JP5828606B2 - Rotary kiln - Google Patents

Description

  The present invention relates to a rotary kiln capable of continuously heat-treating a powder or slurry (hereinafter referred to as “object to be treated”) at a high temperature.

  For example, in the manufacturing field of new materials such as secondary battery electrode materials, semiconductor materials, catalysts, and fluorescent material materials, contamination is generated from the manufacturing equipment itself, especially in manufacturing processes that dislike contamination (trace contamination). Has become a big problem.

  The most important operation in this manufacturing process is a firing process. The object to be treated is baked at a high temperature of several hundred degrees for thermal decomposition, or two or more kinds of objects to be treated are mixed and heated at a high temperature of several hundred degrees to fire the compound. At the time of firing at this high temperature, if the container holding the object to be processed is made of metal, the surface of the container is oxidized by the influence of the high temperature, and this metal oxide contaminates the object to be processed.

  In the case of such a new material field, when strict contamination prevention is required, it is necessary to manage this to the ion level, which is the largest cause of an increase in manufacturing cost.

  The current firing process in this field is to place the object to be fired in a ceramic container (a bowl: a container with a side of 20 to 40 cm and a depth of several centimeters). It is carried out by firing the object to be treated together with the sagger in a continuous furnace such as a roller hearth kiln or a tunnel kiln, or a batch furnace such as a shuttle kiln.

  However, the firing method has the following major drawbacks. First, at least several kilograms of the processing object to be baked must be packed in a pot, and the processing object must be taken out from the baked baking pot. Enormous effort and expense. Secondly, if this method (fired by a mortar) is performed on an industrial scale, hundreds of mortars are required in a series of firing processes, and the mortar itself is a ceramic product. Cracks and cracks are generated during firing, and a few percent of the total number of mortars may be damaged by firing in one cycle. This replenishment greatly increases the cost. Third, in the firing step, the reaction object in the mortar is thermally decomposed to release decomposition gas or absorb gas from the surroundings. At this time, from the treatment object in the mortar Generated or absorbed decomposition gas or atmospheric gas enters and exits only through the opening on the upper surface of the mortar, and the bottom or side of the mortar inhibits the entry and exit of these gases, making it difficult to obtain a homogeneous product. Fourth, place the treatment object in a pot at room temperature, fire it in a furnace for each bowl, cool the treatment object after each firing, and then remove the treatment object from the bowl. Therefore, much of the heat energy (about 50 percent) added in the furnace is spent heating the mortar itself.

  For this reason, instead of firing with a sagger, firing with a rotary kiln is desired, but as long as the rotating container that holds the object to be treated during firing (hereinafter referred to as “retort”) is made of metal, the aforementioned contamination is present. It has been considered impossible.

Here, a typical structure and operation of a conventional rotary kiln will be described with reference to FIGS.
As shown in FIG. 3, in the rotary kiln 50, tires 52 and 53 are provided in the vicinity of both ends of the retort 51, and the retort 51 passes through a heating furnace 55 heated by an electric heating element 54. Has been. As shown in FIG. 3 or FIG. 5, the tires 52 and 53 are supported by a roller wheel 57 provided on a bed 56, and roll with the rotation of the roller wheel 57 by a rotation drive device (not shown). Thus, the retort 51 is configured to rotate. Usually, since the temperature of a retort becomes a high temperature of 800-1100 degreeC, in order to respond to the oxidation by the high temperature of retort metal itself, and the fall of mechanical strength, the retort is formed with the heat resistant steel.

  In FIG. 3, when the processing object is supplied into the retort 51 from the right end of the retort 51 by the raw material supplier 58, the processing object is rotated and inclined (usually about 0.5 to 2 °). To slowly move left. As shown in FIG. 4, since the entire retort 51 is heated by the electric heating element 54 of the heating furnace 55, the processing object in the retort 51 is baked by heat transfer from the retort 51. The fired processing object is configured to be discharged to the outside through a discharge hood 59 provided at the left end.

