JP2003190910A - Incinerated ash treatment method and apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an incinerated ash treatment method with which heavy metal elution can be suppressed by heat treatment at a relatively low temperature and the energy cost and the fixed cost can be saved, and an apparatus therefor. <P>SOLUTION: The incinerated ash treatment apparatus 10 is provided with a furnace 11 for incinerating ashes and an oxygen concentration control apparatus 20 in the furnace 11. The incinerated ashes are fired in the furnace 11 and at the same time, the oxygen concentration in the furnace 11 is controlled depending on the firing temperature. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for heat treating incinerated ash for the purpose of using the incinerated ash of waste as a construction / civil engineering material.

[0002]

2. Description of the Related Art In order to use incineration ash as a construction / civil engineering material, it is necessary to suppress elution of a predetermined metal (mainly a heavy metal) contained in the incineration ash from an environmental viewpoint. , “Environmental standards for soil pollution” (1991.
8.23, Announcement 46) is used.

As a method of heat treating the incinerated ash to suppress the elution of heavy metals, a method of melting the incinerated ash at a high temperature of about 1300 ° C. or higher to form a slag has been known.

[0004]

However, in order to melt the incineration ash at a high temperature, a great energy cost is required, and the manufacturing cost of the device capable of withstanding the high temperature is also high.

The present invention has been made in view of the above-mentioned circumstances, and is a method for treating incinerated ash, which can suppress the elution of heavy metals by heat treatment at a relatively low temperature and can reduce energy costs and equipment costs. An object is to provide a processing device.

[0006]

DISCLOSURE OF THE INVENTION The above-mentioned object of the present invention is to treat incinerated ash by firing the incinerated ash in a furnace and controlling the oxygen concentration in the oven according to the firing temperature. Achieved by the method.

In this case, for example, the firing temperature is 8
When the temperature is from 00 to 900 ° C., it is preferable to control the oxygen concentration in the furnace to more than 0% and less than 10%.

The above method for treating incinerated ash can be carried out by an incinerator ash treatment apparatus comprising a furnace for firing the incinerated ash and an oxygen concentration control device for controlling the oxygen concentration in the furnace.

In this case, the oxygen concentration control device comprises an oxygen concentration meter for measuring the oxygen concentration in the furnace, and a gas supply for supplying a predetermined gas into the furnace based on the measurement result of the oxygen concentration meter. And a device.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below.
The present inventors that the elution of heavy metals is sufficiently suppressed by firing even if the incineration ash is not necessarily melted, the relationship between the firing temperature and the elution amount of heavy metals tends to be different for each heavy metal, It was clarified that the amount of elution easily depends on the oxygen concentration during firing, and the incinerator ash is fired in the furnace.
The present invention was completed by controlling the oxygen concentration in the furnace according to the firing temperature.

That is, in the method for treating incinerated ash according to the present invention, the elution of heavy metals is suppressed by firing the incinerated ash at a temperature lower than that of the conventional melting treatment. Further, the relationship between the firing temperature and the elution amount of heavy metals tends to differ depending on each heavy metal, and there is uncertainty in collectively suppressing the elution of multiple heavy metals only by controlling the firing temperature. By controlling the oxygen concentration in the furnace according to the above, the effect of suppressing elution of each heavy metal during firing is enhanced. This surely suppresses the elution of each heavy metal.

In the method for treating incinerated ash according to the present invention,
The firing temperature (heating temperature, furnace temperature) is, for example, 600 to 1.
The temperature is preferably 100 ° C. When the firing temperature is lower than 600 ° C, the elution of heavy metals is not sufficiently suppressed, which is not preferable, and when the firing temperature exceeds 1100 ° C, the energy cost is significantly increased, which is not preferable.

Further, in the above treatment method, when the firing temperature is 800 to 900 ° C., it is preferable to control the oxygen concentration in the furnace to more than 0% and less than 10%. When the oxygen concentration in the furnace is 0%, the amount of lead (Pb) elution is greatly increased, and when it is 10% or more, the amount of hexavalent chromium (Cr + 6) is greatly increased, which is not preferable.

