JP3116024B2 - Granulation method of lime cake, baked product and production method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for granulating lime cake, a baked product, and a method for producing the same.

[0002]

2. Description of the Related Art Lime cake is mainly discharged from sugar beet sugar factories and contains calcium carbonate as a main component. Such lime cake, not only calcium carbonate,
It also contains P ₂ O ₅ , K ₂ O and organic substances (nitrogen compounds) and is used as an excellent soil conditioner. Granulation is performed to improve the handleability.

[0003] As a method for granulating lime cake,
A method disclosed in US Pat. In this method, a lime cake discharged from a sugar beet sugar factory is dehydrated, and a granulating agent containing a concentrated solution of stephen wastewater and the lime cake are subjected to a kneading step under a high pressure of 25 to 70 kg / cm ² . Post-extrusion granulation is performed, and drying is performed after the granulation.

[0004] It has been considered for many years to obtain quicklime from lime cake. Quicklime can provide a fertilizer having a higher alkalinity than the granulated product for agricultural use, and a soil stabilizer for industrial use.

[0005]

The above-mentioned Japanese Patent Publication No. Hei 2-4
According to the method of 9773, a lime cake dewatering step;
It requires a kneading step at high pressure with the addition of a granulating agent. This method requires dewatering of the lime cake before granulation, which is troublesome, and kneading at a high pressure is also difficult. As described above, in the above-described known method, the process is troublesome and difficult, and the apparatus for performing the process is complicated, and the granulated product as a product must be expensive. .
In addition, the necessity of adding a granulating agent further increases the cost.

It is known that calcining a lime cake can provide quick lime, but calcining the above granulated product is extremely expensive, and it is easy to granulate it. If the lime cake is baked as it is, it becomes fine powder and scatters, which causes problems during the manufacturing process or handling. So, up to now,
There is no baked lime cake.

[0007] In view of such circumstances, an object of the present invention is to provide a granulating method for a granulated lime cake which is simple and inexpensive to produce, a baked product, and a method for producing the same.

[0008]

According to the present invention, the above objects can be attained as follows with respect to a method for granulating a lime cake, a baked product and a method for producing the same. <Granulation method> The lime cake granulation method of the present invention is characterized by sequentially passing through an extrusion granulation molding step of extruding a lime cake discharged from a sugar factory and a drying step of drying a granulated body. I have. In such a method, when the lime cake is more or less blocky and clumpy, it is preferable to go through a kneading step before the extrusion granulation step. The method of kneading is not particularly limited, and it is sufficient to use a usual kneading machine.

In the present invention, the extrusion is carried out at 150 to 400.
It is desirable to carry out under an extrusion pressure of kg / cm ² .

[0010] The drying step is preferably carried out at room temperature to 15
Heating is performed for 15 minutes to 3 hours with warm air at 0 ° C.

The extrusion granulation step is preferably performed so that the granules obtained in the extrusion granulation step have a spherical or columnar shape having a diameter of 3 to 10 mm. <Baking Product and Method for Producing the Same> In the baking method of the present invention, a granulating step of extruding and forming a lime cake discharged from a sugar factory, a drying step of drying the granulated body, and firing the dried granulated body. It is performed by sequentially passing through a firing step.

In this firing method, as in the case of the above-mentioned granulation method, a kneading step can be carried out, if necessary, before the extrusion granulation molding step. Further, in the present invention, kneading, extrusion, drying, the preferred form of the shape of the granulated body,
This is the same as in the case of the granulation method described above. Thus, a baked product is obtained by going through each step of the calcination method.

[0013]

Embodiments of the present invention will be described below.

According to the present invention, the lime cake discharged from the sugar factory is granulated by sequentially passing through an extrusion granulating step of extruding and a drying step of drying the granules. In such a step, if the lime cake has any block-like lumps, a kneading step is preferably performed before the extrusion granulation step.

