JP4245195B2 - Reduction melting furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal reduction technique and a waste treatment technique. In the furnace, a packed bed made of a carbon-based combustible material is formed. The present invention relates to a reduction melting furnace configured to be melted so that a reduced melt can be taken out from a lower part.
[0002]
[Prior art]
As such a reduction melting furnace, a so-called cupola type reduction melting furnace is known. In such a reductive melting furnace, as shown in FIG. 2, a packed bed made of a carbon-based combustible material is formed in the furnace, and this packed bed is brought into a high-temperature reducing state to perform reduction melting of the object to be treated. Is called. In the operation of the furnace, a reduction target object, a reduction accelerator, and the like are introduced from the vicinity of the top of the furnace.
[0003]
[Problems to be solved by the invention]
However, in the furnace of the queue port la type as described above has the following problems. That is, in a conventional furnace, since only solid fuel such as coke is used as a heat source and a reducing atmosphere forming source, it is relatively difficult to stably control the temperature and reducing atmosphere required for reducing melting. Therefore, an operator who is skilled in the operation of the furnace is required, and the time and cost for nurturing the skilled operator are excessive. On the other hand, there is a problem that the operation of the furnace is difficult for operators with low skill levels, and the quality of the reduced melt obtained from the furnace is not stable.
Furthermore, regarding the temperature control in the furnace, in order to raise the temperature of the solid fuel, it was necessary to supply oxygen-containing gas from the tuyere attached in the vicinity of the packed bed. There was a problem that a non-uniform reductive melting zone was formed by each part inside.
In addition, since the reduction accelerator was put together with the object to be treated from the top of the furnace, it took a long time to pass through the packed bed. It was difficult to take measures to do.
Accordingly, an object of the present invention is to solve the above problems.
[0004]
[Means for Solving the Problems]
According to the first aspect of the present invention for achieving this object, a packed bed made of a carbon-based combustible material is formed, and an object to be treated is introduced into the packed bed, and the reduced melt melted by reduction in the packed bed The characteristic configuration of the reductive melting furnace that can be taken out from the lower part is as follows.
〔Constitution〕
That is, a support part that supports the packed bed from below is provided in a state in which the reduced melt can be dropped, and a burner that can adjust the air-fuel ratio of the oxygen-containing gas is provided below the support part. A packed bed in which the reduced melt of the object to be treated can be taken out from the lower part of the combustion chamber in which the reduced melt is stored, and the packed bed is filled with the carbon-based combustible material from the support portion. Provide a tuyere that can supply oxygen-containing gas at the part on the side of the support, which is less than half the height, and adjust the supply amount of oxygen-containing gas supplied from the burner and tuyere to fill The reductive melting furnace is configured by providing a reductive melt treatment material input port capable of supplying a treatment material for the reductive melt in the combustion space in the combustion chamber while maintaining the bed and the combustion chamber in a reducing atmosphere state. .
[Action]
In the reductive melting furnace of the present application, the object to be treated is put into the packed bed and is reduced and melted in the packed bed as in the conventional furnace. Here, a combustion chamber provided with a burner is provided below the packed bed, and heat necessary for melting is mainly supplied by combustion of the burner and combustion of the carbon-based combustible material in the combustion chamber. The In this case, the carbon-based combustible material plays the role of maintaining the shape of the packed bed and maintaining the temperature. Further, the reducing atmosphere state of the packed bed is mainly governed by the relationship between the combustion control in the burner provided in the combustion chamber and the amount of combustion oxygen supplied from the tuyere. The role of the supply amount in the furnace operation is reduced compared to the conventional one. That is, it is possible to form a reduced state relatively easily by appropriately controlling the air-fuel ratio in the burner.
That is, the thermal control of the furnace and the reducing atmosphere control are facilitated.
The reduced melt melted by reduction in the packed bed drops the support portion, enters the combustion chamber, is stored at the bottom of the combustion chamber, and is taken out from the furnace.
Now, in the reduction melting furnace having this structure, the operation by a skilled operator is reduced as in the prior art for the above reasons. Furthermore, the consumption of carbon-based combustible substances can be reduced.
Further, in the structure of the present application, the combustion flame from the burner is formed in the combustion chamber, so that the bottom of the combustion chamber storing the reduced melt can be stably maintained at a relatively high temperature for a long time. It becomes. Accordingly, as will be described later, the product quality can be easily controlled.
On the other hand, the amount of heat necessary for melting may not be obtained sufficiently by the heat from the burner. Furthermore, when the support portion is configured, the support portion is configured with a cooling structure (for example, a cooling pipe such as a water pipe). In such a case, the temperature near the support portion is lowered. Is also possible. Therefore, in the reductive melting furnace of the present application, a tuyere capable of supplying an oxygen-containing gas is provided at a site on the support portion side of the packed bed. The portion on the support portion side, which is the attachment position of the tuyere, is a portion of the packed bed that is less than half the height of the packed bed filled with the carbon-based combustible material from the support. From this tuyere, oxygen that does not inhibit the reduced state in the packed bed is supplied toward the packed bed formed of the carbon-based combustible material. If it does in this way, the problem of the temperature fall in the vicinity of a support part and a fusion defect can be controlled suitably.
