Abstract: The present invention reduces temperature gradient in the direction of the radius of solidified ingots of silicon immediately after solidification, which has serious influences on the quality as a solar cell and improves the quality. Silicon raw materials are melted inside a bottomless crucible combined with an induction coil by electromagnetic induction heating. The silicon melt formed inside the bottomless crucible is allowed to descend and solidified ingots of silicon are manufactured continuously. Plasma heating by a transferred plasma arc torch is also used for melting the silicon raw materials. The plasma arc torch is moved for scanning along the inner surface of the bottomless crucible in the horizontal direction. A plasma electrode on the solidified ingot side to generate transferred plasma arc is allowed to contact the surface of the solidified ingot at positions where the temperature of the solidified ingot becomes 500 to 900° C.

Abstract: To restrict to a low level a temperature gradient of an ingot immediately after solidification in a bottomless crucible in a electromagnetic induction casting method using an electrically conductive bottomless crucible. An upper section and a lower section of an electrically conductive bottomless crucible to be disposed inside an induction coil are configured as a water-cooled section and a non-water-cooled section. Both the water-cooled section and the non-water-cooled section are divided by vertical slits into a plurality of portions in a circumferential direction. Rapid cooling with water in the lower section of the crucible is restricted.

Abstract: To restrict to a low level a temperature gradient of an ingot immediately after solidification in a bottomless crucible in a electromagnetic induction casting method using an electrically conductive bottomless crucible. An upper section and a lower section of an electrically conductive bottomless crucible to be disposed inside an induction coil are configured as a water-cooled section and a non-water-cooled section. Both the water-cooled section and the non-water-cooled section are divided by vertical slits into a plurality of portions in a circumferential direction. Rapid cooling with water in the lower section of the crucible is restricted.

Abstract: The present invention reduces temperature gradient in the direction of the radius of solidified ingots of silicon immediately after solidification, which has serious influences on the quality as a solar cell and improves the quality. Silicon raw materials are melted inside a bottomless crucible 3 combined with an induction coil 2 by electromagnetic induction heating. The silicon melt 19 formed inside the bottomless crucible 3 is allowed to descend and solidified ingots of silicon 12 are manufactured continuously. Plasma heating by a transferred plasma arc torch 9 is also used for melting the silicon raw materials. The plasma arc torch 9 is moved for scanning along the inner surface of the bottomless crucible 3 in the horizontal direction. A plasma electrode on the solidified ingot side to generate transferred plasma arc is allowed to contact the surface of the solidified ingot at positions where the temperature of the solidified ingot becomes 500 to 900° C.