JP3381949B2 - Magnesium lime fertilizer and its production method - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a granular magnesia quicklime fertilizer having excellent disintegrating property or solubility when fertilizing a field or the like and, as a result, exhibiting excellent fertilizing effect, and a composition thereof. And a manufacturing method thereof.

[0002]

2. Description of the Related Art Magnesium quicklime fertilizer has been widely used for a long time as a crop nutrient for fields and trees and a soil improving material. This magnesia quicklime fertilizer is generally used in the form of granules in order to improve handleability, fertilizer application, fertility and the like. As a method of granulating magnesia quicklime fertilizer,
Conventionally, for example, a method of coarsely crushing a raw material of magnesia lime such as dolomite into fine granules and calcining this to make magnesia quicklime, or a powder of calcined dolomite (that is, powder of magnesia quicklime) A method such as granulation is generally adopted.

The present inventor has also proposed a method for producing granular magnesia quicklime fertilizer, in which iron oxide and water are added to dolomite fine granules and the mixture is fired at a predetermined temperature (Japanese Patent Application Laid-Open No. Sho 4).
9-117242). According to this method, it is possible to obtain a granular magnesia quicklime fertilizer having a black coating made of molten iron oxide formed on its surface. And in this granular magnesia quicklime fertilizer, the following effects can be produced by the above black coating.

(1) Since pulverization is slow, heat generation and alkalinization due to a rapid hydration reaction do not occur, and therefore there is no adverse effect on crops, no immediate leaching, and fertility. continue. (2) Free iron oxide is present on the surface layer, so that the supply of iron to the crop is ample and so-called fall of crops can be prevented. (3) Since it is black, it has a snow melting effect.

[0005]

However, in the granular magnesia quicklime fertilizer having a black coating formed thereon, while exhibiting various effects as described above, the following problems are inherent. It became clear by the subsequent research by the present inventor.

That is, when the black coating is formed on the entire surface of the magnesia quicklime particles, it is difficult for the magnesia quicklime inside the particles to come into contact with water, and the hydration reaction is extremely difficult to proceed.
In an extreme case, the hydration reaction may start and proceed after the growing season of the crop ends.
This tendency is remarkable because the smaller the particle size of the magnesia quicklime particles, the more the inside is sintered and becomes chemically inactive. As is well known, a magnesia quicklime fertilizer supplies an alkaline component necessary for growing fields and eventually crops only after contact with water to cause a hydration reaction. Therefore, if the contact with water is hindered by the black coating, the original fertility of the magnesia quicklime fertilizer will be lost.

In such a case, there is a concern that the growth of the crop will be insufficient and that the fermented lime fertilizer applied will be wasted. However, while the effect of the above hydration reaction is continuing, when planting the next crop, or when it is necessary to replenish a small amount of alkali for a long period of time, etc., the above black coating The slow solubility due to is essential and the concept of waste of fertilization cannot occur. However, in Japan, the period from the harvest of a crop to the planting time of the next crop is generally several months, and during this period, the effect of the hydration reaction disappears.

Further, as described above, the smaller the particle size, the more the above-mentioned concerns exist. Therefore, if only the large particle size is used, the above waste does not occur. However, if only those having a large particle size are used by, for example, sieving, the amount of waste of the product increases, which causes a new problem of rapidly increasing the product cost.

Under the above circumstances, the granular magnesia quicklime fertilizer having a black coating has the solubility required for general fields and trees, regardless of the size of the particle. The development of the possession is desired.

Therefore, the present invention solves the above problems inherent in granular magnesia quicklime fertilizer having a black coating, without losing the above-mentioned various effects of the fertilizer.
An object of the present invention is to provide a granular magnesia quicklime fertilizer that can be eliminated and a method for producing the same.

[0011]

Means for Solving the Problems As a result of repeated studies to achieve the above object, the present inventor first found that a black coating film of iron oxide was not formed on the entire surface of the magnesia quicklime particles. If it can be partially formed, the above-mentioned solubility problem can be solved, and such partial formation of the black coating can be performed by lowering the firing temperature or by firing at a high temperature for a short time. I obtained the knowledge of. As a result of further studies based on these findings,
Focusing on the fact that certain elements of the trace elements necessary for crops act as a flux of iron oxide, and using these trace elements together with iron oxide to burn dolomite, which is the raw material of magnesia quicklime, It was found that a black coating film of iron oxide can be partially formed on the surface of the magnesia quicklime particles.

