspect, wherein the heating is performed by directly heating a slope formed by stacking the vanadium pentoxide deposits.
The method for melting vanadium pentoxide of the third invention is characterized in that, in the first or second invention, the heating is performed by radiating a flame generated by complete combustion.
The method for melting vanadium pentoxide according to a fourth aspect of the invention is characterized in that, in the first or second aspect of the invention, the heating is performed by radiating high-temperature hot air generated by complete combustion in a hot air furnace.
The method for melting vanadium pentoxide of the fifth invention is characterized in that, in the second invention, vanadium pentoxide is deposited in one place in the melting furnace and the slope is heated.
The method for melting vanadium pentoxide of the sixth invention is characterized in that, in the second invention, vanadium pentoxide is deposited in a plurality of adjacent locations in the melting furnace, and the slopes forming the valleys are heated. To do.
The method for melting vanadium pentoxide according to a seventh aspect of the present invention is the method according to the first or second aspect, wherein the vanadium pentoxide deposit is a cake containing moisture after solid-liquid separation. Features.
The method for melting vanadium pentoxide according to an eighth aspect of the present invention is characterized in that, in the first or second aspect, the vanadium pentoxide deposit is a granulated product obtained by granulating a cake or a dried product thereof.
The method for melting vanadium pentoxide of the ninth invention is characterized in that, in the first or second invention, the exhaust gas is discharged so that heat after heating passes through the inside of the vanadium pentoxide deposit accommodated in the melting furnace. And
The method for melting vanadium pentoxide according to a tenth aspect of the invention is characterized in that, in the first or second aspect, the molten metal pool portion in the melting furnace is cooled by forced cooling or heat dissipation.
The method for melting vanadium pentoxide according to the eleventh aspect of the present invention is characterized in that, in the first or second aspect of the invention, when a certain amount of molten metal in which vanadium pentoxide is melted is collected, it is taken out.
The melting method of vanadium pentoxide of the twelfth invention is characterized in that, in the first or second invention, the molten metal in which the vanadium pentoxide is melted is continuously taken out.

According to the first invention, the following effects are obtained.
a) Since only a limited range of the surface of the vanadium pentoxide deposit is heated to a temperature above the melting point and directly heated, the furnace wall of the melting furnace is kept at a temperature below the melting point of vanadium pentoxide. It becomes difficult for the molten metal to penetrate into the furnace material. As a result, impurities are not mixed due to damage to the furnace wall, and the vanadium pentoxide product can be maintained at a high purity.
b) At the same time , the surface of the deposit is wide and covered with the combined material by semi-melting or sintering, so that no dust is generated. For this reason, it is possible to prevent the health hazard of workers.
c) Also, when the molten vanadium pentoxide is solidified in the form of flakes, it can be started from a lower temperature than in the case of the reflection furnace system, so that the time is short and the work can be done easily.
According to the second aspect of the invention, since the slope of the vanadium pentoxide deposit is heated in a spot shape, the heating area is limited, and the furnace wall and the like other than the heating area are not heated and do not reach a high temperature. For this reason, the molten metal hardly penetrates into the furnace wall, and at the same time, impurities from the furnace wall are eliminated and the vanadium pentoxide product can be maintained in high purity.
According to the third aspect of the invention, if vanadium pentoxide deposits are heated by radiating a completely burned flame, vanadium pentoxide is not reduced, so that the production of lower oxides can be suppressed.
According to the fourth aspect of the present invention, when vanadium pentoxide deposits are heated by radiating high-temperature hot air that has been completely combusted, vanadium pentoxide is not reduced, so that generation of lower oxides can be suppressed.
According to the fifth aspect of the invention, since one piled slope in the vanadium pentoxide deposit is heated, the molten metal flows out naturally on the slope. At this time, the molten metal is surrounded by the vanadium pentoxide deposit and the molten metal is less likely to come into direct contact with the melting furnace side wall, so that the furnace side wall can be protected from penetration of vanadium pentoxide.
According to the sixth aspect of the present invention, the two adjacent stacked valleys in the vanadium pentoxide deposit are heated and the molten metal flows out of the valley, so that the furnace sidewall is covered with vanadium pentoxide to protect the furnace sidewall from penetration. be able to.
According to the seventh invention, since the vanadium pentoxide deposit contains moisture, it is difficult to generate dust, and health damage to workers can be prevented.
According to the eighth invention, not only dust generation can be prevented, but also a gap is formed between the charged granular materials, so that heat reaches the inside of the deposit and can be efficiently heated and melted.
According to the ninth invention, when the exhaust gas in the melting furnace is sucked and discharged, the heat after heating is sucked and flows through the inside of the vanadium pentoxide deposit, so that it can be preheated in advance and the melting by the heater can be efficiently performed. Yes.
According to the tenth aspect of the invention, in addition to escaping heat due to the heat conductivity of the furnace wall, the furnace wall is forcibly cooled, so the portion near the furnace wall in the molten vanadium pentoxide is cooled and solidified, The solidified portion can be used as a protective layer for the furnace bottom or the side wall of the furnace, or the surface temperature of the furnace inner wall can be lowered in advance to suppress the penetration of the vanadium pentoxide solution into the furnace material.
According to the eleventh aspect of the present invention, when the molten metal is taken out in a batch manner, the molten vanadium pentoxide can be prevented from penetrating into the furnace wall by taking out the molten metal quickly.
According to the twelfth aspect of the present invention, when the molten metal is continuously taken out, if the flaking operation in the subsequent process is a continuous type, the cooperation between both operations can be simplified.