Furthermore, by providing such tuyere separately, it becomes easy to control the temperature and atmosphere in the packed bed formed of carbon-based combustible materials, and control of the packed bed height, which is indispensable as a processing condition of the processing object. It is also possible to do.
And, the treatment material for the reduced melt is introduced from the reduced melt treatment material charging port. As such a treatment material, a reduction accelerator, a material that combines with oxygen existing in the combustion chamber, a reduced melt A fluidity adjusting material or the like for adjusting the fluidity of an object can be introduced.
Then, the molten reductate collected at the bottom of the combustion chamber, which can be maintained at a relatively high temperature (for example, about 1000 ° C.), is reacted at this high temperature for a relatively long time, and the reduced melt is taken out as a desired state. be able to.
[0005]
[Configuration / Function / Effect]
Here, when the treatment material is a reduction promoting material for the reducing melt, the reduction promoting material can be directly introduced into the reducing melt, and the treatment object is reduced to the reducing melt. Further reduction treatment can be performed in a state in which the temperature, gas atmosphere and time are appropriately controlled, and a product of good quality can be obtained efficiently and easily.
Furthermore, when a defective product is generated due to insufficient reduction, it is possible to respond quickly by putting the treatment material directly into the reduced melt. In this regard, in the conventional structure, reduction promoting material to be introduced from above the packed bed, for effective starting led to the furnace bottom, a time lag is large, cut with improved large problem that it is difficult quality control .
[0006]
[Configuration / Function / Effect]
Further, here, when the treatment material is a material that floats on the surface of the reduced melt and is combined with oxygen existing in the combustion chamber, the following actions and effects can be obtained.
In the reduction melting furnace of the present application, since the combustion chamber is provided with a burner, oxygen is supplied into the combustion chamber for combustion of the burner no matter how the reduction state is obtained. This oxygen tends to exert an oxidizing action on the reduced melt stored in the lower part of the combustion chamber. However, as the treated material, a material that binds with oxygen existing in the combustion chamber (e.g., coke powder which can be suspended in the molten treated surface) If left as you put, contact with such oxygen and reducing melt Is suppressed, and a stable reduced product can be obtained.
[0007]
[Configuration / Function / Effect]
Further, when the treatment material is a fluidity adjusting material that adjusts the fluidity of the reduced melt, the fluidity of the reduced melt is adjusted by adjusting the input amount of the fluidity adjusting material, It can be easily and quickly removed from the furnace.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The structure of the reduction melting furnace 1 of this application is demonstrated based on drawing.
FIG. 1 shows a longitudinal sectional view of a reduction melting furnace 1 of the present application.
As shown in the figure, the reductive melting furnace 1 of the present application includes a vertical cylindrical packed bed forming portion 2 for forming a packed bed and a combustion chamber 3 provided below the packed bed forming portion 2 as main functional parts. It is configured as. As shown in the figure, the furnace top is provided with a material inlet 4 into which a fluidity adjusting material for adjusting the fluidity of the object to be treated, the reduction accelerator, and the melt can be introduced. In addition, a flue 5 for exhaust gas discharge is extended in the horizontal direction separately from the material inlet 4.
Now, a plurality of water pipes 6 are disposed horizontally across the furnace at a predetermined interval between the packed bed forming portion 2 and the combustion chamber 3, and a carbon-based combustible is disposed above the water pipe 6. It is configured such that a coke packed layer 7 having a predetermined height can be formed by charging a block of coke which is a substance. Therefore, these water pipes 6 are configured as support portions, and the reduced melt melted in the packed bed 7 can drop between the water pipes and fall into the combustion chamber 3.
[0009]
The combustion chamber 3 is configured as a vertical cylindrical space having a large cross-sectional area over the entire lower surface of the packed bed 7, and the air-fuel ratio can be adjusted in the combustion chamber 3. A burner 8 (city gas burner) is provided. In addition, the bottom of the combustion chamber 3 is configured as a reductive melt reservoir, and is provided with a reductive melt outlet 10 connected to the outside of the furnace 9. It is configured to be able to take out a reduced product and a melt of the processing object.
Further, in the packed bed forming unit 2 described above, a tuyere 11 capable of supplying combustion oxygen-containing gas is provided at a portion on the support unit side corresponding to the water pipe side position. The attachment position of the tuyere 11 is a position at a distance of 1/5 to 2D from the water pipe disposition position, where D is the cross-sectional diameter of the packed bed 7. However, the position of the tuyere 11 is not determined only from the relationship with D, and in the operating state, a packed bed having a predetermined height or more is formed above the tuyere 11 position. Naturally, it is about half or less of the height of the packed bed .
