JP5528675B2 - Method for heat treatment of treated product containing chloride obtained by grinding shells - Google Patents

Description

The present invention relates to a heat treatment method for producing calcium oxide by heating a powdery processed product containing calcium carbonate as a main component in a rotating furnace core tube, and in particular, a powder containing chloride by pulverizing shells. granular treated relates to a heat treatment method of processing containing the chloride obtained by pulverizing shells of heating chromium-containing heat-resistant steel furnace tube.

  In recent years, for example, scallop shells, shells such as oysters, eggshells, and wastes related to biological materials mainly composed of calcium carbonate such as bones have been actively studied for their effective use. These wastes are crushed into powdery processed products, and the processed products are baked and heated to produce calcium oxide, and this calcium oxide is used, for example, as a disinfectant or antifreeze agent. It is.

Conventionally, as a heat treatment method for heat-treating a granular processed material containing calcium carbonate as a main component, for example, a technique disclosed in Japanese Patent Application Laid-Open No. 2003-147398 is known.
This is made with scallop shell as the main raw material, and pulverized into a powdery processed product. This processed product is put into a furnace core tube of a rotary kiln, at a temperature of 600 ° C. or higher, and in an oxygen-free state. It is heated and fired for several tens of minutes to several hours to generate calcium oxide. In general, a furnace core tube of a rotary kiln is mainly made of steel or a refractory brick lined on the inner periphery of mild steel. In a steel furnace core tube, in order to improve heat resistance and increase durability, heat-resistant steel containing nickel, chromium or the like is mainly used.

JP 2003-147398 A

However, in the above conventional heat treatment method, when the furnace core tube is the former heat-resistant steel and heat-resistant steel containing chromium, chromium is not removed from the furnace core tube even if heated and fired in an oxygen-free state. There was a problem that it was easily eluted and mixed into calcium oxide as an oxide, the color greened, and the purity was poor and the quality was liable to deteriorate.
The reason for this is that, in general, when the inside of the furnace core tube is in an oxygen-free state or when the oxygen concentration is extremely low, the oxidation reaction between the atmosphere in the furnace core tube and the components of the furnace core tube is suppressed, and the heat is processed. It is thought that it contributes to the decomposition of certain calcium carbonate and the elution of chromium is suppressed, but in the case of scallop shells and oyster shells, chlorides such as NaCl and KCl are contained in the treated material due to the influence of seawater. It is considered that the contamination is increased and the corrosive action of the furnace core tube is promoted by the battery action with the furnace core tube, and the elution of the chromium component as the composition material occurs. This is because, in particular, when the state in which the processed material adheres to the inner surface of the furnace core tube becomes longer, it is considered that the reaction between oxygen and calcium in calcium carbonate is promoted during the adhesion.

  On the other hand, when the furnace core tube is a refractory brick lined on the inner periphery of the latter mild steel, there is no elution of the chromium component, but the treated material adheres to the refractory brick and becomes clogged in a short time. Therefore, it is substantially unsuitable for use.

The present invention has been made in view of the above problems, and in a furnace core tube using chromium-containing heat-resisting steel, the inside of the furnace core tube is made oxygen-free or the oxygen concentration is extremely reduced. Reduces the contact time of the inner surface of the furnace core tube, heat treatment is performed in the atmosphere in the furnace core tube, suppresses the mixing of chromium into the calcium oxide as much as possible, crushed the shell, and chloride It is an object of the present invention to provide a heat treatment method for a treated product containing a chloride obtained by pulverizing a shell made of high-purity and high-quality calcium oxide, even if it is a powder- like treated product containing sucrose .

In order to achieve such an object, the heat treatment method of the present invention is to heat a powdery processed product obtained by pulverizing a shell containing calcium carbonate as a main component and containing chloride in a furnace core tube rotated by a heat treatment apparatus. In the heat treatment method for generating calcium oxide, a plurality of rows are provided in the furnace core tube along the direction of the central axis of the furnace core tube, and the inner peripheral surface of the furnace core tube is formed by rotation of the furnace core tube. A beater member that rolls and applies an impact to the processed material is provided, the peripheral speed of the inner peripheral surface of the furnace core tube is set to 0.1 m / s to 0.5 m / s, and the temperature in the furnace core tube is set. Is set to 800 ° C. to 1200 ° C., an inert gas is supplied into the furnace core tube, and the processed product is heat-treated in the inert gas. The furnace core tube is formed of heat-resistant steel containing chromium, and the processed material is supplied to the furnace core tube with a particle size of 0.60 mm to 2.00 mm.
In this specification, even if it is simply expressed as “peripheral speed”, it means “peripheral speed of the inner peripheral surface of the furnace core tube”.