The lime cake has a water content of 20 to 30%. Conventionally, the water content is removed by a drying process, and a concentrated solution of waste water of stephen is added as a granulating agent (binder). Although kneading (kneading) was performed while applying a high pressure of up to 70 kg / cm ² , the present invention does not require any of the above-mentioned drying before kneading, addition of a granulating agent, and kneading under high pressure. The lime cake is extruded and granulated.

However, if there are block-like lumps in the lime cake, it is preferable to lightly knead them in order to loosen them. Therefore, kneading is not limited to the method (type of apparatus), and the pressure and the like are not particularly limited. Although there are various kneaders, a twin-screw extrusion type (meshing type or non-meshing type) is exemplified.

Thus, in the present invention, the lime cake is kneaded as needed, but in many cases, the lime cake is extruded and granulated without kneading. The pressure during the extrusion granulation is 150 to 400 kg / cm ² , preferably 150 to 200 kg / cm ² . Pressure 150
If it is not more than kg / cm ² , the granules obtained by extrusion granulation will lose their shape due to insufficient hardness, and will also have 400 kg / cm ^2.
When it is more than cm ² , the compaction (compressed and high-density state) is too strong, and for example, there is a problem that it is difficult to bake when baking later.

The extrusion granulation molding machine includes a screw type, a roll type, a blade type, a self-forming type, a ram type, etc.
Either may be used. Among them, the roll type and the blade type are preferable. For example, a roll die will be described as an example. In this type of extrusion granulating machine, a roll rolls on a die (panel) in which many die holes are formed. The lime cake is put on the die, and the roll rolls while pressing the lime cake under its own weight and under load. This pressure is 150 to 400 kg / cm ² . The lime cake pressed into the die hole under this pressure is compacted and subjected to a shearing force to fall into a predetermined shape in a lower opening of the die hole. Thus, granulation is performed. The granulated body granulated by the extrusion granulating machine is then sized, if necessary. Sizing is to give another shape to a granulated body that has become a lump (pellet) of one predetermined shape.
For example, there is a case where a cylindrical granule is made spherical.
Although sometimes referred to as granulation including the sizing step, here, agglomeration of a predetermined shape is referred to as granulation, and giving the next shape to this is referred to as sizing, and is distinguished. It shall be.

For example, a marmelizer (trade name: manufactured by Fuji Paudal) is suitable for making the granules spherical,
Alternatively, a drum rotation type or a dish type rotation type may be used.

Since the granulated body is kept in a compacted state in the extruded granulating machine while containing moisture, it is difficult for the granulated body to be spherical only by rotating. In the marmellaiser, the granulated material is directly roped by the centrifugal force received on the plate rotating on the horizontal plane and the frictional force due to the unevenness of the plate surface, and the cylindrical inner wall of the cylinder erected close to the outer periphery of the plate is just roped. It rotates while twisting like a thread, and finally becomes spherical by this action.

Usually, the time required for sizing is about 20 to 50 seconds for those having good sizing properties, and about 1 to 5 minutes for those having poor sizing properties.

Next, the above-mentioned granulated material is dried in a drying step. Drying is a matter of how much the contained water is, but in the present invention, 10% by weight or less,
Preferably, it is 5% or less. Examples of the drying method include heat drying in addition to natural drying. Examples of the latter include a fluidized bed dryer, a vibration dryer and a rotary dryer.

The temperature of hot air for drying is 400 ° C. or less,
The temperature is preferably from room temperature to 150 ° C., and the heating time is about 15 minutes to 3 hours, and the length is mainly determined by the amount of water contained in the lime cake. The reason for setting the temperature to 400 ° C. or lower is that the granulated material contains an organic substance, and for use in which the granulated substance is used, the temperature at which the organic substance starts burning is about 500 ° C., and the safety factor is considered. The temperature is set to 400 ° C. or lower to prevent the organic substances from disappearing due to combustion.

