JP3284861B2 - Waste treatment method for cement raw materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating waste materials for cement raw materials, and more particularly to various boiler ash, incinerated ash,
The present invention relates to a method for treating waste for cement raw materials that efficiently removes chlorine, fluorine, sulfur, carbon, and the like contained in wastes such as sludge and aims to effectively use the raw materials as cement raw materials.

[0002]

2. Description of the Related Art In recent years, various types of waste such as various boiler ash, incinerated ash, and sludge as cement raw materials have tended to be increased in cement plants. This is due to the fact that it is effective to use these wastes as a raw material for cement as one of the measures to eliminate environmental pollution caused by dumping these wastes into the ocean. In other words, in the production of cement, since the raw material is heated at a high temperature of 1500 ° C., it is possible to decompose harmful organic substances in the waste, and also SO _x
No harmful substances are released.

By the way, wastes such as various boiler ash, incinerated ash and sludge generally contain chlorine, furthermore, fluorine, sulfur and various organic substances. The amount and the amount of fluorine, sulfur and carbon increase.

[0004] On the other hand, the devices currently operating in many cement plants are of the SP and NSP type comprising a suspension preheater and a kiln. Although this device is excellent in thermal efficiency, when the amount of chlorine, fluorine, sulfur, and carbon in the system increases, not only corrosion of the device, but also clogging of the pre-heater occurs, and operation becomes impossible.

Therefore, in order to reduce environmental pollution by using more waste as a cement raw material in a cement plant, chlorine, fluorine, sulfur and carbon in the waste used for the cement raw material must be removed as a pretreatment. Must be performed.

At present, water is washed as a dechlorination method in a cement plant. This is to remove water-soluble chlorine by placing waste in a certain site and sprinkling water from above, as in the salt removal treatment of concrete aggregate.

[0007]

Most of chlorine in various kinds of wastes expected to be effectively used as a cement raw material is water-soluble, and exists as alkali salts on the surfaces of the waste particles. Therefore, in the case of coarse-grained waste having relatively large particles, the specific surface area is small and the amount of adhered chlorine is small, so that chlorine can be removed by simply washing the waste with water.

However, in the case of fine particle waste such as various boiler ash and sludge, the specific surface area is large, the amount of chlorine adhering is large, and the fine particles of waste are suspended in water. It is impossible to remove chlorine sufficiently.

For this reason, conventionally, the dechlorination treatment of waste by washing with water has been applied only to coarse waste having a particle size of several mm or more, and not to fine particle waste. conventionally,
It is considered difficult to economically dechlorinate large amounts of particulate waste, and because it is not possible to dechlorinate,
Many wastes cannot be used as cement raw materials.

[0010] Incidentally, water-insoluble or hardly water-soluble substances containing chlorine, fluorine, sulfur and carbon cannot be removed by washing with water, and at present, no effective method for removing these substances has been proposed.

The present invention solves the above-mentioned conventional problems and efficiently removes chlorine, fluorine, sulfur, carbon, and the like contained in wastes such as various boiler ash, incinerated ash, and sludge.
An object of the present invention is to provide a method for treating waste for cement raw materials, which is intended to be effectively used as a cement raw material.

[0012]

Processing method cement raw material waste claim 1 Means for Solving the Problems], the cement raw material waste after mixing with water, in the processing method of classification to Rousset instrument feedstock waste
The method is characterized in that the coarse particles obtained by the classification are used as the cement raw material, and the slurry containing the fine particles is dewatered to be used as the cement raw material.

[0013] processing method according to claim 2 of the cement raw material waste, in the method of claim 1, and performs classification by a wet cyclone.

The waste is mixed with water to form a slurry, and water-soluble chlorine is eluted. After classification, coarse particles from which the water-soluble chlorine has been sufficiently removed are simultaneously declassified and dehydrated and concentrated to reduce the water content. Therefore, this coarse fraction can be used immediately as a cement raw material. On the other hand, by dewatering the slurry containing the fine particles with a dehydrator, the dechlorinated fine particles can be recovered.

The method for treating waste for cement raw materials according to claim 3 is a method for treating waste for cement raw materials after the waste for cement raw materials is washed with water and then brought into contact with steam at 400 ° C. or higher.
After mixing cement waste with water
The obtained coarse particles are contacted with steam at 400 ° C or higher.
And dehydrate the fine particles, and then contact with steam at 400 ° C or more.
And characterized in that.

By contacting with steam at 400 ° C. or higher, part or all of the cement raw material waste is thermally decomposed, and the chlorine compound, fluorine compound, sulfur compound, and carbon compound in the waste are as follows: It is gasified according to the formula. Hydrofluoric acid generated from a fluorine compound is converted into hydrogen fluorosilicate by a reaction of the following formula when a silicate compound such as silica stone is present in the system. Here, since all generated gas is acidic, it can be absorbed and fixed by an alkaline solution .

