JPS6037175B2 - Degassing and slag removal method for molten metal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for degassing and deliquifying molten aluminum or its alloy.

When air or combustion gas from a furnace comes into contact with molten aluminum and its alloys, the molten metal absorbs gases such as oxygen and hydrogen generated by the reaction, and since this absorbed gas has a low solid solubility, most of it is lost during solidification. is released, creating pores such as pinholes in the casting. In addition, since aluminum is easily oxidized, the absorbed oxygen reacts with the molten metal to produce oxides, which are difficult to separate because the difference in specific gravity from the molten metal is small, and are dispersed in the melt. Deteriorates the mechanical and physical properties of solidified products.

As a method for removing gases, oxides, or discs contained in these molten metals, there is a bubbling process in which nitrogen gas or chlorine gas is directly sucked into the port hot water, and dissolved gases are adsorbed and removed by the bubbles generated. Inorganic chloride flux such as sodium, potassium chloride, aluminum chloride, magnesium chloride, or sodium fluoride, potassium fluoride, calcium fluoride, magnesium fluoride, barium fluoride, aluminum fluoride, cryolite, sodium shelf fluoride , a method in which an inorganic fluoride-based flux such as shelf potassium fluoride is forced into the molten metal using a phosphorizer, and the decomposed gas is degassed and dehulled by the adsorption action of the decomposed gas; There are known ways to do this.

Bubblysog treatment using nitrogen gas does not produce sufficient effects even if the amount of gas is increased, so chlorine gas is generally used instead of nitrogen gas, but chlorine gas is highly toxic and requires careful handling. posing a danger to workers and seriously disrupting the working environment due to the release of harmful fumes. Tokuko Showa 5
According to Japanese Patent Publication No. 1-13085, a method is proposed in which powdered flux is fluidized and mixed with nitrogen gas, chlorine gas, or a mixture thereof, and sucked into Naotoshi's molten metal. A method has been proposed in which aluminum chloride is sublimated in an airtight container and sucked into the molten metal together with a dry inert gas.

However, in the former case, when the powdered flux is sucked into the molten metal along with the gas, clogging occurs in the introduction pipe, and in order to solve this problem, it is necessary to increase the gas suction pressure. As a result, the setting sun causes a great deal of turbulence, causing problems such as the air remelting, and in the latter case, an aluminum chloride heating sublimation device is required.
In addition, aluminum chloride has many inconveniences in handling, such as deliquescent property, smokes in the air and produces hydrochloric acid, and difficulty in adjusting the amount of sublimation and the mixing ratio of absorbed gas.

The inventors of the present invention have conducted intensive studies on how to solve these problems and at the same time obtain high-quality aluminum metal or aluminum alloy. As a result, the inventors have developed a method for solving these problems and at the same time obtaining high-quality aluminum metal or aluminum alloy. By combining a combination of fluoride-based flux and inorganic fluoride-based flux, forming a tablet, and directly introducing it into the sun, the handling operation can be performed safely and easily, and mechanically.
We have developed a method for treating aluminum or its alloys in the sun, which causes extremely little deterioration in physical properties.

A typical chlorinated isocyanuric acid compound that can be used in the present invention is triclo. Examples include isocyanuric acid, dichloroisocyanuric acid, sodium dichloroisocyanurate, potassium dichloroisocyanurate, and among these, trichloroisocyanuric acid, which has a high content of active chlorine, is optimal. In carrying out the method of the present invention, when using tablets in which a chlorinated isocyanuric acid compound is mixed with an inorganic chloride flux and an inorganic fluoride flux, the weight mixing ratio of the former three is 1.0:0.6. ~
1.5:0.7 to 2.0, and when an inorganic chloride flux or an inorganic fluoride flux is mixed alone with a chlorinated isocyanuric acid compound, the former and the latter can be used. They may be mixed in a ratio of 1:1 to 3.5 and then tableted.

Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 10 parts of trichloroisocyanuric acid, 3 parts of sodium chloride
Uniformly mix 9 parts of potassium chloride, 18 parts of sodium fluoride, and load a surface pressure of 7000 kg/bulk into a tablet machine to make cylindrical tablets with a diameter of 3 m and a weight of 20 m per tablet. , molten aluminum 50 heated to a temperature of 750 qo
Using a phosphorizer, 8 of the above tablets per kg were placed in the sun until no gas was observed to be generated.

When the hydrogen gas content in aluminum in this moat treatment was measured, the molten aluminum before treatment contained 0.365 cc of hydrogen gas per 100 ml of aluminum, but the hydrogen gas content in aluminum after treatment was The number of holes decreased by 0.085, and when this was cast using an isolite mold and the surface of the cast product was cut to check the number of holes, there were none.When we observed residual impurities in the structure using a microscope, we found none. .

Example 2 10 parts of sodium dichloroisocyanurate, 2 parts of sodium chloride, 6 parts of potassium chloride, and 12 parts of sodium fluoride were mixed uniformly, and tablets were made in the same manner as in the previous example. The 12 tablets were added in the same manner as in Example 1 to 50k9 of molten aluminum heated to a temperature of 50K9.

As a result, the molten aluminum contained 0.325 cc of hydrogen gas per 100 ml of aluminum, but the hydrogen gas content in the molten aluminum after treatment was 0.090 cc.
There were no holes or residual impurities in the cast article. Example 3 10 parts of trichloroisocyanuric acid and sodium fluoride IJ
250 parts of aluminum were uniformly mixed, tablets were molded in the same manner as in Example 1, and the 6 tablets were added to 50 k9 of molten aluminum heated to a temperature of 750°C in the same manner as in the previous example.

As a result, the hydrogen gas content in the molten aluminum after treatment was 0.09 cc per 100 parts of aluminum, and there were no holes or residual impurities in the aluminum after casting.

Example 4 Trichloroisocyanuric acid 10 bases, potassium chloride 15
Anchor capital, calcium chloride 7 Foundation capital, barium chloride 3 Pass capital 1
Mix this uniformly and make tablets in the same manner as in Example 1.
Molten aluminum heated to a temperature of 50k9
The 6 tablets were immersed in the same manner as in the example above.

As a result, the hydrogen gas content in aluminum flaws after treatment decreased to 0.09 cc per 100 cc of aluminum,
No holes or residual impurities were observed in the casting.

Claims (1)

[Claims] 1. Made of aluminum or its alloy, which is characterized by adding a chlorinated isocyanuric acid compound to one or a mixture of inorganic chloride-based fluxes and inorganic fluoride-based fluxes, and then compressing the resulting tablets, which are then directly placed into a molten metal. Degassing and slag removal method for molten metal.