Thus, a granulated product is obtained. When the product is to be made into quicklime as a calcined product, the granulated body is calcined following the above steps.

The calcium carbonate (CaCO ₃ ) contained in the lime cake is calcined to produce quick lime (CaO) by a reaction of CaCO ₃ → CaO + CO ₂ . Organic matter is burned and lost.

The furnace for firing is preferably a rotary kiln, but may be a fluidized firing furnace or a top furnace.

The firing temperature is determined by the degree of activity required for quicklime obtained after firing. Organic matter starts burning at about 300 ° C., and burns at 700 to 800 ° C., and calcium carbonate (CaCO ₃ ) is converted to quicklime (Ca).
The heat of decomposition required to decompose into O) is about 895 ° C., so that the temperature should be higher for firing, for example, 900 ° C. or higher, but 900 ° C. or higher is required for soft calcined lime having a high required activity.
１1100 ° C., and about 1200 ° C. for hard-burning quicklime having a low required activity. The firing time is 30 minutes to 3 hours, preferably 30 minutes to 1 hour.

[0028]

[Table 3]

Prototype 6 Prototype 7 Prototype 8 Prototype 9 Prototype 10 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− -Firing Rotary Same as left Same as left Same as left Same as left 950 ° C by kiln [Table 4] 7 days 15 days 30 days 60 days 90 days ------------------------------------ −−−−−−−−−−−− 1. Breaking strength 0.37 0.38 0.35 0.34 0.32 (kg / cm ² ) 3 mm 2. 2. Moisture absorption (%) 0 0 0 0 0 (Prototype 1) Powdering rate (%) 0000 000 --------------------------------------------------------------------------------------------------- 1. Breaking strength 0.64 0.63 0.61 0.59 0.58 (kg / cm ² ) 5 mm 2. 2. Moisture absorption (%) 0 0 0 0 0 (Trial 2) Powdering rate (%) 0000 000 --------------------------------------------------------------------------------------------------- 1. Breaking strength 1.69 1.69 1.68 1.67 1.65 (kg / cm ² ) 7 mm 2. 2. Moisture absorption (%) 0 0 0 0 0 (Prototype 3) Powdering rate (%) 0000 000 ------------------------------------------------------------------------ [Table 5 7 days 15 days 30 days 60 days 90 days −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Breaking strength 0.45 0.45 0.42 0.40 0.39 (kg / cm ² ) 3 mm 2. 2. Moisture absorption (%) 0 0 0 0 0 (Prototype 6) Powdering rate (%) 0000 000 --------------------------------------------------------------------------------------------------- 1. Breaking strength 0.85 0.86 0.85 0.83 0.82 (kg / cm ² ) 5 mm 2. 2. Moisture absorption (%) 0 0 0 0 0 (Prototype 7) Powdering rate (%) 0000 000 --------------------------------------------------------------------------------------------------- 1. Breaking strength 0.97 0.98 0.94 0.93 0.92 (kg / cm ² ) 7 mm 2. 2. Moisture absorption (%) 0 0 0 0 0 (Prototype 8) Powdering rate (%) 0 0 0 0 0 0 0------------------------------The above prototype As a result of performing a physical property test and an activity test by appropriately selecting 1 to 5 (granulated product) and prototypes 6 to 10 (baked product), sufficient results were obtained.

Further, as a result of component analysis of the calcined product, as shown in Table 6, CaO is 90%, which sufficiently satisfies 80% or more required for calcareous fertilizer, and can be used as quicklime for agriculture. It is. First, the strength required when handling a granulated product or a fired product is approximately 0.3 kg / cm ² at a water content of 0%, but in the physical properties tests shown in Tables 4 and 5, any of the prototypes (prototype 1 3, prototypes 6 to 8) also have a higher breaking strength, and there was no problem of moisture absorption or powdering during storage for 7 to 90 days in a bag.

