JP2003112988A - Method for manufacturing phosphorus fertilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a fertilizer which is high in concentration of a phosphorus component and is safe from sludge incineration ash. SOLUTION: The sludge incineration ash 1 having the high concentration of the phosphorus component is obtained by adding a ferrous flocculating agent 7 to sewage 6 to settle the phosphorus component included in the sewage 6 and collecting the precipitate 21 together with sludge 22, then dewatering and incinerating the same. Coke 2, magnesium oxide 3, calcium oxide 4 and potassium oxide 5 are added to the sludge incineration ash 1 and the mixture is heated in a fusion furnace 8 to allow molten metals 24 and molten slag 25 to coexist in a two-liquid separation state in the fusion furnace 8. Further, the molten slag 25 is selectively discharged to a hydropulping chamber 19 where the slag is rapidly cooled and is made into a granular form to facilitate its handling as the fertilizer. Granular slag 26 which is high in the concentration of the phosphorus component and is get rid of the metallic components is thus recovered.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a phosphorus fertilizer using incineration ash of sewage sludge as a main raw material.

[0002]

2. Description of the Related Art Phosphorous ore, which is a raw material for phosphorus fertilizer, is not industrially available domestically, and therefore is entirely imported from abroad.

The known reserves of minable phosphate rocks are estimated to be large in quantity, but the quality of the phosphate rocks actually mined gradually increases due to an increase in the content of impurities. It is decreasing and it is difficult to obtain high quality phosphate rock.

The sludge generated by the sewage treatment is dehydrated and incinerated and then disposed of at the final disposal site. In recent years, however, the acceptance of waste at the final disposal site has become tight. It is necessary to further reduce the volume of sewage treatment waste (volume reduction).

Therefore, paying attention to various substances such as nitrogen, phosphorus, magnesium, calcium and potassium existing in sludge, dry sludge or compost made from sludge as a raw material is used as an organic fertilizer. There is.

[0006]

However, the concentration of the phosphorus component contained in the dried sludge and compost is lower than that of the fertilizer produced from phosphate rock, and the fertilizing effect on soil cannot be expected so much.

Further, sludge may contain various metals such as iron, copper, zinc, lead, nickel and chromium, and harmful substances such as arsenic and cadmium. There is concern about pollution.

The present invention has been made in view of the above circumstances, and an object thereof is to produce a safe fertilizer having a high concentration of phosphorus components from sludge incineration ash.

[0009]

In order to achieve the above object, in the method for producing phosphorus fertilizer according to claim 1 of the present invention,
The sludge incineration ash containing the phosphorus component is heated in the melting furnace in a reducing atmosphere, the molten metal and the molten slag coexist in the melting furnace in a two-liquid separated state, and the molten slag is subjected to water granulation treatment. And granulate the molten slag.

In the method for producing a phosphorus fertilizer according to claim 2 of the present invention, sludge incineration ash containing a phosphorus component and a reducing agent are heated in a melting furnace so that molten metal and molten slag are placed in the melting furnace. The two liquids are made to coexist in a separated state, and the molten slag is granulated by water granulation treatment.

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

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

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

In the method for producing a phosphorus fertilizer according to claim 6 of the present invention, sludge incineration ash containing a phosphorus component, a reducing agent, and a potassium component are heated in a melting furnace to melt the molten metal and the molten slag. The molten slag is made to coagulate in the furnace in a two-liquid separated state and granulated by water granulation.

In the method for producing phosphorus fertilizer according to claim 7 of the present invention, sludge incineration ash containing phosphorus component, reducing agent, magnesium component and potassium component are heated in a melting furnace to melt with molten metal. The slag is allowed to coexist in the melting furnace in a two-liquid separated state, and the molten slag is granulated by water granulation treatment.

In the method for producing phosphorus fertilizer according to claim 8 of the present invention, sludge incineration ash containing phosphorus component, reducing agent, calcium component, and potassium component are heated in a melting furnace to melt with molten metal. The slag is allowed to coexist in the melting furnace in a two-liquid separated state, and the molten slag is granulated by water granulation treatment.

In the method for producing a phosphorus fertilizer according to claim 9 of the present invention, sludge incineration ash containing a phosphorus component, a reducing agent, a magnesium component, a calcium component, and a potassium component are heated in a melting furnace to obtain a molten metal. And molten slag coexist in a melting furnace in a two-liquid separated state, and the molten slag is granulated by water granulation treatment.