It is explanatory drawing of 1st Embodiment in the melting method of this invention, Comprising: (A) is a front view, (B) is a top view. It is explanatory drawing of the melting method which concerns on 1st Embodiment, Comprising: (I) is explanatory drawing of the middle period of melting operation, (II) is explanatory drawing of the last stage of melting operation, (III) is explanatory drawing of the tapping operation. It is explanatory drawing of 2nd Embodiment in the melting method of this invention. It is explanatory drawing of 3rd Embodiment in the melting method of this invention. It is sectional drawing of the batch type melting furnace used by this invention. It is a top view of the melting furnace of FIG. It is explanatory drawing of 4th Embodiment and the continuous-type melting furnace in the melting method of this invention.

  The object to be melted by the melting method of the present invention is vanadium pentoxide, which includes (a) narrowly defined vanadium pentoxide, (b) ammonium vanadate, (c) narrowly defined vanadium pentoxide and ammonium vanadate. In this specification, “vanadium pentoxide” is used in a broad sense including (a), (b), and (c).

(Technical principle of the present invention)
The melting method of the present invention is a method for once melting in order to form vanadium pentoxide, which is a solid-liquid separated cake, a granulated granulated cake, or a dried product thereof into flakes. is there.
As described above, vanadium pentoxide is a harmful substance and dust generation for the human body, so it is necessary to prevent dust generation during processing, and vanadium pentoxide has high penetration corrosion properties. Therefore, it is necessary to protect the furnace wall of the melting furnace and prevent the quality of the vanadium product from being deteriorated due to the contamination of the furnace wall.
As a response to these problems, the melting method of the present invention directly heats vanadium pentoxide deposited in the melting furnace with a heater, and focuses on the directly heated portion (that is, the blown portion). The temperature is raised to the melting point or higher and melted from the surface of the vanadium pentoxide deposit, and then poured into a hot water pool. In this melting process, dust generation is prevented by covering the vanadium pentoxide deposit with molten metal or a sintered product. Is. In addition, a part of the molten metal is solidified to function as a protective layer for the furnace wall of the melting furnace, or the surface temperature of the furnace inner wall is lowered to suppress the penetration of the vanadium pentoxide solution into the furnace material. The product quality is kept high.