[0017]

Embedded image

In the present invention, the water-soluble chlorine in the cement raw material waste is previously eluted and removed with water, and then the above-mentioned steam treatment is carried out, so that more efficient dechlorination and defluorination can be achieved.
Desulfurization and decarbonization can be performed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1 is a system diagram showing a method according to the first and second embodiments.

In the method shown in FIG. 1, a dechlorination apparatus including a slurry hopper 1, a slurry pump 2, a wet cyclone 3 and a dehydrator 4 is used. And mix to form a slurry to elute the water-soluble chlorine. In this case, it is necessary to efficiently elute the slurry by stirring it. In this embodiment, the slurry hopper 1 and the slurry pump 2 are connected and the slurry is circulated to rotate the impeller of the slurry pump 2. The chlorine is efficiently eluted by using the power for stirring. Next, the slurry after the stirring is classified by the wet cyclone 3. By this classification, the slurry containing the coarse particles is concentrated at the same time as the classification, so that in general, a dechlorinated coarse particle having a water content of 20% or less is obtained. It can be used immediately as a cement raw material. On the other hand, the slurry containing fine particles is diluted by classification, so that the elution of chlorine is promoted. This can be dewatered by the dehydrator 4 and used as a cement raw material. If the slurry containing fine particles classified by the wet cyclone 3 is a low-concentration slurry, a part of the slurry may be returned to the slurry hopper.

The amount of water mixed with the cement raw material waste depends on the chlorine content and the particle size of the cement raw material waste.
It is about 200 to 2000 parts by weight with respect to 0 parts by weight.

According to such a method, chlorine can be efficiently eluted by connecting the slurry hopper 1 and the slurry pump 2 and circulating the slurry between the two, thereby enabling a large amount of fine particles to be eluted. Even in the case of treating waste, the elution treatment of chlorine can be easily performed without the need for a large-scale stirring device. In addition, large-scale dewatering equipment is required to dewater a large amount of slurry. However, by using the wet cyclone 3 and the dehydrator 4 together, efficient dehydration in a narrow site is possible.

Such a dechlorination treatment according to the present invention is particularly effective for treating various kinds of fine particle waste such as boiler ash and sludge, which are difficult to dechlorinate by a conventional method of washing with water.
In a normal case, waste having a chlorine content of 300 ppm or more can be reduced to a chlorine content of 100 ppm or less.

FIG. 2 is a side view showing an example of an apparatus used in the method according to the third embodiment.

The method according to claim 3 is a method of mixing the waste to be treated with water and then classifying the waste and the fine particles.
The dewatered material is brought into contact with high-temperature steam of 400 ° C. or more, and as an apparatus therefor, means for heating the powder and granules, and steam addition means for including steam in the atmosphere of the heating means Various types having the following can be used. FIG. 2 shows that a raw material (waste to be treated) and high-temperature steam are introduced from one end of the rotating drum 5 and the rotating drum 5 is rotated.
1 shows an apparatus in which a raw material and high-temperature steam are brought into contact with each other to take out treated waste from a product outlet 6. Reference numeral 7 denotes a driving roller, and reference numeral 8 denotes a support roller. Of course, the method of the present invention can be implemented using various devices other than FIG.

Thus, chlorine, fluorine, sulfur, and carbon in the waste for cement raw material are gasified by the above-mentioned reaction (1), and are efficiently removed from the waste for cement raw material.

The temperature of the steam for treating the cement raw material waste is 400 ° C. or higher, but in order to shorten the processing time, the higher the temperature, the better, and it is preferable to use the steam of 800 ° C. or higher. The amount of steam and the treatment time are appropriately determined according to the chlorine, fluorine, sulfur, and carbon contents in the waste for cement raw material, the amount of waste for cement raw material to be treated, the steam temperature, and the like.

In the present invention, the steam treatment after removal of water-soluble chlorine mixtures, classifying the row processing by the steam after dechlorination by Utame, in the waste with cement raw material waste and water above This makes it possible to perform dechlorination, defluorination, sulfur removal, and carbon removal more efficiently.

[0030]

The present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Example 1 According to the method shown in FIG. 1, various kinds of cement raw material wastes shown in Table 1 were dechlorinated.

First, the amount of water shown in Table 1 was mixed with the waste for cement raw materials (the chlorine content is as shown in Table 1).
The slurry hopper 1 and the slurry pump 2 were circulated, and a stirring treatment was performed for the time shown in Table 1.

This was classified by a wet cyclone to obtain coarse particles having an average particle diameter, a water content and a chlorine content shown in Table 1. On the other hand, the slurry containing fine particles was dehydrated by a dehydrator to obtain fine particles having an average particle diameter, a water content and a chlorine content shown in Table 1.

[0034]

[Table 1]

From Table 1, it is clear that according to the present invention, chlorine in wastes for cement raw materials can be efficiently removed.