The present invention has been made based on the above findings. [1] A black coating film of iron oxide is formed on the surface of magnesia quicklime particles, and the area of the black coating film is 20 to 8 of the surface of magnesia quicklime particles.
Ni will Shimeyo 0% Ri Na is formed, and verbosity quicklime 1
Solubility of at least 0.1 parts by weight with respect to 00 parts by weight
Manganese and / or at least 0.05 part by weight
Including soluble boron and 0.5 to 3 parts by weight of iron oxide
A magnesia quick lime fertilizer, characterized in Rukoto, in [2] dolomite ore (1) and manganese and / or boron, or mixed with iron oxide, or oxide containing (2) manganese and / or boron A method for producing a magnesia quicklime fertilizer according to [1 ], wherein iron is mixed, calcined in a rotary kiln at 900 to 1500 ° C., and then cooled, and [ 3 ] (1) manganese and / or boron , Iron oxide, or (2) iron oxide containing manganese and / or boron,
The method for producing a magnesia quicklime fertilizer according to [4] is characterized in that the method is introduced together with secondary air or pressurized air from a burner section of a rotary kiln or a vicinity thereof.

The magnesia quicklime fertilizer of the present invention is one in which a black coating of iron oxide is partially formed on the surface of the magnesia quicklime particles. This partial means that the coating is unevenly distributed in one place. It refers to the case of being formed, the case of being scattered in various shapes of islands, the case of forming spots, and the case of being formed in various other appropriate modes.

An example of this aspect is schematically shown in FIG. FIG. 1 (A) shows a case where a black coating 2 made of iron oxide is unevenly formed in one place, and a white portion 1 made of magnesia quicklime is covered by the black coating 2 leaving one place. There is. FIG. 1 (B) shows a case where black coatings 2 of iron oxide are scattered and formed in various shapes of islands on a white portion 1 of quick-burning lime, and FIG. White part of quicklime 1
Shown above are the cases where the black coating 2 of iron oxide is formed in various shapes and in the form of spots.

When the above black coating film of iron oxide occupies an excessively large area, the granular magnesia quicklime fertilizer proposed by the present inventor (hereinafter referred to as "previously proposed magnesia quicklime fertilizer") is used. As in the case, the contact with water is not good, and the hydration reaction is difficult to proceed especially in the case of a small particle size. Conversely, if the area is too small, the effect of forming a black film does not occur, and the previous proposal In addition to not being able to obtain the effects of (1) and (3) described above by the magnesia quicklime fertilizer, the yield is reduced due to pulverization during the production, the volume is increased, and the bulk density is constant. There will be new problems such as failure. Therefore, in the magnesia quicklime fertilizer of the present invention, it is suitable that the black coating film of iron oxide covers about 20 to 80%, preferably about 40 to 60% of the surface of the magnesia quicklime particles.

Within this numerical range, the desired solubility, disintegration, progress of hydration reaction, etc. can be obtained without being significantly affected by the size of the particles. However, the smaller the particle size, the more the hydration reaction tends to be difficult to proceed, so it is preferable to appropriately select a suitable value from the above numerical range depending on the size of the particle size. Specifically, the larger the particle size, the larger the numerical value within the above numerical range, and the smaller the particle size, the smaller the numerical value.

Further, the magnesia quicklime fertilizer of the present invention, together with magnesia quicklime and iron oxide, is one of the other trace elements required for the growth of crops, such as cousable manganese and cousable boron (hereinafter,
The term "trace element" refers to these manganese and boron). These trace elements may be blended separately from iron oxide, or those contained in iron oxide, which is a raw material of the magnesia quicklime fertilizer of the present invention, may be used. As iron oxides containing such trace elements, slag obtained at steel mills, dust collected at steel mills, blast furnace dust, iron ore, scale and the like can be used.