By the way, in the field of manufacturing new materials described at the beginning, various methods such as ceramic layer formation by spraying, ceramic tube insertion, ceramic brick lining, etc. inside this metal retort (site where the object to be treated contact) Attempts were made to lay ceramic linings, but it failed. The reason was due to the difference in thermal expansion between the metal retort and the ceramics provided inside. For example, the linear expansion coefficient of the heat-resistant steel forming the metal retort is 15 to 20 × 10 ⁻⁶ / ° C., whereas the linear expansion coefficient of the alumina ceramics to be lined is 7 to 8 × 10 ^{− It is 6} / ° C and there is a big difference between the two. Since the metal retort lined with the ceramic layer is heated in a short time from the cold state (room temperature) to the operating state (800 to 1100 ° C.), the ceramic layer is peeled off from the metal retort immediately due to a difference in thermal expansion. Conversely, when returning from the operating state to the cold state, the metal retort shrinks according to the temperature drop, but the ceramic layer cannot shrink at a rate according to the temperature drop and cracks occur.

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  Accordingly, an object of the present invention is to prevent the contamination of contaminants in the product due to the reaction between the metal retort and the object to be treated during the heat treatment, and the ceramic caused by the difference in thermal expansion between the metal retort and the ceramic layer. It is providing the rotary kiln which can prevent generation | occurrence | production of the crack of a layer.

Solves the aforementioned problems is a rotary kiln retort having a processing object supply opening at the other end has a processed product discharge outlet at one end is rotatably arranged about an axis, said The retort is composed of a metal shell and a ceramic tube disposed inside the metal shell so as to be slidable in the axial direction with respect to the metal shell. pressing mechanism is provided to press against the other end of the ceramic tube, a stopper mechanism for restricting the movement of the other end of the retort is provided on the other end of the retort, the pressing mechanism A tire boss having a pressing surface for pressing the ceramic tube toward the other end, tire moving means for moving the tire in the axial direction of the retort, Pressing means for pressing the ear moving means toward the other end side of the ceramic tube, and the tire boss has a pressing surface for pressing the one end side surface of the ceramic tube at the other end side surface. An annular body, the pressing surface is configured to come into surface contact with one end side surface of the ceramic tube, and the tire boss is provided on one end side of the retort including the metal shell and the ceramic tube. The stopper mechanism includes a second tire boss having a locking surface for locking the other end side surface of the ceramic tube, and a second tire in the axial direction of the retort. and a second tire detent means for inhibiting a moving, the metal shell, one end sides of the ceramic tube Even if the metal shell extends in the axial direction due to thermal expansion caused by heating in the heating furnace, the one end side surface of the metal shell is made of the ceramic. It is a rotary kiln characterized by being arranged so that it may be located in the other end side from the one end side of a tube.

  The pressing means is preferably formed by weight means. The ceramic tube is preferably composed of a plurality of ceramic tubes connected in the axial direction.

According to the first aspect of the present invention, the metal retort and the object to be treated can be prevented from reacting with each other during the heat treatment, and contaminants can be prevented from being mixed into the product. The occurrence of cracks in the resulting ceramic layer can be prevented.
According to the second aspect of the invention, in addition to the effect of the first aspect, the pressing mechanism can be configured at a low cost with a structure using the retort rotation mechanism.
According to the invention described in claim 3 , in addition to the effect of claim 1, the manufacturing cost can be reduced by dividing the ceramic tube into a plurality of parts.

It is the longitudinal cross-sectional schematic of one Example of the rotary kiln of this invention. FIG. 2 is a schematic perspective sectional view of the rotary kiln shown in FIG. 1. It is the longitudinal cross-sectional schematic of the conventional rotary kiln. FIG. 4 is a sectional view taken along line AA in FIG. 3. FIG. 4 is a sectional view taken along line BB in FIG. 3.

