Alu Refining Agent

17 6月 Alu Refining Agent

Alu Refining Agent is usually composed of alkali metal, alkaline earth metal chloride and fluoride, and its main components are KCl, NaCl, CaF, Na3 AlF6, Na2 SiF6 and so on.
The physical and chemical properties of Alu Refining Agent (melting point, density, viscosity, volatility, hygroscopicity and interface with oxides) play a decisive role in the refining effect.

Chloride salt is the most common basic ingredient in aluminum alloy Refining Agent, the most commonly used is a mixed salt of 45%NaCl and 55%KCl.
Due to their strong ability to penetrate solid al2o3, inclusions and oxide film, the specific gravity of NaCl and KCl at the melting temperature is only 1.55g/cm and 1.50g/cm, respectively, which is significantly smaller than that of aluminum melt.
Therefore, Alu Refining Agent can be well dispersed on the surface of the aluminum melt, crushing and absorbing the oxide film on the surface of the melt.
However, the flux contains only chloride salts, and its crushing and adsorption processes proceed very slowly, and must be stirred manually to accelerate.
Chloride ion has low surface tension and good wettability, suitable for covering agent.

Add a small amount of fluorine salt (such as NaF, Na3 AlF6, CaF2) to the chloride salt mixture, mainly used for refining.
Fluoride flux can also effectively remove the oxide film on the surface of the melt and improve the degassing effect.

(1) Fluoride can react with aluminum melt to produce gaseous AlF, SiF 4, BF3, etc., promote the separation of oxide film in aluminum melt, and squeeze the oxide film.

(2) The current generated at the interface where the above reaction occurs will also cause the oxide film to be “cleaned” and broken. Therefore, the presence of the fluorine salt significantly accelerates the destruction process of the oxide film on the surface of the aluminum melt, and hydrogen in the melt easily escapes.

(3) Fluoride (especially CaF 2) can increase the surface tension of the mixed molten salt, spheroidize the molten salt of the adsorbed oxide, promote the separation from the molten salt, and reduce the loss of slag inclusions.

Aluminum alloy Refine Flux
The flux refining method has a good effect on the discharge of non-metallic inclusions.
In addition to the physical and chemical properties of the flux, the degree of purification also depends largely on the refining process conditions.
Such as the amount of flux, the contact time and area of ​​flux and melt, stirring conditions, temperature, etc.

When smelting aluminum alloy scrap, the quality of the scrap is different, and the amount of covering agent and refining agent is also different.
When smelting high-quality waste residue, the amount of covering agent and refining agent is relatively small.
When smelting inferior waste residue, the amount of covering agent and refining agent is large.
For high-magnesium aluminum alloys, fluxes without sodium salts should be used to avoid contact with sodium-containing fluxes.
Sodium-free refining agent is mainly used for high-magnesium alloy flat ingots such as 5052 and 5754.

How to use Alu Refining Agent
Alu Refining Agent method is widely used in aluminum alloy smelting production.
The aluminum alloy melt is refined in the furnace, the flux is loaded into the refining tank, the refining tube is used as the carrier, and the inert gas is used to purge the aluminum liquid into the aluminum liquid continuously, so that the flux and the melt are fully mixed.
Stirring can achieve the purpose of refining.
The greater the stirring intensity, the more uniform the powder coating and the better the clarification effect.
But it should be noted that the fluctuation of aluminum liquid should not be too large. Otherwise, a new oxide film will be formed.

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