JPS6025400B2 - Granular fertilizer manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a granular fertilizer, and more specifically, a method for producing a granular fertilizer, in which a suspension obtained by preparing an oversized granulated fertilizer is used as a binder to granulate the fertilizer. Regarding the manufacturing method.

Conventionally, the production of granular fertilizer has been carried out through a granulation process in which fertilizer as a raw material is granulated while adding water, a drying process in which the granular fertilizer obtained by granulation is dried, and a ring separation process in which the dried granular fertilizer is fed. At that time, the large grains above the knots (hereinafter referred to as oversize) produced in the marring process, that is, those of non-standard size, are crushed using a dry grinder to produce the fine grains below the knots (non-standard fine grains). (hereinafter referred to as undersize)
It is then returned to the granulation process and used again as a raw material for granular fertilizer.

As mentioned above, the conventional method for producing granular fertilizer requires drying the granulated granular fertilizer, which is uneconomical from a thermoeconomic perspective. There are drawbacks such as the fact that dust is generated when the process is carried out, so dust-proof measures are required in the working environment.

Furthermore, in conventional production methods, attempts have been made to use waste molasses, pulp waste liquid, CMC, etc. as a binder in order to improve the granulation efficiency of fertilizers, but satisfactory results have not always been obtained.

As a result of studying a manufacturing method that does not involve the above-mentioned drawbacks in the production of granular fertilizer, the present inventor found that granulated granular fertilizer does not necessarily need to be dried when it is divided into sections, and oversize that is generated during sectioning. The present invention was made based on the knowledge that the above-mentioned drawbacks can be overcome by using a suspension obtained by wet-mixing and pulverizing in the presence of a specific amount of water as a binder for granulation.

Therefore, the present invention does not necessarily require drying when dividing the granulated granular fertilizer, and also eliminates the need to subject oversized particles generated during simplification to dry pulverization that generates dust, thereby improving granulation efficiency. The purpose of the present invention is to provide an improved method for producing granular fertilizer. The present invention will be explained in detail below.

The main feature of the present invention is that the suspension obtained by crushing the oversize produced when granulated granular fertilizer is divided into stripes in the presence of water is used as a binder for granulating the fertilizer. The purpose is to return it to the process and use it.

In the present invention, first, fertilizer as a raw material is granulated under water by a conventional method, and the resulting granular fertilizer is separated.

In this sectioning, the granulated granular fertilizer may be sectioned as it is without drying, or it may be separated after drying.

In addition, since granular fertilizer immediately after granulation has about 10% water content, if it is separated as it is, the knots are likely to become clogged, so a wheel equipped with a mechanical clogging prevention device is used. It's good to do that. In the present invention, the oversize produced during the subsequent separation of the granular fertilizer is then introduced into a wet mixer and pulverized in the presence of a specific amount of water into a suspension form.

As the above-mentioned pulverizer, it is preferable to use, for example, a wet mixing pulverizer consisting of a cylindrical tank and a rotary pulverizer. In this wet grinding of oversize, if the oversize obtained by separating the granular fertilizer immediately after granulation is crushed, the grinding time can be significantly shortened because it is easier to grind compared to separating the granular fertilizer after drying. There are advantages. Further, the amount of water used in the above-mentioned oversized wet pulverization may be adjusted in consideration of the viscosity of the suspension obtained by the pulverization.

In other words, since this suspension is used as a binder for granulating the raw fertilizer, the viscosity of the suspension is adjusted so that the desired hardness can be obtained for the granular fertilizer particles obtained by granulating the suspension. Adjust. Incidentally, it is important that the amount of water is generally 60 to 80% by weight based on the oversize; if it is less than 6% by weight, the viscosity of the particles becomes too high and the granulation state is not good. , 8% by weight is not preferable because it becomes slurry-like and the granulation state becomes poor. The suspension obtained as described above has a suitable viscosity and exhibits an extremely excellent binder effect in granulating the raw fertilizer, so that a granular fertilizer with the desired hardness can be obtained. Since the fertilizer component ratio is the same as that of the raw material fertilizer, this can be seen when using a conventionally known binder.

