JP6939519B2 - Fluid roasting furnace - Google Patents

Description

The present invention relates to a fluidized roasting furnace. More specifically, the present invention relates to a fluidized roasting furnace capable of roasting an object to be roasted, which requires high quality.

In general, a fluidized roasting furnace creates a mixed state with a medium by suspending the granular raw material to be roasted as if it were a fluid while supplying gas with the raw material alone or using a fluid medium, and is efficient. It is a device for roasting. By roasting in a state where the raw material to be roasted and the fluidized medium are mixed, roasting proceeds while the raw material and the fluidized medium collide with each other, and the raw material can stay in the fluidized bed for a relatively long time. It can be roasted efficiently.

In order to reliably roast the raw material supplied by using such a fluidized roasting furnace, the flow velocity of the gas flows with the raw material (hereinafter, may be referred to as "roasted object" in the present specification). The superficial velocity of the mixture with the medium must be precisely controlled to be in the range greater than or equal to the minimum fluidization velocity and less than the terminal velocity.

Here, the "superficial velocity" is the actual velocity obtained by the gas flow rate / cross-sectional area in the furnace. The "minimum fluidization rate" is the minimum rate at which the powder (mixture of the material to be roasted and the fluid medium) begins to flow. The "terminal velocity" is the speed at which the powder rises from the fluidized bed and begins to pop out.

The reason why the speed control needs to be performed accurately as described above is as follows. That is, if the flow velocity of the supplied gas is less than the "minimum fluidization rate" of the mixture of the raw material and the fluidized medium, roasting does not proceed uniformly because the raw material does not fluidize, and the raw materials aggregate. Problem arises.

On the other hand, if the flow velocity of the gas is equal to or higher than the "terminal velocity" of the mixture, the flow velocity is too high and the raw material or the fluid medium is flown together with the gas, so that roasting cannot be performed effectively. There arises a problem that the recovery rate is greatly reduced.

That is, in fluidized roasting, it is necessary to control the gas flow rate within an appropriate range and fluidize the raw material in the fluidized bed for a time sufficient for roasting.

Patent Documents 1 and 2 disclose the configuration of the fluidized roasting furnace described above. These fluid roasting furnaces have some problems in order to carry out industrial production. The four listed below are considered to be important.

The first problem is that continuous processing is difficult. From the viewpoint of efficiency, raw materials are continuously added during continuous processing. At this time, if the raw material being roasted and the raw material not roasted are mixed and roasting cannot be performed efficiently, the quality of the product to be roasted is deteriorated, which is not preferable.

In order to solve the above problem, it is conceivable to separate the raw material input port and the raw material recovery port so that the raw material goes from the input port to the recovery port, but in the case of fluid roasting, the granular raw material is used. Since it is fluidized like a fluid, the raw materials that have not been roasted immediately after being put in and the raw materials that have been floating in the furnace for a while and have been roasted are immediately mixed, and only the raw materials that have been roasted are collected. It is not possible to do so, and raw materials that are inadequately roasted are also recovered in a mixed state. For this reason, low quality products are collected, and the roasting efficiency is also deteriorated.

In Patent Document 1, old sand dust is supplied to the roasting chamber of a fluidized roasting furnace, fluidized roasted in the roasting chamber, and an overflow port opens at an upper position of a fluidized bed formed in the roasting chamber. A technique for overflowing from the sand and collecting it as recycled dust is disclosed. Here, the old sand dust is obtained by collecting dust generated by a dry regenerator for reclaiming used cast sand. In addition, silica sand is stored as base sand at the bottom of the fluidized roasting furnace.

In addition, it is also disclosed that the compressed air blowing pipe provided at the inlet portion of the chute allows compressed air to be blown toward the outlet of the chute from a nozzle formed at the tip thereof. That is, the old sand dust is supplied into the furnace while blowing compressed air toward the chute, and the old sand dust overflows from the overflow port and is collected.

In the fluidized roasting furnace disclosed in Patent Document 1, since the supply height position of the old sand dust and the height position of the overflow port (recovery port) are almost the same, the old sand dust is fluidized. As for, only the roasted ones are not surely overflowed from the overflow port and collected.

That is, since the old sand dust before roasting is supplied one after another to the old sand dust that has been fluidized and roasted, the old sand dust collected from the overflow port is insufficiently roasted. Sand dust is mixed. Therefore, continuous processing is difficult at this point.

Regarding the first problem above, in order to recover the old sand dust that has been roasted as much as possible by the method disclosed in Patent Document 1, it is necessary to slow down the supply rate of the old sand dust as much as possible. Conceivable. However, in this case, the treatment by the fluidized roasting furnace becomes very inefficient, and continuous treatment is still difficult.

The second problem is that it is difficult to separate the gas used for roasting after roasting and the object to be roasted after roasting.

Patent Document 2 describes a step of oxidatively roasting a metallic iron source in a fluidized roasting furnace, a step of peeling an oxide layer of coarse particles discharged from an overflow port of the roasting furnace, and a step of peeling iron oxide after the peeling step. A method for producing high-grade iron oxide is disclosed, which comprises a step of circulating metallic iron powder in a fluidized roasting furnace and a step of flowing out the produced fine iron oxide together with the roasting gas and capturing and recovering it from the roasting gas. ing.

