JPH06339674A - Method for treating aluminum dross using aluminum dross with controlled water content - Google Patents

Abstract

(57) [Summary] [Purpose] It is possible to convert almidross into stable substances at low cost without generating odorous gas, and to obtain a fired product with a large particle size and good color tone. Provided is a method of treating aluminum dross that can be obtained. [Composition] Aluminum dross comprising adding water to almidros and burning aluminum dross adjusted to have a water content of 5 to 30% by weight relative to aluminum dross at a temperature of 700 to 1500 ° C. Processing method.

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 aluminum dross by combustion, and more particularly to a method for treating aluminum dross by combustion using aluminum dross having a controlled water content.

[0002]

2. Description of the Related Art Aluminum dross is a smelting slag generated during the smelting of aluminum, and is a residual ash having an aluminum content of about 10 to 30% by weight, depending on the type of aluminum to be smelted. Almidros are partially used as heat insulating agents and civil engineering materials, but at present, most of them are discarded as industrial waste because there is no effective treatment method for resource recovery. In particular, recently, recycling of resources has become active, and with respect to aluminum, smelting of aluminum scraps such as automobile parts and aluminum cans to recover aluminum has been actively carried out. However, the aluminum dross produced by refining with such aluminum scrap has a low aluminum content and cannot be dealt with except for disposal. There is.

However, the aluminum dross thus disposed of is usually piled up in the open field and exposed to rain.
Aluminum aluminum and aluminum nitride contained in alumidoros, or other various impurities react with rainwater to generate offensive odor components such as ammonia gas and hydrocarbon gas,
It also causes secondary pollution. Environmental pollution, which causes pollution, has become a problem internationally, and the regulation of industrial waste is being tightened more and more as part of measures against environmental pollution.
Therefore, there is an increasing need for development aimed at making aluminum dross pollution-free more than ever before.

[0004]

[Problems to be Solved by the Invention] However, in the past,
Proposed as a treatment method for aluminum dross that makes alumidos pollution-free, a hydrolysis method, a heat treatment method of adding and burning a fossil shellfish, a method such as an acid-alkali decomposition treatment method,
Both are mainly aimed to recover useful materials that can be used as various chemicals such as aluminum hydroxide and sodium aluminate and building materials, and to treat a large amount of aluminum dross, There are many problems such as cost.

The present invention has been made in view of the above-mentioned actual state of the art. That is, an object of the present invention is to provide a low-cost method for treating aluminum dross. Another object of the present invention is to provide a method for treating aluminum dross, which can convert aluminum dross into a stable substance that does not generate offensive odor gas. Still another object of the present invention is to provide a method for treating aluminum dross which has a large particle size and gives a product having a good color tone.

[0006]

Means for Solving the Problems As a result of various investigations, the present inventor has added water to aluminum dross in advance to make the aluminum dross pollution-free by burning the aluminum dross and set its water content to a specific range. It was found that the above object can be achieved by adjusting the above-mentioned conditions, and the present invention has been completed. That is, the method for treating aluminum dross of the present invention comprises adding water to the aluminum dross and adjusting the aluminum dross having a water content of 5 to 30% by weight to the aluminum dross at 700 to 1500 ° C. It is characterized by burning at a temperature.

The present invention will be described in detail below. The aluminum dross treated in the present invention may be any refining slag generated when refining aluminum or an aluminum alloy. For example, there may be mentioned new ingot type aluminum dross produced when refining a new aluminum ingot, alloy type aluminum dross produced when refining aluminum scrap such as automobile parts and aluminum cans. In addition to metallic aluminum, these aluminum dross contain various impurities such as aluminum nitride that react with rainwater to generate a gas that causes an offensive odor.

In the present invention, water is added to the aluminum dross prior to firing to adjust the water content of the aluminum dross. The water content of almidros is adjusted depending on the difference in the components of aluminum dross.
It is set in the range of% by weight. If the water content is less than 5% by weight, the aluminum dross stabilization process will be incomplete,
On the other hand, if it is 30% by weight or more, the input energy for removing water increases, which is not preferable. When the water content of almidros is in the above range, a calcined product having a good color tone and a large particle size that is easy to handle after baking is obtained. In addition, since the addition of water generates a gas during firing and the combustion of the gas produces combustion heat, the energy required for the firing treatment of the present invention can be reduced.