There is no risk of variations in the fertilizer composition of the granular fertilizer obtained by granulation. It should be noted that non-standard undersize generated when the granulated granular fertilizer is divided into sections is directly returned to the granulation process and subjected to granulation as a raw material fertilizer. As mentioned above, in the present invention, the suspension obtained by wet mixing and pulverizing the oversized granulated fertilizer in the presence of water with a cloud content of about 60 to 8% relative to the oversized material is mixed into a suspension of the raw material fertilizer. Not only can the granulation efficiency of the fertilizer be improved by returning it as a binder for granulation, but also it is not necessary to dry the granulated granular fertilizer when dividing it into sections, so the granulated granular fertilizer in the conventional method can be improved. It is also possible to omit the drying of oversized fertilizers, and in addition, it is possible to prevent the generation of dust caused by the crushing of oversized fertilizers that is generated when separating dried granular fertilizers.

Therefore, according to the present invention, the uneconomical consumption of thermal energy can be eliminated and the working environment can also be improved. The present invention will be described in more detail below by showing examples based on the accompanying drawings (FIGS. 1 and 2) illustrating process diagrams of the manufacturing method according to the present invention. Example 1 This example illustrates a case where granulated granular fertilizer is separated as is without drying.

In Fig. 1, raw fertilizers are measured using scales 1, 2, 3, 4, and 5, mixed so that N:P:K is 12:5:5, and supplied to granulator 7 through line 6. . The granulated fertilizer granulated by the granulator 7 is directly supplied to the node 9 (equipped with a clogging prevention device) through the line 8, where it is striated, and the divided oversize is wet-mixed from the line 1 river. It is introduced into a pulverizer 11, where it is pulverized into a suspension while supplying water from a line 12, and then passed through a line 13 to a granulator 7.
and used as a granulation binder. Note that water was supplied from line 12 at a rate of 7% by weight of the oversized sample. On the other hand, the granular fertilizer that has passed through the node 9 is sent via a line 14 to a dryer 15 for drying, and then sent via a line 16 to a dry vibration node 17.

The non-standard undersized fertilizer that has been knotted and separated is returned to the granulator 7 via a line 18, while the granular fertilizer of standard particles that has been separated is passed through a cooler 20 via a line 19 to become a product 21. Granulate 17 tons of blended fertilizer per hour according to the above procedure, 12. Table 1 shows the results of investigating the granulation efficiency, amount of water used (amount of water added), basic unit of fuel oil, and product hardness in the case of continuous operation for the initial period.

For comparison, the process of granulating 17 tons of mixed fertilizer per hour using the conventional method, drying it, and then separating it into stripes was performed in step 12. The results of a similar investigation for the case of continuous operation between vowels are shown in the table as a comparative example.

In Comparative Example 4, the oversize produced in the knotting process was crushed using a dry pulverizer and returned to the granulation process together with the non-standard undersize. Furthermore, the fertilizer was granulated by the conventional method in the same manner as above, the oversized portion was removed by running for the same time as in the example, and after drying with a rotary dryer, the oversized portion and the undersized portion were separated and cooled. However, the results of the same investigation as above were also shown in Table 1 as Comparative Example 2 in the case where the entire amount of oversized portion produced was dry-pulverized and returned to the granulation process together with the undersized portion.

As shown in Table I, according to the present invention, compared to the conventional method, the granulation efficiency is improved by 1% by weight, the amount of water added can be reduced, and the consumption of heavy oil for drying can be significantly reduced. In addition, the hardness of the product also improves.

Example 2 This example illustrates the case where granulated granular fertilizer is separated into dried halves.

In Fig. 2, raw fertilizers are measured using scales 1, 2, 3, 4, and 5, mixed so that N:P:K is 10:4:4, and fed to the granulator 7 through line 6. .

The granular fertilizer granulated by the granulator 7 is sent to a dryer 15 through a line 8 to be dried, and then supplied to a dry vibrator 17 through a line 16. The oversized pieces that have been knotted and separated are introduced into the wet mixing pulverizer 11 via line 22, where they are pulverized into a suspension while supplying water from line 12, and sent to the granulator 7 via line 13. and used as a granulation binder. Among the granular fertilizers that have passed through the ring 17, non-standard undersized fertilizers are returned to the granulator 7 via a line 18, while sized granules are returned via a line 19 to a cooler 20.
After that, product 21 is obtained. Granulate 2 melons of mixed fertilizer per hour according to the above procedure, 12. Table 2 shows the results of investigating the granulation efficiency, amount of water added, basic unit of fuel oil, and product hardness during continuous operation for an extended period of time.