If the peripheral speed is less than 0.1 m / s, it becomes easy for the treated material to remain. If the peripheral speed exceeds 0.5 m / s, the speed becomes too high, the beater member rolls so that it floats and becomes unstable, and the impact is difficult to be transmitted to the furnace core tube.
If the temperature in the furnace core tube is less than 800 ° C., the thermal decomposition of calcium carbonate becomes insufficient. When the temperature in the furnace core tube exceeds 1200 ° C., high-temperature oxidation of the furnace core tube proceeds, and the durability is significantly adversely affected.

  Thus, when the furnace core tube rotates, the beater member rotates in the same direction as the rotation direction of the furnace core tube to roll on the inner surface of the furnace core tube, and the processed material moves in the furnace core tube. At this time, since the peripheral speed of the inner peripheral surface of the furnace core tube is set to 0.1 m / s to 0.5 m / s, the peripheral speed is relatively high. The object to be adhered and retained on the inner peripheral surface of the tube is immediately separated from the inner peripheral surface of the furnace core tube and dispersed. In this case, even if the processed material adheres to the inner peripheral surface of the furnace core tube and stops, the beater member rotates in the same direction as the rotation direction of the furnace core tube and rolls on the inner surface of the furnace core tube. Since the impact is imparted to the inner peripheral surface of the furnace core tube, the processed material to be retained is forcedly separated from the inner peripheral surface of the furnace core tube and dispersed by the impact. Therefore, the time for which the treated product contacts the inner surface of the furnace core tube becomes extremely short, and therefore, the reaction between oxygen in calcium carbonate and chromium which is a component of the furnace core tube is suppressed.

In addition, since the furnace core tube is filled with inert gas, the furnace core tube is in an oxygen-free state or in an extremely low oxygen concentration, so that the reaction between the chromium component of the furnace core tube and oxygen occurs. As a result, the elution of chromium is suppressed, and the treated product is heat-treated in the atmosphere in the furnace core tube and is chemically changed to calcium oxide.
Furthermore, since the temperature in the furnace core tube is set to 800 ° C. to 1200 ° C., the processed material is surely heat-treated in the atmosphere in the furnace core tube, and is chemically changed to calcium oxide. become.
As a result, mixing of chromium into calcium oxide is suppressed as much as possible, and high-quality and high-quality calcium oxide is produced.

  And it is set as the structure which set the peripheral speed of the inner peripheral surface of the said furnace core pipe to 0.2 m / s-0.4 m / s as needed. Furthermore, it becomes an appropriate range that suppresses the situation where the treatment object adheres and stops. More preferably, the peripheral speed is in the range of 0.25 m / s to 0.35 m / s.

  Moreover, it is set as the structure which set the temperature in the said furnace core pipe to 850 to 1050 degreeC as needed. Further, the thermal decomposition reaction of the processed product can be promoted.

Furthermore, if necessary, the concentration of the inert gas in the furnace core tube is set to 90% to 100%. The reaction between the chromium component of the furnace core tube and oxygen can be reliably suppressed. If it is less than 90%, the reaction suppression with the chromium component becomes worse.
In this case, it is effective to set the concentration of the inert gas in the furnace core tube to 98% to 100%. The reaction between the chromium component of the furnace core tube and oxygen can be more reliably suppressed. When the concentration of the inert gas is set to less than 100%, more desirably, when the inert gas concentration is set to 99% or less, the confidentiality of the apparatus can be configured somewhat easily. Can be lowered.

Specifically, the heat treatment apparatus used in the heat treatment method for the treatment containing chloride obtained by pulverizing the shell of the present invention is a heat treatment apparatus that generates calcium oxide by heating a granular treatment mainly composed of calcium carbonate. ,
A processed product supply unit that supplies the processed product, and a heat-resistant steel containing chromium that receives and rotates the processed product supplied from the processed product supply unit at one end and discharges the processed product from the other end. A plurality of rows in the furnace core tube along the direction of the central axis of the furnace core tube and rolling the inner peripheral surface of the furnace core tube by the rotation of the furnace core tube A beater member that gives an impact to the workpiece, a drive unit that rotationally drives the furnace core tube, a heating unit that heats the furnace core tube from the outside, and an inert gas that supplies an inert gas into the furnace core tube A supply unit, and a control unit that controls the drive unit, the heating unit, and the inert gas supply unit. The control unit has a peripheral speed of 0.1 m / s to 0. Rotation drive unit control means for setting to 5 m / s, and heating unit for setting temperature in the furnace core tube to 800 ° C. to 1200 ° C. And control means, are configured to include a inert gas control means for setting the concentration of the inert gas of the furnace core tube 90% to 100%.

