JP2009233531A - Pcb contaminated matter treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a PCB decomposition treatment method in which the slag is stably discharged while keeping the property of slag proper. <P>SOLUTION: The PCB contaminated matter treatment method includes: a melting and cracking process of feeding a PCB contaminated matter into a melting and cracking furnace 12 together with a basicity conditioning agent for conditioning the basicity of the slag, melting and cracking the PCB contaminated matter by irradiating it with plasma, and discharging the slag, generated by melting and cracking, from the melting and cracking furnace 12; and a conditioning agent amount determining process of determining the amount of the basicity conditioning agent before feeding the PCB contaminated matter into the melting and cracking furnace 12. The conditioning agent amount determining process includes: a prediction process of predicting the composition of the slag to be generated on the basis of the components of the PCB contaminated matter; and a calculation process of calculating the feed amount of the basicity conditioning agent so as to settle the weight ratio of a specific component, which affects the flowability of the slag among the components contained in the slag, within a preset target range on the basis of the predicted result. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a PCB contaminant treatment method for melting and decomposing PCB (polychlorinated biphenyl) contaminants to produce slag.

  The PCB is a chemically stable non-flammable substance that is liquid at room temperature, and is widely used for insulating oils for electric parts such as capacitors because of its high electrical insulation and high boiling point and resistance to thermal decomposition. It was done. However, at present, since the PCB has an adverse effect on the human body, its manufacture and use are prohibited, and a PCB contamination contaminated by the PCB such as the electrical component is being detoxified.

For example, Patent Document 1 discloses a method of irradiating the PCB contaminants with plasma and melting and decomposing the PCB contaminants as a method for safely processing the PCB contaminants without decomposing the PCB contaminants. In this method, the PCB contaminant is introduced into a melting cracking furnace, and the PCB contaminant is irradiated with plasma in the melting cracking furnace. And while detoxifying PCB, slag is produced | generated by melt decomposition of PCB contaminant. The generated slag is discharged from the melting cracking furnace, cooled and solidified, and then reused for road roadbeds through predetermined processes such as crushing and particle size adjustment.
JP 2005-262196 A

  As described above, the PCB is widely used as an insulating oil, and the types of products containing the PCB, that is, the composition of PCB contaminants, vary widely. Therefore, there is a problem that the properties of the slag produced by the melt decomposition of the PCB contaminants are not constant, and it is difficult to stably extract the slag. That is, the fluidity of the slag may not be in an appropriate state depending on the basicity of the slag or the ratio of the specific component in the slag.

  In view of such circumstances, an object of the present invention is to provide a PCB decomposition processing method that can appropriately maintain the properties of slag generated by melt decomposition of the PCB contaminants and realize stable slag outflow. .

  The invention according to claim 1 for solving the above problem is a method for treating PCB contaminants for detoxifying the PCB contaminants and generating slag by melting and decomposing the PCB contaminants. And putting the substance into a melting cracking furnace together with a basicity adjusting agent for adjusting the basicity of the slag produced by melting and decomposing the PCB pollutant, and irradiating the PCB pollutant with plasma in the melting and cracking furnace The PCB contamination is melted and decomposed, and the slag generated by the melt decomposition is discharged from the melting and cracking furnace, and before the PCB contaminant is put into the melting and cracking furnace, A regulator amount determining step for determining the amount of the basicity modifier to be introduced together with the PCB contaminant, the modifier amount determining step being based on the components of the PCB contaminant. The weight ratio of the specific component which influences the fluidity | liquidity of the said slag among the components contained in the said slag based on the prediction process which estimates the composition of the slag produced | generated by the melt decomposition of the said PCB contaminant, and the prediction result Including a calculation step of calculating the input amount of the basicity adjusting agent so as to fall within a preset target range (Claim 1).