However, although Patent Document 2 describes that fine iron oxide is discharged together with roasting gas and captured and recovered from the roasting gas, specifically how fine iron oxide is discharged together with roasting gas is described. Is not clearly shown. That is, it is completely unknown how to efficiently separate the fine iron oxide and the roasting gas and capture and recover the fine iron oxide.

Further, Patent Document 2 also discloses that the peeled oxide film is accompanied by the exhaust gas of the fluidized roasting furnace and discharged to the outside of the furnace. It is also unclear whether it will be discharged.

The third problem is that the purity of the product required for the product to be roasted differs depending on the product to be roasted. A specific example of the raw material of the fluidized roasting furnace will be described. Nickel oxide (NiO), which is often used as a raw material for a secondary battery, for example, is a very strict product to be roasted in terms of purity and the like. Nickel oxide is produced by adding an alkali to an aqueous solution containing _{nickel sulfate (NiSO 4 ), neutralizing it to obtain nickel hydroxide (Ni (OH) 2} ), and roasting the nickel hydroxide.

Regarding this nickel oxide, the sulfur grade of impurities contained in the obtained nickel oxide is high, and if it exceeds 100 ppm, for example, the characteristics of a battery manufactured from nickel oxide are deteriorated, which is not preferable. Therefore, it is indispensable to remove the sulfur adhering by the pretreatment such as washing and to reduce the sulfur by roasting uniformly and surely. That is, the configuration of the fluidized roasting furnace disclosed in Patent Document 1 and the like has a problem that the uniformity of roasting cannot be sufficiently improved with respect to a predetermined raw material.

The fourth problem is related to the characteristics of the object to be roasted. In the above-mentioned liquid roasting of nickel hydroxide, it is also necessary to consider the influence of the generated gas. That is, at the same time the nickel oxide by roasting nickel hydroxide is produced, the water along with the decomposition of the nickel hydroxide (H 2 _O), i.e. water vapor gases generated. Due to the volume of the generated steam gas, the flow velocity in the fluidized roasting furnace rises sharply, and as a result, the object to be roasted is discharged with incomplete roasting, which causes a problem of deterioration in quality and recovery rate.

The influence of the gas generated by the above roasting occurs not only in the case of nickel hydroxide and the like, but also in the case of roasting copper concentrate, for example, to separate arsenic. That is, when the copper concentrate is roasted in an inert gas, arsenic sulfide is generated as a gas, and the copper concentrate is discharged to the outside of the furnace.

Regarding this fourth problem, when gas is generated by roasting, in order to prevent the discharge of unreacted raw materials from the fluidized roasting furnace, the amount of gas generated is predicted in advance and the amount of gas generated is used. It is necessary to reduce the amount of gas sent to the equivalent amount of fluidization. However, the above-mentioned water vapor gas and the like are generated in the fluidized bed as a result of the roasting reaction, and if the amount of gas supplied for fluidization is uniformly reduced, fluidization does not occur and the reaction does not proceed or is excessive. There arises a problem that the desired roasting does not proceed smoothly due to the flow rate.

In response to this fourth problem, in Patent Document 1, a portion having an enlarged cross-sectional area inside the furnace is installed on the outlet side of the core body of the flow roasting furnace, and the gas flowing in the furnace of the flow roasting furnace is provided. In addition, the flow velocity of the object to be roasted is reduced by expanding the cross-sectional area to prevent the discharge of raw materials that are insufficiently roasted.

Japanese Unexamined Patent Publication No. 2000-42515 Japanese Unexamined Patent Publication No. 61-236616

In response to the third and fourth problems, when a portion with an enlarged in-core cross-sectional area is installed on the outlet side of the core body of the fluidized roasting furnace as described in Patent Document 1, the diameter is increased. The rate of increase in the cross-sectional area in the furnace is too large compared to the rate of increasing. That is, the response parameter fluctuates too much compared to the parameter to be changed. For example, if the diameter of 30Cmm, when the diameter is 1.5 times the 45cm, the cross section furnace, the 707Cm ^2, 2.25 times the 1590 cm ^2. If the cross-sectional area inside the furnace becomes too large in this way, the superficial velocity will be lower than expected, which may lead to a decrease in the quality and recovery rate of the product to be roasted.

The present invention has been proposed in view of such circumstances, and it is possible to efficiently roast by making it easy to determine the rate of increase in the cross-sectional area in the furnace and controlling the superficial velocity. It is an object of the present invention to provide a fluidized roasting furnace having excellent quality and recovery rate of the product to be roasted.

The fluidized roasting furnace of the first invention includes a tubular core portion in which an object to be roasted is roasted using a gas flowing from downward to upward, a heater provided on the outer periphery of the tubular core portion, and the above. a material injection pipe for introducing material into the cylindrical core portion, and the front Symbol the roasting material is flowing can branch pipe from the inside of the cylindrical core portion, is provided with the branch pipe, It is provided separately from the raw material input pipe and is connected to the tubular core portion on the upper side of the heater. The branch pipe vibrates the roasted product deposited on the branch pipe. It is characterized in that a peeling device for peeling using the above is provided.

