When selecting the composition of the aluminum liquid refining agent, in addition to the physical properties of the refining agent (such as melting point, viscosity, surface tension, density, volatility, etc.), the characteristics of the chemical interaction between the refining agent and the metal and the gaseous medium must also be considered, so that It has a strong ability to absorb and dissolve inclusions, a low melting point, and good slag-aluminum separation performance, and it allows certain components of the refining agent to change the properties of the furnace gas when heated and melted, forming a certain reducing atmosphere to reduce oxidation of aluminum.
Aluminum Liquid Refining Agent Function
(1) Conducive to the removal of oxide film at the interface between the molten aluminum and the refining agent, and the removal of inclusions and gases.
(2) It is easy to react with molten aluminum to promote the destruction of oxide film, and hydrogen can escape from the surface of molten aluminum.
(3) It has the function of dissolving and adsorbing inclusions, which is conducive to the removal of inclusions and gases.
When the refining flux mainly plays a protective role, the salt-chloride that is inert to the aluminum liquid should be selected. When degassing purification is the main purpose, the refining flux that effectively reacts to the aluminum liquid to generate gaseous substances should be selected. When it is mainly used to eliminate inclusions, the slag discharge capacity of the refining agent should be fully considered.
Commonly used chloride salts in production include zinc chloride, manganese chloride, potassium chloride, sodium chloride, hexachloroethane, carbon tetrachloride, etc., which can be used alone or in combination. If the refining agent is required not only to purify, but also to modify or refine crystal grains, a composite refining agent composed of adding modification and refining agents can be used to achieve the purpose of comprehensive treatment of molten aluminum.