  According to this method, by introducing a basicity adjusting agent, it is possible to adjust both the basicity of the slag and the weight ratio of specific components of the slag, and more stable slag can be produced. Become. That is, in this method, a basicity adjusting agent is introduced into the melt cracking furnace together with PCB contaminants, and the basicity of the slag can be adjusted. Moreover, the composition of the slag is predicted based on the component of the PCB contaminant, and based on the prediction result, the weight ratio of the specific component that affects the fluidity of the slag is within a preset target range. The input amount of the basicity adjusting agent is calculated, and the weight ratio of the specific component can be adjusted by using the basicity adjusting agent that is introduced into the melting cracking furnace together with the PCB contaminant. it can. If the basicity of the slag and the weight ratio of the specific component of the slag are adjusted to an appropriate state in this way, the fluidity of the slag can be improved and more stable slag output can be realized. .

Here, the calculation step included in the adjusting agent amount determining step includes the input amount of the basicity adjusting agent so that the weight ratio of Al ₂ O ₃ which is a component that affects the fluidity of the slag is 20% or less. It is preferable that the method includes a step of calculating (Claim 2).

Since Al has the property of increasing the viscosity of slag, if the weight ratio of Al ₂ O ₃ is suppressed to 20% or less in this way, the slag will have a viscosity and a melting point that achieves favorable fluidity. Therefore, it is possible to keep the slag in an easy-to-catch state.

Further, the calculation step included in the adjusting agent amount determination step converts Fe, which is a component affecting the fluidity of the slag, into Fe ₂ O ₃ and keeps the weight ratio of the Fe ₂ O ₃ to 60% or less. Thus, it is preferable to include a step of calculating the input amount of the basicity adjusting agent.

Since Fe has a characteristic of reducing the viscosity of slag, if the weight ratio of Fe ₂ O ₃ is suppressed to 60% or less in this way, it is possible to suppress the viscosity of the slag from being lowered too much, The melting point of the slag can be suppressed to a low value, and it becomes possible to keep the slag in a state where it can be easily discharged.

  In the present invention, an acidic substance that lowers the basicity of the slag and a basic substance that increases the basicity of the slag as the basicity adjusting agent and the basic substance that increases the basicity of the slag are charged into the melting cracking furnace in the melt decomposition step. In addition to the calculation step of calculating the input amount of the basicity adjusting agent, the total amount of the acidic substance input amount and the basic material input amount is calculated in the calculation step. Under the condition that the calculated amount of the basicity adjusting agent is input, the input amount of the acidic substance and the input amount of the basic substance are set so that the basicity of the slag falls within a preset target range. It is preferable to include a step of calculating the ratio (claim 4).

  In this way, while ensuring the total input amount of the basicity adjusting agent for keeping the weight ratio of the specific component of the slag in an appropriate range, the input amount of the acidic substance and the base in the previous input amount are secured. By calculating the ratio with the amount of the charged substance, the basicity of the slag can be kept within an appropriate range.

  Examples of the target range of the basicity of the slag include a range of 0.67 to 1.5 (Claim 5).

The acidic substance is, for example, a substance mainly composed of SiO ₂ , and the basic substance is, for example, CaO, or a substance that changes to CaO by melt decomposition treatment such as CaCO ₃ or Ca (OH) _2. The substance which has at least one of these as a main component is mentioned (Claims 6 and 7).

  As described above, according to the present invention, it is possible to provide a PCB contaminant treatment method capable of maintaining the properties of slag generated by melt decomposition of the PCB contaminant in a range suitable for brewing.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  In the PCB contaminant treatment method according to the present invention, the PCB contaminant is melted and decomposed using the plasma melting and decomposing apparatus 10 shown in FIG. 1 to render the PCB contaminant harmless and to generate slag by melting and decomposing the PCB contaminant. To do.

  The plasma melting and decomposing apparatus 10 includes a melting and decomposing furnace 12, a drum can charging chamber 14, and a slag discharge container 16.

  The drum can loading chamber 14 is a portion for loading a drum 20 filled with PCB contaminants. The drum can charging chamber 14 is connected to the melting cracking furnace 12, and the charged drum can 20 is guided to the melting cracking furnace 12.