According to the first invention, since the branch pipe through which the roasted material can flow is provided in the upper part of the cylindrical core portion, the cross-sectional area in the furnace can be increased by the cross-sectional area of the branch pipe, and the furnace can be increased. The rate of increase in the internal cross-sectional area can be easily determined. As a result, the superficial velocity can be easily controlled, efficient roasting can be performed, and the recovery rate can be increased while improving the quality of the object to be roasted .
In addition , by applying vibration to the branch pipe by the peeling device, the object to be roasted accumulated on the branch pipe is removed, so that the productivity of the fluidized roasting furnace can be maintained for a long period of time. In addition, maintenance of the peeling device can be easily performed.

It is sectional drawing from the front direction of the fluid roasting furnace which concerns on 1st Embodiment of this invention. It is sectional drawing from the front direction of the fluid roasting furnace which concerns on 2nd Embodiment of this invention. It is sectional drawing from the front direction of the fluid roasting furnace which concerns on 3rd Embodiment of this invention. It is sectional drawing from the front direction of the fluid roasting furnace which concerns on 4th Embodiment of this invention. It is sectional drawing from the front direction of the fluid roasting furnace which concerns on 5th Embodiment of this invention.

Next, an embodiment of the present invention will be described with reference to the drawings. However, the embodiments shown below exemplify a fluidized roasting furnace and an operating method thereof for embodying the technical idea of the present invention, and the present invention describes the fluidized roasting furnace and its operating method as follows. Not specific to. The size or positional relationship of the members shown in each drawing may be exaggerated to clarify the explanation. Further, in the present specification, the notation of "X to Y" (X and Y are arbitrary numerical values) means "X or more and Y or less".

(First Embodiment)
FIG. 1 shows a cross-sectional view of the fluidized roasting furnace 10 according to the first embodiment of the present invention from the front direction. In FIG. 1, the thick black arrow indicates the flow direction of the flowing gas. The fluidized roasting furnace 10 of the present embodiment is provided with a cylindrical core portion 11 having a cylindrical shape in a state where the axis is vertical. A fixed layer 15 is provided below the tubular core portion 11. As the fixed layer 15, one filled with ceramics such as spherical alumina can be used, and the ceramics may be porous or may have a high filling rate. Then, the fixed layer 15 may be composed of several layers so that the object to be roasted does not fall under the fixed layer 15. For example, spherical alumina may be used in the lower part of the fixed layer 15, and smaller spherical alumina may be used in the upper part of the fixed layer 15. On the lower surface of the fixed layer 15, a flow gas introduction pipe 12 for introducing the flow gas from below the tubular core portion 11 is provided. When the fluidized gas is supplied from the fluidized gas introduction pipe 12 in the direction indicated by the thick arrow, the fluidized medium 31 and the raw material 32 located on the fixed layer 15 are fluidized to form a fluidized bed. Roasting is performed with the raw material 32 floating in the fluidized bed.

A heater 13 for holding the flow medium 31 and the like at a constant temperature is provided in the lower part of the tubular core portion 11. The heater 13 may not be provided depending on the raw material 32. When the heater 13 is not used, for example, hot gas may be flowed through the flow roasting.

The raw material 32 to be supplied to the tubular core portion 11 is appropriately charged by the raw material input pipe 14 provided on the side portion of the tubular core portion 11. Then, after the raw material is charged, the raw material input pipe 14 is closed with a lid or a valve.

In the fluidized roasting furnace 10 according to the present embodiment, a branch pipe 16 into which the material to be roasted, that is, the raw material 32 can flow in is connected to the upper part of the cylindrical core portion 11. The upper portion of the tubular core portion 11 refers to a portion located above the fluidized bed in which the fluidized medium 31 and the raw material 32 are fluidized, but it does not have to be strictly above the fluidized bed. That is, a part of the fluidized bed may be located at the junction of the branch pipe 16 with respect to the tubular core portion 11.

In this embodiment, two branch pipes 16 are provided in the cylindrical core portion 11 as shown in FIG. However, the number of branch pipes 16 may be one, or three or more. It is preferable that two or more branch pipes 16 are provided evenly on the entire circumference of the tubular core portion 11. In the present embodiment, the branch pipe 16 located on the left side of FIG. 1 is arranged at a position where the branch pipe 16 located on the right side is moved by 180 ° about the axial center of the tubular core portion 11.

The axis of the branch pipe 16 is a straight line, and when viewed from the front, this axis is only a predetermined angle from the junction of the branch pipe 16 with respect to the tubular core portion 11 with respect to the axis of the tubular core portion 11. It is leaning upwards. In the present embodiment, the axis of the branch pipe 16 is a straight line, but it may be a curved line. However, the end of the branch pipe 16 on the side opposite to the side where the tubular core portion 11 is located is located above the joint portion of the branch pipe 16 with respect to the tubular core portion 11.

Since the branch pipe 16 through which the roasted material can flow in is provided in the upper part of the tubular core portion 11, the cross-sectional area in the furnace is increased by the cross-sectional area of the branch pipe 16 and the rate of increase in the cross-sectional area in the furnace is increased. Can be easily determined. In this sense, as the number of branch pipes 16 increases, the rate of increase in the cross-sectional area in the furnace can be finely changed. Then, as will be described later, the superficial velocity can be easily controlled, the roasted material can be prevented from being taken away together with the flowing gas, efficient roasting is performed, and the roasted material is recovered while improving the quality. The rate can be increased.