  If the peripheral speed is less than 0.1 m / s in the setting of the control unit, the processing object is likely to remain. If the peripheral speed exceeds 0.5 m / s, the speed becomes too high, the beater member rolls so that it floats and becomes unstable, and the impact is difficult to be transmitted to the furnace core tube. If the temperature in the furnace core tube is less than 800 ° C., the thermal decomposition of calcium carbonate becomes insufficient. When the temperature in the furnace core tube exceeds 1200 ° C., high-temperature oxidation of the furnace core tube proceeds, and the durability is significantly adversely affected. Furthermore, if the concentration of the inert gas is less than 90%, elution of the chromium component in the furnace core tube occurs, and the reaction suppression becomes worse.

  Thereby, when heat-treating the processed material, the control unit sets the required settings, operates the drive unit, the heating unit, and the inert gas supply unit, and the processed product from the processed product supply unit to one end side of the furnace core tube. Supply. Thus, when the furnace core tube rotates, the beater member rotates in the same direction as the rotation direction of the furnace core tube to roll on the inner surface of the furnace core tube, and the processed material moves in the furnace core tube. At this time, since the peripheral speed of the inner peripheral surface of the furnace core tube is set to 0.1 m / s to 0.5 m / s, the peripheral speed is relatively high. The object to be adhered and retained on the inner peripheral surface of the tube is immediately separated from the inner peripheral surface of the furnace core tube and dispersed. In this case, even if the processed material adheres to the inner peripheral surface of the furnace core tube and stops, the beater member rotates in the same direction as the rotation direction of the furnace core tube and rolls on the inner surface of the furnace core tube. Since the impact is imparted to the inner peripheral surface of the furnace core tube, the processed material to be retained is forcedly separated from the inner peripheral surface of the furnace core tube and dispersed by the impact. Therefore, the time for which the treated product contacts the inner surface of the furnace core tube becomes extremely short, and therefore, the reaction between oxygen in calcium carbonate and chromium which is a component of the furnace core tube is suppressed.

In addition, the concentration of the inert gas in the furnace core tube is set to 90% to 100%, and the furnace core tube is filled with the inert gas. Since there is very little state, there is almost no reaction between the chromium component of the furnace core tube and oxygen, so that the elution of chromium is suppressed and the processed material is heat-treated in the atmosphere in the furnace core tube, resulting in calcium oxide. It will be changed chemically. When the concentration of the inert gas is set to less than 100%, more desirably, when the inert gas concentration is set to 99% or less, the confidentiality of the apparatus can be configured somewhat easily. Can be lowered. Furthermore, since the temperature in the furnace core tube is set to 800 ° C. to 1200 ° C., the processed material is surely heat-treated in the atmosphere in the furnace core tube, and is chemically changed to calcium oxide. become.
As a result, mixing of chromium into calcium oxide is suppressed as much as possible, and high-quality and high-quality calcium oxide is produced.

More specifically, the present invention provides the control unit with a rotational drive unit control means for setting the peripheral speed of the inner peripheral surface of the furnace core tube to 0.2 m / s to 0.4 m / s, A heating unit control means for setting the temperature in the furnace core tube to 850 ° C. to 1050 ° C., and an inert gas control means for setting the concentration of the inert gas in the furnace core tube to 98% to 100%. It is composed.
By setting the peripheral speed of the inner peripheral surface of the furnace core tube to 0.2 m / s to 0.4 m / s, it becomes an appropriate range in which the situation where the treatment object adheres and stays is suppressed. Moreover, it becomes the range which can accelerate | stimulate the thermal decomposition reaction of a processed material further by setting the temperature in a furnace core pipe to 850 to 1050 degreeC. Furthermore, by setting the concentration of the inert gas in the furnace core tube to 98% to 100%, the reaction between the chromium component of the furnace core tube and oxygen can be more reliably suppressed, and the inert gas When the gas concentration is set to less than 100%, more desirably, when the gas concentration is set to 99% or less, the confidentiality of the apparatus can be configured somewhat easily, and accordingly, the manufacturing cost of the apparatus is reduced accordingly. Can do.