  The melt cracking furnace 12 is a part that melts and decomposes the PCB contaminant. A plasma torch 18 is attached to the ceiling of the melting cracking furnace 12. This plasma torch 18 is for generating plasma, and has an anode and a cathode in the torch body. The plasma torch 18 generates a gas having a very high temperature (15000 ° C. or higher) by energizing the gas between the anode and the cathode. In the melting and decomposing furnace 12, the generated plasma is irradiated onto the drum 20 to melt the PCB contaminants together with the drum 20 to decompose the PCB to the atomic level. In this method, the drum can 20 is melted and decomposed in this way, so that the PCB contamination can be safely processed without being crushed and separated, and the contaminated container is also processed at the same time.

  In the melting cracking furnace 12, slag is generated by melting non-combustible materials when the PCB contaminants are melted and decomposed. The generated slag accumulates at the bottom of the melting cracking furnace 12 to form a slag bath 40. The inside of the melting cracking furnace 12 is maintained at 1400 ° C. or higher by the plasma irradiation, and the slag bath 40 is maintained at a high temperature equivalent thereto. Accordingly, PCB contaminants in the drum 20 can be melted and decomposed by being immersed in the slag bath 40.

  The slag stored at the bottom of the melting cracking furnace 12 is appropriately discharged to the outside and transferred to a predetermined processing facility for reuse. Specifically, a slag discharge port 12a is provided in the vicinity of the bottom of the melting cracking furnace 12, and the slag is tilted by the melting cracking furnace 12, so that the slag discharge container 16 extends from the slag discharge port 12a. To be met. And the slag 30 put out to the slag discharge container 16 is conveyed in processes, such as subsequent cooling and crushing, sequentially.

Here, in this embodiment, the melting point of the slag is lowered while maintaining the viscosity of the slag appropriately by performing the following adjustment in order to stably and smoothly extract the slag. That is, SiO ₂ (acidic substance) and CaO (basic substance), which are basicity adjusting agents, together with PCB contaminants are charged into the melting cracking furnace 12, and (1) the weight ratio of Al ₂ O _{3 in} the slag is predetermined. (2) The weight ratio of Fe ₂ O _{3 in} the slag is suppressed to a predetermined target value or less, and (3) the basicity of the slag is maintained at the predetermined target value. Here, the basicity adjusting agent is not particularly limited as long as it is a substance capable of adjusting the basicity of slag, but as described above, an acidic oxide such as SiO ₂ and a basic oxide such as CaO are preferable. Further, basicity of the slag is most easily can be represented by the ratio CaO / SiO ₂ of CaO and SiO ₂ contained in the slag, in the present embodiment, this ratio is used as the basicity of the slag.

First, using the ternary phase diagram of CaO—SiO ₂ —Al ₂ O ₃ of FIG. 2 showing the relationship between the basicity of the slag and the melting point of the slag, with respect to the target value of the basicity of the slag (3). I will explain. Here, the basicity of slag can be represented by the ratio CaO / SiO ₂ of CaO and SiO ₂ contained in the slag, as described above. Therefore, the left hypotenuse in FIG. 2 represents basicity.

  In FIG. 2, the shaded area is the area where the melting point is 1500 ° C. or less. Therefore, the melting point of the slag can be kept low by setting the composition of the slag to the composition of the region indicated by the oblique lines. However, it has been found that when the basicity is set to 0.67 or less of the line L1 and the composition of the slag is the composition of the region A, the viscosity of the slag becomes high and it becomes difficult to discharge the slag. On the other hand, in the region C, the change rate of the melting point is large with respect to the change of the composition. Therefore, it was found that when the basicity is set to 1.5 or more of the line L2 and the composition of the slag is the composition of the region C, the melting point of the slag is difficult to stabilize. That is, it was found that the basicity of the slag is preferably within the range of 0.67 to 1.5. Therefore, in this embodiment, the basicity of the slag is maintained at 1.0, and the viscosity and melting point of the slag are kept within an appropriate range.