In the method for producing a phosphorus fertilizer according to claim 10 of the present invention, an iron-based coagulant for trapping phosphorus components is added to sewage, and the phosphorus components contained in the sewage are allowed to settle and collected together with sludge, These are dehydrated and incinerated to obtain sludge incineration ash to be heated in the melting furnace.

In the method for producing phosphorus fertilizer according to claim 11 of the present invention, the phosphorus content of the sludge incineration ash is grasped in advance, and the granular material obtained by the water granulation process of the molten slag is diphosphorus pentoxide and oxidized. The amounts of magnesium component and calcium component relative to the sludge incineration ash are determined so that the molar ratio of magnesium and calcium oxide is about 1: 2 to 4: 2 to 4.

In any of the methods for producing phosphorus fertilizer according to any of claims 1 to 9 of the present invention, molten metal and molten slag are made to coexist in a two-liquid separated state in a melting furnace kept in a reducing atmosphere. The metal is separated from the molten slag, and the molten slag is subjected to water granulation treatment to form the slag containing the phosphorus component into particles that are easy to handle.

In any of the methods for producing phosphorus fertilizers according to claims 3, 5, 7, and 9 of the present invention, the magnesium component should be increased by separately adding the magnesium component.

In any of the methods for producing phosphorus fertilizers according to claims 4, 5, 8 and 9, the calcium component is added separately to increase the calcium component to be contained in the slag.

In any of the methods for producing phosphorus fertilizer according to any of claims 7 to 9 of the present invention, by adding a potassium component separately, the temperature at which the slag becomes a molten state is lowered and the slag should be contained. Aim to increase potassium content.

In the method for producing a phosphorus fertilizer according to claim 10 of the present invention, the phosphorus component dissolved in the wastewater is precipitated by adding an iron-based coagulant and collected together with the sludge, and the phosphorus contained in the sludge incineration ash is added. Increase the concentration of ingredients.

In the method for producing phosphorus fertilizer according to claim 11 of the present invention, the amounts of magnesium component and calcium component to be heated together with the sludge incineration ash are determined by adjusting the amount of diphosphorus pentoxide and oxidation contained in the slag after the water granulation treatment. The molar ratio of magnesium and calcium oxide is set to about 1: 2 to 4: 2 to 4 to obtain a phosphorus fertilizer having an optimum component ratio.

[0026]

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 the phosphorus fertilizer production method of the present invention. In this phosphorus fertilizer production method, sludge incineration ash 1, coke 2 as a carbon (C) -based reducing agent, oxidation Magnesium (MgO) 3, calcium oxide (CaO) 4, and potassium oxide (K ₂ O) 5 are used as fertilizer raw materials.

Further, in order to produce a fertilizer from each of the above raw materials, an iron-based coagulant 7 for trapping the phosphorus component contained in the wastewater 6 with iron chloride as a main component, and a melting furnace 8 are used.

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 phosphorus fertilizer is produced, after adding the iron-based coagulant 7 to the sewage 6 stored in the aeration tank 20, the sewage 6 is stirred or ventilated to be contained in the sewage 6. Allow the phosphorus component to settle.

The sediment 21 and the sludge 22 that has settled on the inner bottom of the aeration tank 20 are collected, and the water contained therein is removed by a means such as a centrifugal dehydrator or a belt press dehydrator to dehydrate the sludge. Sludge 23 is used.

Further, the dehydrated sludge 23 is incinerated (not shown).
Is incinerated at a temperature of about 800 ° C. to produce sludge incineration ash 1.

Therefore, the concentration of the phosphorus component remaining in the treated water obtained by purifying the sewage 6 is reduced, and the phosphorus component contained in the sewage 6 is transferred to the dehydrated sludge 23 and the sludge incineration ash 1 The concentration of the phosphorus component of is increased.