  In the present invention, the retort 4 is composed of a metal shell 5 and a ceramic tube 6 that is slidable in the axial direction with respect to the metal shell 5 inside the metal shell 5. Since the object to be treated comes into contact with the ceramic tube 6 and does not come into contact with the metal shell 5, the metal retort (metal shell 5) and the object to be treated react during the heat treatment, and contaminants are mixed into the product. It is prevented. Further, a pressing mechanism 7 for pressing the ceramic tube 6 toward the other end side is provided on one end side of the retort 4, and the other end side of the retort 4 is for restricting movement of the retort 4 to the other end side. By providing the stopper mechanism 8, the stress required for the shrinkage of the ceramic tube 6 is preloaded, resulting from a difference in thermal expansion between the metal retort (metal shell 5) and the ceramic layer (ceramic tube 6). A rotary kiln that can prevent cracks in the ceramic layer has been realized.

The rotor kiln of the present invention will be described with reference to one embodiment shown in FIG. 1 or FIG.
The rotary kiln 1 of this embodiment is a rotary kiln in which a retort 4 having a processing object discharge port 2 on one end side and a processing object supply port 3 on the other end side is arranged to be rotatable around an axis 4a. The retort 4 is composed of a metal shell 5 and a ceramic tube 6 disposed inside the metal shell 5 so as to be slidable in the axial direction with respect to the metal shell 5. A pressing mechanism 7 that presses the ceramic tube 6 toward the other end is provided at one end of the retort 4, and a stopper mechanism 8 for restricting movement of the retort 4 toward the other end is provided at the other end of the retort 4. Is provided. Hereinafter, each configuration will be described in detail.

  This rotary kiln 1 is similar to the conventional rotary kiln 50 shown in FIGS. 3 to 5, and is a rotary drive device for rotating the wheel 9, a raw material supply machine provided at the right end in FIG. 1 or FIG. 1 is provided, but is omitted in FIG. 1 or FIG.

  In the rotary kiln 1, the retort 4 can roll on the wheel 9 so that one end side of the retort 4 (processing object discharge port 2 side) is slightly lower than the other end side (processing object supply port 3 side). It is placed. When the processing object is introduced from the processing object supply port 3 of the retort 4 while rotating the retort 4 by rotating the wheel 9 by the rotation driving device, the transmission from the electric heating element 11 disposed inside the heating furnace 10 is performed. Heat treatment (firing) is performed by heat. The processing object is configured to sequentially move to the processing object discharge port 2 of the retort 4 and be discharged to the outside through the discharge hood.

The retort 4 is composed of a metal shell 5 and a ceramic tube 6 disposed inside the metal shell 5 so as to be movable in the axial direction with respect to the metal shell 5.
Both the metal shell 5 and the ceramic tube 6 are formed in a cylindrical shape, and the metal shell 5 is formed of heat-resistant steel to ensure bending stress and rotational stress due to its own weight. Yes. On the other hand, the ceramic tube 6 is formed of a sintered body (a material that does not react with the object to be processed) such as alumina or zirconia.

  The ceramic tube 6 is composed of three ceramic tubes 5A, 5B, and 5C connected along the axial direction, and the end faces of the ceramic tubes are surface-bonded at the connecting portion.

  The ceramic tube 6 is disposed inside the metal shell 5 so as to be slidable in the axial direction with respect to the metal shell 5, and thereby can expand without interfering with each other due to a difference in thermal expansion between the two. It is configured as follows.

  A pressing mechanism 7 that presses the ceramic tube 6 toward the other end is provided on one end of the retort 4. Specifically, the pressing mechanism 7 of this embodiment moves the tire boss 12 having a pressing surface 12 a for pressing the ceramic tube 6 toward the other end side, and the tire 13 in the axial direction of the retort 4. Tire moving means 14 for the purpose, and weight means 15 for pressing the tire moving means 14 toward the other end of the ceramic tube 6. Thereby, a press mechanism can be comprised at low cost by the structure using a retort rotation mechanism.