In the magnesia quicklime fertilizer of the present invention, it is important that the content of the above-mentioned Cu-soluble manganese is at least 0.1 part by weight and the content of the C-soluble boron is at least 0.05 part by weight. is there. When the content of C-soluble manganese and / or C-soluble boron is less than the above, not only the fertilizing effect of manganese and boron when fertilizing the magnesia quicklime fertilizer of the present invention is not sufficient, but also as a flux for iron oxide. However, the partial formation of the black coating film of iron oxide becomes defective. The upper limit of the content of the fusible manganese and / or the fusible boron is not particularly limited, but the cost is increased even if it is too much. Therefore, about 0.4 parts by weight, preferably 0.2 parts by weight of the fusible manganese. It is suitable that the content of the fusible boron is about 0.2 part by weight, preferably about 0.2 part by weight.

If the amount of iron oxide is too large, an iron oxide coating will be formed on the entire surface of the hard lime particles, and if it is too small, the surface area of the coating will be too small. It becomes impossible to obtain the above-mentioned effects (1) to (3) by the previously proposed magnesia quicklime fertilizer. Therefore, in order to form the iron oxide coating in an area within the above-mentioned numerical range, it is important to set the content to 0.5 to 3 parts by weight with respect to 100 parts by weight of quicklime.

The magnesia quicklime fertilizer of the present invention having the above surface constitution and composition can be produced by the production method of the present invention as follows. Dolomite ore, which is the raw material of magnesia lime, is mixed with the above trace elements and iron oxides (or iron oxides containing the above trace elements in the above proportions) and, if necessary, water, and a rotary kiln is used. Bake. At this time, dolomite ore is crushed to 600
It is preferable to use as fine particles or powder of about 0 to 2000 μm and crush iron oxide (whether or not it contains trace elements) to use as powder of about 150 to 200 μm or less. In addition to the above, partially forming a black coating of iron oxide as described above,
It is also preferable for improving the baking in the rotary kiln.

Further, the mixing ratio of each of the above raw materials may be adjusted so as to be the composition of the above-described magnesia quicklime fertilizer of the present invention. The same applies to iron oxide containing trace elements. Water is
It is added in order to facilitate the adhesion of iron oxide powder to the surface of dolomite ore grains.If it is too small, this action will not be fully obtained, and if it is too large, this action will not only be saturated. , The amount of heat required for latent heat of vaporization of water increases,
It is not preferable from the viewpoint of heat economy in the rotary kiln. Therefore, in the present invention, it is preferable that the compounding amount be about 2 to 4 parts by weight with respect to 100 parts by weight of the entire composition excluding water.

Further, the firing temperature (the temperature at the high temperature portion of the rotary kiln (for example, the portion indicated by reference numeral 27 in FIG. 2))
Has a function as a fluxing material for a trace amount of elements, and therefore has a melting temperature equal to or lower than the melting temperature of iron oxide of 900 to 1500
C., preferably about 1000 to 1200.degree. 15
If the temperature is higher than 00 ° C, iron oxide may be sufficiently melted to form a black coating film on the entire surface of the magnesia quicklime particles. If the temperature is lower than 900 ° C, the trace elements act as a melting material. Even if iron oxide is insufficiently melted, black coating cannot be formed with an area ratio within the above numerical range, and magnesia quicklime cannot be obtained due to thermal decomposition of dolomite ore.

As shown in FIG. 2, each raw material is supplied with dolomite ore from the hopper 21 and trace elements and iron oxide (or iron oxide containing trace elements) from the hopper 22, respectively, and the belt conveyor. It is thrown into the hopper 24 through 23a, where water is sprinkled from above 2
It will be 5. After that, these raw materials were introduced into the rotary kiln 26 through the inlet portion 26a thereof and burned at a predetermined temperature by the fuel and primary and secondary (combustion) air supplied from the combustion burner 28. After that, it is discharged from the outlet portion 26b. Incidentally, reference numeral 31 in FIG.
Indicates a flue connected to a chimney (not shown).