Next, the target value of the weight ratio of Al ₂ O _{3 in} the slag (2) will be described with reference to FIG. FIG. 3 shows the melting point and melting point of the slag when the Al ₂ O ₃ weight ratio in the slag is changed by changing the amounts of SiO ₂ and CaO while keeping the basicity of the slag at 1.0. Changes in pour point and softening point are shown. Each value in this figure is a measurement result when a circuit element containing almost the same mass of Al and Fe is melted and decomposed in the melting cracking furnace 12. In this figure, L11 indicates a change in melting point, L12 indicates a change in melting point, and L13 indicates a change in softening point. As shown in FIG. 3, when the amounts of SiO ₂ and CaO added are increased and the weight ratio of Al ₂ O ₃ is lowered, the melting point, melting point and softening point of slag are lowered. For example, when the weight ratio of Al ₂ O ₃ is 20%, the melting point of slag decreases to 1300 ° C. Here, as described above, the inside of the melting cracking furnace 12 is maintained at about 1400 ° C., and it is preferable to maintain the melting point of the slag at 1400 ° C. or lower in order to more reliably suppress the adhesion of the slag. . Therefore, in this embodiment, the target range of the weight ratio of Al ₂ O ₃ is set to 20% or less, and the melting point of the slag is lowered to around 1300 ° C., thereby realizing smooth slag extraction. In addition, when the weight ratio of Al ₂ O ₃ is reduced to 20% in this way, the increase in the viscosity of the slag due to Al is suppressed by reducing the Al content in the slag, so that the slag can be easily formed. It is possible to come out.

Next, the target value of the weight ratio of Fe ₂ O _{3 in} the slag (3) will be described with reference to FIG. FIG. 4 shows that the melting point and the melt flow of the slag when the basicity of the slag is 1.0 and the weight ratio of Fe ₂ O ₃ in the slag is changed by changing the input amounts of SiO ₂ and CaO. This shows the change of the point and the softening point. Each value in this figure is a measurement result when a ballast mainly made of Fe is melted and decomposed in the melting cracking furnace 12. In this figure, L21 indicates a change in melting point, L22 indicates a change in melting point, and L23 indicates a change in softening point. As can be seen from this figure, with regard to Fe, the melting point of slag can be suppressed to 1300 ° C. or less by suppressing the weight ratio of Fe ₂ O ₃ to 60% or less. Therefore, in the present embodiment, the target range of the weight ratio of Fe ₂ O ₃ is set to 60% or less, the melting point of slag is maintained low to suppress slag sticking, and the viscosity of slag is excessively lowered by Fe. Suppress.

  Next, a procedure for melting and decomposing PCB contaminants using the plasma melting and decomposing apparatus 10 while making each adjustment will be described with reference to the flowchart of FIG.

  First, components of PCB contaminants charged into the melting cracking furnace 12 are analyzed (step S2). This component analysis may be performed for each PCB contaminant, but is previously performed for each type of PCB contaminant, and the analysis result and the type of PCB contaminant filled in the drum 20 are determined. Based on this, the components of the PCB contaminant in the drum 20 may be specified.

Next, based on the component of the specified PCB contaminant, the composition of the slag and the total weight W_total of the slag generated by melting and decomposing the PCB contaminant in the melting cracking furnace 12 are predicted (step S4). ). And predicting the weight of Al ₂ O _{3 in} the slag based on the Al content of PCB contaminants, converting Fe in the slag to Fe ₂ O ₃ based on the Fe content of the PCB contaminants, The weight of this Fe ₂ O ₃ is predicted (prediction process).

Specifically, from the component analysis, an analysis result that Al is contained in about W_Al [kg] and Fe is contained in about W_Fe [kg] is obtained with respect to the PCB contaminant introduced into the melting cracking furnace 12. Assuming that the weight of Al ₂ O _{3 in} the slag is W_Al ₂ O ₃ [kg] based on these values, the atomic weight of Al ₂ O ₃ is 102, and the atomic weight of Al is 27. , W_Al ₂ O ₃ = W_Al × 102 / (2 × 27) [kg]. Similarly, the atomic weight of Fe ₂ O ₃ is 159.6, the atomic weight of Fe is 55.8, and the weight W_Fe ₂ O ₃ [kg] of Fe ₂ O _{3 in} the slag is W_Fe ₂ O ₃ = W_Fe × 159.6. /(2×55.8) [kg].