If necessary, an end cover for covering one end of the furnace core tube and another end cover for covering the other end of the furnace core tube are provided, and an inert gas is supplied to the other end cover in the furnace core tube. An inert gas supply port is provided, the other end cover is provided with an outlet for taking out the processed material discharged from the other end of the furnace core tube, and the exhaust gas from the furnace core tube is exhausted to the one end cover. An exhaust port is provided, and the inert gas supply unit supplies the inert gas from the inert gas supply port.
The furnace core tube can be filled with an inert gas with a relatively simple structure.

  Further, if necessary, the beater member has an axis that is eccentric with respect to the axis of the furnace core tube, is provided radially about the axis, and an outer edge abuts against the inner peripheral surface of the furnace core tube. It is configured with three or more fins. When the beater member rolls, the fin collides with the processing object, so that the processing object is divided, so that the vibration can be reliably applied and dispersed.

According to the heat treatment method of the treatment containing chloride obtained by pulverizing the shell of the present invention, since the peripheral speed of the inner peripheral surface of the furnace core tube is set to be relatively fast, it adheres to the inner peripheral surface of the furnace core tube. As a result, the processed material to be retained can be immediately separated from the inner peripheral surface of the furnace core tube and dispersed. In this case, the processed material adheres to the inner peripheral surface of the furnace core tube and is retained. Even if trying to do so, the beater member rotates in the same direction as the rotation direction of the furnace core tube and rolls on the inner surface of the furnace core tube to give an impact to the processed material, so that it adheres to the inner peripheral surface of the furnace core tube. The treated object to be retained can be forcibly separated from the inner peripheral surface of the furnace core tube by this impact, so that the time for which the treated object contacts the inner surface of the furnace core tube is extremely shortened, and calcium carbonate It is possible to suppress the reaction between oxygen therein and chromium which is a component of the furnace core tube. In addition, since the furnace core tube is filled with an inert gas, the furnace core tube is in an oxygen-free state or in an extremely low oxygen concentration. In this respect, the elution of chromium can be suppressed. Further, the processed product can be reliably heat-treated in the atmosphere in the furnace core tube. Furthermore, the temperature setting in the furnace core tube is good, and the processed product can be reliably heat-treated in the atmosphere in the furnace core tube, so that calcium oxide can be reliably generated. As a result, mixing of chromium into calcium oxide can be suppressed as much as possible, and high-purity and high-quality calcium oxide can be generated.

Hereinafter, based on an accompanying drawing, the heat processing method of the processed material containing the chloride which grind | pulverized the shell which concerns on embodiment of this invention is demonstrated in detail. Heat treatment method according to the present embodiment, Ru is achieved by the heat treatment apparatus of the present embodiment.

The heat treatment apparatus according to the present embodiment generates calcium oxide by heating a granular processed material containing calcium carbonate as a main component. For example, the processed material mainly composed of calcium carbonate to be treated by the heat treatment apparatus is a well-known pulverization of wastes related to biological materials mainly composed of calcium carbonate such as shells such as scallops and oysters, eggshells and bones. The powder is pulverized by a machine.
The particle size of the processed product is, for example, a particle size of 0.30 mm to 5.00 mm, preferably 0.50 mm to 3.00 mm, and more preferably 0.60 mm to 2.00 mm.

  As shown in FIGS. 1 to 3, the heat treatment apparatus S according to the present embodiment includes a processed product supply unit 1 that supplies a processed product W. The processed product supply unit 1 includes a hopper 2 that stores the processed product W, and a screw conveyor 3 that conveys the processed product W in the hopper 2 to one end side of a furnace core tube 10 to be described later. The screw conveyor 3 is driven via a transmission mechanism including a sprocket 5 and a chain 6 that are rotated by a motor 4.

  Moreover, this heat processing apparatus S is provided with the furnace core tube 10 which receives the processed material W supplied from the processed material supply part 1 by the one end 10a side, is rotated, and discharges the processed material W from the other end 10b. The furnace core tube 10 is made of heat-resistant steel containing nickel and chromium in order to improve heat resistance and increase durability. Outer rings 11 are fixed to the outer sides of the one end 10a side and the other end 10b side of the furnace core tube 10, respectively. The outer ring 11 is supported by a roller 13 provided on a frame 12 provided on the installation floor surface, so that the furnace core tube 10 can be rotated via the roller 13 and the outer ring 11. . Further, the furnace core tube 10 is supported by being inclined downward from the one end 10a side toward the other end 10b side, and moves the workpiece W from the one end 10a side to the other end 10b side by rotation.

