JP6782061B2 - Silicic acid fertilizer for gramineous plants - Google Patents

Description

The present invention relates to a siliceous fertilizer for gramineous plants using general waste as a raw material.

The growth of gramineous plants requires a large amount of silicic acid because the stems (rice) and roots grow healthy. However, since the silicic acid absorbed by the stems (rice) etc. is taken out from the paddy field as rice straw etc., in order to repeatedly grow gramineous plants in the same soil, some means is used to bring the silicic acid to the soil. Need to replenish. In general, silicic acid fertilizer is used as a means of supplementing silicic acid because the soil has little soluble silicic acid that can be absorbed by plants and the supplementation of silicic acid from irrigation water is also small.

As the siliceous fertilizer, ore silicic acid fertilizer (commonly known as "silicic acid") and the like have been conventionally used. For example, in Patent Document 1, a soluble silicic acid having a particle size of 75 μm or less, which is selected from one or more of iron ore, steel ore, ferroalloy ore, and molten fertilizer for cultivation of gramineous crops, is contained. Disclosed is a highly alkaline fertilizer that is enriched with available silicic acid by adding and reacting an elution accelerator to the product.

Japanese Patent No. 3439685 Japanese Patent No. 5594707 Japanese Patent No. 5590920

Molten slag produced by melting general waste, sewage sludge, and their incineration ash in a melting furnace and then cooling and solidifying them is an aggregate for asphalt synthesis and secondary concrete products from the viewpoint of effective use of resources. It is used as aggregate and backfill material.

In order to expand the use of molten slag, Patent Document 2 discloses a method of utilizing molten slag generated from sewage sludge as fertilizer. Specifically, the sewage sludge molten slag contains sewage-soluble phosphoric acid, and the sewage sludge molten slag is classified according to the analyzed sewage-soluble phosphoric acid content and stored in a plurality of storage facilities for production. A method for producing a fertilizer is disclosed in which sewage sludge molten slag is taken out from the storage facility and mixed according to the content of solubilized phosphoric acid in the fertilizer to be used.

However, the application of molten slag produced from general waste to silicic acid fertilizer has not yet been planned.
Patent Document 3 discloses an invention of a lawn growth promoting material composed of a water-cooled molten slag produced by melting general waste and / or industrial waste in a melting furnace and rapidly crushing the melt with water. However, the lawn growth promoting material is used as a lawn soil (soil sprayed on the lawn according to its purpose in lawn management). Since the growth point of turf grass on the ground surface moves year by year to a position higher than the ground surface due to treading, the lawn is easily affected by the outside world such as pests and outside air temperature. Therefore, the soil is sprayed for the purpose of protecting the lawn. Furthermore, Patent Document 3 has no description or suggestion regarding silicic acid fertilizer.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a new silicic acid fertilizer for gramineous plants using general waste (including designated industrial waste treated by local governments) as a main raw material. To do.

In order to achieve the above object, the silicic acid fertilizer for gramineous plants according to the present invention is made from general waste, contains 32% by mass to 38% by mass of soluble silicic acid, 35% by mass or more of alkali content, and is a base. It is characterized by being composed of molten slag having a degree of 0.8 to 1.2 and a particle size of 0.12 mm or more and 2.5 mm or less. However, the lawn growth promoting material used as the soil for the lawn is excluded.

The "general waste" in the present invention includes designated industrial waste treated by the local government.

The ash content (Ca, Si, Al) in general waste and the ash content of auxiliary raw materials (coke, limestone or slag) are melted at high temperature in a gasification melting furnace, and this is water-cooled (quenched) to the ash content. Molten slag containing silicate (SiO ₂ ) and lime (CaO) as main components is produced. At this time, the silicic acid and lime contained in the molten slag become soluble.
At that time, by putting coke into the gasification melting furnace together with the general waste, the lower part of the gasification melting furnace becomes a high temperature (1700 ° C to 1800 ° C) and a strong reducing atmosphere, and lead and the like contained in the general waste Low-boiling heavy metals volatilize and transfer to molten slag is suppressed. On the other hand, high boiling point heavy metals such as iron and copper are separated and removed after the water grinding treatment to obtain molten slag containing almost no heavy metals and having the same safety as natural materials.

