JP2005233568A - High calcareous waste incinerator melting method of incineration ash - Google Patents

Abstract

【Task】
The present invention relates to a method for melting high calcareous garbage incinerator incineration ash, and more specifically, provides a novel method capable of rapidly and mass melting high calcareous incineration ash such as incineration fly ash.
【Solutions】
When the high calcareous incinerated ash is heated and melted, the ash is pelletized and the pellets of the thermite reactant are mixed with the ash pellets at a weight ratio of 8: (2-8) and heated. Features.
[Selection] Figure 1

Description

The present invention relates to a method for melting high calcareous waste incinerator incineration ash, and more specifically, dust collection ash (incineration fly ash) generated from an exhaust gas treatment facility when waste such as municipal waste is incinerated in a garbage incinerator. Or, it relates to a melting method for incinerator ash containing a large amount of lime.

  Exhaust gas generated by incinerating municipal waste and other waste in a garbage incinerator contains harmful components such as dust, HCl, dioxin, and SOX. In order to remove these harmful components, conventionally, powder such as slaked lime is sprayed into the exhaust gas to convert it into a Ca compound and collected by a dust collector.

Dust collection ash (incinerator fly ash) separated and removed in this way has a higher concentration of heavy metal components such as organochlorine compounds, Pb, Zn, and Cd than incineration ash, so it is designated as “specially managed waste”. Is required, and is processed by various methods such as melt solidification, cement solidification, chemical treatment, and stabilization by solvent extraction. Among these treatment methods, a method in which fly ash is mixed with ordinary incineration ash and melted and solidified together is most widely used (Patent Document 1).
The recent trend is that the amount of lime (CaO) added to the exhaust gas has increased remarkably due to further strengthening of desalination and dioxin regulations. Recently, lime accounts for 30-50% of fly ash.

The higher the amount of calcium (CaO) component, the higher the melting temperature. When melting high calcareous incineration ash such as fly ash, it is necessary to heat it to 1350 ° C or higher.
In commercial melting furnaces, regardless of furnace type, for example, burner melting, electric melting (plasma method, arc method, Joule heating method), even if it is fast to reach a temperature environment exceeding 1300 ° C, about 10 hours, Joule The law requires 20 days of rise time, and the productivity is extremely poor. Therefore, it is virtually impossible to melt these high calcareous incineration ash alone. Therefore, there is currently only a method in which a small amount of fly ash is mixed with incineration ash and melted and solidified together.
For these reasons, the amount of untreated fly ash continues to increase.

JP-A-10-19228

The present invention has been made in view of such problems, and an object of the present invention is to provide a novel method capable of melting in a large amount and rapidly even with only high calcareous incineration ash alone.

The inventor conducted intensive studies on the above problems and obtained the following knowledge.
That is,
(1) When high calcareous incineration ash is heated and melted, pelletizing the incineration ash and mixing and heating the pellets of the thermite reactant to the ash pellets, regardless of the type of melting furnace, It has been found that the melting temperature can be reached.
(2) The mixing ratio of the high calcareous incineration ash and thermite reactant pellets is a weight ratio,
8: The range of (2-8) is most preferable.
(3) When pelletizing the high calcareous incineration ash, water is preferable as a binder. (4) When pelletizing the high calcareous incineration ash, a siliceous inorganic binder is also preferable as a binder.
(5) When a siliceous inorganic binder is used, the melting temperature of the high calcareous incineration ash is lowered and it becomes easy to melt.
The above knowledge was acquired.
The present invention has been made based on the above findings.
It consists of the following composition.
(1) Incineration ash of high calcareous waste incinerator High calcareous waste incineration characterized in that the incineration ash is pelletized and the pellets of thermite reactant are mixed and heated in the incineration ash pellets. Melting method of furnace incineration ash.
(2) The high calcareous waste incinerator incineration ash according to (1), wherein the high calcareous waste incinerator incineration ash is dust collection ash.
(3) The method for melting the high calcareous refuse incinerator incineration ash according to (1) or (2) above, wherein water is used as a binder when the incineration ash is pelletized.
(4) When pelletizing the incineration ash, a siliceous inorganic binder is used as a binder, and the high calcareous refuse incinerator incineration ash melting method according to the above (1) or (2).
(5) The high ratio according to any one of (1) to (4) above, wherein the mixing ratio of the incinerated ash and the thermite reactant pellets is 8: (2-8) in weight ratio. The melting method of calcined ash incinerator ash.
(6) When the high calcareous waste incinerator ash is heated and melted, the incinerated ash is pelletized and heated using a siliceous inorganic binder as a binder. Melting method.

