Abstract: A melt is stored in a vessel, and a lower half portion of a rod-formed porous member is immersed in the melt. The porous member is made of a porous material having pores which is permeable to gas and impermeable to melts, such as molten metal, molten slag, and molten matte. When the vessel is placed in a decompression container and the portion of the porous member which protrudes above a surface of the melt is put in vacuum or under reduced pressure, gases in the melt or gases produced by reactions between components of the porous member and the melt pass through pores of the porous member and are released to vacuum or depressurized atmosphere in the decompression container. Thus, gas-forming components are removed from the melt.

Abstract: A melt is stored in a vessel. A lower half of a degassing member is immersed in the melt. The degassing member has a cylindrical form with the lower end closed, and the lower half section is made of a porous material which is permeable to gas and impermeable to melts as molten metal, molten slag, or molten matte. This lower half section is a partitioning member. When an internal space inside the degassing member is sucked to realize vacuum or reduced pressure atmosphere, gas producing components in the melt pass through the partition member of the degassing member, and are exhausted to inside the degassing member, thus being separated from the melt. Also, by making the degassing member rotate or move in a horizontal or vertical direction, the melt is stirred. With these features, gas-producing components in the melt can be removed at a high efficiency.

Abstract: A melt is stored in a vessel placed in a decompression vessel. On the bottom of the vessel is arranged a bubble generator made of porous bricks, and bubbles of argon gas are introduced into the melt through this bubble generator. Also a lower half section of a degassing member is immersed in the melt. This degassing member has a cylindrical form with the lower end closed and the section immersed in the melt is made of a porous material permeable to gases and impermeable to melts.With these features, a surface of molten metal can be put under reduced pressure and high content components of the melt can be removed by means of bubbling, and also solute components in the melt can be removed into bubbles of argon gas. Also, gases in the melt and gases produced by reactions between the melt and the porous material can be sucked through a wall of the degassing member into inside thereof and removed.

Abstract: Part of a melt vessel is formed from a porous member which is permeable to gas and impermeable to melts. Alternatively, a bottomed cylindrical partitioning member immersed in a melt in the melt vessel, or part of a circulating vessel through which the melt circulates, or a dam disposed in the course of circulation of the melt in the melt circulating vessel is formed from the porous member.Vacuum pump is used to suck gas from the melt or gas produced by a reaction at the interface between the melt and the porous member through the porous member, to the side of that surface of the porous member which is not in contact with the melt and kept at a vacuum or at reduced pressure.Then, the pressure at the interface between the melt and the porous member is lowered, and a space which is in a vacuum or at reduced pressure can be easily created in the melt. Thus, solute ingredients of the melt nucleate easily to form gaseous substances, so that the gaseous substances are sucked into the space and removed from the melt.