JPH1190386A - Treatment of ash - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly treat ash to a material harmless to the human body at a lower temp. by molding a mixture prepd. by mixing volcanogenous products and slaked lime into the ash and sintering or melting the molded products. SOLUTION: Since the volcanogenous products are mixed into the ash, the heat transfer rate of the mixture is increased by the characteristics of the volcanogenous products, and further a heat storage efficiency is obtd. The temp. difference between the inside and outside of the mixture is made very slight even if the rapid heating is executed. The high-speed heating of a sintering furnace by far IR rays is made possible, by which the sintering time may be shortened as well. Even more, since the slaked lime is incorporated into the ash, the heavy metals, such as lead and chromium, harmful to the human body are made alkaline, by which the m.p. is lowered and the sintering temp. is lowered. The sintered compact sintered in such a manner does not allow the elution of the heavy metals into the water and is the harmless and safe material as the ash and the heavy metals are crystallized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for treating ash.

[0002]

2. Description of the Related Art Conventionally, the following methods are known as methods for treating incinerated ash discharged from incineration of industrial waste and fly ash discharged from a dust collector.

(1) A method in which ash is formed into a lump and then sintered at about 1200 ° C. or higher for about 2 to 3 days.

(2) A method in which a mixture obtained by mixing clay and the like in ash is formed into a lump and then sintered at about 1200 ° C. or more for about 2 to 3 days.

(3) Ash or a mixture of ash and glass at about 1400 ° C.
A method of melting under the above conditions.

[0006]

However, the above-mentioned conventional ash treatment method has the following disadvantages.

That is, in the processing method described in (1), the ash molded body ruptures at the time of sintering, and not only is it difficult to mold the sintered body, but also the ash is contained in the ash. Heavy metals such as lead and chromium, which are toxic to the human body, cannot be contained in the sintered body, and the heavy metal elutes from the sintered body into water, which may cause pollution.

Further, in the treatment method described in the above (2), clay or the like is required in an amount equal to or more than that of ash by volume ratio,
In addition, the volume after sintering is about twice as large as the ash to be treated, and the strength of the sintered body is insufficient, which leads to an increase in the volume, which makes the treatment difficult, increases the cost, and increases profitability. There were practical problems such as bad.

Further, the processing method described in the above (3) has a disadvantage that the ash is melted under a high temperature condition of about 1400 ° C. or more, which increases the equipment cost and the operating cost.

Further, the processing methods described in the above (1) to (3) have a disadvantage that it takes a long time to process ash.

[0011]

Therefore, in the present invention, in view of the above-mentioned drawbacks of the conventional ash treatment method, the present invention is applied in a short time and
At a lower temperature, an object of the present invention is to provide a processing method for converting ash into a substance that is harmless to the human body.Specifically, a mixture obtained by mixing a ash with a volcanic product and slaked lime is molded, Sintered or melted.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for treating ash according to the present invention will be described below. In this specification, "ash" is a generic term for incinerated ash discharged from incineration of industrial waste, fly ash discharged from dust collectors, and the like.

First, a volcanic product and slaked lime are mixed in the ash.

[0014] Volcanic products include lizard, shirasu,
It is preferred to use a powder such as marble in an amount of about 10% to 20% by weight based on the ash. Also, slaked lime is preferably used in an amount of about 10% by weight with respect to the ash.

Next, the above mixture is pressed and molded. The pressure at that time is 1500 kg / cm ^{2 to} 2000 kg / cm ² . This is experimentally obtained as a pressure range in which a mixture having a required density can be obtained while maintaining appropriate air permeability when molding the mixture. That is, the ash may contain a large amount of a substance that is gasified by heating, and in such a case, the mixture is ruptured by sintering. It is necessary to set the mixture to a suitable pressure in advance to form the mixture, leaving a suitable air permeability to prevent rupture and the density required for sintering in a short time. Is what you can do.

Next, the pressure-formed mixture is sintered in a sintering furnace. Such sintering has a furnace temperature of about 1090 ° C.
And take about 1.5 to 2 hours.