In the fluidized roasting furnace 10 of the present embodiment, the flow velocity of the flowing gas above the tubular core portion 11 can be made lower than the flow velocity below the tubular core portion 11 as in the conventional roasting furnace. As a result, even if the flow velocity of the flowing gas partially exceeds the terminal velocity in the cylindrical core portion 11 in the turbulent flow state, the raw material is removed from the roasted portion of the tubular core portion 11. It is possible to avoid being taken out (taken out). Therefore, since the value of the cross-sectional area in the furnace is larger in the upper part than in the lower part of the tubular core portion 11, the superficial velocity is lowered, the raw material falls to the lower part of the furnace, and roasting can be performed more efficiently.

By the way, in the conventional roasting furnace, a portion having an enlarged inner cross-sectional area is installed on the outlet side of the core body of the roasting furnace. Therefore, when the diameter is increased, the furnace is compared with the ratio of increasing the diameter. The rate of increase in the internal cross-sectional area becomes too large. That is, the response parameter fluctuates too much compared to the parameter to be changed. For example, if the diameter of the cylindrical core portion 11 is 30Cmm, when the diameter is 1.5 times the 45cm, the cross section furnace, the 707Cm ^2, 2.25 times the 1590 cm ^2.

On the other hand, in the fluidized roasting furnace 10 of the present embodiment, the area of the branch pipe 16 is smaller than that of the cylindrical core portion 11, so that the cross-sectional area of the branch pipe 16 can be increased or the branch pipe 16 can be increased. Even if the number of 16 is increased, the ratio of the increase in the in-core cross-sectional area to the cross-sectional area of the tubular core portion 11 can be relatively suppressed. This makes it easy to control the superficial velocity with high accuracy.

In the present embodiment, the cross-sectional area inside the reactor when calculating the empty tower speed is the tubular core portion 11 in the upper part of the tubular core portion 11 and the tubular core portion 11 in the plane perpendicular to the axis. Is considered to be the sum of the cross-sectional area of the branch pipe 16 and the cross-sectional area of the branch pipe 16 in the plane perpendicular to the axis of the branch pipe 16.

In the fluidized roasting furnace 10 of the present embodiment, since the superficial velocity can be easily controlled, heating with a soaking body can be reliably performed, and thus heat can be continuously applied to the object to be roasted more uniformly. It can be roasted reliably and evenly, and high quality products can be obtained. In addition, since the product to be roasted can be reliably controlled to the terminal velocity or lower, good fluid roasting can be performed, and the product to be roasted does not scatter, and a high recovery rate can be obtained.

(Operation method of the fluidized roasting furnace 10 according to the first embodiment)
As shown in FIG. 1, the fluidized roasting furnace 10 is charged with a fluidized medium 31 for forming a fluidized bed together with the raw material 32. The flow gas is introduced into the flow roasting furnace 10 from the flow gas introduction pipe 12, and the raw material 32 is charged in a predetermined amount. The flow velocity of the fluidizing gas is adjusted so that the "superficial velocity" of the mixture of the raw material 32 and the fluidizing medium 31 is equal to or more than the "minimum fluidization velocity" and less than the "terminal velocity".

It is preferable that the fluidized roasting furnace 10 is kept heated by the heater 13 and the raw material 32 is added to roast. This is because if the raw material is heated after being charged, it takes time and the efficiency deteriorates. It is preferable that the heater 13 is an electric type because it is easy to control. Further, although not shown, a gas burner or the like is preferable because it is cheap in terms of cost.

(Second Embodiment)
FIG. 2 shows a cross-sectional view of the fluidized roasting furnace 10 according to the second embodiment of the present invention from the front direction. The difference from the fluidized roasting furnace 10 of the first embodiment is that the branch pipe 16 is provided with a shutoff device 17 that blocks the flow of gas in the branch pipe 16.

The breaking device 17 is not particularly limited, but for example, a ball valve, a butterfly valve, or the like can be used. As long as the gas flow in the branch pipe 16 can be blocked, the position where the blocking device 17 is provided is not particularly limited.

As described above, the shutoff device 17 that shuts off the flow of gas in the branch pipe 16 can control the superficial velocity by changing the cross-sectional area inside the furnace according to the situation of the tubular core portion 11.

(Operation method of the fluidized roasting furnace 10 according to the second embodiment)
The step of forming a fluidized bed and roasting is the same as that of the fluidized roasting furnace 10 according to the first embodiment. In the second embodiment, the blocking device 17 is shut off when the fluidized roasting is completed.

That is, when the object to be roasted has been roasted, the branch pipe 16 is cut off by the cutoff device 17 of the branch pipe 16, and the in-core cross-sectional area when calculating the superficial velocity is the in-core cross-sectional area of the tubular core portion 11. The value of. As a result, the flow velocity of the fluidized gas can be set to be equal to or higher than the "terminal velocity", and the object to be roasted can be recovered together with the fluidized gas.

In the fluidized roasting furnace 10 of the present embodiment, the roasted material can be recovered only by closing the shutoff device 17. In this case, the object to be roasted can be efficiently recovered, and the fluidized roasting furnace 10 of the present embodiment has high productivity.

(Third Embodiment)
FIG. 3 shows a cross-sectional view of the fluidized roasting furnace 10 according to the third embodiment from the front direction. The difference from the fluidized roasting furnace 10 of the second embodiment is that the branch pipe 16 is provided with a peeling device for peeling the object to be roasted accumulated on the inner surface of the branch pipe 16. In the fluidized roasting furnace 10 of the present embodiment, the peeling device peels using vibration, and for example, the knocker 20 corresponds to this. In the present embodiment, the knocker 20 is arranged at the lower part of the outer circumference of each branch pipe 16.