In order to clarify the characteristics of the present invention, a description will be given in comparison with a reflection furnace. The reflection furnace is a method in which the temperature inside the furnace is raised as a whole by supplying heat to the interior space of the furnace, and the raw material is melted by the reflected heat of the furnace wall. In this reflection furnace method, the gas layer and the furnace wall temperature in the whole furnace are melted relatively higher than the melting temperature of the raw material vanadium pentoxide. In this case, even if it is just above or near the melting temperature, since the raw material deposits are unlikely to exist between the molten metal and the furnace side wall at the time of melting, the vanadium pentoxide melt is formed on the furnace wall due to the high permeability of vanadium pentoxide. Such inconveniences may occur that the furnace wall permeates and damages the furnace wall, and impurities enter the molten vanadium pentoxide from the damaged furnace wall. In addition, since the furnace temperature is relatively high, it takes time to solidify into flakes.
On the other hand, in the present invention, the melted part being blown has reached the melting temperature of vanadium pentoxide (690 ° C.), but other parts can be made below the melting point, so that vanadium pentoxide is brought into the furnace wall. Infiltration can be prevented. For this reason, the furnace wall of a melting furnace can be protected and the contamination from the damaged furnace wall can also be prevented. In addition, when the molten vanadium pentoxide is solidified in the form of flakes, it is possible to start from a lower temperature than in the case of the reflection furnace method, so that there is an advantage that the work can be done easily with a short time.

(Melting furnace)
Before describing the melting method of the present invention, an example of a melting furnace used in the present method will be described with reference to FIGS.
The melting furnace 1 shown in the figure is a furnace for containing the vanadium pentoxide deposit Vh, and there is no particular limitation as long as it is a furnace capable of containing the vanadium pentoxide deposit Vh and blowing it. A simple furnace may be used.

  5 to 6, 2 is a furnace bottom, 3 is a furnace side wall surrounding four surfaces, and 4 is a furnace lid. In the present specification, the furnace bottom 2, the furnace side wall 3, and the furnace lid 4 are collectively referred to as a furnace wall. Each of these furnace walls consists of an inner wall refractory material, an outer wall refractory material, and a steel shell as a structural material. The inner wall refractory material is preferably made of vanadium pentoxide using a material having high corrosion resistance, and the outer wall refractory material is made of a material having high heat conductivity.

  The furnace lid 4 of the melting furnace 1 is provided with a chute 5 for depositing vanadium pentoxide V in one place. The raw material thrown into the melting furnace 1 from the chute 5 is deposited in a conical shape with the apex directly below the chute 5. Deposited in this manner is the vanadium pentoxide deposit Vh.

A heater 6 is attached to the melting furnace 1 at a position where the slope of the vanadium pentoxide deposit Vh charged into the melting furnace 1 can be directly heated. In the illustrated embodiment, the furnace side wall 3 close to the vanadium pentoxide deposit Vh and the furnace side wall 3 to which the heater 6 is attached are opposed to each other.
The heater 6 may be any heating means as long as it can directly heat the vanadium pentoxide deposit Vh accommodated in the melting furnace 1, that is, can blow it. Typically, a burner that injects a flame, a hot air nozzle that radiates hot air, and the like can be given. Then, the surface of the vanadium pentoxide deposit Vh is blown by the flame radiated from the burner.

  In the burner as the heater 6, the fuel may be a liquid fuel such as oil or a gaseous fuel such as gas. The flame injected from the burner must be completely burned, so that the ratio between the amount of fuel burned and the amount of air adapted thereto is always adjusted to be constant.

  The hot air nozzle as the heater 6 radiates hot air of completely burned temperature generated in a hot air furnace provided separately from the melting furnace 1. The hot air radiated from the hot air nozzle can be blown against the surface of the vanadium pentoxide deposit Vh.

  A cooling jacket 7 for forcibly cooling the outer periphery of the furnace side wall 3 is attached to the melting furnace 1, and the mounting height of the cooling jacket 7 matches the height of the molten metal pool in the melting furnace 1. The cooling jacket 7 is a jacket through which a coolant such as water or air passes, and the inlet side introduction pipe 7a and the outlet side introduction pipe 7b are connected to each other. In addition, the arrow has shown the exit / entry direction of a refrigerant | coolant.

The melting furnace 1 is provided with a molten metal outlet 8 at a portion where molten metal melted from the vanadium pentoxide deposit Vh is accumulated.
Thus, when there is the outlet 8 at the portion where the molten metal is accumulated, the molten metal can be discharged in a short time, and it is easy to prevent the molten metal from penetrating and damaging the furnace side wall 3. The vanadium pentoxide product can be maintained at a high purity.