Next, a processing apparatus capable of carrying out the incineration ash processing method of the present invention will be described. FIG. 1 is a diagram conceptually showing an example of an embodiment of an incineration ash treatment apparatus according to the present invention. The processing apparatus 10 includes a firing furnace 11,
The incineration ash put into the firing furnace 11 is fired. That is, the firing furnace 11 includes the heating means 1 for heating the incineration ash.
2 and a thermometer 13 for measuring the temperature in the firing furnace 11 and the like, and by heating the incineration ash at a predetermined temperature, a chemical reaction is caused in the incinerator ash to cure it. As the heating means 12, various known ones such as one utilizing combustion energy and one utilizing electric energy are applied. Further, the measurement result of the thermometer 13 is sent to the control device 14, and the control device 14 controls the heating means 12 based on the measurement result so as to reach a predetermined firing temperature.

The processing apparatus 10 also includes an oxygen concentration control device 20 for controlling the oxygen concentration in the firing furnace 11, and the oxygen concentration control device 20 measures the oxygen concentration in the firing furnace 11 with an oxygen concentration meter 21. The firing furnace 11 is provided with a gas supply system 22 for supplying a predetermined gas, the control device 14 and the like. The oxygen concentration meter 21 measures the oxygen concentration in the gas in the furnace (the oxygen concentration may be insufficient), and various known ones are applied. Further, the measurement result is sent to the control device 14. The gas supply system 22 supplies an inert gas (or reducing gas) such as nitrogen or helium into the furnace to reduce the oxygen concentration in the furnace, and is a tank for storing the gas (or liquefied gas). And a supply pipe, or a flow control valve, etc.
Controlled by. The oxygen concentration control device 20 is not limited to the above configuration as long as it can control the oxygen concentration in the firing furnace 11. For example, the oxygen concentration in the furnace may be controlled by controlling the flow rate of the exhaust gas from the baking furnace 11.

In the processing apparatus 10 having the above-mentioned structure, when the incineration ash is put into the firing furnace 11, the incineration ash is fired at a predetermined temperature, for example, a temperature in the range of 600 to 1100 ° C. Further, during firing, the oxygen concentration in the firing furnace 11 is controlled within a predetermined range via the oxygen concentration control device 20. For example, when the firing temperature is 800 to 900 ° C., the oxygen concentration in the firing furnace 11 is controlled to be higher than 0% and lower than 10%. As a result, in this processing apparatus 10, a burned material of incinerated ash in which elution of heavy metals is suppressed is generated. After a lapse of a predetermined calcination time, a calcinated product of incinerated ash is taken out from the calcination furnace 11, and the calcinated product is used as a construction / civil engineering material (aggregate, etc.).

[0017]

[Example] The waste was incinerated in a stalker furnace (manufactured by Ishikawajima Harima Heavy Industries, Ltd.), and the incinerated ash (main ash) was incinerated in a muffle furnace. After the baked processed product was left to stand in an air atmosphere and cooled, an elution test was performed on the processed product. The firing temperature (heating temperature) was 900 ° C., and the firing time (heating time) was 60 minutes. Oxygen concentration in the furnace is 0%, 3%, 5%, 7%, 10%, 21% based on nitrogen, respectively.
% And 30%. The dissolution test is performed in accordance with Notification 46 (Heisei 3.8.23), and copper (Cu), zinc (Z
n), hexavalent chromium (Cr + 6), arsenic (As), selenium (Se), cadmium (Cd), and lead (Pb) were investigated. For the analysis, mainly ICP mass and luminescent ICP (ICP-AES) were used. Only hexavalent chromium was analyzed by a colorimetric method (JIS K1020). The analysis results are shown in FIG.