Then, the sludge incineration ash 1, the coke 2, the magnesium oxide 3, the calcium oxide 4, and the potassium oxide 5 are fed from the raw material charging machine 13 to the melting space of the furnace body 10 from the raw material charging port 14, and both electrodes are fed. An electric current is applied to 11 and 12 through a substance to be fed to the melting space, sludge incineration ash 1, magnesium oxide 3, calcium oxide 4, potassium oxide 5
Is heated by Joule heat to be 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, magnesium oxide 3, calcium oxide 4, and potassium oxide 5 are melted, iron, nickel, and chromium contained in the sludge incineration ash 1 are caused due to the difference in specific gravity between metal and nonmetal. Various metals such as, and a layer of the molten metal 24 mainly composed of the iron component of the iron-based coagulant 7,
Diphosphorus pentoxide (P ₂ O ₅ ), which was originally formed in the sludge incineration ash 1 and was formed on the inner bottom side of the melting space, magnesium oxide,
Calcium oxide, potassium oxide, and silicic acid (Si
O), and a layer of the molten slag 25 mainly composed of magnesium oxide 3, calcium oxide 4, and potassium oxide 5 added for the raw material are formed on the upper side of the layer of the molten metal 24, and the molten metal 24 and the molten slag 25 are formed. However, they 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, this slag 26 is fertilized in the same manner as phosphorus fertilizer using phosphorus ore as a raw material. Produce an effect.

In addition to this, since the various metals contained in the sludge incineration ash 1 and the iron component of the iron-based coagulant 7 are contained in the molten metal 24, even if the slag 26 is sprinkled as fertilizer, the soil Do not pollute.

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, magnesium oxide 3 and calcium oxide 4 are melted to produce a phosphorus fertilizer by the procedure described above, the phosphorus content per unit weight of the sludge incineration ash 1 is measured in advance. Incidentally, 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). Degree)
If the amounts of magnesium oxide 3 and calcium oxide 4 with respect to the sludge incineration ash 1 are determined, a phosphorus fertilizer having an optimum composition can be obtained.

The method for producing phosphorus fertilizer according to the present invention is not limited to the above-mentioned embodiment, but the addition of magnesium component, calcium component, potassium component depending on the component of sludge incineration ash or the use of fertilizer. Omitting,
Of course, other changes can be made without departing from the scope of the present invention.

[0049]

INDUSTRIAL APPLICABILITY As described above, the method for producing phosphorus fertilizer of the present invention can exhibit various excellent effects as described below.

(1) In any of the methods for producing phosphorus fertilizer according to any one of claims 1 to 9 of the present invention, molten metal and molten slag are separated into two liquids in a melting furnace kept in a reducing atmosphere. The metal is separated by coexistence, and the molten slag is subjected to water granulation treatment to form granules that are easy to handle, so fertilizer with a high phosphorus concentration and safe fertilizer can be produced from sludge incineration ash, and is associated with sewage treatment. The sludge generated as a result can be effectively used.

(2) In any of the methods for producing a phosphorus fertilizer according to claims 3, 5, 7, and 9 of the present invention, the magnesium component is added separately to increase the magnesium component of the slag used as the phosphorus fertilizer. Can be planned.

(3) In any of the methods for producing phosphorus fertilizers according to claims 4, 5, 8 and 9 of the present invention, the calcium component of the slag used as phosphorus fertilizer is increased by adding a calcium component separately. Can be planned.

(4) In any of the methods for producing phosphorus fertilizers according to claims 7 to 9 of the present invention, the potassium component is added separately to lower the temperature at which the molten state of the slag can be maintained. In addition, the potassium component of slag used as a fertilizer can be increased.

(5) In the method for producing phosphorus fertilizer according to claim 10 of the present invention, since the phosphorus component contained in the wastewater is precipitated by the addition of the iron-based coagulant, the sludge used as the raw material for the fertilizer. Since the concentration of the phosphorus component contained in the incineration ash is high and the coagulant is iron-based, the iron component can be reliably incorporated into the molten metal.

(6) In the method for producing a phosphorus fertilizer according to claim 11 of the present invention, the amounts of the magnesium component and the calcium component to be melted together with the sludge incinerated ash are determined by the dipentapentoxide contained in the slag after the water granulation treatment. Since the molar ratio of phosphorus, magnesium oxide and calcium oxide is determined to be about 1: 2 to 4: 2 to 4, a slow-release fertilizer with excellent solubility (solubility in a 2% citric acid solution) should be used. Obtainable.