The device that gives vibration is not limited to the knocker 20. Other devices that give vibration include vibrators and ultrasonic oscillators.

The type of the knocker 20 is not particularly limited, but it is preferable to use an air type knocker. This is because pneumatic knockers are generally popular, can be obtained at low cost, and have a great effect.
The type of vibrator is not particularly limited, but an air type, which is inexpensive and has a large effect like the knocker 20, is preferable.
Since the ultrasonic oscillator has lower heat resistance than the knocker 20 or the like, it is preferable to insulate or cool the ultrasonic oscillator.

In fluidized roasting, since roasting is performed in a turbulent state, the flow velocity of the fluidized gas partially increases, and when the particle size distribution of the object to be roasted is wide, a part of the object to be roasted flows out from the fluidized bed together with the gas. It may end up. When the branch pipe 16 is provided, the branch pipe 16 may have an inclined portion or a horizontal portion, and the object to be roasted is likely to be deposited. The fluidized roasting furnace 10 according to the present embodiment suppresses the accumulation of the roasted material in the branch pipe 16 by applying vibration to the branch pipe 16 by a peeling device. That is, when the material to be roasted is deposited on the branch pipe 16, the deposited material is dropped below the tubular core portion 11 of the fluidized roasting furnace 10 by applying vibration from the peeling device to the branch pipe 16. Liquid roast again.

In the fluidized roasting furnace 10 of the third embodiment, the branch pipe 16 is vibrated by the peeling device, so that the object to be roasted accumulated on the branch pipe 16 is removed, and the fluidized roasting furnace 10 extends for a long period of time. You can maintain productivity. In addition, maintenance of the peeling device can be easily performed.

(Operation method of the fluidized roasting furnace 10 according to the third embodiment)
The step of forming a fluidized bed and roasting is the same as that of the fluidized roasting furnace 10 according to the first embodiment. In the third embodiment, the user of the fluidized roasting furnace 10 operates the knocker 20 so that the object to be roasted does not adhere to the inner surface of the branch pipe 16. The operating conditions of the knocker 20 differ depending on the raw materials to be input. The knocker 20 may be operated continuously, for example, during roasting of the fluidized roasting furnace 10, or may be intermittently operated for several minutes per hour.

Further, it is the same as the second embodiment that the blocking device 17 is shut off when the fluidized roasting is completed.

(Fourth Embodiment)
FIG. 4 shows a cross-sectional view of the fluidized roasting furnace 10 according to the fourth embodiment from the front direction. The difference from the fluidized roasting furnace 10 of the second embodiment is that the branch pipe 16 is provided with a peeling device for peeling the object to be roasted accumulated on the inner surface of the branch pipe 16. In the fluidized roasting furnace 10 of the present embodiment, the peeling device peels using a peeling gas.

As shown in FIG. 4, the release gas introduction pipe 21 for introducing the release gas is provided on the upper side of the branch pipe 16 so that it can be directly sprayed on the lower inner surface of the branch pipe 16. One release gas introduction pipe 21 is provided for each branch pipe 16. Two or more release gas introduction pipes 21 may be provided in the branch pipe 16. For example, several branch pipes 16 can be provided along the axial direction.

Any type of peeling gas that does not affect roasting can be used, but the same gas as the fluidized gas or the gas discharged from the fluidized roasting furnace 10 is repeatedly used. preferable.

In the fluidized roasting furnace 10 according to the present embodiment, the peeling device sprays the branching pipe 16 with the peeling gas, so that the object to be roasted accumulated on the branching pipe 16 is removed, and the fluidized roasting furnace extends for a long period of time. You can maintain productivity. Further, since the roasted object can be removed by directly blowing the gas on the roasted object adhering to the inner surface of the branch pipe 16, the productivity of the fluidized roasting furnace 10 can be maintained more reliably.

(Operation method of the fluidized roasting furnace 10 according to the fourth embodiment)
The step of forming a fluidized bed and roasting is the same as that of the fluidized roasting furnace 10 according to the first embodiment. In the fourth embodiment, the peeling gas is introduced continuously or intermittently depending on the state of adhesion of the material to be roasted. When it is introduced intermittently, it is preferable because the average flow velocity of the gas including the peeling gas and the flowing gas can be suppressed, and the possibility that the roasted product is taken away by this gas is further reduced.

Further, it is the same as the second embodiment that the blocking device 17 is shut off when the fluidized roasting is completed.

(Fifth Embodiment)
FIG. 5 shows a cross-sectional view of the fluidized roasting furnace 10 according to the fifth embodiment from the front direction. The difference from the fluidized roasting furnace 10 of the second embodiment is that the branch pipe 16 is provided with a peeling device for peeling the object to be roasted accumulated on the inner surface of the branch pipe 16. In the fluidized roasting furnace 10 of the present embodiment, the peeling device corresponds to both a peeling device using vibration and a peeling device using a peeling gas. The peeling device using vibration is the same as the peeling device of the third embodiment, and the peeling device using the peeling gas is the same as the fourth embodiment.

