JP2002348618A - Method for igniting thermite reaction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new method for igniting a thermite reaction, which easily ignites and keeps the thermite reaction, in a method for recovering metal in metal-containing scrap by supplying it to the thermite reaction. SOLUTION: In the method for recovering metal in the metal-containing scrap by disposing it to the thermite reaction, the ignition method is characterized by adding a chloride of 1-10 pts.wt. to a raw material for the thermite reaction of 100 pts.wt. as an ignition accelerator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for igniting and maintaining a thermite reaction in a method for recovering metals by subjecting a metal-containing waste to a thermite reaction treatment.

[0002]

2. Description of the Related Art In recent years, a technique has been developed in which various metal-containing wastes, which have often been disposed of by landfill treatment, are rendered harmless by a thermite reaction treatment, and a specific metal is recovered and reused. Have been.

[0003] Examples of such metal-containing wastes include iron-based waste such as iron-made dust, steel-made dust, electric furnace dust, and heat-oxidized products of plating sludge, and aluminum-based waste such as aluminum dross. it can.

However, when these metal-containing wastes are subjected to a thermite reaction treatment, the metal oxide is stabilized by ferrite formation, and the contained metal is vaporized to hinder the propagation of the thermite reaction. For example, the ignition for starting the thermite reaction is difficult or the combustion reaction may be stopped even if the ignition occurs.

In view of these problems, measures have been taken such as adding metal aluminum indispensable to the thermite reaction to the metal-containing waste separately, or applying external heating to promote the reaction. However, even when these methods are employed, there is a limit to the improvement of the above-mentioned problems, and a large-scale apparatus is required.In particular, when metal aluminum is separately added, a large amount of cost is required. is there.

Therefore, there is a need for the development of a new method for igniting a thermite reaction that can efficiently ignite and maintain the combustion reaction even for metal-containing wastes that have been conventionally difficult to ignite and maintain. I have.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention relates to a method for recovering metal by subjecting a metal-containing waste to a thermite reaction treatment, wherein the metal-containing waste is conventionally difficult to ignite and maintain. However, an object of the present invention is to provide a new thermite reaction ignition method that can efficiently ignite and maintain a combustion reaction.

[0008]

The present inventor has conducted intensive studies to solve the problems of the prior art, and as a result, has found that the above object can be achieved when a specific ignition method is used. The present invention has been completed.

That is, the present invention relates to the following thermite reaction ignition method.

[0010] 1. A method for recovering a metal by subjecting a metal-containing waste to a thermite reaction treatment, wherein 1 to 10 parts by weight of a chloride is added as an ignition accelerator to 100 parts by weight of the raw material for the thermit reaction treatment.

2. Item 2. The method according to Item 1, wherein the chloride is one or more selected from magnesium chloride, calcium chloride, zinc chloride, iron chloride and aluminum chloride.

3. Item 3. The method according to Item 1 or 2, wherein the thermite reaction raw material is a mixture of aluminum dross and at least one selected from electric furnace dust and heat-dried plating sludge.

4. Thermitite-treated raw material containing chloride according to any one of the above items 1 to 3, is charged as a raw material in the form of a tube or a plate in the vertical direction into a raw material of thermite reaction-treated material containing no chloride, and A method for igniting a thermite reaction, comprising igniting.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the first invention of the present invention, in a method of subjecting a metal-containing waste to a thermite reaction treatment to recover a metal, a thermite reaction treatment raw material (hereinafter abbreviated as "treatment raw material"). 100
1 to 10 parts by weight of a chloride is added as an ignition accelerator to the parts by weight.

[0015] Metal-containing wastes used as processing raw materials include:
There is no particular limitation, and examples thereof include iron-based waste such as iron-made dust, steel-made dust, electric furnace dust, and heat-oxidized products of plating sludge, and aluminum-based waste such as aluminum dross. These metal-containing wastes can be mixed and used as a processing raw material in any combination as long as the thermite reaction proceeds.

The processing raw material used in the present invention is preferably a mixture of aluminum dross and a metal oxide. In particular, a mixture of aluminum dross and at least one selected from electric furnace dust and heat-dried plating sludge can be suitably used.

