Aluminum and aluminum alloy in the smelting time, easy to inhale and oxidation, it must be sprinkled with insulation covering agent to protect. Its main components are chlorine and fluoride salts, and other salts and compounds. All components are treated by appropriate heat treatment to remove adsorbed water and crystal water, and after screening, to ensure uniform size, the best proportion of each component formula to ensure that the melting point of cover agent for the 700-760 ??, after melting in the Aluminum liquid surface viscosity is small, good flow properties, sprinkle with cover agent, to ensure that in a very short period of time in the aluminum liquid surface to form a thin layer of liquid protective film.
     Insulation covering agent can form a dense protective layer to reduce the involvement of the gas, reducing the surface is oxidized due to metal loss. Moderate melting point, good fluidity, good cover and so on, the amount of less, low cost, the formation of the slag in the metal content is very low.