In addition, limestone or silica sand is put into the gasification and melting furnace together with general waste. Specifically, the input ratio of limestone or silica sand is set in consideration of the type of the object to be treated and the ratio of ash in the object to be treated, and the components (SiO ₂ , CaO) of the generated molten slag are analyzed regularly. Then, the input ratio of limestone or silica sand is adjusted based on the result. Thus, Ru can be constantly stable quality of the molten slag.

Here, "soluble" means that it is insoluble in water but soluble in root acid from the roots, and "soluble silicic acid" is in 0.5 M hydrochloric acid at 30 ° C of the silicic acid component of fertilizer. It refers to soluble silicic acid. Further, "alkali content" is an index showing the total amount of alkali of lime (CaO) and bitter soil (MgO), and alkali content (mass%) = CaO mass% + MgO mass% x (56 (molecular weight of CaO) / 40). (Molecular weight of MgO)).

In the present invention, general waste, coke, limestone or silica sand are put into a gasification melting furnace for melting treatment, the melt is hydrolyzed, and then the metal contained in the generated molten slag is separated and removed. As a result, it is possible to produce a limestone fertilizer for grasses of stable quality containing almost no harmful substances.

It is a schematic diagram of the gasification melting furnace used for the production of the silicic acid fertilizer for gramineous plants which concerns on one Embodiment of this invention.

Subsequently, an embodiment embodying the present invention will be described with reference to the attached drawings, and the present invention will be understood.

FIG. 1 shows a gasification melting furnace 10 used for producing a siliceous fertilizer for gramineous plants according to an embodiment of the present invention. The gasification and melting furnace 10 in the present embodiment is a shaft furnace type gasification and melting furnace. The furnace body is composed of a cylindrical shaft portion 11, an inverted conical portion 12 whose diameter is reduced downward from the lower end of the shaft portion 11, and a furnace bottom portion 13.

A charging port 20 for charging general waste and auxiliary raw materials (coke, limestone or silica sand) is provided at the top of the shaft portion 11, and exhaust gas generated in the furnace is discharged to the side of the charging port 20. A discharge port 21 for discharging is provided.
On the other hand, a hot water outlet 18 for discharging the molten material generated in the furnace is provided on the side wall of the furnace bottom portion 13.

Further, blower ports 15 and 14 for supplying air into the furnace are provided on the lower end of the side wall of the shaft portion 11 and the side wall of the furnace bottom portion 13. The air blown by the blower 16 is supplied into the furnace from the blower ports 15 and 14. The air supplied into the furnace from the air outlet 14 provided on the side wall of the furnace bottom 13 is oxygen-enriched by the oxygen generator 17.

Next, a method for producing a siliceous fertilizer for grasses using the gasification melting furnace 10 having the above configuration will be described.
Municipal waste, coke, limestone or silica sand are charged into the furnace from the inlet 20. The amount of coke charged into the gasification melting furnace 10 is 20 kg to 70 kg per ton of general waste input, and the amount of limestone or silica sand input is 15 kg to 70 kg per ton of general waste input. In addition, general waste is waste other than industrial waste, and includes designated industrial waste treated by local governments.

Inside the gasification and melting furnace 10, from the top, drying / pre-tropical A (300 ° C to 400 ° C), pyrolysis gasification zone B (300 ° C to 1000 ° C), combustion zone C (1000 ° C to 1700 ° C), melting zone It is classified into D (1700 ° C to 1800 ° C).

[Melting process]
The general waste charged into the furnace from the inlet 20 is heated in the drying / pre-tropical A, and the water contained in the general waste is evaporated by the combustion decomposition gas rising from the lower part of the furnace. The dried general waste gradually descends, and the combustible component is gasified in the pyrolysis gasification zone B and discharged from the discharge port 21.
The ash content in the general waste passes through the combustion zone C together with the coke and falls to the melting zone D. The coke that has fallen to the melting zone D is burned at a high temperature of 1700 ° C. to 1800 ° C. by the oxygen-enriched air blown from the air outlet 14, and a coke bed layer (grate) is formed on the bottom 13 to create a reducing atmosphere. Achieves stable melting of ash and formation of ash. Low boiling point heavy metals (lead, etc.) in the ash volatilize to melt fly ash, which is discharged from the discharge port 21 together with the exhaust gas.