Next, the total of SiO ₂ and CaO so that the weight ratio of Al ₂ O ₃ in the slag is 20% or less and the weight ratio of Fe ₂ O _{3 in} the slag is 60% or less. The input amount is calculated (step S6, calculation process). That is, the total input amount W1_adj of SiO ₂ and CaO so that the weight ratio of Al ₂ O ₃ to the sum of the total weight of slag generated by PCB contamination and the input amount of SiO ₂ and CaO is 20% or less. The range of [kg] is calculated from W_Al ₂ O ₃ /(W_total+W1_adj)≦0.2. Similarly, the range of the total input amount W2_adj [kg] of SiO ₂ and CaO is set to W_Fe ₂ O ₃ /(W_total+W2_adj)≦0.6 so that the weight ratio of Fe ₂ O _{3 to} the sum is 60% or less. Calculate from Then, the larger value of W1_adj and W2_adj is determined as the final input amount W_adj of SiO ₂ and CaO.

Then, on the basis of the composition of the predicted slag, as the slag basicity is 1.0, i.e., so that the mass of SiO ₂ mass and CaO in the slag is equal, the SiO ₂ introduced The ratio of the amount and the input amount of CaO is calculated (step S8). Then, the the total input amount W_adj of SiO ₂ and CaO, the ratio of the SiO ₂ of the input amount and CaO of input amount, calculates the respective input of the SiO ₂ and CaO (step S10).

As an example, the calculation procedure of each input amount of SiO ₂ and CaO when 7 kg of the circuit element is put into a 2 kg drum 20 and melted and decomposed by the plasma melting and decomposing apparatus 10 will be described. Assume that the circuit element 7 kg is analyzed to contain 1.9 kg of Al. Also, assuming that the drum 20 is made of 2 kg of Fe, Al ₂ O ₃ is 1.9 kg × (102/54) = 3. 6 kg is produced, and 2 kg × (159.6 / 11.6) = 2.9 kg of Fe ₂ O ₃ is produced. For the sake of simplicity, assuming that no other slag is generated here, the total weight W_total of the generated slag is W_Al ₂ O ₃ + W_Fe ₂ O ₃ = 3.6 + 2.9 = 6.5 kg.

On the other hand, the total amount W1_adj of the basicity adjusting agent in which the weight ratio of Al ₂ O ₃ is 20% or less is calculated as W1_adj ≧ 11.5 kg from W_Al ₂ O ₃ /(W_total+W1_adj)≦0.2. The On the other hand, the total amount W2_adj of the basicity adjusting agent with which the weight ratio of Fe ₂ O ₃ is 60% or less is calculated from W_Fe ₂ O ₃ /(W_total+W2_adj)≦0.6 to W2_adj ≧ 0 kg. Therefore, the final input amount W_adj of the basicity adjusting agent is determined to be 11.5 kg.

Finally, when the basicity adjusting agent is SiO ₂ and CaO, the amount of SiO ₂ input is calculated to be 5.75 kg in order to satisfy the ratio CaO / SiO ₂ = 1, and the amount of CaO input is 5 Calculated at .75 kg. Here, CaO / SiO ₂ = 1 is an example, and it goes without saying that the effect expected by the present invention can be obtained if CaO / SiO ₂ is in the range of 0.67 to 1.5.

After calculating the input amount of SiO _{2 and} the input amount of CaO as described above, a predetermined container is filled with SiO ₂ and CaO by the calculated amounts. Of course, the SiO ₂ and CaO may be filled in the drum 20 together with the PCB contaminants. Then, the container filled with SiO ₂ and CaO, the drum can 20 filled with the PCB contaminants, and the drum can introduction chamber 14 are put into the melting cracking furnace 12 (step S12). If it is confirmed that the drum 20 or the like has been put into the melting and decomposing furnace 12, the plasma torch 18 is operated to irradiate the drum 20 with plasma, and the PCB contaminants are melted and decomposed to generate slag ( Step S14). At this time, as described above, the PCB contaminants are also melted and decomposed by the heat of the slag bath 40 stored at the bottom of the melting and cracking furnace 12.

  In this way, Steps S2 to S14 are repeated to sequentially melt and decompose the PCB contaminants, detoxify the PCB and generate slag. Here, in the present embodiment, the slag generated by the melt cracking is stored in the bottom of the melt cracking furnace 12 to form the slag bath 40, and when this storage amount becomes a predetermined value or more, The melt cracking furnace 12 is tilted and slag is discharged from the slag discharge port 12a (step S16) (melt cracking step).