  In the furnace core tube 10, a plurality of rows are provided along the direction of the central axis Pa of the furnace core tube 10, and the inner peripheral surface of the furnace core tube 10 is rolled by the rotation of the furnace core tube 10. A beater member 20 for applying an impact to W is provided. The beater member 20 is formed of the same material as the furnace core tube 10, has an axis Pb that is eccentric with respect to the center axis Pa of the furnace core tube 10, is provided radially around the axis Pb, and has an outer edge. Three or more (three in the embodiment) rectangular plate-shaped fins 21 that are in contact with the inner peripheral surface of the furnace core tube 10 are provided.

As shown in FIG. 2, the fins 21 are integrally joined at one side edge so as to be equiangularly spaced, and a circle whose radius is the other side edge of the fin 21 from the center is formed on the core tube 10. It is set slightly smaller than a circle having a radius from the central axis to the inner peripheral surface. When the furnace core tube 10 rotates in the rotation direction R shown in FIG. 2, the beater member 20 falls down and rotates. Of the three fins 21, the other side edge of the two fins 21 is inside the furnace core tube 10. The remaining fins 21 are in contact with the peripheral surface and are upright in the internal space of the furnace core tube 10. As the furnace core tube 10 rotates, the two fins 21 that are in contact with the inner peripheral surface of the furnace core tube 10 also rotate along with the rotation of the one fin 21 that stands upright in the internal space due to its own weight. And one of the other two fins 21 separates from the inner peripheral surface and stands upright in the internal space.
The other end 10b of the furnace core tube 10 is provided with a stopper 22 that allows the workpiece W to be discharged and presses the beater member 20 positioned on the other end 10b side.

  Further, the heat treatment apparatus S includes a drive unit 30 that rotationally drives the furnace core tube 10. The drive unit 30 includes a motor 31, a driving sprocket 32 rotated by the motor 31, a driven sprocket 33 provided outside the one end 10 a of the furnace core tube 10, and a chain spanned over the driving sprocket 32 and the driven sprocket 33. 34 is constituted by a transmission mechanism.

  The heat treatment apparatus S further includes a heating unit 40 that heats the furnace core tube 10 from the outside. The heating unit 40 includes a heat insulating tube 42 that is provided on the gantry 41 and is a heat insulating member that surrounds the furnace core tube 10, and a heater 43 that is provided inside the heat insulating tube 42 and heats the furnace core tube 10. ing.

Furthermore, the heat treatment apparatus S includes an inert gas supply unit 50 that supplies an inert gas into the furnace core tube 10. The inert gas supply unit 50 supplies a rare gas such as nitrogen gas or argon gas. In the embodiment, nitrogen gas is supplied.
Specifically, in the heat treatment apparatus S, one end cover 51 that covers one end 10 a of the furnace core tube 10 and the other end cover 52 that covers the other end 10 b of the furnace core tube 10 are provided. The other end cover 52 is provided with an inert gas supply port 53 for supplying an inert gas into the furnace core tube 10, and the inert gas supply unit 50 is connected to the inert gas supply port 53 through the inert gas. Is configured to supply. Further, the other end cover 52 is provided with an outlet 54 for taking out the processed product W discharged from the other end 10b of the furnace core tube 10. The outlet 54 is provided with a pair of ball valves 54a and 54b spaced apart from each other. By alternately opening and closing the ball valves 54a and 54b, the workpiece W accommodated between the ball valves 54a and 54b can be removed. The predetermined amount can be taken out. The other end cover 52 is provided with another gas supply port 55 for supplying another gas such as hydrogen.
On the other hand, the screw conveyor 3 of the processed product supply unit 1 is disposed through the one end cover 51. Further, an exhaust port 56 for exhausting exhaust gas from the furnace core tube 10 is provided at the upper portion of the one end cover portion 51. An exhaust pipe 58 whose outlet is sealed with a water seal 57 is connected to the exhaust port 56, and the exhaust from the outlet of the exhaust pipe 58 is discharged to the outside air through bubbling with respect to water in the water seal 57. . As a result, the furnace core tube 10 can be filled with an inert gas and exhausted with a relatively simple structure.