In addition to this method, in the manufacturing method of the present invention,
A trace element and iron oxide (or an iron oxide containing a trace element) are allowed to accompany secondary (combustion) air or pressurized air from a combustion burner 28 provided in the rotary kiln 26 or its vicinity. A supply method can also be adopted. According to this method, the trace elements and the iron oxide (or the iron oxide containing the trace elements) are supplied to the high temperature portion 27 of the rotary kiln 26, so that the trace elements and the iron oxide are instantly melted. For example, it easily adheres to the high temperature magnesia quicklime particles in the above-described manner, and the magnesia quicklime fertilizer of the present invention having the above-mentioned surface constitution can be easily produced.

After being baked in the rotary kiln 26 as described above and discharged from the outlet 26b, it is cooled by the cooler 29 and the magnesia quicklime fertilizer of the present invention is taken out from the product outlet 30 to the belt conveyor 23b. Be done.

[0026]

In the magnesia quicklime fertilizer of the present invention, since the black coating film of iron oxide is partially formed, the exposed portion of the magnesia quicklime not covered with the coating film can easily come into contact with water. The hydration reaction starts from this part, and the reaction proceeds toward the inside of the magnesia quicklime particles. Therefore, in the magnesia quicklime fertilizer of the present invention, even if the black coating film of iron oxide is formed, the problem of solubility does not occur unlike the previously proposed magnesia quicklime fertilizer.

On the other hand, the black coating film of iron oxide described above exhibits the same action as the previously proposed magnesia quicklime fertilizer described above (1) prevention of rapid pulverization due to hydration, (2) supply of iron content,
(3) A snow melting effect is produced. Moreover, since the black coating of the present invention contains not only iron oxide but also trace elements,
The supply of trace elements necessary for growing crops will be ample.

Further, in the production method of the present invention, the above-mentioned trace elements act as a fusing material for iron oxide, and the iron oxide is easily melted at the location where the fusing material exists, so that the surface of the magnesia quicklime particles is A black coating of iron oxide is formed partially (extremely, at the location where the melt is present).

At this time, if a trace element and iron oxide (or iron oxide containing a trace element) are added during firing of dolomite ore, which is a raw material of quick-lime lime (specifically, for burning a rotary kiln). When the iron oxide is fed from the burner or a nearby portion while being entrained in the secondary (combustion) air flow or the pressurized air), the iron oxide is fed into a high temperature atmosphere, and part of the iron oxide is instantaneously heated by the heat in the atmosphere. Melts into
A further part of this adheres to the surface of the magnesia quicklime particles. Alternatively, a part of it contacts the surface of magnesia quicklime particles that are fired at a high temperature, instantly melts and adheres. These initially adhere in a dot form and become a dot-like black film as they are, or dot-like adherents are fused together to form an island-like black film. Form a partial black coating.

[0030]

【Example】

Example 1 Using the apparatus shown in FIG. 2, dolomite ore having a particle size adjusted to a range of 2500 to 6000 μm was supplied from a hopper 21 so as to have the composition shown in Table 1, and trace elements and iron oxide (scale (Use) and supplied from the hopper 22,
Sprinkle 25 water on this compound with a hopper 24 to prepare compound 1
2.6 parts by weight of water was added per 00 parts by weight. The inlet portion 26a is about 600 ° C., and the high temperature portion 27 is about 120 ° C.
Approximately 5 when put in the rotary kiln 26 maintained at 0 ° C.
After calcining for an hour, it was cooled in a cooler 29 at a cooling rate of 40 ° C./min to produce a magnesia quicklime fertilizer of the present invention.

This magnesia quicklime fertilizer is shown in FIG.
As shown in FIG. 1C, the black coatings formed in various forms are mixed, and by visual observation, most of the forms shown in FIG. ), (C)
However, the black coating film formation area was about 50%.

The components of this magnesia quicklime fertilizer are shown in Table 2.
It was as shown in. In addition, the numerical values in Table 2 are obtained by thoroughly mixing the above-mentioned magnesia quicklime fertilizer, crushing and sieving, and thoroughly mixing 212 μm to give a value of 1
It is an average value obtained by collecting g and analyzing it as a sample.

