JPS6016399B2 - Method for producing slag phosphate fertilizer that also serves as a soil improvement material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a slag-based fertilizer using converter slag as a raw material.

A large amount of converter slag generated from steel plants is partially reused as raw material for blast furnaces, but the majority is used as roadbed material and landfill.

Converter slag is also used as a soil improvement agent because it contains lime, silicic acid, etc., but compared to other soil improvement agents (charcoal, slaked lime, etc.), it is less specialized and is less expensive. It has no advantages and is powdery, which poses problems in handling and use, so there is currently very little use of it. On the other hand, the Ministry of Agriculture, Forestry and Forestry and Zen-Noh are leading the ``soil preparation campaign.''
is being promoted, and the demand for fertilizers for soil improvement, such as soluble phosphorus fertilizer, military phosphorus, and silica fertilizer, is increasing.

Particularly in Japan, where there are many acidic soils, demand for basic or neutral fertilizers can be expected. For this reason, a silicic acid fertilizer has been proposed in which a silicic acid fertilizer is reacted with a phosphoric acid solution, but this is not suitable as a basic fertilizer for improving acidic soil.

The present invention was made in view of the above-mentioned circumstances, and its purpose is to focus on the fact that converter slag contains a large amount of basic substances and fertilizer components, and to utilize this converter slag. The present invention provides a method for producing a slag type fertilizer that can easily and inexpensively obtain a neutral or basic phosphate fertilizer having a soil improving effect.

That is, in the present invention, a pulverized converter slag or a mixture containing the same as a main component is placed in a granulator, and while rotating, a phosphoric acid solution is sprayed onto the granulator, which is then mixed and granulated to produce a neutral or basic slow-release fertilizer. This is a method of manufacturing.

The method of the present invention will be explained in detail below with reference to the drawings.

First, converter slag generated from steelworks is crushed into powder.

This pulverized converter slag contains fertilizer components such as phosphoric acid (P2Q) and magnesia (M), basic substances such as lime (Ca○), and silicic acid (Si02). Therefore, even as it is, it can be used as a soil conditioner by the action of lime, silicic acid, etc. However, although phosphoric acid and bitter acid are fertilizer components, they are not water-soluble or soluble.
In this state, it will not work effectively as a fertilizer.
In the present invention, the above-mentioned pulverized converter slag is used alone, or a mixture obtained by adding a predetermined amount of bitter raw materials such as potassium chloride and dolomite brick powder is mixed with a phosphoric acid solution and then granulated.

When the pulverized converter slag and the phosphoric acid solution are mixed, the phosphorus compounds in the converter slag react with the phosphoric acid solution, converting into soluble phosphoric acid or soluble phosphoric acid, which becomes an active ingredient. This is presumed to be because the phosphorus compound in the converter slag is hydroxyapatite [C(OH)(P04)3] and is converted to dicalcium phosphate by reaction with the phosphoric acid solution. In addition, the phosphoric acid solution itself is also converted into an active ingredient as soluble phosphoric acid. Therefore, this fertilizer functions as a slow-release fertilizer due to the action of soluble phosphoric acid, and also functions as a quick-release fertilizer due to the action of soluble phosphoric acid. Furthermore, the slag compound contained in the converter slag reacts with the phosphoric acid solution and turns into soluble slag and water-soluble slag, which become active ingredients. Therefore, due to the action of this fertilizer, it acts as a slow-release fertilizer,
It also has a fast-acting function due to the action of water-soluble soybeans. As described above, according to the method of the present invention, most of the phosphoric acid and magnesium soil in the converter slag (more than 90%) can be used as a lotus- or fast-acting fertilizer by reacting with a phosphoric acid solution, and can be used as a crop-effective fertilizer. Become.

When the main purpose of the phosphoric acid solution is to use it as a soil conditioner, the mixing ratio can be reduced, and when the main purpose is to use it as a phosphoric acid fertilizer, the mixing ratio can be increased. For 100 parts by weight of slag (P205)
The amount of the phosphoric acid-containing component can be adjusted by appropriately adjusting the amount within the range of 4 to 30 parts by weight.

Furthermore, in the present invention, converter slag and potassium chloride may be mixed and the phosphoric acid solution may be reacted with the mixture.