At this time, in the slag, the weight ratio of Al ₂ O ₃ is maintained at 20% or less, and the weight ratio of Fe is maintained at 60 or less in terms of Fe ₂ O ₃ , and the melting point of the slag is 1300 ° C. It is kept below. In addition, the weight ratio of Al ₂ O ₃ is suppressed to 20% or less, and the basicity of the slag is maintained at 1.0, and the viscosity is adjusted to an appropriate range. Therefore, the slag is smoothly discharged from the slag discharge port 12a.

Then, Steps S2 to S16 are performed again to process other PCB contaminants. Even if PCB contaminants of different components are melted and decomposed in the melting cracking furnace 12, they are dependent on the components. Te weight of the weight and _Fe 2 _{O 3} of _Al 2 _{O 3} in the slag is predicted, so that the weight ratio of the _Al 2 _{O 3} is below 20%, 60% weight ratio of Fe in terms _{of Fe} 2 _{O 3} Since SiO ₂ and CaO are introduced so that the basicity of the slag becomes 1.0, the melting point and viscosity of the slag are stably maintained in the proper state as described above. It is.

  As described above, in this PCB processing method, the basicity of the slag and the weight ratio of Al and Fe in the slag can be kept within a predetermined range even if the components of the PCB contaminant change, so that the melting point and viscosity of the slag can be reduced. It is kept in an appropriate state, and stable slag can be extracted.

  The slag discharged from the slag discharge port 12a flows down to the slag discharge container 16, is cooled, and is conveyed to another processing facility.

Here, only the weight ratio of either one of Al ₂ O ₃ and Fe ₂ O ₃ in the slag may fall within a predetermined target range. It may also be in place as Al ₂ O ₃ and Fe ₂ O ₃ to accommodate the weight ratio of the other components of the slag to a predetermined target range. However, PCBs are widely used as insulating oils for electrical components such as capacitors, and many PCB contaminants are electrical products such as circuit elements and ballasts and contain a large amount of Al and Fe. And Al has the characteristic of increasing the viscosity of slag while Fe decreases the viscosity of slag. Therefore, the fluidity of the slag varies greatly due to the contents of Al and Fe in the melting cracking furnace 12 depending on the type of PCB contaminant introduced into the melting cracking furnace 12. Therefore, if the weight ratio of Al ₂ O ₃ and Fe ₂ O ₃ is adjusted, the slag can be more reliably and stably extracted.

Moreover, the target range of the weight ratio of the Al ₂ O _3, the weight ratio of the Fe ₂ O ₃ and the basic value of the slag are not limited to the above. However, if the weight ratio of Al ₂ O ₃ is suppressed to 20% or less and the weight ratio of Fe ₂ O ₃ is suppressed to 60% or less as described above, the melting point of slag can be sufficiently lowered and slag can be reduced. The viscosity of can be kept within an appropriate range. Further, when the basicity of the slag is in the range of 0.67 to 1.5, the viscosity and melting point of the slag can be more reliably within the proper range.

Moreover, the specific kind of basicity adjusting agent for adjusting the basicity of slag is not restricted to the above. That is, in the embodiment, SiO ₂ is exemplified as an acidic substance basicity adjusting agent, is exemplified CaO as the basic substance of basicity adjusting agent, the use of these non-acidic substance and basic substance Is possible. For example, CaCO ₃ or Ca (OH) ₂ may be used instead of CaO. However, in that case, considering the decrease in weight when CaCO ₃ or Ca (OH) ₂ is changed to CaO in step S8, CaO / SiO ₂ in the slag = 0.67-1. The input amount of CaCO ₃ or Ca (OH) ₂ may be determined so as to be in the range of 5. Further, as the basic material, it may be used Na ₂ O and _Na 2 CO _3.