Even with high calcareous garbage incinerator incineration ash alone, regardless of the type of melting furnace, the temperature of all melting furnaces can be quickly reached to the melting temperature of incineration ash and can be melted in large quantities and at low cost.
Even fine dust particles such as fly ash can be melted without being scattered by a flame.

Any existing melting furnace can be used as the heating furnace. For example, a burner melting furnace (surface melting furnace), an electric melting furnace (plasma furnace, arc furnace, Joule heating furnace) can be used regardless of the type.

FIG. 1 is a schematic view when incineration ash is melted using a burner heating furnace.
In FIG. 1, a molten raw material (melted material) mixed in advance is pushed in with a pusher from a melted material insertion port provided in the upper part of the inclined hearth. The raw material pushed into the furnace pushes the raw material pushed first from behind, and pushes the raw material put in front downwards down the slope of the hearth. A burner is opened to the inclined hearth on the ceiling inside the furnace, and the flame heats the raw material placed on the hearth surface. The molten raw material is heated by the flame while flowing downward on the slope of the hearth, melts and flows as slag, and falls from the gate to the lower water tank. Or it falls on the slag conveyor which is not shown in figure, and will be carried out outside, gradually cooling.
The inclined hearth is a concave curved surface, and the curvature radius of the curved surface gradually decreases from the top to the bottom of the hearth surface and converges toward the gate. For this reason, the slag that flows down from the top to the bottom of the furnace floor converges as one flow toward the gate and flows down from the gate.

When pelletizing high calcareous garbage incinerator ash, a binder that binds ash powder is required. In particular, fly ash is fine powder, scatters, and is scattered by arc and flame, so it is difficult to melt.
High calcareous trash incinerator incineration ash contains lime, and as a recent trend, especially in large quantities (30-50%), the ash is focused on the hydration bond between water and lime. When water is added to the mixture, hard high-strength pellets are obtained. This pellet can maintain the bonding strength up to a high temperature, can stably maintain the strength against arcs and flames, and is effective in preventing scattering due to arcs and flames. Water is the most preferred binder.
In addition, siliceous inorganic binders such as silica-containing sodium silicate and silica sol can be suitably used. Silicic inorganic binder is effective in lowering the melting temperature of incinerated ash.
The amount of water added is preferably about 3 to 8% of the ash weight.
About 5 to 10% of the siliceous inorganic binder is good.

Bentonite, kaolin, porcelain powder, and other inorganic powders containing silica components may be added to the high calcareous refuse incinerator incineration ash in order to lower the melting softening point. Although there is no special restriction | limiting in the addition amount, when the addition amount is increased, the blending ratio of fly ash is relatively reduced, which is economically disadvantageous. The addition amount is preferably about 5 to 10%.

The thermite reactant comprises a mixture of a raw material containing an aluminum component and a raw material containing an iron oxide component.
As the raw material containing aluminum components, waste containing aluminum components such as waste aluminum cans for beverages and aluminum residual ash generated during remelting of aluminum bullion is effective, but is not limited thereto.

Raw materials containing iron oxide components are general metal waste such as iron scrap and iron rust, dust collection ash such as converter dust and blast furnace dust generated in the steel industry, and also generated as a by-product during magnetic iron oxide production Iron oxide sludge to be produced and red mud to produce aluminum hydroxide from bauxite are effective, but are not limited thereto.
These raw materials may be used as they are, or two or more different starting materials may be appropriately mixed and used.

As mentioned above, when the aluminum-containing raw material is a crushed piece of an aluminum can, the one mixed with the iron oxide-containing raw material is pressed into a plate and divided into appropriate sizes and mixed and dispersed in the incineration ash You may let them.
The thickness of the crimping piece is preferably about 3 to 6 mm and about 5 to 30 in length.
An adhesive component remains in the pressure-bonded piece obtained by evaporating the moisture of the aluminum can, and appropriate strength is exhibited.
The size of the crushed pieces of the waste aluminum can may be such that the crushed pieces are crushed into small pieces of about 5 to 10 mm by a cutting machine and then secondarily crushed to 1 to 3 mm or less.