[0033]

[Table 1]

[0034]

[Table 2]

The dissolution test of the above-mentioned magnesia quicklime fertilizer for citric acid and water was conducted in the following manner. 250g of sample 1g prepared by mixing product fertilizer thoroughly
Place in a volumetric flask (hereinafter, referred to as “mL”) having a volume of 2 ml, and add 2% citric acid aqueous solution or water at 30 ° C.
After adding mL and shaking with a rotary shaker for 30 minutes and 60 minutes, the amount of alkali content (CaO weight% + MgO weight% × 1.39) dissolved in the shaking liquid was quantified. The results are shown in Table 4.

Example 2 Example 1 was repeated except that 0.3 part by weight of boric acid was used instead of 0.4 part by weight of borax in Example 1 and the amount of water supplied was 3.3 parts by weight. Magnesium quicklime fertilizer was manufactured in exactly the same manner. The components of this magnesia quicklime fertilizer were almost the same as in Example 1. Also, with respect to this magnesia quicklime fertilizer, the same dissolution test for citric acid and water as in Example 1 was performed. The results are shown in Table 4.

Example 3 A magnesia quicklime fertilizer of the present invention was produced in the same manner as in Example 1 except that dolomite ore adjusted to a particle size of 2000 to 4000 μm was used. This magnesia quicklime fertilizer is also shown in Figure 1.
There are mixed black films formed in various modes as shown in (A) to (C).
The areas shown in (A) and (B) accounted for the majority, the areas shown in (C) had a small amount, and the formation area of the black coating was about 60%. When the components of the magnesia quicklime fertilizer were analyzed in the same manner as in Example 1, it was almost the same as in Table 1 of Example 1. Also, with respect to this magnesia quicklime fertilizer, the same dissolution test for citric acid and water as in Example 1 was performed. The results are shown in Table 4.

Example 4 Instead of supplying the trace elements and iron oxide from the hopper 22 of FIG. 2, a burner 28 of the rotary kiln 26 is used.
The magnesia quicklime fertilizer of the present invention was produced in the same manner as in Example 1, except that the secondary (combustion) air flow was supplied together.

This magnesia quicklime fertilizer is also shown in FIG.
As shown in FIG. 1C, there are mixed black films formed in various modes as shown in FIG. 1C.
The speckled shape shown in FIG.
A small amount of the form as shown in (B) was formed, and the formation area of the black coating was about 40%. When the components of the magnesia quicklime fertilizer were analyzed in the same manner as in Example 1, it was almost the same as in Table 1 of Example 1. Also, with respect to this magnesia quicklime fertilizer, the same dissolution test for citric acid and water as in Example 1 was performed. The results are shown in Table 4.

Comparative Example A magnesia quicklime fertilizer was produced in the same manner as in Example 1 except that iron oxide (roll scale) powder containing trace amounts of manganese and boron was used. In this magnesia quicklime fertilizer, a black coating was formed on almost the entire surface of the particle (the black coating formation area ratio by visual observation was about 90%).
The components of this magnesia quicklime fertilizer were analyzed in the same manner as in Example 1, and were as shown in Table 3.

[0041]

[Table 3]

Furthermore, regarding this magnesia quicklime fertilizer,
The same dissolution test for citric acid and water as in Example 1 was performed. The results are shown in Table 4.

[0043]

[Table 4]

Embodiments 5 to 8 The temperature of the high temperature section 27 of Embodiment 1 is set to 1100 ° C and 1000
Magnesium quicklime fertilizer was produced in the same manner as in Examples 1 and 2 except that the temperature was changed to 0 ° C. In Example 5 (borax, 1100 ° C.) and Example 6 (boric acid, 1100 ° C.), a slight whiteish tinge was observed compared to the magnesia quicklime fertilizers obtained in Examples 1 and 2. A black gray magnesia quicklime fertilizer was obtained. In Example 7 (borax, at 1000 ° C.) and Example 8 (boric acid, at 1000 ° C.), a dark brownish gray magnesia quicklime fertilizer was obtained. The leachability of these magnesia quicklime fertilizers to citric acid and water similar to that in Example 1 was slightly higher than that in Examples 1 and 2 (that is, when citric acid was shaken for 30 minutes). 99.5% by weight or more, 102.4% by weight or more for 60 minutes or more, 12.0% by weight or more for shaking for 30 minutes)
showed that.