In the fluidized roasting furnace 10 according to the present embodiment, the branch pipe 16 is vibrated by the peeling device, so that the object to be roasted accumulated on the branch pipe 16 is removed, and the fluidized roasting furnace 10 extends for a long period of time. You can maintain productivity. In addition, maintenance of the peeling device can be easily performed. Further, since the peeling gas is sprayed on the branch pipe 16 by the peeling device, the object to be roasted accumulated on the branch pipe 16 is removed, and the productivity of the fluidized roasting furnace can be maintained for a long period of time. Further, since the roasted object can be removed by directly blowing the gas on the roasted object adhering to the inner surface of the branch pipe 16, the productivity of the fluidized roasting furnace 10 can be maintained more reliably.

(Operation method of the fluidized roasting furnace 10 according to the fifth embodiment)
The step of forming a fluidized bed and roasting is the same as that of the fluidized roasting furnace 10 according to the first embodiment. Further, the operating conditions of the peeling device are the same as those in the third embodiment for peeling using vibration, and the same as those in the fourth embodiment for peeling using a peeling gas.

(Use of the present invention, etc.)
The fluidized roasting furnace 10 according to the first to fifth embodiments can be effectively used for raw materials whose specific gravity is small and lightened by roasting, and in particular, raw materials that generate gas during roasting. Can be effectively used in.

In the present invention, in addition to powdery products to be roasted, ores such as copper or nickel, concentrates obtained by concentrating these ores through treatment such as crushing or flotation, and nickel sulfate or nickel hydroxide, etc. It can be roasted using salts or the like used as a material for batteries as a raw material.

Hereinafter, experiments related to the present invention will be carried out, and examples of each embodiment of the present invention will be described. The present invention is not limited to the following examples.

(Experiment 1) (Verification of significance of branch pipe 16, raw material: nickel hydroxide)
<Raw materials>
_{Nickel hydroxide (Ni (OH) 2} ) was prepared as the raw material (to be roasted) 32 to be roasted. Nickel hydroxide has an average particle size of 20.5 to 22.5 μm, and was preheated to 175 ° C. in a vacuum and subjected to vacuum heat treatment for 3 hours to substantially remove the water content. When this nickel hydroxide was analyzed, the sulfur content was 1.9 to 2.1% by weight. The content of other components was low and was substantially negligible.

In each of the following experiments, batch processing was performed. That is, each raw material 32 is charged into the fluidized roasting furnace 10 in a predetermined amount, and then air is sent as a fluidizing gas from the lower part of the furnace to be fluidized, and the temperature is raised to a predetermined temperature and maintained for fluid roasting. The flow gas after roasting was discharged from the upper part.

<Fluid roasting process>
In Experiment 1, the fluid roasting furnace 10 according to the second embodiment shown in FIG. 2 and the roasting furnace in which the branch pipe 16 was removed from the fluidized roasting furnace 10 were used. These roasting furnaces were used to roast the raw material nickel hydroxide, and the nickel oxide (NiO) to be roasted after roasting was recovered.

Examples 1 and 2 use the fluidized roasting furnace 10 of the second embodiment, and the roasting furnace in which the branch pipe 16 is removed from the fluidized roasting furnace 10 of the second embodiment is used. Is Comparative Example 1.

In Example 1, the valve, which is the shutoff device 17, was left open during both the fluid roasting and the sample recovery, and after cooling the furnace, the sample in the furnace was recovered. In Example 2, the valve was left open during fluid roasting, and the valve was closed during sample recovery, and the sample was flowed and recovered by the fluid gas. For Comparative Example 1, the sample in the furnace was recovered after cooling the furnace.

The weights of the input raw materials were all the same, and the roasting conditions were all the same. Specifically, the roasting temperature was 900 ° C., the roasting time was 20 minutes, and air was used as the flow gas.

<Evaluation>
In each of the treatments of Examples 1, 2 and Comparative Example 1, the recovery rate (actual yield) of the sample obtained by roasting, the content of nickel oxide in the recovered sample, and the content of sulfur in the recovered sample. The quantity was evaluated. Table 1 shows the measurement results. The evaluation method is as follows.

[Recovery rate of samples obtained by roasting]
The recovery rate of the sample obtained by roasting was calculated by the following equation 1.

(Number 1)
R = W ₁ / (W _2- S) x 100

R: Recovery rate [%]
W ₁ : Weight of the recovered sample W ₂ : Weight when all the charged raw material 32 (Ni (OH) ₂ this time) is roasted (this time NiO) S: Sulfur contained in the charged raw material 32 Weight

[Ratio of nickel oxide content in the recovered sample]
For the ratio of the nickel oxide content in the recovered sample, the contents of nickel oxide (NiO) and nickel hydroxide (Ni (OH) ₂ ) contained in the recovered sample are calculated, and the respective contents are calculated. It was calculated as the ratio (% by weight) of the NiO content to the total value.

[Sulfur content in the recovered sample]
The sulfur content in the recovered sample was measured using a sulfur analyzer (manufactured by Mitsubishi Chemical Corporation, model: TOX-100).

As shown in Table 1, good results were obtained in Examples 1 and 2 using the fluidized roasting furnace 10 having the structure with the branch pipe of the second embodiment. That is, the recovery rate showed a high value of 99% or more, and the content ratio of nickel oxide in the recovered sample was 99% or more, and almost all of the samples could be roasted to NiO. In addition, the sulfur content in the recovered sample was as low as 19 to 21 ppm, and high-quality nickel oxide with low sulfur grade could be obtained.

