JP2017137224A - Method for treating incineration main ash - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilize incineration main ash as cement raw material while efficiently controlling a chromium content in a cement clinker.SOLUTION: Provided is a method for treating incineration main ash A where incineration main ash A is separated into a magnetic material M and a non-magnetic material N by magnetic force selection, the non-magnetic material N obtained by the separation is made into cement raw material in a cement firing apparatus, and the magnetic material M obtained by the separation is used as cement raw material in the cement firing apparatus in accordance with a chromium concentration in a clinker exhausted from the cement firing apparatus. The magnetic force selection can be performed by a drum type magnetic force separator 1, and the magnetic flux density of a drum 3 in the drum type magnetic force separator 1 can be controlled to 3,000 gausses or more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for effectively using incineration main ash generated in an incinerator such as municipal waste as a cement raw material.

  Incinerator main ash is discharged from the hearth of incinerators such as municipal waste, and the discharged incinerator main ash is landfilled as a general waste in a managed disposal site. However, in recent years, since the remaining capacity of the final landfill site has decreased, various alternative treatment methods for incineration main ash have been proposed.

  For example, in Patent Document 1, incineration main ash is supplied to a vibrating sieve equipped with a magnetic separator, iron scraps and foreign matters having a large particle diameter in the incineration main ash are removed, and iron scraps and foreign matters are removed. It describes that incinerated main ash is used as a cement raw material.

JP 2004-41895 A

  However, when the incinerated main ash is used as a cement raw material, the chromium in the incinerated main ash is included in the cement clinker as hexavalent chromium. The elution amount of hexavalent chromium from cement mortar and concrete hardened body using such cement clinker is extremely small, but depending on the properties and types of cement-based solidification material such as ground improvement material using it, solidification treatment The elution amount of hexavalent chromium from the soil may increase.

  Therefore, it is necessary to adjust the chromium content of the cement clinker, but the chromium content of the incinerated main ash is not constant, so in order to keep the hexavalent chromium content of the clinker below the specified value, In some cases, the amount used must be reduced, and the use of incinerated main ash as a raw material for cement has been virtually limited.

  Therefore, the present invention has been made in view of the above problems in the prior art, and aims to effectively use the incinerated main ash as a cement raw material while efficiently adjusting the chromium content of the cement clinker. To do.

  In order to achieve the above object, the present invention is a method for treating incinerated main ash, wherein the incinerated main ash is separated into a magnetic material and a nonmagnetic material by magnetic separation, and the nonmagnetic material obtained by the separation is cemented. It is characterized in that it is used as a cement raw material in a firing device, and the magnetic material obtained by the separation is used as a cement raw material in the cement firing device according to the chromium concentration in the clinker discharged from the cement firing device.

  According to the present invention, the chrome content of the clinker can be lowered by using a non-magnetic material having a low chromium content as a cement raw material. Further, by using a magnetic material having a higher chromium content than the non-magnetic material as a cement raw material in accordance with the chromium content in the clinker, the clinker chromium content can be adjusted to be a predetermined value or less. . By these, incineration main ash can be used effectively as a cement raw material, adjusting the chromium content rate of a cement clinker efficiently.

  In the incineration main ash treatment method, the magnetic separation can be performed by a drum magnetic separator, and the magnetic flux density of the drum of the drum magnetic separator can be 3000 gauss or more. Thereby, chromium in incineration main ash can be efficiently concentrated to a magnetic body.

  As described above, according to the present invention, incinerated main ash can be effectively used as a cement raw material while efficiently adjusting the chromium content of the cement clinker.

It is sectional drawing of the drum type magnetic separator which is used with the processing method of incineration main ash concerning the present invention.

  Next, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a sectional view of a drum type magnetic separator used in the method for treating incinerated main ash according to the present invention. The drum type magnetic separator 1 includes a supply port 2 for supplying the incinerated main ash A, and a counterclockwise. Drum 3 made of stainless steel, fiber reinforced plastic, etc., rotating around, magnet 4 fixed inside drum 3 so as not to rotate together with drum 3, and nonmagnetic material N in incineration main ash A are discharged And a second discharge port 6 for discharging the magnetic body M in the incineration main ash A.