Salted potassium is water-soluble and becomes a fast-acting fertilizer as it is, but when it reacts with the phosphoric acid solution, it partially changes into port potash, making it effective as a slow-acting fertilizer. Although the mixing ratio of potassium chloride is not particularly limited, it is practically preferable to add about 10 to 4 parts by weight of potassium chloride to the weight of the converter slag 10.

Furthermore, in the present invention, potassium chloride and a magnesium raw material may be added to the converter slag, or only the magnesia raw material may be added to the converter slag, and the phosphoric acid solution may be reacted therewith.

Converter slag contains slag, which is made soluble or water-soluble by the phosphoric acid solution and becomes an active ingredient in fertilizers, but some fertilizers require a high content of slag. In this case, additional raw materials are added to replenish the raw materials. The raw materials for bitterness are magnesium hydroxide, diamongan, and do. There are mite brick powders, among which dolomite brick powder is particularly suitable because it is inexpensive. In this case, it is usually preferable to add 5 to 1 part by weight of dolomite brick powder to the weight of converter slag 10. It should be noted that the bitter components contained in this dolomite brick powder have very few active ingredients as they are, but when reacted with a phosphoric acid solution, they become soluble or water-soluble, and more than 90% of them become active ingredients in fertilizers. What is the above-mentioned converter slag, etc. and phosphoric acid solution? For example, powder such as converter slag is put into a dish-type granulator, pug mill-type granulator, etc., and while rotating, phosphoric acid solution is injected to granulate it. When granulated in this manner, granulation properties are extremely good.

The reason for this is probably that the mineral composition of the raw material converter slag used includes a moderate amount of crystalline materials with poor reactivity and amorphous materials with high reactivity. That is, crystalline Ca2M
It is presumed that reaction products (gelled silica, apatite, etc.) of gSi0207, Ca3MgSi0208, and unknown compounds act as a glue to granulate and improve granulation properties.

Further, during this granulation, the calcium and magnesium components in the converter slag react with the phosphoric acid solution, and the granules are heated by the reaction heat, so a drying step after granulation is not required. The granular fertilizer obtained in this way contains both water-soluble phosphoric acid, which is effective for early growth, and soluble phosphorus, which is effective for a long time until the harvesting period.It also contains active ingredients such as bittersweet, and is neutral. It is also extremely effective as a basic slow-release fertilizer. In addition, this fertilizer contains many ingredients that contribute to soil improvement, such as lime and silicic acid, so it can be used as a soil conditioner.
It is particularly effective as an improvement agent for acidic soil. Next, examples of the present invention will be described. Example 1 Production of basic fertilizer containing phosphate magnesium (6% phosphoric acid) Converter slag 851 having the composition shown in Table 1 was placed in a dish-shaped granulator.
While rotating, 167% P20533% phosphoric acid solution was added to the mixture while spraying it to react, and granular fertilizer LK9 was produced without going through a drying process.

The fertilizer thus obtained contains 6.2% water, but
The particles appeared to be smooth and granular, and even when the particles were packaged and piled up, no crumbling or caking of the particles was observed, and the product could be used as is.

In addition, we analyze the active ingredients of fertilizers, check their solubility (the proportion of soluble, soluble, and water-soluble substances), and
H was measured.

The results are shown in Table 1. Example 2 Production of neutral phosphoric acid fertilizer (16% phosphoric acid) Converter slag 685% having the same composition as in Example 1 was placed in a dish-shaped granulator, and P20547% phosphoric acid solution 340% was added to it while rotating. The fertilizer was added while spraying and allowed to react, producing granular fertilizer LK9 without going through a drying process.

As in Example 1, the thus obtained fertilizer could be used as a product as it was, with no grain collapse or caking observed.

In addition, the active ingredients and solubility of the fertilizer were investigated, as well as the pH.

The results are shown in Table 1. In the above table, T indicates the overall composition, 0 indicates soluble, S indicates soluble, and W indicates water-soluble.

Also, (()/T) is the proportion of soluble items in the total wealth K, (S/T) is the proportion of soluble items, (W/T)
is the proportion of water-soluble substances. According to the table above, it was confirmed that the fertilizer of Example 1 was basic with a pH of 11.6, and acted effectively as a soil conditioner.