The firing temperature in the present invention is 700.
It is set to ˜1500 ° C., but it is particularly preferable to set it to 1000 ° C. or higher. When the temperature is 1000 ° C. or higher, a white, high-alumina burned material having an alumina content of 90% or higher is obtained, and a product having a composition stabilized against the environment without chemically changing can be obtained. .

[0010]

In the present invention, the calcining process stabilizes the aluminum dross because the exothermic reaction shown by the following reaction formula occurs and the aluminum dross is finally oxidized to stable alumina and NO _x. This is due to the fact.

[Chemical 1] In addition, the addition of water improves the combustion efficiency,
Energy can be reduced for the following reasons. That is, in aluminum dross, contained aluminum or aluminum nitride is hydrolyzed by water to generate flammable hydrogen gas, ammonia gas, and reaction heat as shown in the following reaction formula. Further, combustion heat is generated by the combustion of the hydrogen gas or the ammonia gas, and the combustion efficiency is improved. Further, the thermite reaction is added by the reaction between the iron content contained in the aluminum dross and the aluminum content, and the combustion efficiency is further improved.

[Chemical 2]

[0011]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. In Examples and Comparative Examples, aluminum dross having the following composition was used.

[Table 1]

Example 1 30 parts of water was added to 70 parts of Almidros A to adjust the water content of aluminum dross to 30% by weight, and the aluminum dross was inserted into a firing furnace at an internal temperature of about 1000 ° C. It was baked for 1 hour. As a result, a fired product having a composition of alumina of 92% by weight, a white color tone and a large particle size was obtained. When a stabilization test was performed on this baked product as follows, no unpleasant odor was generated. Stabilization test A part of the fired product was taken and pulverized into a sample having a typical particle size of about 2 to 10 μm to obtain a sample. 1 liter of water was placed in an iron container having a volume of 2 liters, 200 g of a sample was placed in the container, heated until boiling, and continued to boil for about 2 hours. During this time, the vapor generated from the container had no unpleasant odor. In addition, as a result of component analysis by atomic absorption, the nitrogen component, which is the source of the offensive odor, was 0.09% by weight or less. Energy-saving test When Almidros is burned at a furnace temperature of 1000 ° C, the time during which AlN, which is a source of offensive odor, decreases by 50% by weight, when 30% by weight of water is added to aluminum dross (X) and when not added Time was measured for (Y). The results are shown in Table 1 below.
Shown in. Based on the result, the energy saving amount was calculated by the following formula.

[Table 2]

Example 2 Example 1 except that aluminum dross B was used in place of alumidoros.
When calcined in the same manner as above, the composition of alumina was 8
A fired product having a large particle diameter and a white color tone of 1% by weight was obtained.
When the obtained fired product was subjected to a stability test in the same manner as in Example 1, no unpleasant odor was generated in the fired product. Further, when the energy saving test was conducted in the same manner as in Example 1, it was possible to reduce the amount by about 18%.

COMPARATIVE EXAMPLE 1 When calcination was carried out in the same manner as in Example 1 except that water was not added to alumidoros, the composition of alumina was 6
A powdery fired product having a gray scale of 2.8% by weight and a gray color was obtained. When the obtained fired product was subjected to a stability test in the same manner as in Example 1, generation of an unpleasant odor was observed in the fired product.

COMPARATIVE EXAMPLE 2 A calcination was conducted in the same manner as in Example 1 except that aluminum dross B was used as the almidros and no water was added. As a result, the composition of alumina was 70.5% by weight and the color tone was A grayish brown powdery product was obtained. When the obtained fired product was subjected to a stability test in the same manner as in Example 1, generation of an unpleasant odor was observed in the fired product.

[0016]

EFFECTS OF THE INVENTION Since the present invention has the above-mentioned structure, it is possible to change aluminum dross into a stable substance at low cost without generating a malodorous gas. Further, it is possible to obtain a fired product having a large particle size and a good color tone.

Claims (3)

[Claims] 1. Aluminum dross, to which water is added, is adjusted to have a water content of 5 to 30% by weight relative to aluminum dross, and the aluminum dross is burned at a temperature of 700 to 1500 ° C. And aluminum dross treatment method. 2. The method for treating aluminum dross according to claim 1, wherein the almidros contains aluminum nitride. 3. The method for treating aluminum dross according to claim 1, wherein the treated product has a coarse particle size.