JPH06263496A - Treatment of aluminum dross - Google Patents

Abstract

PURPOSE:To efficiently remove a chlorine component from an aluminum dross and to reform the aluminum dross into the component suitable to an aggregate for a cement, etc. CONSTITUTION:The chlorine component is removed from the aluminum dross by heating the aluminum dross produced in an aluminum refining process, etc., at 1300-1600 deg.C.

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, and more particularly to a method for treating aluminum dross in a reusable state as an aggregate such as cement.

[0002]

2. Description of the Related Art Conventionally, in the aluminum smelting process, aluminum dross is produced as an oxide when aluminum is melted. Almost all of this aluminum dross is subjected to dissolution treatment again to recover the aluminum component, and then discarded as industrial waste. It reacts with ammonia to generate ammonia and hydrogen chloride, which causes pollution such as offensive odor. Therefore, various pollution-free treatments and reuses have been studied.

As one of the methods of this reuse, Japanese Patent Laid-Open No.
As disclosed in JP-A-3-291678, it is possible to add limestone or dolomide to aluminum dross to prepare aluminum cement.

[0004]

However, even in such processing, the following points to be solved still remain. That is, in the aluminum cement as described above, a large amount of chlorine component still remains even after the above treatment, and this chlorine component is present in various facilities such as a cement manufacturing plant or a structure such as a metal after actual casting. This is a problem that it has a bad influence on the properties of cement, such as causing corrosion. The present invention has been made in view of such conventional problems, an aluminum dross capable of efficiently removing a chlorine component from an aluminum dross, and modifying the aluminum dross into a component suitable for an aggregate such as cement. It aims at providing the processing method of.

[0005]

In order to achieve the above object, the method for treating aluminum dross according to claim 1 of the present invention is a method for treating aluminum dross produced from an aluminum smelting process or the like from 1300 ° C to 1600 ° C. The chlorine component is removed from the aluminum dross by heating the aluminum dross. In the method for treating aluminum dross according to claim 2, the aluminum dross produced in the aluminum smelting process or the like is treated at 1300 ° C to 145 ° C.
A chlorine component is removed from the aluminum dross by heating at 0 ° C.

Here, the reason why the temperature of the heat treatment is limited to the above range will be explained. Below 1300 ° C., although a chlorine component removing effect is observed, it takes a lot of time to remove to a satisfactory value. However, it is not preferable in terms of treatment efficiency, and when the temperature exceeds 1600 ° C., the chlorine component removing effect becomes saturated, so the range is limited to the above range.

Further, especially, the temperature of the heat treatment is 1300 ° C.
By setting the temperature in the range of ˜1450 ° C., the fuel cost can be reduced while maintaining the effect of removing the chlorine component.

[0008]

EXAMPLES An example of the present invention will be described below.
First, a processing apparatus suitable for effectively carrying out the aluminum dross processing method of the present embodiment will be described.

In FIG. 1, reference numeral 1 indicates a processing device,
In this processing apparatus 1, while the aluminum dross D is introduced, the rotary kiln 2 that heats the aluminum dross D while stirring and the untreated aluminum dross D are stored, and the aluminum dross D is also stored.
To the rotary kiln 2 from one end side thereof, a burner 4 disposed at the other end side of the rotary kiln 2 for heating the inside thereof, and a fossil fuel such as coal powder or heavy oil to the burner 4. And a recovery box 6 arranged to cover the other end openings of the burner 4 and the rotary kiln 2.

More specifically, the rotary kiln 2 is provided so as to be inclined at a predetermined angle so that one end side thereof is upward, and the aluminum introduced from the one end side in association with the inclination and the rotation around the axis. The dross D is agitated and conveyed toward the other end.

On the other end of the rotary kiln 2,
An exhaust duct 7 is connected in series, and the gas in the rotary kiln 2 is guided to a neutralization facility 9 via a water washing facility 8 provided in a subsequent stage. The water washing equipment 8 is adapted to act chlorine on the rotary kiln 2 with steam to generate hydrogen chloride, and the neutralization equipment 9 reacts the hydrogen chloride sent from the water washing equipment 8 with lime. By doing so, calcium chloride is generated.

Further, a preheater is arranged between the dross hopper 3 and the rotary kiln 2 if necessary,
Aluminum dross D thrown into rotary kiln 2
Is preheated.

Next, the processing apparatus 1 thus constructed
The processing method of this embodiment will be described together with the action of. First,
The burner 4 is ignited to heat the inside of the rotary kiln 2 to a predetermined temperature, and the rotary kiln 2 is rotated around a shaft at a predetermined rotation speed.

From this state, untreated aluminum dross D is continuously charged from the dross hopper 3. The aluminum dross D thrown into the rotary kiln 2 from one end is repeatedly scraped up by the rotation of the rotary kiln 2 and then dropped, and is sequentially fed to the other end by the inclination of the rotary kiln 2. At the same time, it is heated to a predetermined temperature while reaching the other end.

