JP2003112989A - Method for manufacturing fertilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilize calcareous wastes and sludge incineration ash. SOLUTION: The calcareous wastes 4, such as shells (a) of scallops, shells (b) of oysters and eggshells (c) of eggs, sludge incineration ash 1, coke 2, magnesium oxide 3, and potassium oxide 5 are heated in a fusion furnace 8 to allow molten metals 24 and molten slag 25 to coexist in a two-liquid separated state. Further, the molten slag 25 is selectively discharged to a hydropulping chamber 19 where the slag is rapidly cooled. Granular slag 26 which contains the phosphorus component and calcium component and is get rid of metals is recovered. This slag 26 is used as a fertilizer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fertilizer using, as a main raw material, calcium-based waste generated by food processing and incineration ash of sewage sludge.

[0002]

2. Description of the Related Art Conventionally, most of scallops, oyster shells, shells and eggshells generated by processing chicken eggs are disposed of at the final disposal site.

[0003] The sludge generated by the sewage treatment is dehydrated and incinerated, and then disposed of at the final disposal site.

[0004]

However, in recent years,
The acceptance of waste at the final disposal site is tight, shells,
Further volume reduction (volume reduction) of eggshell, sludge incineration ash, etc. is desired.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to effectively utilize calcium waste such as shells and eggshells and sludge incineration ash.

[0006]

In order to achieve the above object, in the method for producing a fertilizer according to claim 1 of the present invention, the sludge incineration ash containing the calcium waste and the phosphorus component is stored in a reducing atmosphere. The molten metal and molten slag are allowed to coexist in the melting furnace in a two-liquid separated state by heating in the melting furnace, and the molten slag is granulated by water granulation treatment.

In the fertilizer manufacturing method according to the second aspect of the present invention, the calcium metal waste, the sludge incineration ash containing the phosphorus component, and the reducing agent are heated in the melting furnace to melt the molten metal and molten slag. The two liquids are made to coexist in the melting furnace and the molten slag is granulated by water granulation.

In the method for producing a fertilizer according to claim 3 of the present invention, calcium waste, sludge incineration ash containing phosphorus component, reducing agent, and magnesium component are heated in a melting furnace to form molten metal. The molten slag is allowed to coexist in the melting furnace in a two-liquid separated state, and the molten slag is granulated by a water granulation process.

In the method for producing a fertilizer according to claim 4 of the present invention, calcium waste, sludge incineration ash containing a phosphorus component, a reducing agent, and a potassium component are heated in a melting furnace to form a molten metal. The molten slag is allowed to coexist in the melting furnace in a two-liquid separated state, and the molten slag is granulated by a water granulation process.

In the method for producing a fertilizer according to claim 5 of the present invention, calcium waste, sludge incineration ash containing a phosphorus component, a reducing agent, a magnesium component, and a potassium component are heated in a melting furnace, Molten metal and molten slag coexist in a melting furnace in a two-liquid separated state, and the molten slag is granulated by a water granulation process.

In the method for producing a fertilizer according to claim 6 of the present invention, the phosphorus content of the sludge incineration ash is grasped in advance, and the granular diphosphorus pentoxide and magnesium oxide obtained by the water granulation treatment of the molten slag , And the molar ratio of calcium oxide is about 1: 2 to 4: 2 to 4 about the amount of calcium waste and magnesium component to sludge incineration ash.

In any of the fertilizer production methods according to the first to fifth aspects of the present invention, molten metal and molten slag are allowed to coexist in a two-liquid separated state in a melting furnace kept in a reducing atmosphere. After separating the metal, the molten slag is subjected to a water granulation process to form a slag containing a phosphorus component and a calcium component into particles that are easy to handle.

In any of the fertilizer manufacturing methods according to the third and fifth aspects of the present invention, the magnesium component to be contained in the slag is increased by adding the magnesium component separately.

In any of the methods for producing a fertilizer according to claims 4 and 5 of the present invention, by separately adding a potassium component, the temperature at which the slag becomes in a molten state is lowered, and at the same time the potassium component of the slag should be contained. Aim to increase.

In the method for producing a fertilizer according to the sixth aspect of the present invention, the amounts of the calcium-based waste component and the magnesium component to be heated together with the sludge incineration ash are the phosphorus pentoxide contained in the slag after the water granulation treatment. A phosphorus fertilizer having an optimum component ratio is obtained by adjusting the molar ratio of magnesium oxide, magnesium oxide, and calcium oxide to about 1: 2 to 4: 2 to 4.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an embodiment of a fertilizer production method of the present invention. In this fertilizer production method, sludge incineration ash 1, coke 2 as a carbon (C) -based reducing agent, magnesium oxide (MgO) is used. ) 3, Calcium waste (Ca)
4. Potassium oxide (K ₂ O) 5 is used as a fertilizer raw material.

