JP2011214998A - Achieved temperature evaluation method in heat treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an achieved temperature evaluation method in heat treatment which can accurately and easily evaluate achieved temperatures of members when applying the heat treatment on the members while overlapping a plurality of the members.SOLUTION: The members 1 undergoes heat treatment while overlapping the plurality of the members 1. Glass powder 2 is interposed between the mutually overlapped members 1. The existence of fusion of the glass powder 2 after the heat treatment serves as an index of the achieved temperature of the member in the heat treatment at a position where the glass powder 2 is arranged.

Description

  The present invention relates to a method for evaluating the ultimate temperature of a member during heat treatment when the member is subjected to heat treatment in a state where a plurality of members are stacked.

  When asbestos slate, asbestos cement board, and other materials containing asbestos (asbestos) are discarded, it is necessary to make asbestos harmless. In order to make asbestos harmless in these members, heat treatment is mainly employed. That is, as these members are heated, asbestos in the members is thermally denatured and rendered harmless. Asbestos has a needle-like crystal that causes damage, but it is known that when asbestos is heated to a certain temperature or higher, its crystallinity is denatured and detoxified (see Patent Documents 1 and 2). ).

  When heat treatment is performed on a member such as asbestos slate or asbestos cement board, the heat treatment is generally performed in a state in which a plurality of members are stacked from the viewpoint of improving processing efficiency.

Japanese Patent Laid-Open No. 3-60789 Japanese Patent Laid-Open No. 7-171536

  When a plurality of members are stacked, it is difficult to make the temperature in the members uniform even if these members are heated. Particularly in a member containing asbestos, the asbestos itself has a high heat insulating property, and when this member is a cement hardened material, the cement and filler contained in the member are also materials having low thermal conductivity. Therefore, temperature non-uniformity tends to occur. If a portion where the temperature is lower than the denaturation temperature of asbestos occurs in the member being heat-treated, the asbestos at that portion will not be rendered harmless. For this reason, confirmation of the ultimate temperature at the time of the heat processing of a member becomes important.

  In evaluating the ultimate temperature during the heat treatment, it is necessary to evaluate the temperature of the member at a position between the stacked members. In such a position, heat is not sufficiently transmitted, and it is likely that the ultimate temperature is lowered. In addition, it is conceivable to sufficiently heat the inside of the member by microwave oscillation, but in this case also, it is necessary to evaluate the temperature inside the actual member.

  As a temperature evaluation method, a method using a reference thermometer, a Zeger cone, a sheath thermocouple, etc., which are often employed for temperature evaluation during high-temperature heat treatment, can be considered first.

  However, it is difficult to evaluate the temperature of the reference thermostat if it is not heated for a considerable period of time, and there is a risk of reaction between the member and an alumina plate or the like is interposed between the reference thermother and the member. Because it is necessary, it is very inconvenient.

  It is difficult to arrange the Segel cone between members because of its shape.

  It is difficult to move the sheath thermocouple together with the member in high-temperature heat treatment in a mobile tunnel furnace such as a roller hearth kiln. In addition, when a member is heated by microwave oscillation, countermeasures against microwaves are necessary, so that constant measurement is difficult.

  Temperature measurement using a radiation thermometer is also conceivable. The radiation thermometer includes a contact type radiation thermometer and a non-contact type radiation thermometer.

  However, the contact-type radiation thermometer is difficult to move with the member, as in the case of a sheathed thermocouple. Moreover, in the non-contact type radiation thermometer, since the measurable location is restricted, the temperature inside the stacked members cannot be measured.

  As described above, the evaluation of the reached temperature of the member by the existing temperature measuring method is accompanied by a great restriction.

  The present invention has been made in view of the above-mentioned reasons, and when the heat treatment is performed on the member in a state where a plurality of members are stacked, the arrival temperature at the time of the heat treatment can be evaluated accurately and easily. An object is to provide a temperature evaluation method.

  In the ultimate temperature evaluation method during heat treatment according to the present invention, when performing heat treatment on this member in a state where a plurality of members are stacked, glass powder is interposed between the members overlapping each other, The presence or absence of glass powder welding is used as an indicator of the temperature reached by the member during the heat treatment at the position where the glass powder is disposed.

  In the present invention, a plurality of types of glass powders having different softening temperatures may be interposed between the overlapping members.

  In the present invention, the glass powder may have an average particle size in the range of 1 to 1000 μm.

  According to the present invention, when the heat treatment is performed on a member in a state where a plurality of members are stacked, the temperature reached by the member can be accurately and easily evaluated.