The aluminum dross D conveyed to the other end of the rotary kiln 2 is dropped from the rotary kiln 2 into the collection box 6 and collected.

During such heat treatment, chlorine is removed from the aluminum dross D, and this chlorine is sent to the water washing facility 8 through the exhaust duct 7 and reacted with water vapor to be converted into hydrogen chloride. By being reacted with lime in the neutralization facility 9 in the latter stage, it is converted into calcium chloride and rendered harmless.

The relationship between the heating temperature of the aluminum dross D and the amount of residual chlorine in the aluminum dross D after the treatment was examined by using the heating time as a parameter, and the results shown in FIG. 2 were obtained. . The chlorine concentration measurement in FIG. 2 is based on alkali melting analysis.

As is clear from this result, 1300 ° C.
In the range of ˜1600 ° C., most of the chlorine components in the aluminum dross D are removed in a heating time of several tens of minutes.

In particular, at a heating temperature of 1450 ° C. or higher, the chlorine component removing action is observed, but since the degree of change in the removal efficiency is small, sufficient treatment can be performed even at a heating temperature up to 1450 ° C. Therefore, the heat treatment at a temperature up to 1450 ° C. can reduce the fuel cost without lowering the treatment efficiency.

Therefore, the aluminum dross D thus treated is modified into a component that does not adversely affect its properties even when used as an aggregate of cement, and the aluminum dross D is treated to be pollution-free. And recycling are achieved at the same time. Further, since the chlorine in the aluminum dross D is removed in a short time by the heat treatment within the above temperature range, the treatment cycle can be shortened and the energy efficiency can be improved.

In this embodiment, fossil fuel is used for heating the aluminum dross D. However, since water is generated when the fossil fuel is burned and reacted with chlorine in the aluminum dross D, the rotary kiln is used. The same hydrolysis treatment as in the water washing treatment facility 8 is carried out in 2 as well,
From this point as well, it is considered that the processing efficiency is improved.

In the above-mentioned embodiment, the processing method by the continuous processing apparatus using the rotary kiln 2 is illustrated, but the processing method is not limited to this and, for example, the batch processing is performed by using the processing equipment 20 as shown in FIG. It is also possible to process with.

The processing equipment 20 includes a tunnel furnace 21 and
Conveyor 22 that can be run in this tunnel furnace 21
And a plurality of burners 2 installed in the tunnel furnace 21.
3 and the exhaust duct 2 connected to the upper wall of the tunnel furnace 21
4, a water washing equipment 25 provided in the middle of the exhaust duct 24, and a neutralization equipment 26. The aluminum dross D is filled in a crucible 27 placed on the conveyor 22. Is the tunnel furnace 2
It is supposed to be sent within 1.

Although not shown, a rotary furnace can be used in the batch type treatment, and a plasma arc can be used instead of fossil fuel for heating the aluminum dross D.

[0025]

As described above, the method for treating aluminum dross according to the present invention is characterized by removing the chlorine component from the aluminum dross by heating the aluminum dross at 1300 ° C to 1600 ° C. It has the following excellent effects.

Most of the chlorine in the aluminum dross is removed, and even when it is used as an aggregate of cement, it can be reformed into a component that does not adversely affect its properties. Processing and recycling can be achieved at the same time.

Further, by performing the heat treatment within the above temperature range, chlorine in the aluminum dross can be removed in a short time, thereby shortening the treatment cycle and increasing the energy efficiency to improve the operation of the treatment. The efficiency can be increased.

Particularly, the heating temperature is 1300 ° C to 1450 ° C.
As a result, the fuel cost can be reduced without lowering the processing efficiency.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a processing apparatus for carrying out the method of the present invention.

FIG. 2 is a diagram showing a relationship between a heating temperature and an amount of residual chlorine when aluminum dross is heat-treated by the apparatus shown in FIG.

FIG. 3 is a perspective view showing the outline of another example of a processing apparatus for carrying out the method of the present invention.

[Explanation of symbols] 1 treatment device 2 rotary kiln 3 dross hopper 4 burner 5 fuel tank 6 collection box 7 exhaust duct 8 water washing equipment 9 neutralization equipment 20 treatment equipment 21 tunnel furnace 22 conveyor 23 burner 24 exhaust duct 25 water washing equipment 26 neutralization Facility

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Mitsuo Fujigo 85 Hiramatsu, Susono, Shizuoka Prefecture Mitsubishi Aluminum Co., Ltd. Fuji Works

Claims (2)

[Claims] 1. A method for treating aluminum dross, which comprises removing aluminum chloride from the aluminum dross by heating aluminum dross produced in the aluminum smelting process or the like at 1300 ° C. to 1600 ° C. 2. A method for treating an aluminum dross, which comprises removing a chlorine component from the aluminum dross by heating the aluminum dross produced from an aluminum smelting step or the like at 1300 ° C. to 1450 ° C.