In addition, phosphoric acid, magnesia, etc. in converter slag are water-soluble, soluble,
It has been confirmed that it is soluble and acts as an active ingredient in fertilizers. It also contains soluble phosphoric acid and a high proportion of repellent phosphoric acid, making it a slow-release fertilizer. Further, the fertilizer of Example 2 is a neutral fertilizer with a pH of 7.5, and
As in Example 1, the active ingredients of both phosphoric acid and magnesium are increased, making it effective as a fertilizer, as well as the high proportion of twill material makes it effective as a slow-release fertilizer. Example 3 Production of neutral potassium phosphate fertilizer (phosphoric acid 15%, potassium 10%) Converter slag 520 saw potassium chloride 17 with the composition of Example 1
1 kg of granular fertilizer was produced by mixing and granulating P20547% phosphoric acid and 323% P20547% phosphoric acid in the same machine as in Example 1.

The fertilizer thus obtained was the same as that of Example 1, and no broken grains or caking were observed.

In addition, the active ingredients of the fertilizer were analyzed, their solubility was examined, and the pH was measured. The results are shown in Table 2. Table 2 Note) Above table [“1T, 0, S, “V, (〈)/T), (
The symbols for S/'r) and (VnotT) are the same as in Table 1.

According to the table above, this fertilizer has a neutral pH of 7.2.
The active ingredients of both phosphoric acid and magnesia increase, making it effective as a fertilizer, and the high proportion of soluble substances makes it effective as a slow-release fertilizer.

Also, for potash, a delayed effect due to a decrease in water drop rate was observed. Example 4 Potassium phosphate fertilizer with neutral magnesia (15% phosphoric acid, 10% potassium
%, bitterness 5%) Production of a phosphoric acid solution P2Q47% in the same manner as in Example 1 A mixture of 480 g of the converter slag of Example 1, 177 g of potassium chloride, and 40 g of dolomite brick powder was prepared in the same manner as in Example 1.
323 to produce granular fertilizer LK9.

The fertilizer thus obtained was similar to that of Example 1,
No grain collapse or caking was observed.

We also analyzed the active ingredients of the fertilizer, examined its solubility, and measured the fence. The results are shown in Table 3. Note to Table 3) In the above table T, 0, S, W (0/T), (S/T'
, (WT) indicate the same symbols as in Table 1.

From the above table, this fertilizer has a neutral pH of 7.3 and is effective as a fertilizer because its active ingredients increase together with the phosphoric acid and bitterness in the converter slag and the bitterness in the dolomite brick powder.

It also has a high proportion of soluble substances, making it effective as a slow-release fertilizer. Also, for potash, a delayed effect due to a decrease in water drop rate was observed. As is clear from the above results, according to the method of the present invention, the fertilizer component in the converter slag is reacted with a phosphoric acid solution to become an active ingredient, and the resulting fertilizer is made into a slow-release neutral or basic fertilizer. It has remarkable effects such as being able to improve the soil and simplifying the manufacturing process.

[Brief explanation of drawings]

The drawings are process explanatory diagrams showing the method of the present invention.

Claims (1)

[Claims] 1. Put the ground converter slag or a mixture containing it as the main component into a granulator, spray a phosphoric acid solution thereon while rotating, mix and granulate it, and make it neutral or basic. A method for producing a slag phosphate fertilizer that also serves as a soil improvement material, characterized by producing a slow-release fertilizer. 2. A method for producing a slag phosphate fertilizer that also serves as a soil conditioner as claimed in claim 1, characterized in that a mixture of pulverized converter slag and potassium chloride is used. 3. A method for producing a slag phosphate fertilizer that also serves as a soil conditioner according to claim 1, characterized in that a mixture of crushed converter slag and magnesia raw material is used. 4. A method for producing a slag phosphate fertilizer that also serves as a soil conditioner as set forth in claim 1, characterized in that a mixture of crushed converter slag, potassium chloride, and magnesia raw materials is used as a mixture. . 5. A method for producing a slag phosphate fertilizer that also serves as a soil conditioner according to claim 3 or 4, characterized in that dolomite brick powder is used as a raw material for magnesium.