It is a figure which shows an example of embodiment of this invention, (a) is a front view which shows the load which consists of a some member, (b) is the schematic which shows the heat processing process of a member. It is a figure explaining the test method in an Example, (a) is a front view of the test load, (b) shows the state which removed one piece from the test load shown in (a). It is a top view.

  Examples of the member 1 include, but are not limited to, the member 1 containing asbestos. Specific examples of the member 1 containing asbestos include building materials such as asbestos slate, asbestos cement board, asbestos cement siding, and the like.

  Prior to the heat treatment, a plurality of members 1 are stacked as shown in FIG. Hereinafter, the set of the plurality of stacked members 1 is referred to as a load 3. The number of members 1 constituting one load 3 is appropriately determined in consideration of the capacity of the heating furnace 4, processing efficiency, and the like, and is not particularly limited.

  Before the heat treatment, glass powder 2 is interposed between the members 1 that overlap each other in the load 3. When the number of members 1 constituting the load 3 is three or more, even if the glass powder 2 is interposed between all the members 1 that overlap each other, between any members 1 that are appropriately selected The glass powder 2 may intervene only. Furthermore, between the members 1 in which the glass powder 2 is disposed, the glass powder 2 may be disposed in only one place, or may be disposed in a plurality of places. As a place where the glass powder 2 is arranged in the load 3, a position where the ultimate temperature in the load 3 is to be confirmed is appropriately selected.

  It is preferable that a large amount of glass powder 2 is disposed between the members 1 in a dense state. The amount of the glass powder 2 disposed at one place is preferably in the range of 0.5 to 5.0 g.

  When heat treatment is applied to the load 3 on which the glass powder 2 is arranged in this way, the glass powder 2 heated to the softening point or more is solidified after melting, and the particles in the glass powder 2 are welded together. To do. On the other hand, no welding is observed on the particles of the glass powder 2 that have not been heated to the softening point. For this reason, if the presence or absence of the welding of the particles of the glass powder 2 in the load 3 after the heat treatment is confirmed, the ultimate temperature at the place where the glass powder 2 is disposed is softened. It is easily confirmed whether or not the number is above the point. That is, whether or not the glass powder 2 is welded is an index of the temperature reached by the member 1 during the heat treatment at the position where the glass powder 2 is disposed.

  The average particle diameter of the glass powder 2 is preferably in the range of 1 to 1000 μm. In this range, it is easy to determine whether or not the glass powder 2 is welded. The average particle diameter is a median diameter measured by a laser diffraction / scattering method. If the particle size of the glass powder 2 is too large, it may be difficult to confirm the adhesion between the particles, for example, the contact between the particles is reduced. On the other hand, if the particle size of the glass powder 2 is too small, the glass powder 2 may be hardened due to the load from the member 1, which may make it difficult to confirm the adhesion between the particles.

  A plurality of types of glass powders 2 having different softening points may be arranged in one load 3. In this case, if there is a glass powder 2 in which welding is observed after the heat treatment and a glass powder 2 in which welding is not observed, the ultimate temperature is equal to or higher than the softening point of the glass powder 2 in which welding is observed, And it is evaluated that it is less than the softening point of the glass powder 2 in which welding is not recognized. Although the location where the glass powder 2 where welding is observed is arranged and the location where the glass powder 2 where welding is not allowed cannot be arranged, these glass powders 2 are not loaded 3 If it is arranged at each of the locations where the temperature reached during the heat treatment is predicted to be approximately the same, accurate evaluation of the temperature reached is possible.

  The evaluation of the reached temperature in the load 3 according to the present embodiment is applied, for example, in a preliminary test for determining the heat treatment condition of the member 1. That is, for example, in the preliminary test, the heat treatment conditions of the member 1 are variously changed, and the ultimate temperature in the load 3 is evaluated under each condition, and appropriate heating conditions are determined based on the results.

  Even after the heat treatment conditions are determined, the evaluation of the reached temperature in the load 3 according to the present embodiment can be applied during the heat treatment of the member 1. In this case, it is easily confirmed whether or not the heat-treated member 1 has been heat-treated under the required conditions.

