| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To cope with a lowering of calorific power in carrying out resistance heating of fly ash containing much salt and burned ash containing much zinc component in an electric melting furnace for waste burned ash. <P>SOLUTION: This burned ash melting electric furnace for melting burned ash 2 of waste by applying an alternating current to three-phase electrodes are provided with a means 15 for lifting the electrodes 3; means 6-8 for detecting electric power inputted to the electrodes 3 or furnace internal resistance; and control means 9-14 carrying out resistance heating by inserting the electrodes 3 in the burned ash 2 until the input electric power P detected by the detecting means 6-8 is lowered to a set value Pa and then lifting the electrodes 3 from the burned ash 2 by a lifting means 15 to carry out arc heating when the input electric power P is lowered to the set value Pa or less. When the upper face of slag is determined to be covered with molten salt due to the fall of input electric power P, the molten salt in the upper layer of slag is heated at high temperature with arc heat and vaporized to prevent a lowering of resistance heating efficiency due to the formation of molten salt. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