Further, in the present heat treatment apparatus S, there are provided a control unit 60 for controlling the gas supply amount of the motor 4 of the processed product supply unit 1, the motor 31 of the drive unit 30, the heater 43 of the heating unit 40 and the inert gas supply unit 50. It has been. The control part 60 is implement | achieved by functions, such as CPU of a computer, for example, and sets the peripheral speed of the internal peripheral surface of the furnace core tube 10 to 0.1 m / s-0.5 m / s, as shown in FIG. Rotation drive unit control means 61, heating unit control means 62 for setting the temperature in the furnace core tube 10 to 800 ° C. to 1200 ° C., and the concentration of the inert gas in the furnace core tube 10 to 90% to 100% An inert gas control unit 63 to be set and a process supply control unit 64 to control the motor 4 of the process supply unit 1 are provided. The inert gas control means 63 may be configured by a valve that can be manually operated to adjust the opening.

In the above setting, if the peripheral speed is less than 0.1 m / s, the workpiece W is likely to be stopped. If the peripheral speed exceeds 0.5 m / s, the speed becomes too high, the beater member 20 rolls so as to float, becomes unstable, and the shock is not easily transmitted to the furnace core tube 10, which is not preferable.
The peripheral speed of the furnace core tube 10 is preferably set in the range of 0.2 m / s to 0.4 m / s, and more desirably in the range of 0.25 m / s to 0.35 m / s. Furthermore, it becomes an appropriate range that suppresses the situation where the treatment object adheres and stops.

  Moreover, in said setting, if the temperature in the furnace core tube 10 is less than 800 degreeC, thermal decomposition of calcium carbonate will become inadequate. When the temperature in the furnace core tube 10 exceeds 1200 ° C., high-temperature oxidation of the furnace core tube 10 proceeds, and the durability is significantly adversely affected. More desirably, the temperature in the furnace core tube 10 is set to 850 ° C to 1050 ° C.

  Furthermore, in the above setting, the concentration of the inert gas in the furnace core tube 10 is set to 90% to 100%. In this range, the reaction between the chromium component of the furnace core tube 10 and oxygen is ensured. Can be deterred. If it is less than 90%, the reaction suppression with the chromium component becomes worse. The concentration of the inert gas in the furnace core tube 10 is preferably set to 98% to 100%. The reaction between the chromium component of the furnace core tube 10 and oxygen can be more reliably suppressed. When the concentration of the inert gas is set to less than 100%, more desirably, when the inert gas concentration is set to 99% or less, the confidentiality of the apparatus can be configured somewhat easily. Can be lowered.

Therefore, when the processing object W is processed by the heat treatment apparatus S according to this embodiment, it is as follows.
The drive unit 30, the heating unit 40, and the inert gas supply unit 50 are operated with the required setting by the control unit 60. Thereby, the furnace core tube 10 rotates, and the beater member 20 rotates in the same direction as the rotation direction of the furnace core tube 10 to roll the inner surface of the furnace core tube 10. And if the processed material W is supplied to the one end 10a side of the furnace core tube 10 from the processed material supply part 1, the processed material W will move gradually in the furnace core tube 10, and the processed material W will be heated in this movement. The By this heating, the calcium carbonate is pyrolyzed and produced as calcium oxide, discharged from the other end 10 b of the furnace core tube 10, and taken out from the outlet 54.

  During the heat treatment of the workpiece W, the peripheral speed of the inner peripheral surface of the furnace core tube 10 is set to 0.1 m / s to 0.5 m / s, so that the peripheral speed is relatively high. For this reason, the workpiece W which is attached to the inner peripheral surface of the furnace core tube 10 and is to be retained is immediately detached from the inner peripheral surface of the furnace core tube 10 and dispersed. In this case, even if the workpiece W adheres to the inner peripheral surface of the furnace core tube 10 and stops, the beater member 20 rotates in the same direction as the rotation direction of the furnace core tube 10 to rotate the inner surface of the furnace core tube 10. Since it moves and gives an impact to the workpiece W, the workpiece W which is attached to the inner peripheral surface of the furnace core tube 10 and is to be retained is forcibly separated from the inner peripheral surface of the furnace core tube 10 by this impact. To be distributed. In this case, since the beater member 20 includes the fins 21, when the beater member 20 rolls, the fins 21 collide with the workpiece W, so that the workpiece W is divided. The vibration can be imparted to and dispersed. Therefore, the time during which the processed product W comes into contact with the inner surface of the furnace core tube 10 is extremely short, and therefore, the reaction between oxygen in calcium carbonate and chromium which is a component of the furnace core tube 10 is suppressed.