The calcium waste 4 is, for example, a scallop shell a, an oyster shell b, an egg shell c, etc. The scallop shell a contains 96% by weight of calcium.

A melting furnace 8 is used to produce fertilizer from each of the above raw materials.

The melting furnace 8 has a furnace body 10 having a melting space surrounded by a lining 9 of a carbonaceous block, and an electrode 11 incorporated in the lining 9 so as to be located below the melting space.
And a carbonaceous electrode 12 provided on the upper part of the furnace body 10 so that the tip portion is located at the center of the melting space.

The furnace body 10 has a screw-type raw material charging machine 13 and a raw material charging port 14 communicating from the outside of the furnace body 10 to the upper part of the melting space, and a secondary combustion furnace of the exhaust gas treatment equipment from the upper part of the melting space. Gas outlet 15 communicating with (not shown)
A slag discharge port 16 that communicates with the outside of the furnace body 10 from an intermediate portion in the vertical direction of the melting space, and a metal discharge port 17 that communicates with the outside of the furnace body 10 from the vicinity of the inner bottom of the melting space.

Further, below the slag discharge port 16 outside the furnace body 10, a water granulation tank 19 storing water 18 is installed.

When the fertilizer is manufactured, the raw material feeding machine 13
The sludge incineration ash 1, the coke 2, the magnesium oxide 3, the calcium waste 4, and the potassium oxide 5 are fed from the raw material charging port 14 to the melting space of the furnace body 10.

Further, an electric current is applied to both electrodes 11 and 12 through a substance to be fed to the melting space to heat sludge incineration ash 1, magnesium oxide 3, calcium waste 4, and potassium oxide 5 by Joule heat. Then, it is melted, and the melting space is kept in a reducing atmosphere by carbon as the main component of the coke 2.

The amount of coke 2 is 5% or less by weight of the total amount of the substances fed to the melting space of the furnace body 10 (sludge incineration ash 1
The amount of potassium oxide 5 is adjusted to several% of the total amount of the substance fed to the melting space of the furnace body 10.

Further, by feeding the coke 2 to the melting space of the furnace body 10, the consumption of the lining 9 and the electrode 12 can be suppressed.

When the sludge incineration ash 1, the magnesium oxide 3, the calcium waste 4, and the potassium oxide 5 are melted, iron and nickel contained in the sludge incineration ash 1 are caused by the difference in specific gravity between metal and nonmetal. A layer of the molten metal 24 mainly composed of a metal such as chromium is formed on the inner bottom side of the melting space, and originally,
Diphosphorus pentoxide (P ₂ O ₅ ), magnesium oxide, calcium oxide, potassium oxide, and silicic acid (SiO) contained in sludge incineration ash 1, magnesium oxide 3 added as a raw material, and calcium waste 4 A layer of the molten slag 25 mainly containing potassium oxide 5 is formed on the upper side of the layer of the molten metal 24, and the molten metal 24 and the molten slag 25 coexist in a two-liquid separated state.

Since this molten slag 25 contains potassium, it is 50 when compared with the case where potassium is not added.
The knowledge that the melting temperature can be reduced in the range exceeding ℃ was obtained by experiments.

Therefore, when potassium is added, the electrodes 11 and 1 are heated to heat the substance charged into the melting space of the furnace body 10.
It is possible to reduce the amount of power that should be supplied to 2.

The harmful substances such as lead, zinc, arsenic and cadmium contained in the sludge incineration ash 1 are sent to the secondary combustion furnace of the exhaust gas treatment facility outside the furnace body 10 through the gas outlet 15. Detoxification is achieved.

Further, the molten slag 25 is supplied to the slag discharge port 1
6 to the water granulation tank 19 through the water trough 27,
A water granulation process of quenching with water 18 is performed to recover the granulated slag 26.

Since the molten slag 25 containing diphosphorus pentoxide, magnesium oxide, calcium oxide, potassium oxide, and silicic acid is solidified, the slag 26 is fertilized in the same manner as a phosphorus fertilizer made of phosphate rock. Produce an effect.

In addition to this, since various metals contained in the sludge incineration ash 1 are contained in the molten metal 24, the slag 2 is contained.
Spreading 6 as fertilizer does not pollute the soil.

Further, the molten metal 24 is discharged from the metal outlet 17 to the outside of the furnace body 10, and the metal solidified by natural air cooling is discarded.

When the sludge incineration ash 1, the magnesium oxide 3, and the calcium waste 4 are melted to produce a fertilizer by the procedure as described above, the phosphorus content per unit weight of the sludge incineration ash 1 is previously set. After measurement, the molar ratio of diphosphorus pentoxide, magnesium oxide and calcium oxide contained in the recovered slag 26 is about 1: 2 to 4: 2 to 4 (preferably 1: 3.5: 3. 5),
If the amounts of magnesium oxide 3 and calcium waste 4 relative to the sludge incineration ash 1 are determined, a phosphorus fertilizer having an optimum composition can be obtained.