The aluminum dross preferably has a metal aluminum content of 10% by weight or more, and more preferably has a content of about 15 to 30% by weight.

In the raw material to be treated, the content of metallic aluminum is preferably at least 5% by weight, more preferably about 8 to 15% by weight. If the metal aluminum content in the processing raw material is low, the metal aluminum content can be adjusted by adding aluminum crushed pieces derived from recycled aluminum products, aluminum powder, and the like, if necessary. .

The content of the metal oxide in the raw material for treatment is preferably at least 15% by weight, more preferably about 25 to 45% by weight.

In the present invention, such a processing raw material 1
1 to 10 parts by weight of chloride as an ignition accelerator per 100 parts by weight.
Parts by weight, preferably about 1 to 4 parts by weight. The amount of chloride added can be appropriately adjusted within the above range. Although it varies depending on the content of metal aluminum in the processing raw material, the type of chloride, and the like, it is generally preferable to adjust the addition amount to a large amount when the ignition is difficult due to the low content of metal aluminum in the processing raw material.

The chloride is not particularly limited, and a known chloride can be used. In the present invention, it is particularly preferable to use one or more selected from magnesium chloride, calcium chloride, zinc chloride, iron chloride and aluminum chloride.

In the present invention, the addition of 1 to 10 parts by weight of a chloride as an ignition accelerator to 100 parts by weight of the processing raw material as described above is not known in detail, but conventionally, the ignition and the sustaining of the thermite reaction are conventionally performed. It is possible to efficiently ignite and maintain the combustion reaction even if the metal-containing waste is difficult to be used.

For example, when aluminum dross having a metal aluminum content of about 10% by weight is generally mixed with a metal oxide as a raw material for processing, it may be difficult to ignite and maintain the thermite reaction. However, when the thermite reaction ignition method of the present invention is used, even when such a processing raw material is used, ignition can be performed at a temperature of about 1000 ° C. and the combustion reaction can be maintained.

By the way, the propagation speed of the thermite reaction is
Depending on the type and concentration of chloride, the higher the concentration, the greater. For example, when a mixture of aluminum dross and electric furnace dust (metal aluminum content is about 25% by weight) is used as the processing raw material, the combustion temperature is about 1300 ° C., and the thermite reaction propagation speed is about 1 to 2 cm / min in the horizontal direction. However, if 2 parts by weight of MgCl ₂ is added to the processing raw material, the speed is approximately doubled.

[0025] The present In the second invention The present invention, igniting the process feedstock containing chloride according to claim 1, into a cylindrical shape or a plate shape in a vertical direction to the processing in the raw materials containing no chloride Fill as raw material and ignite ignition material.

The filling method is not particularly limited.
For example, a method is preferable in which a tubular body of aluminum foil is filled with an ignition raw material to form an ignition rod, and this is filled. In addition, a method is also preferable in which a hole reaching the bottom surface of the reaction vessel is made in advance in a vertical direction with a rod or a plate in the processing raw material, and the ignition raw material is filled in this hole.

According to the method of the present invention, when the ignition raw material which is vertically filled in the thermit reaction processing raw material which does not contain chloride is ignited, first, the vertically charged ignition raw material which is the processing raw material is charged. Is burned, and the generated heat causes the surrounding processing materials to burn sequentially in a radial manner, so that the thermite reaction proceeds efficiently.

Conventionally, even a processing raw material whose metal aluminum content is 20% or more and which can be reliably burned,
In the method using a thermite agent as an ignition raw material, it was difficult to instantaneously burn the ignition raw material, deposit molten iron at the lower portion of the reaction vessel, damage the reaction vessel, and ignite the vertical surface of the processing raw material. .

However, in the method of the present invention, the vertically charged ignition raw material burns faster than the contacting processing raw material, ignites the vertical surface of the processing raw material efficiently, and thermit reaction in the horizontal direction from the ignition surface of the processing raw material. Progresses efficiently,
The time required for the thermite reaction of the whole processing raw material is reduced by 1/2
This can be reduced to about 1/4 and the metal recovery efficiency can be improved.

