Molten metal mixing system

A molten metal mixing system, comprising:

• 1 st melting apparatus for melting by heating a 1st melt raw material to produce a 1st molten metal,
• 2nd melting apparatus for melting by heating a 2nd melt raw material to produce a 2nd molten metal, and
• a connecting pipe connecting the 1st melting apparatus and the 2nd melting apparatus,
• wherein the system is configured to transfer the 2nd molten metal produced in the 2nd melting apparatus through interior space of the connecting pipe to the 1st melting apparatus to mix with at least one of the 1st melt raw material and the 1st molten metal in the 1st melting apparatus,
• wherein the 2nd melting apparatus has a molten-metal-tapping chamber for retaining therein the 2nd molten metal to be transferred to the 1st melting apparatus,
• wherein the 1st melting apparatus has a molten-metal-receiving chamber for retaining therein the 2nd molten metal received from the 2nd melting apparatus,
• wherein the system is configured that, when part of the 2nd molten metal retained in the molten-metal-receiving chamber is discharged out of the molten-metal-receiving chamber to lower a surface of a molten metal in the molten-metal-receiving chamber, the 2nd molten metal in the molten-metal-tapping chamber is transferred through the connecting pipe into the molten-metal-receiving chamber by siphon principle,
• wherein one end of the connecting pipe is positioned below a surface of the 2nd molten metal in the molten-metal-tapping chamber,
• wherein another end of the connecting pipe is positioned below the surface of the molten metal in the molten-metal-receiving chamber, and
• wherein the system is configured such that the 2nd molten metal is transferred from the molten-metal-tapping chamber into the molten-metal-receiving chamber without contacting air through the interior space of the connecting pipe.