[Exhaust gas treatment]
The exhaust gas discharged from the discharge port 21 is introduced into a cyclone (not shown) as needed, and flammable dust in the exhaust gas is collected by the cyclone. The collected flammable dust is blown into the gasification melting furnace 10 from the air outlet 14. On the other hand, the exhaust gas discharged from the cyclone is introduced into a combustion chamber (not shown), completely burned, then heat is recovered by a boiler (not shown), and finally released from a chimney (not shown) into the atmosphere. ..

[Water grinding]
The melt in which the ash is melted is discharged from the hot water outlet 18 in a state where the fluidity is sufficiently increased by the basicity adjusting action of limestone, and is charged into the granulator 22 via the gutter 19.
The water crusher 22 injects water into the casing 23 for storing the cooling water that cools and solidifies the melt discharged from the gasification melting furnace 10 and the melt discharged from the gasification melting furnace 10 to melt the melt. It includes an injection nozzle 24 that finely disperses objects, and a scraper-type conveyor 25 installed in a casing 23. The melt finely dispersed by the jet water is cooled and solidified in the casing 23 to become molten slag and metal such as iron and copper, which is carried out from the casing 23 by the conveyor 25 and conveyed to the magnetic separator 26.
[Metal separation process]
Metal is separated and removed from the molten slag by the magnetic separator 26 to obtain molten slag containing almost no harmful substances.

[Crushing / polishing process]
The molten slag produced by rapidly crushing the melt with water includes those having a non-uniform particle size distribution and a needle-like or angular surface. Therefore, in the present embodiment, a crushing treatment or a grinding treatment is performed using a crushing device (not shown) or a grinding device (not shown) to adjust the particle size and smooth the surface of the molten slag. For the particle size adjustment by the crushing treatment or the grinding treatment, the treatment conditions are set so that the particle size of the molten slag is 5 mm or less, preferably 2.5 mm or less.

Finer particles by crushing or grinding can increase the specific surface area and improve the reactivity at the roots, and can promote the supply of fertilizer components to grasses. However, since fine particles may scatter when fertilizer is sprayed, the particle size is preferably 0.12 mm or more.

The silicic acid fertilizer for gramineous plants produced by the above method contains 20% by mass or more of soluble silicic acid (32% by mass to 38% by mass as measured in the operating facility) and 35% by mass or more of alkali content (operating facility). 39% by mass to 41% by mass), and the basicity is 0.8 to 1.2.

For reference, the official standard for mineral silicic acid fertilizers with a registration validity period of 6 years states that soluble silicic acid and alkali content are guaranteed to be 10.0% by mass or more and alkali. The minute is 35.0% by mass or more.

Table 1 shows the content of harmful substances contained in the silicate fertilizer for gramineous plants produced by the above method, and Table 2 shows the elution amount of harmful substances together with the environmental standard values of the Soil Contamination Countermeasures Law. From the table, it can be seen that the harmful substances contained in the siliceous fertilizer for gramineous plants produced by the above method are one digit smaller than the environmental standard value.

As described above , the silicic acid fertilizer for gramineous plants produced by the above method is suitable as a fertilizer for gramineous plants because it contains a large amount of soluble silicic acid and hardly contains harmful substances.

Although one embodiment of the present invention has been described above, the present invention is not limited to the configuration described in the above-described embodiment, and is within the scope of the matters described in the claims. It also includes other possible embodiments and variations.

10: Gasification melting furnace, 11: Shaft part, 12: Inverted cone part, 13: Furnace bottom part, 14, 15: Blower, 16: Blower, 17: Oxygen generator, 18: Hot water outlet, 19: Gutter, 20 : Input port, 21: Discharge port, 22: Water crusher, 23: Casing, 24: Injection nozzle, 25: Conveyor, 26: Magnetic separator, A: Drying / pre-tropical, B: Pyrolysis gasification zone, C: Combustion zone, D: Melt zone

Claims (1)

Using general waste as a raw material, it contains 32% by mass to 38% by mass of soluble silicic acid, 35% by mass or more of alkali content, basicity of 0.8 to 1.2, and particle size of 0.12 mm or more and 2.5 mm or less. Silicic acid fertilizer for gramineous plants, which is characterized by being composed of molten slag (excluding lawn growth promoting materials used as lawn soil) .

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