[0030]

According to the method for igniting the thermite reaction of the present invention, it is possible to efficiently ignite and maintain the combustion reaction even if the metal-containing waste has conventionally been difficult to ignite and maintain. Is possible. Therefore, it is possible to reliably stabilize and detoxify the metal-containing waste having a low content of metal aluminum by the thermite reaction, which has conventionally been often used for landfill.

Further, according to the thermite reaction ignition method of the second invention of the present application, the ignition raw material previously filled in the vertical direction of the processing raw material burns, and the surrounding processing raw material is sequentially and radially burned by the generated heat. The thermite reaction proceeds well, and the reaction time, metal recovery efficiency, and the like can be improved.

[0032]

The present invention will be described more specifically with reference to the following Examples and Comparative Examples. However, the present invention is not limited by these descriptions.

Reference Examples 1-2, Examples 1-2, and Comparative Example 1
~ 23 kinds of aluminum dross (A, B and C), electric furnace dust and magnesium chloride powder were prepared and mixed at the mixing ratio shown in Table 1 to prepare samples 1 to 6. In each case, the aluminum dross and the electric furnace dust were prepared by mixing at a mixing ratio (aluminum dross / electric furnace dust = 1) at which a thermite reaction occurs without excess or deficiency.

After weighing 200 g of each of the prepared samples 1 to 6 and filling them in a graphite crucible having a capacity of 300 cc (outside diameter 80φ, height 100 mm), a thermite agent was filled in an aluminum foil cylinder having an inside diameter of 5 mm and ignited. Sample 1
~ 6 in the vertical direction.

After the ignition rod was ignited, samples 1 to 6 were examined for the presence or absence of a combustion reaction. In the case of burning, the combustion temperature was measured. The combustion temperature was measured by inserting a thermocouple (type R) into a magnetic protective tube having an outer diameter of 4 mm, piercing the center of the crucible, and monitoring the combustion temperature with a data logger. Table 1 shows the experimental results.

Table 2 shows the metal aluminum content of the aluminum dross used. Table 3 shows the composition of the electric furnace dust used.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

As is clear from Table 1, when aluminum dross A having a metal aluminum content of 25.6% by weight was used (Reference Examples 1 and 2), the combustion reaction was performed regardless of the addition of magnesium chloride. Happened.

On the other hand, the metal aluminum content was 17.7.
In the case of using aluminum dross B of 1% by weight and aluminum dross C of 10.6% by weight, the combustion reaction occurred only when magnesium chloride was added.

Examples 3 to 7 and Comparative Examples 3 to 7 Samples 7 to 16 were prepared by mixing aluminum dross B, electric furnace dust and magnesium chloride powder in the mixing ratio shown in Table 4. In each case, the aluminum dross and the electric furnace dust were prepared by mixing at a mixing ratio (aluminum dross / electric furnace dust = 1) at which a thermite reaction occurs without excess or deficiency.

The prepared samples were examined for the presence or absence of a combustion reaction in the same manner as in Example 1. In the case of burning, the combustion temperature was measured. The experimental results are shown in Table 4.

[0044]

[Table 4]

As is clear from Table 4, magnesium chloride was mixed with aluminum dross and electric furnace dust.
When 1 to 10 parts by weight was added to 0 parts by weight, a combustion reaction occurred in all cases. When the dross / dust ratio was increased, the combustion temperature decreased, but combustion occurred.

On the other hand, when magnesium chloride was not added (samples 12 to 15) and when the addition amount was less than 1 part by weight (sample 16), no combustion reaction occurred.

Examples 8 to 10 and Comparative Example 8 Aluminum dross A and electric furnace dust were mixed at a mixing ratio (aluminum dross / electric furnace dust = 1) at which a thermite reaction was generated without excess or shortage. Were mixed to prepare Samples 17 to 20. The amount of magnesium chloride added in Examples 8 to 10 was 1 to 100 parts by weight of the processing raw material.
The range is from 10 to 10 parts by weight.

Each of the prepared samples 17 to 20 was filled in a rectangular box (length: 20 cm, width: 15 cm, depth: 10 cm) made of a heat insulating board, and a thermite agent was inserted into the end face so as to have a width of 1 cm. The thermocouples were placed at intervals of 5 cm in the sample in the longitudinal direction.