The melting furnace 1 includes a tilting mechanism that tilts the melting furnace 1 to discharge the molten metal. This tilting mechanism comprises a tilting shaft portion 11 attached to the furnace side wall 3 in the vicinity of the tap 8 and tilting means 14 for tilting the melting furnace 1 with the tilting shaft portion 11 as a fulcrum.
The tilt shaft portion 11 includes a tilt shaft 12 and a bearing 13 that rotatably supports the tilt shaft 12. As the tilting means 14, a push-up tilting means 14 as shown in the figure, a means for raising and lowering a chain, a rope, etc. (not shown) with a hoisting device or the like may be used.

  The melting furnace 1 includes an exhaust gas duct 16 for circulating hot gas in the furnace. The illustrated duct 16 includes a movable duct 17, a fixed duct 18, and a vertical duct 19, but is not limited to such a configuration. The exhaust gas duct 16 can discharge the high-temperature exhaust gas in the melting furnace 1 to the outside both when the melting furnace 1 is stationary and during the tilting operation.

(The melting method of the first embodiment)
Next, a first embodiment of a melting method using the melting furnace 1 will be described.
FIG. 1 shows a situation immediately after the start of the melting operation. Vanadium pentoxide is introduced from the chute 5 and accumulated in a piled state. The top of the vanadium pentoxide deposit Vh is in the vicinity of the chute 5, and the side of the deposit facing the heater 6 is a gentle slope.

  The vanadium pentoxide deposit Vh is charged in the state of a wet cake still containing water after being subjected to solid-liquid separation, or in the form of granulated or granulated or dried product.

  As shown in FIG. 1, when the long slope of the vanadium pentoxide deposit Vh is blown by the flame f emitted from the heater 6, the vanadium pentoxide V melts from a part of the slope and flows out as a molten metal m. The molten metal m flows down from the top to the bottom. In FIG. 1, the molten metal m does not cover the furnace bottom surface of the melting furnace 1.

  What is visible on the furnace bottom surface when the molten metal m is not covered is a protective layer c, which is a self-coating layer in which the melted vanadium pentoxide V is once cooled and solidified. This protective layer c covers the entire surface of the furnace bottom 2 and rises slightly higher along the four side walls 3 of the furnace, and the protective layer c has a shallow dish shape. Further, vanadium pentoxide V is previously melted and formed so as to have such a shape. The protective layer c is naturally formed during operation, but the protective layer c may be formed in advance at the beginning of operation.

Next, the melting method will be described with reference to FIG.
FIG. 11 (I) shows a state in which the melting of the vanadium pentoxide deposit Vh has progressed on the long slope, and the molten metal m, which is the vanadium pentoxide V melt, flows downward and is accumulated on the upper surface of the protective layer c. Show.
This melting is performed by so-called contact blowing in which the flame f or hot air sprayed by the heater 6 directly hits the surface of the vanadium pentoxide deposit Vh, thereby creating a melting area. By doing so, the surface of the other vanadium pentoxide deposit Vh that has been heated at the same time is also partially melted or sintered to prevent the vanadium pentoxide V from being dusted.

  When the temperature of the portion blown by the heater 6 exceeds 690 ° C., which is the melting point of vanadium pentoxide, as described above, a melted portion is generated in the vanadium pentoxide deposit Vh. However, the portions other than the melted portion, for example, the furnace side wall 3 and the furnace lid 4 are not directly heated and are kept below the melting point. Further, the inner wall surface of the furnace side wall 3 and the furnace bottom 2 covered with the unmelted vanadium pentoxide deposit Vh does not come into contact with a high-temperature flame or hot air exceeding the melting temperature, and the furnace wall itself transfers heat, Furthermore, since it cools with a cooling jacket (refer the code | symbol 7 of FIG. 5 and FIG. 6), it will be maintained below below melting | fusing point. For this reason, the penetration of vanadium pentoxide into the furnace wall can be prevented.

  FIG. 1 (II) shows a state during the melting operation further advanced from FIG. 1 (I). The peak of the vanadium pentoxide deposit Vh gradually decreases with the height decreasing, and the amount of molten metal m corresponding to the reduced vanadium pentoxide deposit Vh increases.