On the other hand, in Comparative Example 1 in which the roasting furnace according to the present invention was not used, the recovery rate was as low as 63% and the sulfur grade in the recovered sample was as high as 25 ppm as compared with the above-mentioned Example.

(Experiment 2) (Verification of significance of branch pipe 16, raw material: copper concentrate)
<Raw materials>
As the target raw material (roasted product) 32, a copper concentrate containing arsenic and sulfur in the proportions shown in Table 2 was used.

<Fluid roasting process>
In Experiment 2, the fluid roasting furnace 10 according to the second embodiment shown in FIG. 2 and the roasting furnace in which the branch pipe 16 was removed from the fluidized roasting furnace 10 were used. Examples 3 and 4 use the fluidized roasting furnace 10 of the second embodiment, and Comparative Example 2 uses a roasting furnace from which the branch pipe 16 is removed.

In Example 1, the valve, which is the shutoff device 17, was left open during both the fluid roasting and the sample recovery, and after cooling the furnace, the sample in the furnace was recovered. In Example 2, the valve was left open during fluid roasting, and the valve was closed during sample recovery, and the sample was flowed and recovered by the fluid gas. For Comparative Example 1, the sample in the furnace was recovered after cooling the furnace.

The weights of the input raw materials were all the same, and the roasting conditions were all the same. Specifically, the roasting temperature was 900 ° C., the roasting time was 4.0 hours, and nitrogen was used as the fluidizing gas.

<Evaluation>
In each of the treatments of Examples 3, 4 and Comparative Example 2, the recovery rate (scattering rate) of the sample with the filter and the arsenic content in the copper concentrate after roasting were evaluated. Table 3 shows the measurement results. The evaluation method is as follows.

[Sample recovery rate with filter]
After roasting, the roasted material that was discharged together with the exhaust gas was collected with a bag filter, and the recovery rate (scattering rate) with the filter was calculated from the collected amount by the following formula. It should be noted that the lower the recovery rate (scattering rate) of the filter, the higher the rate of non-scattering from the fluidized roasting furnace, which is a preferable result.

(Number 2)
R ₂ = W ₃ / W ₄ x 100

R ₂ : Recovery rate with filter [%]
W ₃ : Weight of recovered sample W ₄ : Weight of raw material (copper concentrate this time)

[Arsenic content in the sample before and after the experiment]
Arsenic and sulfur were analyzed for the samples before and after the test using an ICP emission spectrophotometer.

As shown in Table 3, good results were obtained in Examples 3 and 4 using the fluidized roasting furnace 10 having the structure with the branch pipe of the second embodiment. That is, in all the samples, the arsenic grade was reduced to less than 0.1% by weight, and the contents of arsenic and sulfur in the concentrate were greatly reduced. As the arsenic and sulfur in the concentrate decreased in this way, the copper content in the ore increased by 10% or more.

On the other hand, Comparative Example 2 gave an unfavorable result. That is, the lowest arsenic content was 0.1% by mass, and the amount recovered by the filter was 18% or more. As described above, it was found that the fluid roasting furnace 10 of the second embodiment of the present invention can efficiently roast.

(Experiment 3) (Verification of significance of peeling device, raw material: nickel hydroxide)
<Raw materials>
_{Nickel hydroxide (Ni (OH) 2} ) was prepared as the raw material (to be roasted) 32 to be roasted. Nickel hydroxide has an average particle size of 22.5 to 24.5 μm, and was preheated to 175 ° C. in a vacuum and subjected to vacuum heat treatment for 3 hours to substantially remove the water content. When this nickel hydroxide was analyzed, it contained a sulfur content of 2.0 to 2.2% by weight. The content of other components was low and was substantially negligible.

<Fluid roasting process>
In Experiment 3, the fluid roasting furnace 10 according to the fifth embodiment shown in FIG. 5 and the roasting furnace in which the branch pipe 16 was removed from the fluidized roasting furnace 10 were used. These roasting furnaces were used to roast the raw material nickel hydroxide, and the nickel oxide (NiO) to be roasted after roasting was recovered.

In the fluidized roasting furnace 10 of the fifth embodiment, an air-type knocker 20 and a gas introduction pipe 21 for peeling were provided as a peeling device. In Examples 5 and 6, vibration was applied to the branch pipe 16 by the knocker 20, but the release gas was not blown. In Examples 7 and 8, vibration was applied to the branch pipe by the knocker 20, and the peeling gas was introduced from the peeling gas introduction pipe 21. The release gas was blown from the outside of the branch pipe 16 at 1-minute intervals. When the release gas was blown in, the flow rate of the flow gas introduced from below was reduced so that the total flow rate of the flow gas and the release gas would be the same as when only the flow gas was blown.

In Examples 5 and 7, the valve, which is the shutoff device 17, was left open during both the fluid roasting and the sample recovery, and after cooling the furnace, the sample in the furnace was recovered. In Examples 6 and 8, the valve was left open during fluid roasting, and the valve was closed during sample recovery, and the sample was flowed and recovered by the fluid gas. For Comparative Example 3, the sample in the furnace was recovered after cooling the furnace.