Comparative Example 1 After mixing the fluidized-bed boiler ash and water in the same manner as in Example 1, the mixture was dewatered by a dehydrator without classification by a wet cyclone.
% And a chlorine content of 180 ppm, the chlorine removal efficiency was poor.

Comparative Example 2 In accordance with the method shown in FIG. 3, the waste materials for cement raw materials shown in Table 2 were subjected to dechlorination, defluorination, desulfurization and decarbonization.

In the method shown in FIG. 3, waste 10 for cement raw material is put in a magnetic tube 12 of a muffle furnace 11,
Into this magnetic tube 12, hot water 13 of about 70 ° C. is transported by oxygen supplied from an oxygen cylinder 14 through a flow meter 15,
Steam treatment is performed by heating. Gas generated by thermal decomposition of cement raw material waste is
Absorb and fix with an alkaline solution such as

The steam temperature, the steam flow rate, the treatment time, and the chlorine content, fluorine content, sulfur content, and ignition loss of the cement raw material waste after treatment are as shown in Table 2. According to the present invention, the efficiency was It is clear that typical dechlorination, defluorination, desulfurization and decarbonization can be performed.

Comparative example3  Except that the steam temperature was 300 ° CComparisonN of Example 2
o. After performing the same procedure as in 4, for the cement material after treatment
The amounts of chlorine, fluorine, sulfur, and ignition loss of waste are shown in the table.
As shown in 2, dechlorination, defluorination, desulfurization, decarburization
I couldn't do enough.

[0041]

[Table 2]

Example 2 As wastes for cement raw materials, The fluidized-bed boiler ash having the chlorine amount, the fluorine amount, the sulfur amount, and the loss on ignition shown in No. 4 was subjected to No. After the dechlorination treatment was performed in the same manner as in Example 1, the obtained coarse particles and fine particles were separated by the N method of Comparative Example 2.
o. Steam treatment was performed in the same manner as in Example 4.

As a result, the amount of chlorine, the amount of fluorine, the amount of sulfur, and the loss on ignition of the coarse and fine particles after the treatment are as shown in Table 3, and efficient dechlorination, defluorination, de-sulfurization, decarbonization Was able to do.

[0044]

[Table 3]

[0045]

As described in detail above, according to the method for treating waste for cement raw materials of the present invention, chlorine in waste for cement raw materials, and furthermore, chlorine, fluorine, sulfur and carbon are efficiently removed. Thus, it can be effectively used as a cement raw material in a large amount.

Therefore, according to the present invention, the waste disposed of by landfilling, dumping at sea, etc. is rendered harmless as a cement raw material and is effectively used, thereby solving the environmental pollution problem and reducing the raw material cost. Therefore, the industrial utility of the present invention is extremely large.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of a method for dechlorinating waste for cement raw materials according to the present invention.

FIG. 2 shows the dechlorination of cement raw material waste according to the present invention;
It is an apparatus block diagram which shows a defluorination, a sulfur removal, and a carbon removal method.

FIG. 3 is an apparatus configuration diagram showing a method for dechlorination, defluorination, sulfur removal, and decarbonization of cement raw material waste in Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Slurry hopper 2 Slurry pump 3 Wet cyclone 4 Dehydrator 10 Waste 11 Muffle furnace 12 Magnetic tube 13 Hot water 14 Oxygen cylinder 15 Flow meter 16 Sodium carbonate aqueous solution

Continuing from the front page (72) Inventor Tomohiko Sakamoto 1-Donan-cho, Yawatanishi-ku, Kitakyushu-city, Fukuoka Prefecture Inside the Cement Development Center of Mitsubishi Materials Corporation (72) Inventor Ichiro Ebato 1-Donami-cho, Yawata-Nishi-ku, Fukuoka Prefecture 1 Mitsubishi Materials Inside the Cement Development Center Co., Ltd. (72) Norio Sankoda, 1-Donan-cho, Yawata-nishi-ku, Kitakyushu-city, Fukuoka Prefecture 1 Inside the Cement Development Center, Mitsubishi Materials Corporation (56) References JP-A-7-51652 (JP, A) Hei 2-504626 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C04B ⁷ /00-7/60 C04B 18/00-18/30

Claims (3)

(57) [Claims] 1. A cement raw material waste is mixed with water.
After, classifyRuseOf raw material wasteSo
hand, When the coarse particles obtained by classification are used as cement raw materials,
Then, after dewatering the slurry containing fine particles,
Of waste for cement raw materials characterized by the following
Law. 2. The method according to claim 1, wherein the classification is performed by a wet cyclone. 3. After the cement raw material waste is washed with water,
Contact with steam over 00 ° CRuseRaw material waste
Processing methodAnd After mixing the waste for cement raw materials with water and classifying it,
The coarse fraction is brought into contact with steam at 400 ° C or higher,
After dehydration, contact with steam of 400 ° C or more
The method of treating waste for cement raw materials.