When using iron oxide sludge produced as a by-product during the production of magnetic iron oxide as the iron oxide-containing raw material, the water content may be dried to about 5 to 1% by sun drying or the like. In order to further improve the mixing with the aluminum raw material, the lump is preferably finely pulverized.

The aluminum content in the thermite reaction composition mainly comprising an aluminum-containing raw material and an iron oxide-containing raw material is preferably 5% or more. If it is less than 5%, the thermite exothermic reaction does not occur, which is not preferable.
The mixing ratio of aluminum and iron oxide is preferably a ratio of iron oxide content of 2.5 to 3.0 with respect to aluminum content of 1, and 3 to 12% by weight of titanium oxide and 1 to 3% by weight of manganese oxide in the mixture. It is preferable.
When titanium oxide and manganese oxide are already contained in the aluminum raw material and iron oxide raw material, the shortage of titanium oxide and manganese oxide may be added after mixing the aluminum raw material and the oxidation raw material.
As a method of adding titanium oxide and manganese oxide, titanium oxide and manganese oxide itself may be added, or those containing titanium oxide and a manganese oxide component may be added. It is also effective to add waste particles containing titanium oxide and manganese oxide.

If the ratio of the aluminum-containing raw material and the iron oxide-containing raw material exceeds the upper limit, the iron oxide becomes excessive and the thermite exothermic reaction does not occur, which is not preferable. On the other hand, if it is less than the lower limit, the amount of aluminum becomes excessive and aluminum remains in the reaction product, which is not preferable.

If the titanium oxide content is less than the lower limit, the thermite reaction product has a high viscosity, so that the meltability becomes poor and continuous operation is not possible. Further, even if the content exceeds the upper limit, no further improvement effect of the meltability can be expected. About the mixing method of these compositions, for example, it may be mixed using an ordinary stirring mixer such as a fret mill, a high-speed mixer, a mixer, and the addition and mixing methods of titanium oxide and manganese oxide are also special. There is no limitation.

When pelletizing the thermite agent, dry compression molding may be used as it is, but a binder may be added to further increase the bond strength.
As the binder, organic starches such as various starches, polyhydric alcohols such as poval, and various celluloses such as MC and CMC can be used as appropriate.

There are no particular restrictions on the shape of the high calcareous refuse incinerator incineration ash and the thermite reactant beret. Any shape such as a granular shape, a granular shape, or a small-cut columnar shape may be used. The size is preferably about 5 to 30 mm.

The mixing ratio of the pellets of the high calcareous incineration ash and the thermite reactant is mixed at a ratio of 2 parts by weight of the pellets of the thermite reactant with respect to 8 parts by weight of the high calcareous incineration ash pellets. Even if the thermite reactant is added in excess of the upper limit, the effect of increasing the rise rate of the melting furnace cannot be expected. Moreover, since the viscosity of a molten slag becomes high and a hot water flow worsens, it is rather unpreferable. On the other hand, if it is less than the lower limit value, the rising speed of the melting furnace does not increase, which is not preferable. Here, it is conceivable that the high calcareous incinerated ash and the thermite reactant are mixed in advance and pelletized, but in this case, the effect of adding the thermite reactant cannot be obtained.
The effect of the present invention is obtained for the first time when high calcareous incinerated ash pellets and thermite reactant pellets are mixed.

The pellets of the high calcareous waste incinerator ash and thermite reactant of the present invention can be mixed and melted with ordinary incinerated ash, that is, incinerated ash containing low calcareous or calcareous. At this time, the mixing ratio of the incineration ash can be freely set to 0 to 100%. That is, it can be adjusted freely from 100% incinerated ash to 100% pellets (incinerated ash: 0%).
When mixed with normal incineration ash and melted, the ratio of high calcareous incineration ash: thermite reactant pellets is greater than that of 8: (2-8), depending on the proportion of incineration ash to be mixed. You may make a ratio high suitably.