As described above, the heater 6 can be directly heated by radiating flame or hot air from a position facing the slope of the vanadium pentoxide deposit Vh, so that the heating efficiency is increased. In addition, since the molten metal that is melted out is indirectly heated, the fluidity until the molten metal is discharged can be maintained, and the molten metal can be easily discharged.
And when the flame is burning completely, since vanadium pentoxide is not reduced, the production | generation of V lower oxide can be suppressed. In addition, the flame includes an inner reducing flame and an outer oxidizing flame. When the portion of the flame at the tip of the flame is applied to the vanadium pentoxide deposit Vh and blown, Generation can be suppressed.
Also in the case of hot air blowing, if the hot air is obtained by complete combustion, vanadium pentoxide is not reduced and no V lower oxide is produced, as described above.

  As the heater 6, a heater having a radiation angle (open angle in a horizontal plane) that can blow and blow the outer surface of the vanadium pentoxide deposit Vh within a necessary range, or a heater that can adjust the open angle to be wide or narrow is used. When the radiation angle is widened, the slope of the vanadium pentoxide deposit Vh can be melted in a wide area, the efficiency of the melting operation is increased, and the outer surface of the vanadium pentoxide deposit Vh is widely covered with the molten metal, It becomes easy to suppress dust generation.

Further, it is preferable that the radiation angle on the vertical plane of the heater 6 can be variably adjusted according to the distance between the height of the peak of the vanadium pentoxide deposit Vh and the vanadium pentoxide deposit Vh. As a result, even if the distance between the heater 6 and the vanadium pentoxide deposit Vh becomes long or the height of the pile of the deposit becomes low, the flame and hot air can surely reach the slope of the raw material deposit Vh. You can continue to blow.
When the angle adjustment in the horizontal plane and the vertical plane is made possible in this way, the surface heating range of the vanadium pentoxide deposit Vh can be expanded, and the melting rate can be properly maintained.

  While the vanadium pentoxide deposit Vh is applied and blown as described above, the vanadium pentoxide V melt melts from the surface of the vanadium pentoxide deposit Vh. If the upper layer portion of the molten metal that has flowed down on the furnace bottom 2 is taken out as a product while maintaining a high temperature, and the lower layer portion is cooled by the cooling jacket 7 and solidified, the solidified portion of the vanadium pentoxide V is Since it becomes a protective layer, damage to the furnace wall can be prevented by self-coating. The protective layer may be formed in advance.

As described above, the present invention employs self-coating in which solidified vanadium pentoxide V is used as a protective layer against molten vanadium pentoxide V. Since the solidified vanadium pentoxide V does not have permeability, by interposing the solidified vanadium pentoxide V between the furnace wall and the molten metal, the penetration of the molten vanadium pentoxide into the furnace wall is prevented. Can prevent damage. Alternatively, even if the molten metal is not solidified, the penetration of the vanadium pentoxide solution into the furnace material can be stopped by cooling the furnace wall and lowering the surface temperature of the furnace inner wall below the melting point, thereby suppressing damage to the furnace wall. it can.
In other words, in the present invention, in addition to avoiding contact between the molten vanadium pentoxide and the furnace wall, the furnace wall can be protected from vanadium pentoxide by cooling the furnace side wall of the molten metal reservoir portion in contact with the molten metal. it can.

FIG. 1 (III) shows a state in which the molten furnace m is taken out by tilting the melting furnace 1.
As shown in the figure, in the state where the vanadium pentoxide deposit Vh remains to some extent and the slope is formed, it is more efficient to proceed with the melting operation than the heating until the raw material deposit Vh is almost exhausted in the hot water discharge operation. Can do.

In addition, it is preferable that the molten metal is quickly discharged after the molten metal has accumulated to a level near the outlet. By doing so, it is easy to prevent the penetration of vanadium pentoxide into the furnace wall by shortening the time for the molten metal m to contact the furnace wall as much as possible.
The tilting of the melting furnace 1 extends the tilting means 14 and tilts the pouring gate 8 downward so that the molten metal m can be taken out from the pouring tap 8.
The molten metal m taken out in this way is subjected to a flaking process to be commercialized.