As a comparison, the process of granulating, drying, and then sorting 2 ml of fertilizer per hour using the conventional method was carried out in 12. Table 2 shows the results of a similar investigation for continuous operation for hours.
This is shown as Comparative Example 3. In addition, in Comparative Example 3, the oversize produced in the sectioning process was pulverized using a dry pulverizer.
The product was returned to the granulation process along with the non-standard undersize. Table 2 As shown in Table 2, in the present invention, even when the granulated fertilizer is separated into dried wheels, the granulation efficiency is improved compared to the conventional method, and the amount of water added is reduced, so heavy oil for drying is used. It also reduces consumption and improves the hardness of the product.

Example 3 This example is a fertilizer composition that is conventionally considered to have extremely low granulation efficiency.

Fertilizer lit with a ratio of N:P:K of 18:10:7
This is an example of the case in which the sample was granulated according to the procedure described in Example 1. Table 3 shows the results of investigating the granulation efficiency, amount of water added, basic unit of fuel oil, and product hardness for the obtained product. For comparison, Table 3 shows the results of a similar investigation in which the compound fertilizer was granulated and dried using the conventional method, and then granulated according to age using the same procedure as described in Comparative Example 1. It was shown as In addition, in the same procedure as described in Comparative Example 2 above, a striping process was provided between the granulation process and the drying process, and between the drying process and the cooling process, and the sections were divided into oversize and undersize parts. Comparative Example 5 is also shown in Table 3, where it was dry-pulverized and returned to the granulation process. Table 3 As shown in Table 3, when the oversized suspension produced when the granular fertilizer granulated according to the present invention is sorted while wet is used as a granulation binder, the granulation efficiency is lower than that of the conventional method. Even in the case of a raw fertilizer with an extremely low fertilizer composition of 28 to 3 box weight %, the granulation efficiency is improved by 9 to 14 weight %, the amount of water added and the amount of heavy oil used can be reduced, and the product hardness is also improved.

Next, in the present invention, the large particles (oversize) on the nodes generated when the granulated granular fertilizer is fermented are divided into 1,000 (about 60 to 8% water by weight relative to the large particles). In order to specifically explain the technical effects of wet mixing and pulverization in the presence of granules, we will use the suspensions obtained by wet mixing and pulverizing the large particles by varying the amount of water added to them. The results of testing when the resin was recycled and used as a binder are shown as a comparative test example.

Comparative Test Example A compounded fertilizer in which the raw fertilizer was mixed so that each component of N:P:K was 12:5:5 was granulated at a rate of 17.5 tons per hour using the same procedure as described in Example 1. Driving 12.
In that case, the amount of water added is 100%, 80%, 70%,
The state of each suspension obtained when adjusted to 60% and 40% (weight), the state when the suspension was granulated using the binder, and the granular fertilizer obtained by granulation. Granulation efficiency was investigated.

The results are shown in Table 4. Table 4 As shown in Table 4, the granulated granular fertilizer was separated as it was without drying, and about 60 to 8% by weight of water was added to the large particles (oversize) on the nodes that were generated. When fertilizer is granulated using a suspension obtained by wet mixing and pulverization, granular fertilizer with excellent granulation efficiency can be obtained.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams illustrating the manufacturing process of the granular fertilizer according to the present invention. In the figure, 7... Granulator, 9... Ball equipped with a clogging prevention device, 11... Green type mixing grinder, 15... Dryer, 17...Dry vibration node. Figure boat diagram N sphere

Claims (1)

[Claims] 1. A method for producing granular fertilizer by granulating fertilizer,
The granulated granular fertilizer is sieved, and the large particles (oversize) on the sieve that are generated at this time are approximately 60 to 80% of the large particles.
A method for producing a granular fertilizer, characterized in that a suspension obtained by wet mixing and pulverization in the presence of % by weight of water is returned and used as a binder for the granulation. 2. The manufacturing method according to claim 1, wherein the granular fertilizer is granulated and sieved without drying.