Further, the specific configuration of the plasma melting and decomposing apparatus 10 for treating the PCB contaminant is not limited to the above. That is, in the said embodiment, although the case where the PCB contaminant which is a process target object was enclosed in a drum can and processed was illustrated, not only this but only a process target object with said feeders, such as a pusher and a double damper, said It may be charged directly into the melting cracking furnace 12. In the above embodiment, a case has been exemplified filled with basicity adjusting agent such as SiO ₂ in a predetermined container, not limited to this, using a basicity adjusting agent dedicated feeder of the basicity adjusting agent It may be directly charged into the melting cracking furnace 12.

1 is a schematic view of a plasma melting and decomposing apparatus to which a PCB contaminant treatment method according to an embodiment of the present invention is applied. It is a ternary phase diagram for explaining the relationship between the basicity of slag and the melting point. It is a diagram for explaining the relationship between the weight ratio of al ₂ O ₃ and the melting point or the like. It is a diagram for explaining a relationship between a weight ratio of Fe ₂ O ₃ and the melting point or the like. It is a flowchart which shows the process sequence of the PCB contaminant processing method which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Plasma melt decomposition apparatus 12 Melt cracking furnace 12a Slag discharge port 14 Drum can insertion chamber 16 Slag discharge container 18 Plasma torch 20 Drum can 40 Slag bath

Claims (7)

A method for treating PCB contaminants for detoxifying the PCB contaminants and generating slag by melt decomposition of the PCB contaminants,
The PCB contaminant is introduced into a melting cracking furnace together with a basicity adjusting agent for adjusting the basicity of the slag produced by melting and decomposing the PCB pollutant, and plasma is generated on the PCB contaminant in the melting cracking furnace. A melting and decomposing step of melting and decomposing the PCB contaminant by irradiating the slag generated by the decomposing and decomposing from the melting and decomposing furnace;
A regulator amount determining step for determining an amount of the basicity modifier to be charged together with the PCB contaminant before the PCB contaminant is charged into the melting cracking furnace,
This regulator amount determination step is based on the component of the PCB contaminant, a prediction step of predicting the composition of slag generated by melt decomposition of the PCB contaminant, and a component contained in the slag based on the prediction result A calculation step of calculating the input amount of the basicity adjusting agent so that the weight ratio of a specific component that affects the fluidity of the slag falls within a preset target range. PCB contamination treatment method. The PCB contaminant treatment method according to claim 1,
The calculating step included in the adjusting agent amount determining step calculates the input amount of the basicity adjusting agent so that the weight ratio of Al ₂ O ₃ which is a component affecting the fluidity of the slag is kept to 20% or less. A method for treating PCB contaminants, comprising the steps of: The PCB contaminant treatment method according to claim 1 or 2,
The calculation step included in the adjusting agent amount determination step converts Fe, which is a component that affects the fluidity of the slag, into Fe ₂ O ₃ so that the weight ratio of the Fe ₂ O ₃ falls within 60%. A PCB contaminant treatment method comprising a step of calculating an input amount of the basicity adjusting agent. In the PCB contamination processing method in any one of Claims 1-3,
In the melt decomposition step, the basicity adjusting agent containing an acidic substance that lowers the basicity of the slag and a basic substance that increases the basicity of the slag is charged into the melt cracking furnace,
In the adjusting agent amount determining step, in addition to the calculating step of calculating the input amount of the basicity adjusting agent, the total of the input amount of the acidic substance and the input amount of the basic substance is calculated in the calculating step. The ratio of the amount of the acidic substance and the amount of the basic substance is set so that the basicity of the slag falls within a preset target range under the condition that the amount of the basicity adjuster is charged. A PCB contaminant treatment method comprising a step of calculating. The PCB contaminant disposal method according to claim 4,
In the adjusting agent amount determination step, the input amount of the acidic substance and the input amount of the basic substance are respectively calculated so that the basicity of the slag is 0.67 to 1.5. PCB contaminant treatment method. The PCB contaminant disposal method according to claim 4 or 5,
A PCB contaminant treatment method, wherein the acidic substance is a substance mainly composed of SiO ₂ . In the PCB contaminant disposal method in any one of Claims 4-6,
The PCB contaminant treatment method, wherein the basic substance is a substance mainly comprising at least one of CaO or a substance that changes to CaO by melt decomposition treatment.