(The melting method of the second embodiment)
The melting method of the second embodiment uses exhaust heat throughflow.
As shown by a solid line or an imaginary line in FIG. 3, when the exhaust gas duct 16 is arranged in the direction in which the heat after heating is drawn into the melting furnace 1, the heat after heating the vanadium pentoxide deposit Vh by the heater 6 is converted to pentoxide. Since it flows through the inside of the vanadium deposit Vh and is drawn to the exhaust gas duct 16, the contact between the heat and the vanadium pentoxide deposit is improved, and it can be efficiently melted by drying in advance or preheating.

(The melting method of 3rd Embodiment)
The melting method of the third embodiment is a method of depositing vanadium pentoxide V at a plurality of locations in the melting furnace 1.
There is no particular limitation as long as the number of deposits is two or more. As shown in FIG. 4, in order to make the vanadium pentoxide deposit Vh in two places in the melting furnace 1 and to make them adjacent to each other, two chutes are provided on the furnace lid 4 or two chutes are provided on the furnace side wall 3. Then, it should be piled up in two places in the furnace. The means of the stacking method is arbitrary, and is not limited to a specific method.

  As illustrated in FIG. 4, if a peak of the vanadium pentoxide deposit Vh is formed adjacent to two places, a valley v is formed between the two peaks. The valley v naturally flows down the valley v where the molten metal m flows when the vanadium pentoxide deposit Vh is blown, so that the molten metal m in the high temperature state does not approach the furnace side wall 3 and the furnace wall is not melted. Since it is surrounded by the vanadium oxide deposit Vh, it becomes easy to prevent damage to the furnace wall. In addition, when it accumulates in three or more places, it is the same that the valley v can be blown and damage to the furnace wall can be prevented.

(The melting method of the fourth embodiment)
The melting method of the first and second embodiments is a batch type in which the molten metal is discharged when a certain amount of molten metal is accumulated. However, in the present invention, a continuous melting method in which the molten metal is continuously discharged is also possible.
The melting furnace 1 shown in FIG. 7 is an example of a melting furnace suitable for a continuous type, and is provided to be inclined so that one of the furnace bottoms 2 is high and the other is low. And the hot water outlet 8 is formed in the furnace side wall 3 with a lower inclination.
A feeder 21 is provided on the furnace side wall 3 having the higher furnace bottom 2, and a hopper 22 is also connected thereto. The vanadium pentoxide deposit Vh fed into the furnace by the hopper 22 and the feeder 21 is piled up on the inclined furnace bottom 2.

And the heater 6 is attached via the furnace side wall 3 and the furnace cover 4 so that a flame or a hot air may hit against the slope of the vanadium pentoxide deposit Vh deposited in piles.
In the illustrated melting furnace 1, two heaters 6 are attached so that heating can be performed from two directions from above the slope of the vanadium pentoxide deposit Vh and from the side facing the slope. Thus, if it heats from two directions, it can melt | dissolve efficiently, but it is arbitrary whether it heats with the one heater 6. FIG.

  When the melting furnace 1 is used, since the furnace bottom 2 is inclined, the molten metal that has melted from the slope of the vanadium pentoxide deposit Vh continues to accumulate at the bottom of the melting furnace 1. The molten metal can be continuously taken out from the tap 8. Since the operation | work which inclines the melting furnace 1 can be abbreviate | omitted in such a continuous type, an operation rate improves. Moreover, if the flaking work of a post process is made into a continuous type, cooperation of both work can be simplified.

The advantages of the melting methods of the first to fourth embodiments are summarized as follows.
(1) Vanadium pentoxide can be treated with a wet or granular material, and dust generation can be suppressed in a series of operations accompanying charging into the melting furnace.
(2) Since the surface of the vanadium pentoxide deposit Vh is directly heated by spraying, the surface of the vanadium pentoxide deposit Vh is covered with a melt or a sintered product, so that no dust is generated. For this reason, it is possible to prevent the health hazard of workers.
(3) The vanadium pentoxide deposit Vh is directly blown and melted in the melting furnace, and the entire furnace need not be heated to a high temperature. For this reason, it is easy to prevent the melt of vanadium pentoxide, which has extremely high permeability, from penetrating into the furnace wall, and at the same time, impurities such as Si and Al due to damage to the furnace wall are eliminated, and the vanadium pentoxide product has a high purity. Can be maintained.
(4) Since the vanadium pentoxide deposit Vh can be melted from a portion having a slope or a valley, and the portion close to the furnace side wall can be avoided from being melted, the influence of the furnace wall melting damage can be reduced.
(5) If the hot water is discharged in a short time, it is easy to prevent the molten metal from penetrating and damaging the furnace wall, and at the same time, impurities from the furnace wall are eliminated and the vanadium pentoxide product can be maintained in high purity.
(6) If the bottom layer portion is cooled and solidified while taking out the upper layer portion of the molten vanadium pentoxide as a product, the solidified portion serves as a protective layer for the furnace bottom, so that damage to the furnace wall can be prevented.