Sample 1 was obtained by igniting the thermite agent.
Each of the end faces 7 to 20 was ignited, a thermite reaction was allowed to proceed, and a reaction propagation speed was calculated from a temperature change of the thermocouple. The experimental results are shown in Table 5.

[0050]

[Table 5]

As is apparent from Table 5, the processing raw material 10
When magnesium chloride was added in the range of 1 to 10 parts by weight with respect to 0 parts by weight, the reaction propagation speed of the thermite reaction increased in proportion to the amount added.

On the other hand, it was found that when magnesium chloride was not added (sample 20), the reaction propagation speed was slower than when magnesium chloride was added (samples 18 to 20).

Examples 11 to 14 Aluminum dross C and electric furnace dust were mixed at a mixing ratio (aluminum dross / electric furnace dust = 1) at which a thermite reaction occurred without excess or deficiency to obtain a processing raw material. Samples 21 to 24 were prepared by adding 4 g of each of the above chlorides. The amount of chloride added is in the range of 1 to 10 parts by weight based on 100 parts by weight of the processing raw material. In addition, all chlorides used anhydrous, and were mixed with the raw material processing efficiently.

The prepared sample was examined for the presence or absence of a combustion reaction in the same manner as in Example 1. The experimental results are shown in Table 6.

[0055]

[Table 6]

As is clear from Table 6, chloride
And MgCl_Two, CaCl_Two, ZnCl _TwoAnd AlCl_Threeof
In each case, ignition was confirmed.

Example 15 A processing material obtained by mixing aluminum dross A and electric furnace dust in a mixing ratio (aluminum dross / electric furnace dust = 1) that causes a thermite reaction without excess or shortage was mixed with a rectangular box ( (Length 20 cm, width 15 cm and depth 10 cm). Next, an ignition raw material obtained by adding 2 parts by weight of magnesium chloride to 100 parts by weight of the same processing raw material was brought into contact with the end face of the processing raw material already filled to a width of about 1 mm.
cm in the vertical direction.

When the ignition material was ignited, the ignition material immediately burned in the vertical direction. Moreover, the combustion reaction of the surrounding processing raw materials proceeded radially by the generated heat. in this case,
Unlike the case where a conventional thermite agent was used as the ignition raw material, the molten iron was not deposited and the reaction vessel was not destroyed.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C22B 7/02 C22B 7/02 A (72) Inventor Masayuki Yokoi 2-7-1, Ayumino, Izumi-shi, Osaka Prefecture Osaka Prefecture Within the National Institute of Advanced Industrial Science and Technology (72) Inventor Taizo Imoto 2-7-1, Ayumino, Izumi-shi, Osaka Prefecture Inside the Osaka Prefectural Institute of Advanced Industrial Science and Technology (72) Shuhei Miyauchi 2-7-1, Ayumino, Izumi-shi, Osaka (72) Inventor Seiji Kaji 4-26-1 Hoshida-Kita, Katano-shi, Osaka Rinko Steel Co., Ltd. (72) Inventor Nankai Hamada 1603-1 Naka-hiroki Higashi-oki, Ako-shi, Hyogo Taiyo Mining Co., Ltd. F term (reference) 4K001 AA02 AA10 BA12 BA13 BA14 DA01 DA14 JA10 KA08

Claims (4)

[Claims] 1. A method for recovering a metal by subjecting a metal-containing waste to a thermite reaction treatment, wherein chloride is used as an ignition accelerator for 100 parts by weight of the thermite reaction raw material.
A method characterized by adding 10 to 10 parts by weight. 2. The method according to claim 1, wherein the chloride is one or more selected from magnesium chloride, calcium chloride, zinc chloride, iron chloride and aluminum chloride. 3. The thermit reaction raw material is a mixture of aluminum dross and at least one selected from electric furnace dust and heat-dried plating sludge.
Or the method of 2. 4. The chloride-containing thermite reaction-treated raw material according to any one of claims 1 to 3 is charged vertically as a tube-shaped or plate-shaped ignition raw material into the thermite-reaction processed raw material. And igniting the ignition raw material.