  Moreover, since the concentration of the inert gas in the furnace core tube 10 is set to 90% to 100% and the furnace core tube 10 is filled with the inert gas, the inside of the furnace core tube 10 is in an oxygen-free state. Or the oxygen concentration becomes extremely low, the reaction between the chromium component of the furnace core tube 10 and oxygen is almost eliminated, so that elution of chromium is suppressed and the processed product W is contained in the furnace core tube 10. It is heat-treated in the atmosphere and is chemically changed to calcium oxide.

Furthermore, since the temperature in the furnace core tube 10 is set to 800 ° C. to 1200 ° C., the processed product W is reliably heat-treated in the atmosphere in the furnace core tube 10 and chemically changed to calcium oxide. You will be let go.
As a result, mixing of chromium into calcium oxide is suppressed as much as possible, and high-quality and high-quality calcium oxide is produced.

Experimental examples are shown below.
[Experimental Example 1]
As Experimental Example 1 of the heat treatment method and heat treatment apparatus according to the present invention, scallop shells crushed to 0.5 mm to 3.0 mm were used as the processed material, and the shape as shown in FIGS. , H = 87.5 mm, t = 6 mm, using a furnace core tube 10 having a diameter of 200 mm and a length of 4000 mm containing a plurality of beater members 20 having a weight of about 6 kg, a furnace body angle (inclination angle of the furnace core tube) 5 The furnace core tube passage time was 12 minutes, the input treatment amount was 8.6 kg, 99% or more in a nitrogen atmosphere, and the heat treatment temperature was set to 950 ° C., and heat treatment was performed. And the change rate and color tone of calcium carbonate to calcium oxide were measured when the peripheral speed of the furnace core tube 10 was 0.02 m / s and 0.26 m / s. The test results are shown in FIG.

  As a result, the scallop shell powder material has a heat treatment temperature of 950 ° C., a nitrogen atmosphere of 99%, a peripheral speed of 0.26 m / s, a conversion rate of calcium carbonate to calcium oxide of 99% or more, and a color tone. A white color was exhibited. In the elemental composition component, the chromium component was 0.141% at a peripheral speed of 0.26 m / s. In contrast, when the peripheral speed was 0.02 m / s, the film was extremely light green and the chromium component was 0.681%. In the heat treatment method of the scallop shell powder using the furnace core tube, it is understood that the peripheral speed of the furnace core tube affects the elution of chromium.

[Experiment 2]
As Experimental Example 2, the peripheral speed was set as 0.04 m / s or 0.26 m / s with the nitrogen concentration being 0%, and the other conditions were the same as described above. The experimental results are shown in FIG. As a result, the rate of change from calcium carbonate to calcium oxide was 89% when the peripheral speed was 0.04 m / s, and green was exhibited. Further, when the peripheral speed was 0.26 m / s, the conversion rate from calcium carbonate to calcium oxide was 99% or more, which was satisfactory, but green was exhibited. As a result of elemental analysis, the chromium content was as high as 1.232% and 1.450%. That is, this green color is considered to be due to the chromium content. Therefore, when producing calcium oxide from scallop shells by heat treatment at 950 ° C., a heat treatment method in a nitrogen atmosphere is essential.

[Experiment 3]
As Experimental Example 3, in order to clarify the influence of the nitrogen concentration on the heat treatment, in each nitrogen atmosphere of 80% and 90%, the peripheral speed was set to 0.26 m / s, and other conditions were the same as above. And experimented. That is, if good calcium oxide can be obtained with the optimum nitrogen concentration by the above method using the furnace core tube, it is obvious that it is economical, and an experiment was conducted on how much the concentration is necessary. The results are shown in FIG. As a result, a light-green heat treatment material was obtained at 80%, but when the nitrogen concentration was 90%, a good calcium oxide with a gray content of 0.213% and a conversion rate of 99% or more was obtained. I was able to.