(Other embodiments)
In the above embodiment, when the wet cake is directly thrown on the deposition of vanadium pentoxide V, the process is simplified because the drying process does not have to be performed before the addition. Moreover, since the wet cake contains moisture, dust generation at the time of charging can be suppressed.
When the granular material granulated from the wet cake is added to the deposition of the vanadium pentoxide V, a gap is formed between the accumulated granular materials, so that it is preheated into the deposit during heating. For this reason, melting efficiency becomes high. In addition, moisture evaporation and pre-drying of the deposit proceeds quickly, and the melting time in the furnace can be shortened.

  Further, in each of the above embodiments, vanadium pentoxide solidified to prevent penetration of molten vanadium pentoxide into the furnace wall is used as a protective layer, and the molten metal is cooled by the cooling jacket 7 to prevent penetration. Those using only the vanadium pentoxide protective layer without using the jacket 7 and those using only the forced cooling by the cooling jacket 7 without forming the vanadium pentoxide protective layer are also included in the melting method of the present invention. . Even when using only such a protective layer or forced cooling, if the surface temperature of the furnace inner wall is lowered below the melting point, damage to the furnace wall can be suppressed by stopping the penetration of the vanadium pentoxide melt into the furnace material. .

DESCRIPTION OF SYMBOLS 1 Melting furnace 2 Furnace bottom 3 Furnace side wall 4 Furnace lid 5 Chute 6 Heater 7 Cooling jacket 8 Outlet 14 Tilting means Vh Vanadium pentoxide deposit m Molten metal

Claims (12)

The furnace of the melting furnace is blown by direct heating with a flame or hot air so that only a limited range of the surface of the vanadium pentoxide deposit accommodated in the melting furnace is equal to or higher than the melting point of vanadium pentoxide, The method for melting vanadium pentoxide, wherein the wall is not directly heated so as to be kept at a temperature below the melting point of vanadium pentoxide . 2. The method for melting vanadium pentoxide according to claim 1, wherein the heating is performed by directly heating an inclined surface formed by stacking the vanadium pentoxide deposits. The method for melting vanadium pentoxide according to claim 1 or 2, wherein the heating is performed by radiating a flame generated by complete combustion. The method of melting vanadium pentoxide according to claim 1 or 2, wherein the heating is performed by radiating high temperature hot air generated by complete combustion in a hot air furnace. 3. The method for melting vanadium pentoxide according to claim 2, wherein vanadium pentoxide is deposited in one place in the melting furnace and the slope is heated. 3. The method for melting vanadium pentoxide according to claim 2, wherein vanadium pentoxide is deposited in a plurality of adjacent locations in the melting furnace, and a slope that becomes a valley is heated. 3. The method for melting vanadium pentoxide according to claim 1 or 2, wherein the vanadium pentoxide deposit is a cake containing moisture after solid-liquid separation. 3. The method for melting vanadium pentoxide according to claim 1, wherein the deposit of vanadium pentoxide is a granulated product obtained by granulating a cake or a dried product thereof. The method for melting vanadium pentoxide according to claim 1 or 2, wherein the exhaust gas is discharged so that the heat after heating passes through the inside of the vanadium pentoxide deposit accommodated in the melting furnace. The method for melting vanadium pentoxide according to claim 1 or 2, wherein a molten metal pool portion in the melting furnace is cooled by forced cooling or heat radiation. 3. The method for melting vanadium pentoxide according to claim 1 or 2, wherein a predetermined amount of molten metal in which vanadium pentoxide is melted is collected. The method for melting vanadium pentoxide according to claim 1 or 2, wherein the molten metal in which vanadium pentoxide is melted is continuously taken out.

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