Next, as a result of performing an activity test on the prototype 7, the activity was higher than that of calcined limestone (conventional product). Prototypes 6 and 8 also showed almost the same results. Here, the activity is a value representing the reaction rate of quick lime, and is represented by HCl (hydrochloric acid) and the reaction rate as an example. In the test method, a quicklime sample (prototype in the example) was put into warm water, neutralized with HCl, and
1 consumption rate is measured.

[0031]

As described above, according to the present invention, granulation is carried out by extrusion granulation using the water content of the lime cake without using a granulating agent (binder). It is not necessary to dry the water content before granulation, and it is possible to make a granulated product with hardness that does not lose its shape using only the water content, and it does not use a granulating agent, which enables cost reduction and drying after granulation. It's easy.

As for the firing, the granulation has sufficient strength and does not lose its shape as described above, so that firing can be performed without powdering in a firing furnace. Thus, quicklime having a predetermined shape can be obtained from the lime cake at low cost.

Both the granulated product and the fired product have sufficient strength during storage and handling so that they do not collapse, and the fired product exhibits a sufficient activity.

[Brief description of the drawings]

FIG. 1 is a diagram showing a result of an activity test of a prototype for an example of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI C09K 17/42 C09K 17/42 H 17/50 17/50 H // C09K 101: 00 (72) Inventor Tatsuo Ono Kitami, Hokkaido No. 439, Miwa (56) References JP-A-2-49773 (JP, A) JP-A-51-85972 (JP, A) JP-A-51-45058 (JP, A) JP-A-59-232167 (JP JP, A) JP-A-47-18650 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01J 2/10 B01J 2/20 C09K 17/00-17/52 C09K 101: 00

Claims (13)

(57) [Claims] 1. A method for granulating a lime cake, comprising sequentially performing an extrusion granulation step of extruding a lime cake discharged from a sugar factory and a drying step of drying a granulated body. 2. A kneading step of kneading a lime cake discharged from a sugar factory, an extruding granulation step of extruding the kneaded lime cake, and a drying step of drying the granules are sequentially performed. Granulation method of lime cake. 3. Extrusion molding is 150 to 400 kg / cm.
^The method for granulating a lime cake according to claim 1 or 2, wherein the method is performed under an extrusion pressure of 2. 4. The drying step is carried out by heating with warm air at room temperature to 150 ° C. for 15 minutes to 3 hours.
Or the granulation method of the lime cake according to claim 2. 5. The extrusion granulation step is performed such that the granules obtained in the extrusion granulation step are spherical or columnar having a diameter of 3 to 10 mm. A granulation method for a lime cake according to the above. 6. An extrusion granulation step of extruding a lime cake discharged from a sugar mill, a drying step of drying the granules, and a firing step of firing the dried granules. Lime cake baking method. 7. A kneading step of kneading a lime cake discharged from a sugar factory, an extrusion granulation step of extruding the kneaded lime cake, and a drying step of drying the granules are sequentially performed. Lime cake baking method. 8. Extrusion molding is 150 to 400 kg / cm.
The lime cake baking method according to claim 6 or 7, wherein the lime cake is performed under an extrusion pressure of ² . 9. The drying step is performed by heating with warm air at room temperature to 150 ° C. for 15 minutes to 3 hours.
A method for baking a lime cake according to claim 7. 10. The extrusion granulation step is performed so that the granules obtained in the extrusion granulation step have a spherical or columnar shape having a diameter of 3 to 10 mm. The method for baking a lime cake according to the above. 11. The firing temperature in the firing step is about 900.
The method for baking a lime cake according to claim 6 or 7, wherein the baking time is about 30 minutes to 1 hour at ~ 1300 ° C. 12. A granulated and calcined lime cake obtained by sequentially extruding, granulating, drying and then calcining a lime cake discharged from a sugar factory. 13. A granulated and calcined lime cake obtained by sequentially kneading, extruding, granulating, drying and then calcining a lime cake discharged from a sugar factory.