  As shown in FIG. 2, the tire boss 12 includes an annular body 12 b whose other side surface is a pressing surface 12 a for pressing one end side surface of the ceramic tube 6, and the pressing surface 12 a is one end of the ceramic tube 6. It is comprised so that a surface may contact | abut. The tire boss 12 is disposed so as to surround the outer surface (outer peripheral surface) on one end side of the retort 4 including the metal shell 5 and the ceramic tube 6, and the metal shell 5 extends in the axial direction due to thermal expansion. Even so, at least one end side surface of the metal shell 5 is disposed at a position that maintains a distance (gap 30) between the one end side surface of the metal shell 5 and the pressing surface 12a by a distance that does not contact the pressing surface 12a. ing. In other words, the metal shell 5 is formed to be shorter in the axial direction than the ceramic tube 6, and one end side surface of the metal shell 5 is pressed even if the metal shell 5 extends in the axial direction due to thermal expansion. Even if the metal shell 5 is extended in the axial direction due to thermal expansion, the one end side surface of the metal shell 5 does not come into surface contact with the pressing surface 12a. The tire 13 is configured not to be displaced in the axial position.

  The tire moving means 14 includes a pair of thrust rollers 16 disposed on both sides of the tire 13 in the axial direction, and a pedestal 18 on which the thrust rollers 16 are rotatably mounted and provided with casters 17. The pedestals 18 are casters. 17 is configured to be movable along the axial direction of the tire 13.

  The weight means 15 includes a weight 19, a wire rope 20 that connects the pedestal 18 and the weight 19, and a pulley 21, and biases the tire moving means 14 toward the other end side. The ceramic tube 6 acts so as to continue pressing toward the other end side.

  On the other hand, a stopper mechanism 8 for restricting movement of the retort 4 to the other end side is provided on the other end side of the retort 4. Specifically, in the stopper mechanism 8, the second tire boss 22 having a locking surface 22 a for locking the other side surface of the ceramic tube 6 and the second tire 23 move in the axial direction of the retort 4. And second tire movement restraining means 24 for restraining this. Thereby, a stopper mechanism can be comprised at low cost by the structure using a retort rotation mechanism.

  As shown in FIG. 1, the second tire boss 22 includes an annular body 22 b whose one end side surface is a locking surface 22 a for locking the other end side surface of the metal shell 5 and the ceramic tube 6. The stop surface 22a is configured to come into surface contact with one end side surfaces of the metal shell 5 and the ceramic tube 6. The second tire boss 22 is disposed so as to surround the outer surface (outer peripheral surface) on the other end side of the retort 4 including the metal shell 5 and the ceramic tube 6.

  The second tire movement restraining means 24 has a pair of thrust rollers 25 arranged on both sides in the axial direction of the second tire 23, and a base 26 on which the thrust roller 25 is rotatably mounted. It is fixedly installed on the table so that it cannot move.

Next, the characteristic action of the rotary kiln 1 of the present invention will be described.
When electric power is applied to the electric heating element 11 of the heating furnace 10 at the start of operation, the temperature in the heating furnace 10 rises and the retort 4 disposed through the heating furnace 10 is heated. Specifically, heat from the electric heating element 11 is transferred to both the metal shell 5 disposed on the outside and the ceramic tube 6 disposed on the inside of the metal shell 5, and each is heated.

  Since the expansion to the other end side is restricted by the stopper mechanism 8 disposed on the other end side, the metal shell 5 extends to one end side by the dimension L1 in FIG. At this time, there is a gap 30 set in consideration of the thermal expansion of the metal shell 5 between the pressing surface 12a of the tire boss 12 and one end side surface of the metal shell 5, so that one end side surface of the metal shell 5 is the tire boss. The 12 pressing surfaces 12a are not in surface contact with each other, and the positional displacement of the tire boss 12 is not affected.

  On the other hand, the ceramic tube 6 is the same as the metal shell 5 in that the expansion to the other end side is restricted by the stopper mechanism 8 disposed on the other end side, so that the L2 dimension in FIG. Elongate. On one end side, a pressing mechanism 7 having a tire moving means 14 for moving the tire 13 in the axial direction of the retort 4 is provided, so that it resists the urging force to the other end side of the weight means 15. The tire boss 12 and the tire 13 having the pressing surface 12a are pressed against one end side surface of the ceramic tube 6 and moved to one end side by the L2 dimension.