In FIG. 2, arsenic (As), selenium (S)
e) and cadmium (Cd) each satisfied the standard (0.01 mg / l or less) at any oxygen concentration. Hexavalent chromium (Cr + 6) has an oxygen concentration of 0
%, 3%, 5%, and 7%, the standard (0.05 mg
/ L or less), the oxygen concentrations are 10% and 21 respectively.
% And 30% exceeded the standard. Lead (Zn)
Exceeded the standard (0.01 mg / l) when the oxygen concentration was 0%, and satisfied the standard at other oxygen concentrations. From this result, it was found that the oxygen concentration in the furnace is preferably more than 0% and less than 10% when the firing temperature is 900 ° C. and the firing time is 60 minutes.

In this way, while burning the incinerated ash,
By controlling the oxygen concentration in the furnace according to the firing temperature, even when multiple heavy metals that show different tendencies with respect to firing temperature conditions are included, the effect of suppressing elution by firing is enhanced, and the elution of these multiple heavy metals is improved. It was confirmed that they can be suppressed collectively.

The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such examples. The shapes, combinations, and the like of the constituent members shown in the above-described examples are merely examples, and various changes can be made based on design requirements and the like without departing from the spirit of the present invention.

[0021]

According to the method and apparatus for treating incinerated ash of the present invention, the incinerator ash is fired in the furnace, and the oxygen concentration in the furnace is controlled according to the firing temperature. Even if the heating temperature is lower than that of the above, the elution of a plurality of heavy metals from the incinerated ash can be suppressed collectively. Therefore, the energy cost and the apparatus cost can be reduced as compared with the conventional melting process. In addition, incineration ash fired by this treatment method and treatment apparatus can be preferably used as a construction / civil engineering material because elution of heavy metals is suppressed.

[Brief description of drawings]

FIG. 1 is a diagram conceptually showing an example of an embodiment of an incineration ash treatment apparatus according to the present invention.

FIG. 2 is a graph showing the results of examining the relationship between the oxygen concentration and the elution amount of heavy metals.

[Explanation of symbols]

10 processor 11 firing furnace 12 Heating means 13 Thermometer 14 Control device 20 Oxygen concentration control device 21 Oxygen analyzer 22 Gas supply system

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shunichiro Ueno             Stone, Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa             Kawaharima Heavy Industries Co., Ltd. Machine and plant development             In the center (72) Inventor Nobuhiko Kubota             Stone, Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa             Kawaharima Heavy Industries Co., Ltd. Machine and plant development             In the center (72) Inventor Masafumi Mimura             3-2-16 Toyosu, Koto-ku, Tokyo Ishikawa Ban             Maru Heavy Industries Tokyo Engineering Center             In the center (72) Inventor Sadahiro Yamada             3-2-16 Toyosu, Koto-ku, Tokyo Ishikawa Ban             Maru Heavy Industries Tokyo Engineering Center             In the center (72) Inventor Koji Seo             3-2-16 Toyosu, Koto-ku, Tokyo Ishikawa Ban             Maru Heavy Industries Tokyo Engineering Center             In the center F-term (reference) 3K061 NA08 NA12                 3K062 AA24 AB03 AC03 BA02 BB02                       CA01 CB03 DA22                 4D004 AA36 AB03 BA02 CA30 CB04                       CB31 DA01 DA02 DA03 DA06                       DA10

Claims (4)

[Claims] 1. A method for treating incinerated ash, which comprises firing the incinerated ash in a furnace and controlling the oxygen concentration in the furnace according to the firing temperature. 2. The method for treating incinerated ash according to claim 1, wherein when the firing temperature is 800 to 900 ° C., the oxygen concentration in the furnace is controlled to be more than 0% and less than 10%. 3. A device for treating incinerated ash, comprising: a furnace for firing incinerated ash; and an oxygen concentration control device for controlling the oxygen concentration in the furnace. 4. The oxygen concentration control device includes an oxygen concentration meter for measuring the oxygen concentration in the furnace, and a gas supply device for supplying a predetermined gas into the furnace based on the measurement result of the oxygen concentration meter. The incineration ash processing apparatus according to claim 3, comprising: