1) strong adsorption, dissolution and chemical slag-forming capabilities.
2) have large specific gravity difference with the metal melt. 3) The interfacial tension between it and the metal melt should be large to facilitate metal separation.
4) high chemical and thermal stability, and should not corrode the metal and furnace lining, or produce harmful gases and impurities.
5) high melting point.
6) low hygroscopicity and low vapor pressure.
7) low activity, is not easy to oxidize, and has small pores.
8) low melting loss.
9) no slag on the surface of the furnace wall.


1) High temperature resistance, not easy to oxidize, long service life, few impurities, pure composition.
2) Very low moisture absorption.
3) Weak activity, large surface tension, can be separated from metal.
4) High chemical and thermal stability, no corrosion to metal and furnace lining.
5) Strong adsorption, dissolution and chemical slag forming ability.
6) Good thermal insulation performance, easy to add materials.
7) Good refining effect, almost no slag on the surface of the furnace wall.
9) prevent the infiltration of gas outside the furnace, and is conducive to the discharge of gas and slag in the melt liquid.
11) loss of smelting metal is small, which reduces the smelting cost and improves the product quality.