  The type of the member 1 in the ultimate temperature evaluation method during the heat treatment according to the present embodiment is not particularly limited as described above, but this method is particularly applicable when the heat treatment for detoxification is performed on the member 1 containing asbestos. In, it is applied suitably. In this embodiment, since it is easily evaluated whether or not the reached temperature at an arbitrary position in the load 3 is equal to or higher than a certain temperature, the entire member 1 is equal to or larger than a certain temperature as in heat treatment for detoxifying the member 1. This is suitable when a simple and efficient treatment is required. Furthermore, the softening point of the glass powder 2 can be adjusted in the range of 650 to 1000 ° C., and the ultimate temperature evaluation method according to the present embodiment is suitable for evaluation of the ultimate temperature in such a temperature range. Since this temperature range overlaps with the temperature at which the crystallinity of asbestos is denatured, this embodiment is also suitable for evaluating the ultimate temperature of the member 1 for surely detoxifying asbestos. Furthermore, the softening point of the glass powder 2 can be adjusted by changing the composition of the glass powder 2, or multiple types of glass powders 2 having different softening points can be used, so that the ultimate temperature can be accurately evaluated. It becomes.

  FIG.1 (b) shows roughly an example of the heating furnace 4 used for the heat processing for detoxifying the member 1 containing asbestos. The ultimate temperature evaluation method during the heat treatment according to the present embodiment is applied, for example, when the member 1 is subjected to the heat treatment by the heating furnace 4 as described above.

  The heating furnace 4 is an elongated tunnel furnace provided with an inlet 41 at one end and an outlet 42 at the other end.

  Prior to the heat treatment by the heating furnace 4, as described above, the plurality of members 1 are stacked in advance to form a load 3, and in the load 3, glass powder is placed between the members 1 that overlap each other. The body 2 is arranged. At the time of heat treatment, the load 3 is introduced into the heating furnace 4 from the inlet 41, sent at a constant speed on a conveying device such as a conveyor, passes through the heating furnace 4, and then exits the heating furnace 4 from the outlet 42. Sent out.

  The inside of the heating furnace 4 is divided into a first heating zone 43, a second heating zone 44, a third heating zone 45, and a cooling zone 46 in order from the inlet 41 side. Each zone may be partitioned by a curtain or the like, or may not be partitioned.

  External heating means and internal heating means are provided in the first to third heating zones 43, 44, 45, respectively. The external heating means is a means for heating the member 1 from the outside by applying heat to the member 1 from the outside by releasing the heat, and specific examples thereof include a heater such as an electric heater. The internal heating means is a means for heating the member 1 from the inside without releasing heat by itself, and a specific example thereof is a microwave oscillator. When a microwave oscillator is used, the member 1 itself generates heat by high-frequency dielectric heating using microwaves (high frequency), and the member 1 is heated from the inside. Examples of the microwave frequency include a 915 MHz band and a 2.45 GHz band permitted by the Japanese Radio Law.

  In the heat treatment of the member 1, the load 3 is introduced into the heating furnace 4 through the inlet 41, and is sequentially heated in the first heating zone 43, the second heating zone 44, and the third heating zone 45, and then the cooling zone. After cooling at 46, the outside is further sent out from the outlet 42.

  For example, in the first heating zone, when the member 1 is heated, free water and crystal water in the member 1 are scattered. In the first heating zone 43, when the internal heating means is operated with a relatively small output, the rate of temperature rise inside the member 1 becomes gradual, so that free water and crystal water gradually evaporate from the member 1. . Free water refers to condensed water, atmospheric moisture, rainwater, etc. taken into the member 1, surplus water for reaction when the member 1 is produced by a hydraulic reaction, and the like. As a result, rapid evaporation of free water and crystal water inside the member 1 is suppressed, and explosion of the member 1 due to such rapid evaporation of water is suppressed.

  The member 1 is further heated in the second heating zone. In the second heating zone, for example, when the output of the internal heating means is made higher than that in the first heating zone, the temperature rise inside the member 1 is increased, and the temperature inside the member 1 and the surface temperature are brought closer.

  In the third heating zone, the member 1 is heated to a temperature at which the asbestos crystallinity is modified. As a result, the member 1 is rendered harmless.

  In addition, although the inside of the heating furnace 4 shown by FIG.1 (b) is divided | segmented into the some heating zone, the heating furnace 4 does not need to be divided into the some heating zone. Moreover, the heating furnace 4 may be provided with only an external heating means among an external heating means and an internal heating means as a heating means, and may be provided with only an internal heating means.

  Below, the Example for clarifying the usefulness of the evaluation method of the ultimate temperature by this embodiment is shown. The following examples do not show specific application examples of the reached temperature evaluation method according to the present embodiment.

[Test Example 1]
As a member, a waste material of cosmetic slate containing asbestos (conventional product of color vest (registered trademark)) was prepared.