Examples 9 to 14 In the same manner as in Examples 1 to 5 except that slag was not used (that is, manganese was not blended) or borax was not blended (that is, boron was not blended). Produced soil lime fertilizer. Example 9 (without manganese, 120
0 ° C.), Example 10 (without manganese, 1100 ° C.)
Case) and Example 11 (without manganese, 1000 ° C.)
In the case of), compared with the magnesia quicklime fertilizers obtained in Examples 1, 5 and 7, black to dark brown gray magnesia quicklime fertilizers with a considerably whiter color were obtained. Example 12 (without boron, at 1200 ° C.), Example 13 (without boron, 1
100 ° C.), and Example 14 (without boron, 1
(In the case of 000 ° C.), black-dark brown gray magnesia quicklime fertilizers of the same degree as the magnesia quicklime fertilizers obtained in Examples 1, 5 and 7 were obtained. Example 1 of these magnesia quicklime fertilizers
Similar elution properties to citric acid and water were similar to those of Examples 1, 5 and 7.

[0046]

As described above in detail, according to the magnesia quicklime fertilizer of the present invention, since the black coating film of iron oxide is partially formed on the surface of the magnesia quicklime particles, the fertilizer and water are sufficiently contacted with each other. Therefore, good solubility after fertilization, and further hydration reactivity can be obtained. Moreover, (1) pulverization prevention similar to the previously proposed magnesia quicklime fertilizer by the coating,
While maintaining the effects of (2) iron supply and (3) snow melting effect, the minor components contained in the coating synergize the effects of supplying trace elements necessary for the growth of crops.

Further, according to the production method of the present invention, the trace elements act to specialize the melting of iron oxide, and the black coating can be partially formed on the surface of the magnesia quicklime particles. Then, by supplying the iron oxide containing the trace elements from the burner side of the rotary kiln, the partial formation effect of the black coating is promoted, and the coating can be easily formed in a desired state. To do.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing an example of a surface state of particles of a magnesia quicklime fertilizer of the present invention, where (A) shows a case where a black coating film of iron oxide is unevenly distributed in one place, (B) ) Is formed by scattering the black coating in various shapes of islands,
(C) is the case where the black coating film is formed in various shapes and in a spot shape.

FIG. 2 is a view for explaining the structure of a rotary kiln for producing the magnesia quicklime fertilizer of the present invention.

[Explanation of symbols]

1 Magnesium quicklime particles 2 Iron oxide black coating 21,22,24 hopper 23a, 23b belt conveyor 25 Sprinkler 26 Rotary kiln 26a Rotary kiln entrance 26b Rotary kiln exit 27 High temperature part of rotary kiln 28 burners 29 cooler 30 product outlet 31 flue

Claims (3)

(57) [Claims] 1. A black coating of iron oxide on the surface of magnesia quicklime particles, and the area of the black coating is 2 times that of the surface of magnesia quicklime particles.
Ni will Shimeyo 0 to 80% Ri Na is formed, and bitter Habu
At least 0.1 parts by weight per 100 parts by weight of lime
C-soluble manganese and / or at least 0.05 weight
Part of Cu soluble boron, 0.5 to 3 parts by weight of iron oxide
Magnesia quick lime fertilizer characterized by comprising at Do Rukoto. 2. A dolomite ore is mixed with (1) manganese and / or boron and iron oxide, or (2) iron oxide containing manganese and / or boron, and then heated in a rotary kiln to obtain 900- The method for producing a magnesia quicklime fertilizer according to claim 1 , wherein the method is cooling after firing at 1500 ° C. 3. (1) Manganese and / or boron and iron oxide, or (2) iron oxide containing manganese and / or boron is added to the secondary air or added from the burner part of the rotary kiln or its vicinity. The method of producing a magnesia quicklime fertilizer according to claim 2 , wherein the method is introduced together with compressed air.