PURPOSE: To heat a material to be melted from above and below to form temperature gradient in the up and down directions to effectively heat it by installing an electrode bar which is ascended and descended, inserted into a furnace, a furnace bottom electrode arranged opposite thereto, and a feeding means for them.
CONSTITUTION: When a melting furnace 1 is started, a feeding means 2 is operated to melt a material to be melted such as fly ash. At this time, an electrode ascending/descending means 3 is operated to ascend and descend an electrode bar 12A, which is brought into contact base metal stored in a recessed part of a furnace bottom electrode 12B to generate sparks thereby the base metal is melted. A fly ash feeding means 4 is then operated to feed fly ash into the melting furnace 1 from two places. That is, a fly ash hopper 45 and a feeding device 46 each are operated to feed the fly ash from a fly ash feeding port 13. If necessary, a fixed quantity feeding device 44 is operated. Further, the separated salt layer, slag layer and base metal are taken out of discharge ports 16A, 16B, 16C respectively.
WATANABE TETSUYA
KOBAYASHI TAKEO
UMEDA JUJIRO
SAKURAI TAKESHI
