JPH01290722A - Method of adjusting magnesium component of molten aluminum - Google Patents

Abstract

PURPOSE:To improve the yield of molten Al and to facilitate Mg component adjustment by melting Al scrap, subjecting the resulted slag part to Mg removal in a regenerating furnace to form an ingot and charging the same into the molten metal from which the slag is removed. CONSTITUTION:The Al scrap is melted in a melting furnace. The upper layer part of the molten metal contg. the formed slag at a high ratio is taken out and is transferred into the regenerating furnace. The temp. of the above- mentioned slag part is increased to about 750-800 deg.C at this time. The Mg in the molten metal is thereby oxidized and is risen and separated into the slag. The Mg of the molten metal is thus removed. The ingot is produced from the molten metal subjected to such heating and Mg removal treatment and is stocked. The stocked ingot is charged into the molten metal from which the slag part is removed in the above-mentioned melting furnace. The content of the Mg in the molten Al is thereby decreased and the Mg component adjustment is easily executed; in addition, the yield of the molten metal is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for adjusting a magnesium (hereinafter referred to as Mg) component in a melting furnace for melting aluminum scrap.

(Prior Art) Some aluminum alloys for die casting that achieve a certain level of hardness during solidification have a Mg content of 0.3 or less.

Meanwhile, the melting furnace that supplies molten metal to the die-casting machine melts aluminum scraps such as aluminum cans, cutting waste, and wheels. In aluminum cans made from well-drawn materials and cutting waste from well-cut materials, these properties are obtained by increasing the Mg content. As a result, the Mg component of the molten metal was 0.6 to 0.
This increases to about 8%.

In order to reduce this Mg component to a desired level of 0.3 or less, chlorine gas blowing treatment, a stirring treatment in which a Mg-removal flux is introduced, a dilution treatment with new aluminum ingots, and a temperature raising treatment of the molten metal are carried out.

(Problems to be Solved by the Invention) Chlorine gas is a gas that is difficult to handle, and since the de-Mg flux is based on chloride, it is also difficult to handle.

In addition, the new aluminum ingot contains 99% aluminum.
With dilution, other elements (Si, Fe
In order to similarly reduce the content of (Nato), it is necessary to supplementally add these elements.

In the temperature raising treatment of the molten metal, the molten metal is held at a temperature higher than the tapping temperature of 720°C, for example, 750 to 800°C, and Mg is oxidized and reduced. However, this process requires cooling the molten metal again to the tapping temperature, which is time consuming and involves loss of energy.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention melts aluminum scrap in a melting furnace, takes out the upper layer of the molten metal containing a large amount of slag, and transfers it to a regeneration furnace. An ingot is manufactured by subjecting it to temperature raised film Mg treatment.

(Function) In a melting furnace where aluminum scrap is melted, the upper layer of the molten metal containing a large amount of slag is removed, and the ingot is then introduced into the molten metal to reduce the M of this molten metal.
g content is reduced.

(Example) Examples of the present invention will be described below with reference to the drawings together with comparative examples.

Table 1 shows the components of the molten metal before the Mg component adjustment treatment, and this molten metal is transferred to the remaining molten metal 3 TON of the 12 TON melting furnace.
It was obtained by additionally melting TON aluminum scrap.

On the other hand, the molten metal needs to be adjusted to the standard values shown in Table 2 in consideration of the hardness of the molded product before being tapped.

Table 1 Table 2 In this example, 127ON aluminum scrap was melted in a melting furnace. Slag and dross gather in the upper layer of the molten metal, and the upper layer containing a large amount of slag is
During the slag tapping process, it is removed from the furnace and transferred to the regeneration furnace.

In a regeneration furnace, the molten metal containing a large amount of slag is heated at 750°C to 8°C.
Maintain a suitable temperature between 00°C. In this temperature range,
The molten metal is heated as described in the prior art, that is, Mg
The components are oxidized and become oxides that rise to the top of the molten metal.

As a result, ingots having the components shown in Table 3 could be produced from the recycled molten metal in the regeneration furnace.

Table 3 This ingot had a unit weight of 250 kg for ease of handling. Incidentally, the ingot ratio of the molten metal in the regeneration furnace was about 50%.

This ingot is kept in stock, and then thrown into the melting furnace during subsequent charging.

Next, the Mg component adjustment method for the molten metal before the Mg component adjustment treatment described in Table 1 will be described based on Table 4 and FIG. 1.

In the ingot method according to the example, 5 TON in the melting furnace
Up to eight ingots are put into the molten metal. As shown in FIG. 1, the Mg content in the molten metal decreased almost in proportion to the input amount, and a molten metal satisfying the standard values shown in Table 2 was obtained.

On the other hand, in the new lump method shown in Comparative Example 1 according to the conventional example, the content of Si, Fe, etc. other than Mg also decreases, so it was necessary to additionally replenish Si lumps.

Furthermore, in Comparative Example 2, the temperature was raised to 3000° C. due to the thermite reaction, and the amount of slag increased rapidly, resulting in a deterioration in the tapping yield. Further, the Fe oxide is reduced to Fe, and the Fe content increases, making it difficult to satisfy the tapping standard value.

Therefore, this example solves or prevents the difficulty in adjusting the components in Comparative Example 1 and the energy loss in Comparative Example 2.

(Effects of the Invention) As described above, according to the method of the present invention, an ingot is regenerated from the upper layer of the molten metal containing a large amount of slag to be disposed of, and the Mg component is adjusted in this ingot. Improve yield and facilitate component adjustment.

[Brief explanation of the drawing]

Figure 1 shows the number of ingots added and M in the molten metal according to this method.
g (This is a graph showing the relationship with U.

Claims (1)

[Claims] Aluminum scrap is melted in a melting furnace, and the upper layer of the molten metal containing a large amount of slag is taken out and transferred to a regeneration furnace.
The ingots are manufactured and stocked by temperature raising demagnesization treatment in this regeneration furnace, and the stocked ingots are put into the molten metal in the melting furnace from which the upper layer containing a large amount of slag has been removed. A method for adjusting the magnesium component of molten aluminum, characterized by reducing the magnesium content of molten aluminum.