The fertilizer production method of the present invention is not limited to the above-described embodiment, and the addition of magnesium and potassium components may be omitted depending on the components of sludge incineration ash and the use of fertilizer. Of course, changes can be made without departing from the scope of the present invention.

[0037]

As described above, the fertilizer manufacturing method of the present invention can exhibit various excellent effects as described below.

(1) In any of the fertilizer production methods according to the first to fifth aspects of the present invention, sludge incineration ash and calcium waste are melted in a melting furnace kept in a reducing atmosphere to remove phosphorus. Since the molten slag containing the component and the calcium component is subjected to the water granulation treatment to be granulated for easy handling, the calcium-based waste and the sludge incineration ash can be effectively used as a fertilizer.

(2) In any of the fertilizer manufacturing methods described in claims 3 and 5 of the present invention, the magnesium component of the slag used for the fertilizer can be increased by adding the magnesium component separately.

(3) In any of the methods for producing a fertilizer according to claims 4 and 5 of the present invention, the temperature can be lowered to a temperature at which the molten state of the slag can be maintained by adding a potassium component separately, Further, it is possible to increase the potassium component of slag used as fertilizer.

(4) In the method for producing a fertilizer according to claim 6 of the present invention, the amounts of calcium waste and magnesium components to be melted together with the sludge incineration ash are contained in the slag after the water granulation treatment. The molar ratio of diphosphorus pentoxide, magnesium oxide and calcium oxide is 1: 2 to 4: 2.
Since it is determined so as to be about 4 to 4, it is possible to obtain a slow-release fertilizer having excellent solubility (solubility in a 2% citric acid solution).

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an example of an embodiment of a fertilizer manufacturing method of the present invention.

[Explanation of symbols]

1 Sludge incineration ash 2 coke (reducing agent) 3 Magnesium oxide (magnesium component) 4 Calcium waste 5 Potassium oxide (potassium component) 8 melting furnace 19 water granulation tank 24 Molten metal 25 Molten slag 26 Slag (granular body)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B09B 3/00 ZAB C05B 13:02 101 // (C05G 1/00 B09B 3/00 303K C05F 7:00 ZAB C05B 13:02) 101 303L (72) Inventor Sadafumi Takagi 1-4-1, Yurakucho, Chiyoda-ku, Tokyo Sanki Kogyo Co., Ltd. (72) Tetsuji Jotsuka 1-1-4, Yurakucho, Chiyoda-ku, Tokyo Sanki Kogyo Co., Ltd. F term (reference) 4D004 AA16 AA36 BA04 CA12 CA14 CA29 CA32 CA37 CB01 CC11 DA03 DA10 4H061 AA02 BB42 CC51 FF08 GG18 GG23 GG26

Claims (6)

[Claims] 1. A calcium waste and sludge incineration ash containing a phosphorus component are heated in a melting furnace in a reducing atmosphere so that molten metal and molten slag coexist in the melting furnace in a two-liquid separated state. A method for producing a fertilizer, characterized in that the molten slag is granulated by a water granulation process. 2. A calcium-based waste, a sludge incineration ash containing a phosphorus component, and a reducing agent are heated in a melting furnace to allow molten metal and molten slag to coexist in the melting furnace in a two-liquid separated state. A method for producing a fertilizer, which comprises granulating the molten slag by water granulation. 3. The calcium waste, the sludge incineration ash containing the phosphorus component, the reducing agent, and the magnesium component are heated in the melting furnace so that the molten metal and the molten slag are separated into two liquids in the melting furnace. A method for producing a fertilizer, which comprises coexisting and granulating the molten slag by water granulation. 4. Calcium waste, sludge incineration ash containing phosphorus component, reducing agent, and potassium component are heated in a melting furnace to separate molten metal and molten slag into two liquids in a melting furnace. A method for producing a fertilizer, which comprises coexisting and granulating the molten slag by water granulation. 5. A calcium-based waste, a sludge incineration ash containing a phosphorus component, a reducing agent, a magnesium component, and a potassium component are heated in a melting furnace, and a molten metal and a molten slag are two-component in the melting furnace. A method for producing a fertilizer, characterized in that the molten slag is made to coexist in a separated state and is granulated by a water granulation process. 6. The phosphorus content of sludge incineration ash is grasped in advance, and the granular ratio of diphosphorus pentoxide, magnesium oxide and calcium oxide obtained by the water granulation treatment of molten slag has a molar ratio of 1: 2. To 4: The fertilizer manufacturing method according to claim 3 or 5, wherein the amounts of the calcium-based waste and the magnesium component with respect to the sludge incineration ash are determined so as to be about 2 to 4.