As described above, according to the present invention, the sintering time can be reduced and the sintering temperature can be reduced as compared with the related art.

This is because the ash is mixed with a volcanic product, so that the heat transfer coefficient of the mixture increases and the heat storage efficiency is obtained due to the characteristics of the volcanic product. The temperature difference between the inside and outside of the mixture becomes small,
By enabling high-speed heating of the sintering furnace with far infrared rays, the sintering time can be reduced.

Furthermore, since slaked lime is mixed in the ash,
Heavy metals, such as lead and chromium, which are toxic to the human body and contained in the ash, are alkalized to reduce the melting point and reduce the sintering temperature.

By crushing the ash in advance, the contact area between the ash and the volcanic products or slaked lime can be increased, and the ash can be treated in a shorter time.

The sintered body sintered as described above is a harmless and safe substance because the ash and the heavy metal are crystallized, so that the heavy metal does not elute into water.

For this reason, by crushing the sintered body and then press-molding it, it is possible to form building materials and the like, and it is possible to effectively use resources.

As described above, the ash can be sintered, but in the present invention, the ash may be melted without sintering.

When the ash is to be melted, it is preferable to use about 30% by weight or more of the volcanic product with respect to the ash and about 15% by weight of slaked lime with respect to the ash.

Then, as described above, a mixture comprising ash, a volcanic product, and slaked lime is pressure-formed, and thereafter,
It is melted by a melting furnace. The melting is performed at a furnace temperature of about 1120 ° C. for about 2 to 2.5 hours.

Also in this case, for the same reason as described above, the melting time can be reduced and the melting temperature can be reduced as compared with the conventional case.

Further, as described above, since the ash and the heavy metal are crystallized, the melt is a harmless and safe substance because the heavy metal does not elute into water.

As described above, according to the present invention, in a very short time and at a lower temperature,
Ash can be processed into substances harmless to the human body.

In addition, as the volcanic product, a large amount of waste discharged during the processing of stone can be used, and slaked lime is a substance that can be obtained at low cost. Can be.

[0030]

【Example】

(Example 1) 150 kg of lizard powder and 100 kg of slaked lime were mixed with 1000 kg of ash, and pressed at 1500 kg / cm ² .

Then, the above mixture was heated at a furnace temperature of about 1090.
When sintering was performed using a sintering furnace set at ℃, complete sintering was confirmed after 1.5 hours.

Furthermore, it was confirmed that even if the thus obtained sintered body was immersed in water, no toxic heavy metals such as lead and chromium were eluted into the human body.

Example 2 Marble powder in 1000 kg of ash
A mixture of 350 kg and slaked lime 150 kg was molded under pressure at 1500 kg / cm ² .

Then, the above mixture was heated at a furnace temperature of about 1120.
When sintering was performed using a sintering furnace set at ℃, it was confirmed that the material was completely melted after 2.5 hours.

Moreover, it was confirmed that even when the thus obtained melt was immersed in water, no toxic heavy metals such as lead and chromium were eluted into the human body.

[0036]

The present invention is embodied in the form described above, and has the following effects.

That is, in the present invention, since the ash contains a volcanic product, the characteristics of the volcanic product increase the heat transfer coefficient of the mixture and increase the heat storage efficiency. Alternatively, the time required for melting can be reduced.

Furthermore, since slaked lime is mixed in the ash,
Heavy metals, such as lead and chromium, which are toxic to the human body and contained in the ash, are alkalized to reduce the melting point, thereby reducing the temperature required for sintering or melting.

Since the ash and the heavy metal are crystallized, the heavy metal does not elute into the water and can be made a harmless and safe substance.

Claims (2)

[Claims] 1. A method for treating ash, comprising: forming a mixture of ash mixed with a volcanic product and slaked lime; and sintering the formed product. 2. A method for treating ash, comprising forming a mixture of ash mixed with a volcanic product and slaked lime, and melting the formed product.