  Next, the operation of the drum type magnetic separator 1 having the above configuration will be described with reference to FIG.

  The incinerated main ash A is supplied to the supply port 2 of the drum type magnetic separator 1 at a rate of 1000 kg / h to 2000 kg / h. The incinerated main ash A dropped from the supply port 2 forms a layer having a thickness of 2.5 cm to 3.5 cm on the surface of the drum 3.

  Here, the magnetic body M of the incinerated main ash A on the surface of the drum 3 is attracted to the surface of the drum 3 by the magnetic force of the magnet 4 in an environment where the magnetic flux density is 3000 gauss or more. On the other hand, the nonmagnetic material N of the incinerated main ash A on the surface of the drum 3 is not attracted to the surface of the drum 3 because no magnetic force is generated between the nonmagnetic material N and the magnet 4. Thereby, the nonmagnetic material N falls from the drum 3 to the first discharge port 5 and is discharged from the first discharge port 5. Further, the magnetic body M attracted to the surface of the drum 3 moves to a portion of the surface of the drum 3 where the magnet 4 is not in contact with the rotation of the drum 3, and the magnetic force applied to the magnetic body M is weakened. M falls from the surface of the drum 3 to the second discharge port 6 and is discharged from the second discharge port 6.

  In Tables 1 and 2, two types of first incinerator main ash and second incinerator main ash having a chromium concentration of 400 to 450 mg / kg are supplied to the drum type magnetic separator at 1800 kg / h and 1200 kg / h, respectively. The sorting result when the magnetic flux density of the drum in the drum type magnetic sorting machine is processed as 3000 gauss is shown. Here, T-Cr described in Tables 1 and 2 means all chromium regardless of the type. According to this, it is possible to remove 1/3 or more of chromium contained in the incineration main ash by simply removing the magnetic material occupying about 13% to 22% of the incineration main ash from the incineration main ash. It can be seen that chromium can be efficiently removed.

  The non-magnetic material N discharged from the first discharge port 5 of the drum type magnetic separator 1 is used as a cement raw material in a cement baking apparatus (not shown). Further, when the chromium concentration of the clinker discharged from the cement baking apparatus is relatively lower than a predetermined reference value, the magnetic material M discharged from the second discharge port 6 is appropriately used as a cement raw material in the cement baking apparatus.

  As described above, according to the above embodiment, by using the nonmagnetic material N having a low chromium content as a cement raw material, the chromium content of the clinker is kept lower than that of the nonmagnetic material while maintaining the chrome content of the clinker low. By using a high magnetic substance as a cement raw material according to the chromium content in the clinker, the chromium content of the clinker can be adjusted to be a predetermined value or less. Thus, the incinerated main ash A can be effectively used as a cement raw material while efficiently adjusting the chromium content of the cement clinker.

  In the above embodiment, the case where the drum-type magnetic separator 1 is used to separate the incinerated main ash A into a magnetic body and a non-magnetic body by magnetic separation, but other types of magnetic separators are used. You can also. Even when a drum type magnetic separator is used, a structure other than the drum type magnetic separator 1 can be used. If the magnetic flux density of the drum is 3000 gauss or more, a preferable separation result is obtained as described above. Although it can be obtained, the magnetic flux density can be less than 3000 gauss depending on the type of magnetic separator used.

DESCRIPTION OF SYMBOLS 1 Drum type magnetic separator 2 Supply port 3 Drum 4 Magnet 5 1st discharge port 6 2nd discharge port A Incineration main ash M Magnetic body N Nonmagnetic body

Claims (3)

Incinerator main ash is separated into magnetic and non-magnetic materials by magnetic separation,
Using the non-magnetic material obtained by the separation as a cement raw material in a cement firing device,
A method for treating incinerated main ash, wherein the magnetic material obtained by the separation is used as a cement raw material in the cement firing device in accordance with the chromium concentration in the clinker discharged from the cement firing device.   The method for treating incinerated main ash according to claim 1, wherein the magnetic sorting is performed by a drum type magnetic sorting machine.   The method for treating incinerated main ash according to claim 2, wherein the magnetic flux density of the drum of the drum type magnetic separator is 3000 gauss or more.

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