Further, a plurality of reducing melt treatment material inlets 12 through which a treatment material for the reduced melt can be charged are provided in the combustion space in the combustion chamber.
The above is the schematic configuration of the reduction melting furnace 1.
[0010]
Hereinafter, the operating state of the reduction melting furnace 1 will be described.
In operation, the packed bed 7 of coke is formed in the packed bed forming section 2 in the pre-operation stage. In a state where the burner 8 in the combustion chamber is operated, the packed bed 7 is maintained in a red hot state. Here, immediately before the processing object is charged, the amount of combustion oxygen-containing gas supplied to the furnace (through the tuyere 11 and the burner 8) is adjusted to maintain the inside of the furnace in a reducing atmosphere.
Then, a non-ferrous metal oxide (for example, lead oxide) that is a processing object to be reduced and melted is charged from the material charging port 4. At this time, coke having a weight ratio of about 1 to 10% is added to the object to be treated. In this state, the preheated air from the tuyere 11 attached to the packed bed 7 is supplied in the range of 0.3 to 1.0 with respect to the required air amount of the supplied coke, and the temperature of the packed bed 7 Control the atmosphere and filling height.
The charged processing object is reduced and melted by the high-temperature reducing gas sent from the combustion chamber 3 in the packed bed or by the high-temperature reducing gas supplied to the packed bed 7 and generated by the reaction between air and coke. It passes through the water pipe 6 and drops as a liquid into the combustion chamber.
The reduced product and the melted material are accumulated at the bottom of the combustion chamber held at a high temperature by the burner 8.
Further, in order to remove impurities such as sulfur from the reductant stored at the bottom of the furnace, a lump of iron, which is a reduction accelerator, is introduced from the reductive melt treatment material inlet 12. The processing material charging interval is calculated from the residence time at the bottom of the furnace, and the charging amount is in the range of about 0.5% to 3% per amount of processing object to be charged into the furnace.
Then, the reduced melt is continuously taken out from the reduced melt outlet 10.
[0011]
[Another embodiment]
In the above embodiment, an example in which the material to be reduced is lead oxide has been shown, but it is also used for removing impurities other than the material to be reduced, for example, composed of many materials. it can. Specifically, copper, aluminum, tin and the like can also be targeted.
Furthermore, in the above-described embodiment, the supply tuyere for supplying the combustion oxygen-containing gas is provided with only one stage in the furnace vertical direction, but it is preferable to provide a plurality of stages.
Furthermore, as the treatment material introduced from the above-mentioned reducing melt treatment material inlet, this was a reduction promoting material (iron), but as such a material, coke or the like is used in relation to the treatment object. it can. In addition, materials that float on the surface of the reduced melt and combine with oxygen existing in the combustion chamber (coke powder, plastic waste, etc.), and fluidity modifiers that adjust the flowability of the reduced melt (calcium oxide, dioxide dioxide) Or silicon).
Furthermore, as a member constituting the support portion, a member provided with a so-called cooling mechanism such as the above-described water pipe as a cooling pipe can be adopted.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a reduction melting furnace of the present application. FIG. 2 is a longitudinal sectional view of a conventional cupola type reduction melting furnace.
3 Combustion chamber 6 Support section (water pipe)
7 Packing layer 8 Burner 11 Tuyere 12 Reduced melt treatment material inlet

Claims (4)

A reductive melting furnace capable of forming a packed bed made of a carbon-based combustible material, throwing a processing object into the packed bed, and taking out the reduced melt melted in the packed bed from the lower part;
A support part that supports the packed bed from below is provided below the packed bed in a state where the reduced melt can be dropped, and a burner that can adjust the air-fuel ratio of the oxygen-containing gas is provided below the support part. Provided with a combustion chamber provided, configured to be able to take out the reduced melt of the object to be processed from the lower portion of the combustion chamber in which the reduced melt is stored,
In the packed bed , a tuyere capable of supplying an oxygen-containing gas is provided at a site on the support unit side , which is a site less than half of the packed bed height filled with the carbon-based combustible material from the support unit , By adjusting the amount of oxygen-containing gas supplied from the burner and the tuyere, the packed bed and the combustion chamber can be maintained in a reducing atmosphere,
A reducing melting furnace provided with a reducing melt treatment material charging port capable of charging a treatment material for the reducing melt in a combustion space in the combustion chamber.   The reduction melting furnace according to claim 1, wherein the treatment material is a reduction accelerator for the reduction melt.   The reductive melting furnace according to claim 1, wherein the treatment material is a material that floats on the surface of the reductive melt and combines with oxygen existing in the combustion chamber.   The reduction melting furnace according to claim 1, wherein the treatment material is a fluidity adjusting material that adjusts the fluidity of the reduced melt.

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