  When the operation is finished and the temperature of the heating furnace 10 is lowered, both the metal shell 5 and the ceramic tube 6 contract toward the other end side in the axial direction. At this time, since the stress necessary for contraction of the ceramic tube 6 is preloaded on the ceramic tube 6 by the action of the weight means 15 of the pressing mechanism 7 (the load of the weight 19), the ceramic tube 6 is in a cold state without cracking. You can return to

  As described above, in the rotary kiln of the present invention, the retort 4 includes the metal shell 5, and the ceramic tube 6 disposed inside the metal shell 5 so as to be slidable in the axial direction with respect to the metal shell 5. Since the object to be processed comes into contact with the ceramic tube 6 and does not come into contact with the metal shell 5, the metal retort (metal shell 5) reacts with the object to be processed during the heat treatment. There is no contamination inside. Further, a pressing mechanism 7 for pressing the ceramic tube 6 toward the other end side is provided on one end side of the retort 4, and the other end side of the retort 4 is for restricting movement of the retort 4 to the other end side. Since the stress required for the shrinkage of the ceramic tube 6 is preloaded by the provision of the stopper mechanism 8, the thermal expansion difference between the metal retort (metal shell 5) and the ceramic layer (ceramic tube 6). The generation of cracks in the ceramic layer due to the above is prevented.

  In addition, although the retort 4 of the rotary kiln 1 of the Example mentioned above is formed in the cylindrical shape, it is not limited to this, The thing formed in the polygonal cylindrical body is also included by the category of this invention. The retort 4 of the rotary kiln 1 is composed of three ceramic tubes 5A, 5B, 5C connected in the axial direction, but is not limited to three and is composed of a plurality of ceramic tubes. These are broadly included in the scope of the present invention. Furthermore, although the pressing mechanism 7 of the rotary kiln 1 is constituted by weight means, for example, those in which the pressing mechanism is constituted by other pressing means such as a spring member are also widely included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Rotary kiln 2 Processing object discharge port 3 Processing object supply port 4 Retort 4a Shaft center 5 Metal shell 6 Ceramic tube 7 Pressing mechanism 8 Stopper mechanism 9 Rolling wheel 10 Heating furnace 11 Electric heating element 12a Pressing surface 12b Ring body 12 Tire boss 13 Tire 14 Tire moving means 15 Weight means 16 Thrust roller 17 Caster 18 Base 19 Weight 20 Wire rope 21 Pulley 22a Locking surface 22b Annular body 22 Second tire boss 23 Second tire 24 Second tire movement restraining means 25 Thrust roller 26 Pedestal 30 Gap

Claims (3)

A rotary kiln in which a retort having a processing object discharge port on one end side and a processing object supply port on the other end side is arranged rotatably about an axis,
The retort is composed of a metal shell and a ceramic tube that is slidable in the axial direction with respect to the metal shell inside the metal shell,
A pressing mechanism for pressing the ceramic tube toward the other end is provided at one end of the retort, and a stopper mechanism for restricting movement of the retort to the other end at the other end of the retort. Is provided,
The pressing mechanism includes a tire boss having a pressing surface for pressing the ceramic tube toward the other end, tire moving means for moving the tire in the axial direction of the retort, and the tire moving means. Pressing means for pressing toward the other end of the ceramic tube;
The tire boss includes an annular body whose other side surface serves as a pressing surface for pressing one end side surface of the ceramic tube, and the pressing surface is configured to come into surface contact with the one end side surface of the ceramic tube. And the tire boss is disposed so as to surround an outer peripheral surface on one end side of the retort including the metal shell and the ceramic tube,
The stopper mechanism includes a second tire boss having a locking surface for locking the other end side surface of the ceramic tube, and a second tire movement for suppressing the second tire from moving in the axial direction of the retort. Deterrence means,
The metal shell is arranged so that one end side surface is located on the other end side from the one end side surface of the ceramic tube, and the metal shell extends in the axial direction due to thermal expansion caused by heating in a heating furnace. Even in this case, the rotary kiln is arranged so that one end side surface of the metal shell is located on the other end side from one end side surface of the ceramic tube. The rotary kiln according to claim 1, wherein the pressing means is constituted by weight means. The rotary kiln according to claim 1 or 2 , wherein the ceramic tube includes a plurality of ceramic tubes connected in the axial direction.

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