[Brief description of drawings]

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

[Explanation of symbols]

1 Sludge incineration ash 2 coke (reducing agent) 3 Magnesium oxide (magnesium component) 4 Calcium oxide (calcium component) 5 Potassium oxide (potassium component) 6 dirty water 7 Iron-based coagulant 8 melting furnace 19 water granulation tank 21 sediment 22 sludge 24 Molten metal 25 Molten slag 26 Slag (granular body)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C05D 3:02 C05D 5:00 5:00) (72) Inventor Yoshihiro Iwai 1-4 Yurakucho, Chiyoda-ku, Tokyo No. 1 Sanki Kogyo Co., Ltd. (72) Inventor Takashi Komatsu 1-4-1, Yurakucho, Chiyoda-ku, Tokyo Sanki Kogyo Co., Ltd. (72) Satoshi Takagi 1-4-4 Yurakucho, Chiyoda-ku, Tokyo No. 1 Sanki Kogyo Co., Ltd. (72) Inventor Tetsuji Kazuka 1-4-1 Yurakucho, Chiyoda-ku, Tokyo F-Term inside Sanki Kogyo Co., Ltd. (reference) 4D067 CG04 EE35 GA20 4H061 AA02 BB42 CC08 CC15 CC51 FF08 GG18 GG23 GG26

Claims (11)

[Claims] 1. A sludge incineration ash containing a phosphorus component is 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, and the molten slag is mixed with water. A method for producing a phosphorus fertilizer, which comprises granulating by crushing treatment. 2. A sludge incineration ash containing a phosphorus component and a reducing agent are heated in a melting furnace so that molten metal and molten slag coexist in the melting furnace in a two-liquid separated state, and the molten slag is mixed with water. A method for producing a phosphorus fertilizer, which comprises granulating by crushing treatment. 3. A sludge incineration ash containing a phosphorus component, a reducing agent, and a magnesium component are heated in a melting furnace so that molten metal and molten slag coexist in the melting furnace in a two-liquid separated state, and the melting is performed. A method for producing a phosphorus fertilizer, which comprises granulating slag by water granulation. 4. A sludge incineration ash containing a phosphorus component, a reducing agent, and a calcium component are heated in a melting furnace so that molten metal and molten slag coexist in the melting furnace in a two-liquid separated state.
A method for producing a phosphorus fertilizer, which comprises granulating the molten slag by water granulation. 5. A sludge incineration ash containing a phosphorus component, a reducing agent, a magnesium component, and a calcium component are heated in a melting furnace so that molten metal and molten slag coexist in the melting furnace in a two-liquid separated state. A method for producing phosphorus fertilizer, characterized in that the molten slag is granulated by a water granulation process. 6. A sludge incinerator ash containing a phosphorus component, a reducing agent, and a potassium component are heated in a melting furnace so that molten metal and molten slag coexist in the melting furnace in a two-liquid separated state, and the melting is performed. A method for producing a phosphorus fertilizer, which comprises granulating slag by water granulation. 7. A sludge incinerator ash containing a phosphorus component, a reducing agent, a magnesium component, and a potassium component are heated in a melting furnace so that molten metal and molten slag coexist in the melting furnace in a two-liquid separated state. A method for producing phosphorus fertilizer, characterized in that the molten slag is granulated by a water granulation process. 8. A sludge incineration ash containing a phosphorus component, a reducing agent, a calcium component, and a potassium component are heated in a melting furnace so that molten metal and molten slag coexist in the melting furnace in a two-liquid separated state. A method for producing phosphorus fertilizer, characterized in that the molten slag is granulated by a water granulation process. 9. A sludge incinerator ash containing a phosphorus component, a reducing agent, a magnesium component, a calcium component, and a potassium component are heated in a melting furnace to separate the molten metal and the molten slag into two liquids in the melting furnace. A method for producing a phosphorus fertilizer, which comprises coexisting and granulating the molten slag by water granulation treatment. 10. An iron-based coagulant that captures phosphorus components is added to sewage, the phosphorus components contained in the sewage are precipitated and collected together with sludge, and these are dehydrated and incinerated in a melting furnace. The method for producing phosphorus fertilizer according to any one of claims 1 to 9, wherein sludge incineration ash to be heated is obtained. 11. The phosphorus content of sludge incineration ash is grasped in advance, and the molar ratio of diphosphorus pentoxide, magnesium oxide, and calcium oxide of the granular material obtained by the water granulation treatment of molten slag is 1: 2. To 4: The method for producing phosphorus fertilizer according to claim 5 or 9, wherein the amounts of the magnesium component and the calcium component with respect to the sludge incineration ash are determined so as to be about 2 to 4.