Abstract: A water-cooled panel for the furnace wall and furnace roof of an electric-arc furnace is integrally fabricated of refractory bricks arrayed on the furnace inner wall in multiple regularly spaced rows to be exposed at the end surfaces and cooling water pipes installed between the rows of refractory bricks (2). A furnace exterior side of the refractory bricks and a furnace interior side of a cooling water pipe are overlapped in a vertical direction of the water-cooled panel, and the cooling water pipe is provided in between an upper and lower side of refractory bricks.

Abstract: To provide a pre-heating apparatus capable of improving the installation reliability of a raw material holding gate of a pre-heating apparatus, reducing an installation cost and reducing melting electric power energy without deteriorating an operation environment while improving the pre-heating effect on raw materials by an exhaust gas, a shaft equipped with a raw material charging portion and an exhaust gas outlet at the top thereof and with a raw material holding gate at the bottom thereof is disposed in the proximity of an arc furnace, a gap is defined between the lower end portion of the shaft and the holding gate, and an outer cylinder connecting with an exhaust gas duct of the arc furnace is disposed around the outer periphery of the gap.