The following three types of glass powder 2 were prepared. The softening point is a value measured by a differential thermal analyzer (DTA).
Glass powder A: Prototype G3-3545 manufactured by Okuno Pharmaceutical Co., Ltd., softening point 770 ° C., average particle size 3 μm.
Glass powder B: manufactured by Okuno Pharmaceutical Co., Ltd., product number GF5770, softening point 740 ° C., average particle size 3 μm.
Glass powder C: Prototype G3-3855 manufactured by Okuno Pharmaceutical Co., Ltd., softening point 669 ° C., average particle size 3 μm.

  As shown in FIG. 2, the load 3 is configured by stacking three members 11, 12, and 13. The member 12 at the second stage from the bottom in the load was cut at the center line and divided into two parts 121 and 122, and the sheath thermocouple 5 was disposed between the two parts 121 and 122. On the second-stage member 12, the glass powder 2 (glass powder A, glass powder B, and glass powder C) was disposed so as to be in the range of 1.5 to 2.0 g. As shown in FIG. 2B, the glass powders 2 were densely arranged at different positions on the second stage member. Each glass powder 2 was interposed, and a third-stage member 13 was stacked on the second-stage member 12 as shown in FIG.

  The load 3 was supported by a crucible 6 as shown in FIG. 2A and placed in an electric furnace, and heated until the temperature of the sheath thermocouple 5 reached the target temperature. The target temperatures were 650 ° C, 700 ° C, 750 ° C, 800 ° C and 850 ° C.

  The load 3 after the heat treatment is taken out from the electric furnace, the appearance of each of the three types of glass powder 2 is visually observed, and when the particles are observed to be welded, “there is welding”, the particles are welded. The case where there was no welding was evaluated as “no welding”. The results are shown in Table 1 below.

  As shown in Table 1, the presence or absence of welding in the glass powder 2 and the softening point of the glass powder 2 correlate well with the set temperature value. Thereby, it has confirmed that the ultimate temperature of the member 1 in the load 3 can be accurately evaluated by the ultimate temperature evaluation method according to the present embodiment.

[Test Example 2]
The following eight types of glass powder 2 were prepared.
Glass powder D: Prototype manufactured by Okuno Pharmaceutical Co., Ltd., softening point 863 ° C., average particle size 10 μm.
Glass powder E: manufactured by Nissho Material Co., Ltd., product number E200, softening point 847 ° C., average particle size 20 μm.
Glass powder F: prototype manufactured by Okuno Pharmaceutical Co., Ltd., softening point 853 ° C., average particle size 30 μm.
Glass powder G: prototype manufactured by Okuno Pharmaceutical Co., Ltd., softening point 884 ° C., average particle size 50 μm.
Glass powder H: Prototype manufactured by Okuno Pharmaceutical Co., Ltd., softening point 847 ° C., average particle size 70 μm.
Glass powder I: manufactured by Nissho Material Co., Ltd., product number E-48-80, softening point 847 ° C., average particle size 270 μm.
Glass powder J: manufactured by Nissho Material Co., Ltd., product number E22-80, softening point 847 ° C., average particle size 420 μm.
Glass powder K: manufactured by Nissho Material Co., Ltd., product number E16-18, softening point 847 ° C., average particle size 1230 μm.

  Using each glass powder 2, the member 1 was heat-treated by the same method as in Test Example 1. However, the set temperature by the sheath thermocouple 5 during the heat treatment was 950 ° C.

  The load 3 after the heat treatment was taken out of the electric furnace, and the appearance of each glass powder 2 was visually observed. As a result, in the glass powders D to J, it was possible to quickly confirm the welding of the particles. On the other hand, in the case of the glass powder K having an average particle size of more than 1000 μm, the particles were welded to each other. However, in order to confirm this, a longer time was required than in the case of the glass powders D to J.

1 member 2 glass powder

Claims (3)

  When heat-treating this member in a state where a plurality of members are stacked, glass powder is disposed between the members that overlap each other, and the glass powder is arranged to indicate whether or not the glass powder is welded after the heat-treatment. An reached temperature evaluation method during heat treatment, which is used as an index of the temperature reached by a member during heat treatment at a position where the heat treatment is performed.   The reached temperature evaluation method during heat treatment according to claim 1, wherein a plurality of types of glass powders having different softening temperatures are interposed between the overlapping members.   3. The method for evaluating an achieved temperature during heat treatment according to claim 1, wherein the glass powder has an average particle size in a range of 1 to 1000 μm.

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