The weights of the input raw materials were all the same, and the roasting conditions were all the same. Specifically, the roasting temperature was 900 ° C., the roasting time was 20 minutes, and air was used as the flow gas.

<Evaluation>
In each of the treatments of Examples 5 to 8 and Comparative Example 3, the recovery rate (actual yield) of the sample obtained by roasting, the content of nickel oxide in the recovered sample, and the content of sulfur in the recovered sample. The quantity was evaluated. Table 4 shows the measurement results. The evaluation method is as follows.

[Recovery rate of samples obtained by roasting]
The recovery rate of the sample obtained by roasting was calculated by the same method as in Experiment 1.

[Ratio of nickel oxide content in the recovered sample]
The ratio of the nickel oxide content in the recovered sample was calculated by the same method as in Experiment 1.

[Sulfur content in the recovered sample]
The sulfur content in the recovered sample was measured using a sulfur analyzer (manufactured by Mitsubishi Chemical Corporation, model: TOX-100) in the same manner as in Experiment 1.

As shown in Table 4, in Examples 5 to 8 using the fluidized roasting furnace 10 having the structure with the branch pipe 16 of the fifth embodiment, the recovery rates were all as high as 99% or more, and the recovered samples were all shown. The content ratio of nickel oxide in the above was 99% by weight or more, and it was almost completely roasted to NiO. The sulfur grade in the recovered sample was also low.

On the other hand, in Comparative Example 3 in which the roasting furnace according to the present invention was not used, the recovery rate was lower and the sulfur grade in the recovered sample tended to be higher than in Examples 5 to 8.

(Experiment 4) (Verification of significance of peeling device, raw material: copper concentrate)
<Raw materials>
As the target raw material (roasted product) 32, a copper concentrate containing arsenic and sulfur in the proportions shown in Table 2 was used.

<Fluid roasting process>
In Experiment 4, the fluid roasting furnace 10 according to the fifth embodiment shown in FIG. 5 and the roasting furnace in which the branch pipe 16 was removed from the fluidized roasting furnace 10 were used.

In the fluidized roasting furnace 10 of the fifth embodiment, an air-type knocker 20 and a gas introduction pipe 21 for peeling were provided as a peeling device. In Examples 9 and 10, vibration was applied to the branch pipe 16 by the knocker 20, but the release gas was not blown. In Examples 11 and 12, the branch pipe 16 was vibrated by the knocker 20, and the peeling gas was introduced from the peeling gas introduction pipe 21. The release gas was blown from the outside of the branch pipe 16 at 1-minute intervals. When the release gas was blown in, the flow rate of the flow gas introduced from below was reduced so that the total flow rate of the flow gas and the release gas would be the same as when only the flow gas was blown.

In Examples 9 and 11, the valve, which is the shutoff device 17, was left open during both the fluid roasting and the sample recovery, and after cooling the furnace, the sample in the furnace was recovered. In Examples 10 and 12, the valve was left open during fluid roasting, and the valve was closed during sample recovery, and the sample was flowed and recovered by the fluid gas. For Comparative Example 4, the sample in the furnace was recovered after cooling the furnace.

The weights of the input raw materials were all the same, and the roasting conditions were all the same. Specifically, the roasting temperature was 900 ° C., the roasting time was 4.0 hours, and nitrogen was used as the fluidizing gas.

<Evaluation>
In each of the treatments of Examples 9 to 12 and Comparative Example 4, the recovery rate (scattering rate) of the sample with the filter and the arsenic content in the copper concentrate after roasting were evaluated. Table 5 shows the measurement results. The evaluation method is as follows.

[Sample recovery rate with filter]
The recovery rate (scattering rate) of the sample with the filter was calculated by the same method as in Experiment 2. It should be noted that the lower the recovery rate (scattering rate) of the filter, the higher the rate of non-scattering from the fluidized roasting furnace, which is a preferable result.

[Arsenic content in the sample before and after the experiment]
The arsenic content in the sample before and after the experiment was measured by the same method as in Experiment 2.

As shown in Table 5, good results were obtained in Examples 9 to 12 using the fluidized roasting furnace 10 having the structure provided with the peeling device of the fifth embodiment. That is, in all the examples, the recovery rate (scattering rate) with the filter was 0%, and arsenic was significantly reduced to less than 0.1% by mass. The copper content in the ore increased by more than 10% because the arsenic and sulfur contents in the concentrate were greatly reduced.

On the other hand, in Comparative Example 4 outside the scope of the present invention, the recovery rate with the filter was 18%, the amount of the object to be treated scattered outside the furnace increased, and the arsenic content was 0.1% by mass.

10 Flow roasting furnace 11 Cylindrical core 16 Branch pipe 17 Shutoff device 20 Knocker 21 Detachment gas introduction pipe

Claims (1)

A cylindrical core in which the object to be roasted is roasted using gas flowing from the bottom to the top.
A heater provided on the outer circumference of the cylindrical core and
A raw material input pipe for charging raw materials into the cylindrical core, and
Before SL and internal from can flow branch pipe of the roasting material is the tubular core portion, is provided with,
The branch pipe is provided separately from the raw material input pipe, and is connected to the cylindrical core portion above the heater.
The branch pipe is a peeling device that uses vibration to peel off the roasted material deposited on the branch pipe.
Is provided ,
A fluid roasting furnace characterized by this.

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