The high calcareous garbage incinerator incineration ash of the present invention means incinerator dust collection ash and incineration ash containing a large amount of calcareous material, and not only dust collection ash. In addition to dust collection ash, incineration ash itself containing a large amount of calcareous material is also included.

Fly ash was used as incineration ash for high calcareous waste incinerator.
Fly ash pelletization
Bentonite 5% was mixed with garbage incinerator dust ash (fly ash) containing 30 wt% of CaO, 5% water was added, and pellets with a diameter of 8 mm and length of 10-20 mm were made with a pelletizer. A pellet was obtained which was hard and had a strength that could not be broken by hand.

Pelletization of thermite reactant Aluminum raw material: A crushed aluminum residual ash generated during remelting of aluminum ingot was used.
Iron oxide component: Red mud used in producing aluminum hydroxide from bauxite was used.
Auxiliary raw materials: Titanium oxide and manganese oxide wastes were used.
The above aluminum raw material, iron oxide component, and auxiliary raw material are prepared in the following composition (wt%), mixed with 3% corn starch (glue), 8mm in diameter and 10-20mm in length with a pelletizer Sano pellets were made.
Component composition of thermite reactant Aluminum component: 18%
Iron oxide component: 40%
Titanium oxide: 5%
Manganese oxide: 2%

The above fly ash pellets, thermite reactant pellets and incineration ash from the garbage incinerator are mixed in the blending ratios shown in Table 1 below and melted in a burner heating furnace (surface melting incinerator) or electric melting furnace (arc furnace). Tested. Heavy oil was used as fuel for the burner.
The heating temperature was 1350 ° C.
When only the fly ash powder was put in a melting furnace and heated, the fly ash was scattered and could not be melted. The fly ash pellets were melted when charged into the furnace and melted.
In an arc furnace, the time required to melt 100 kg of pelletized fly ash in the furnace is
It was 10 hours.
It took 12 hours to obtain 100 kg of molten slag in the burner heating furnace.
On the other hand, when 100 kg of fly ash pellets were mixed with 50 kg of thermite reactant pellets and melted in an arc furnace, the entire amount could be melted in 3 hours. It took 4 hours to obtain 150 kg of molten slag in the burner furnace.
It has been found that the method of the present invention is extremely effective in preventing fly ash scattering and rapid melting.
Next, the mixing ratio of fly ash and thermite reactant pellets was changed and tested.
The fly ash pellet was 100 kg. The heating furnace used was a burner heating furnace.

Test results The results of the melt test are shown in Table 2.
Evaluation was compared with the time required to obtain 100 kg of molten slag.

以上の結果より、本発明方法では溶融炉の溶融温度に到達する時間が極めて早く、短時間で大量に処理できることが判明した。

From the above results, it was found that the method of the present invention takes a very short time to reach the melting temperature of the melting furnace and can be processed in a large amount in a short time.

  The present invention can vitrify the incinerated ash of high calcareous waste incinerator to reduce the volume and make it harmless, and is an invention that brings good news to the ash treatment that is in trouble in the dumping site.

FIG. 1 is a schematic view when a high calcareous refuse incinerator ash is melted using a burner heating furnace.

Claims (6)

High calcareous waste incinerator incineration ash, characterized in that when incineration ash is heated and melted, the incineration ash is pelletized and the pellets of the incineration ash are mixed with thermite reactant pellets and heated. Melting method. The method of melting high calcareous waste incinerator incineration ash according to claim 1, wherein the high calcareous waste incinerator incineration ash is waste incinerator dust collection ash. The method for melting high calcaceous waste incinerator ash according to claim 1 or 2, wherein water is used as a binder when pelletizing the incinerated ash. The method for melting high calcaceous waste incinerator ash according to claim 1 or 2, wherein a siliceous inorganic binder is used as a binder when pelletizing the incinerated ash. The high calcareous refuse incinerator incineration ash according to any one of claims 1 to 4, wherein a mixing ratio of the incineration ash and the pellet of the thermite reactant is 8: (2-8) by weight. Melting method. A method for melting high limestone waste incinerator incineration ash, comprising heating and melting high calcareous trash incinerator incineration ash by pelletizing the incineration ash using a siliceous inorganic binder as a binder.

Images