[Experimental Example 4]
As Experimental Example 4, 99% or more under a nitrogen atmosphere, the peripheral speed was set to 0.26 m / s, and the influence of the heat treatment temperature was tested. The results are shown in FIG. As a result, in the heat treatment at 700 ° C., the conversion rate from calcium carbonate to calcium oxide is as extremely low as 18%, which is not suitable for obtaining calcium oxide. The conversion rate from calcium carbonate to calcium oxide is 90% at 800 ° C, 99% or more at 850 ° C, 1050 ° C, and 1100 ° C, and the chromium content is also 0.131%, 0.161%, 0.181%. , 0.252% and was white. It is obvious that the heat treatment is performed at a temperature as low as possible because the durability of the furnace core tube is increased when the treatment temperature is low, and the heat treatment temperature is 800 ° C. to 1100 ° C. in the method using the furnace core tube. It is possible to easily obtain white calcium oxide containing a very small amount of chromium from scallop shell powder by setting and desirably setting at 850 ° C. to 1050 ° C. and setting the nitrogen concentration to 90% or more. I understood.

It is a front view which shows the heat processing apparatus which concerns on embodiment of this invention. It is sectional drawing which shows the heat processing apparatus which concerns on embodiment of this invention. It is a block diagram which shows the structure of the control part of the heat processing apparatus which concerns on embodiment of this invention. 6 is a table showing the results of Experimental Example 1. FIG. It is a table | surface figure which shows the result of Experimental example 2. It is a table | surface figure which shows the result of Experimental example 3. 10 is a table showing the results of Experimental Example 4. FIG.

Explanation of symbols

S Heat treatment apparatus W Processed object 1 Processed object supply part 2 Hopper 3 Screw conveyor 4 Motor 10 Furnace core tube 10a One end 10b Other end 11 Outer ring 12 Base frame 13 Roller 20 Beater member 21 Fin 30 Drive part 31 Motor 32 Driving sprocket 33 Driven sprocket 34 Chain 40 Heating part 41 Base 42 Insulating tube 43 Heater 50 Inert gas supply part 51 One end cover part 52 Other end cover part 53 Inert gas supply port 54 Outlet 54a, 54b Ball valve 55 Other gas supply port 56 Exhaust port 57 Water sealing part 58 Exhaust pipe 60 Control part 61 Rotation drive part control means 62 Heating part control means 63 Inert gas control means 64 Process supply control means

Claims (3)

In a heat treatment method for a treated product containing chloride obtained by crushing a shell and pulverizing a shell processed to produce calcium oxide by heating a granular processed product containing calcium carbonate as a main component and containing calcium chloride ,
The heat treatment apparatus contains a processed product supply unit that supplies the processed product, and chromium that receives and rotates the processed product supplied from the processed product supply unit on one end side and discharges the processed product from the other end. A furnace core tube formed of heat-resistant steel, and a plurality of rows are provided in the furnace core tube along the direction of the central axis of the furnace core tube and the inner peripheral surface of the furnace core tube is rotated by the rotation of the furnace core tube. A beater member that rolls and applies an impact to the processed material, a drive unit that rotationally drives the furnace core tube, a heating unit that heats the furnace core tube from the outside, and an inert gas in the furnace core tube An inert gas supply unit for supplying, and a control unit for controlling the driving unit, the heating unit, and the inert gas supply unit,
The control unit includes a rotation drive unit control means for setting the peripheral speed of the inner peripheral surface of the furnace core tube to 0.2 m / s to 0.4 m / s , and the temperature in the furnace core tube is set to 850 ° C. to 1050 ° C. A heating unit control means for setting to, and an inert gas control means for setting the concentration of the inert gas in the furnace core tube to 98% to 100% ,
The upper Symbol treated, the particle size of in the 0.60mm~2.00mm supplied to the furnace core tube, the chloride obtained by pulverizing shells, characterized in that the heat treatment the treated product with an inert gas A heat treatment method for a treated product.   In the heat treatment apparatus, a first end covering portion for covering one end of the furnace core tube and a second end covering portion for covering the other end of the furnace core tube are provided, and an inert gas is supplied to the other end covering portion in the furnace core tube. An exhaust for providing an inert gas supply port, an outlet for taking out the processed material discharged from the other end of the furnace core tube at the other end cover, and exhausting exhaust gas from the furnace core tube at the one end cover The heat treatment method for a treated product containing chloride obtained by pulverizing shells according to claim 1, wherein a mouth is provided, and the inert gas supply unit supplies an inert gas from the inert gas supply port.   The beater member has three or more fins that have an axis that is eccentric with respect to the axis of the furnace core tube and that are radially provided about the axis and whose outer end abuts against the inner peripheral surface of the furnace core tube. The heat treatment method of the processed material containing the chloride which grind | pulverized the shell of Claim 2 characterized by the above-mentioned.

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