Abstract: The present invention provides an electric furnace including: a furnace body that includes an electrode; and a slag holding furnace that is configured to hold molten slag in a molten state and is capable of pouring the molten slag into the furnace body when tilted, in which the furnace body includes a cylindrical furnace wall, a furnace cover that is provided at an upper end of the furnace wall, a furnace bottom that is provided at a lower end of the furnace wall and includes a deep bottom portion and a shallow bottom portion as a region having a height of 150 mm to 500 mm from a deepest point of the deep bottom portion, and a slag pouring port that is provided at the furnace cover and through which the molten slag is poured from the slag holding furnace, the slag pouring port overlaps the shallow bottom portion in a plan view, and the area ratio of the shallow bottom portion to the furnace bottom in a plan view is 5% to 40%.

Abstract: The present invention provides an electric furnace including: a cylindrical furnace wall; a furnace cover that is provided at an upper end of the furnace wall; and a furnace bottom that is provided at a lower end of the furnace wall and includes a deep bottom portion and a shallow bottom portion as a region having a height of 150 mm to 500 mm from a deepest point of the deep bottom portion, in which a slag pouring port into which molten slag or a solidified slag lump is capable of being poured from a slag transport container directly or through a tilting trough is provided, the slag pouring port overlaps the shallow bottom portion in a plan view, and the area ratio of the shallow bottom portion to the furnace bottom in a plan view is 5% to 40%.

Abstract: An exhaust gas treatment method includes: burning a combustible component in exhaust gas by causing the exhaust gas, which is produced in an electric furnace, to flow into a slag holding furnace and supplying oxygen-containing gas into the slag holding furnace; causing the burned exhaust gas to flow from the slag holding furnace to a suction device through an exhaust gas pipe; adjusting an internal pressure of the electric furnace by introducing external air into the exhaust gas pipe through an opening portion provided in the middle of the exhaust gas pipe; and changing an area of the opening portion depending on a variation in the internal pressure of the electric furnace by using an opening area changing unit provided in the opening portion.

Abstract: The present invention provides an electric furnace including: a furnace body that includes an electrode; and a slag holding furnace that is configured to hold molten slag in a molten state and is capable of pouring the molten slag into the furnace body when tilted, in which the furnace body includes a cylindrical furnace wall, a furnace cover that is provided at an upper end of the furnace wall, a furnace bottom that is provided at a lower end of the furnace wall and includes a deep bottom portion and a shallow bottom portion as a region having a height of 150 mm to 500 mm from a deepest point of the deep bottom portion, and a slag pouring port that is provided at the furnace cover and through which the molten slag is poured from the slag holding furnace, the slag pouring port overlaps the shallow bottom portion in a plan view, and the area ratio of the shallow bottom portion to the furnace bottom in a plan view is 5% to 40%.

Abstract: The present invention provides an electric furnace including: a cylindrical furnace wall; a furnace cover that is provided at an upper end of the furnace wall; and a furnace bottom that is provided at a lower end of the furnace wall and includes a deep bottom portion and a shallow bottom portion as a region having a height of 150 mm to 500 mm from a deepest point of the deep bottom portion, in which a slag pouring port into which molten slag or a solidified slag lump is capable of being poured from a slag transport container directly or through a tilting trough is provided, the slag pouring port overlaps the shallow bottom portion in a plan view, and the area ratio of the shallow bottom portion to the furnace bottom in a plan view is 5% to 40%.

Abstract: This slag-supplying container of an electric furnace for reduction processing of steel-making slag includes: a container body that causes hot steel-making slag to flow to the electric furnace; a slag discharging portion connected with an electric-furnace-side slag-supplying port; a slag receiving portion that receives the hot steel-making slag supplied; a lid that opens and closes the slag receiving portion; an exhausting portion that discharges exhaust gas from the electric furnace; and, a tilting unit that tilts the container body to adjust the amount of inflow of the hot steel-making slag to the electric-furnace-side slag-supplying port.

Abstract: An exhaust gas treatment method includes: burning a combustible component in exhaust gas by causing the exhaust gas, which is produced in an electric furnace, to flow into a slag holding furnace and supplying oxygen-containing gas into the slag holding furnace; causing the burned exhaust gas to flow from the slag holding furnace to a suction device through an exhaust gas pipe; adjusting an internal pressure of the electric furnace by introducing external air into the exhaust gas pipe through an opening portion provided in the middle of the exhaust gas pipe; and changing an area of the opening portion depending on a variation in the internal pressure of the electric furnace by using an opening area changing unit provided in the opening portion.

Abstract: This reduction processing apparatus for a steel-making slag that continuously performs reduction processing to a hot steel-making slag by using an electric furnace includes: a slag-supplying container that charges the hot steel-making slag into the electric furnace; an electrode that is provided at the electric furnace and heats a molten slag layer on a molten iron produced by reducing the hot steel-making slag; an auxiliary-raw-material supplying unit that supplies an auxiliary-raw-material including a reducing agent to the molten slag layer; and a tilting unit that tilts the slag-supplying container and adjusts a charging amount of the hot steel-making slag to the electric furnace.

Abstract: The method of reduction processing of steel-making slag, includes: a hot steel-making slag inflow process of continuously or intermittently charging, from a slag supplying container, hot steel-making slag to a molten slag layer on a molten iron contained in an electric furnace while adjusting an amount of inflow with the slag supplying container; a reducing agent supplying process of supplying a reducing agent to the molten slag layer; an electrifying and heating process of heating the molten iron and the molten slag layer through application of electric power; and a reduction process of continuing reduction processing of the hot steel-making slag in a non-oxidizing atmosphere while intermittently discharging either one or both of the molten iron or molten slag of the molten slag layer.

Abstract: The method of reduction processing of steel-making slag, includes: a hot steel-making slag inflow process of continuously or intermittently charging, from a slag supplying container, hot steel-making slag to a molten slag layer on a molten iron contained in an electric furnace while adjusting an amount of inflow with the slag supplying container; a reducing agent supplying process of supplying a reducing agent to the molten slag layer; an electrifying and heating process of heating the molten iron and the molten slag layer through application of electric power; and a reduction process of continuing reduction processing of the hot steel-making slag in a non-oxidizing atmosphere while intermittently discharging either one or both of the molten iron or molten slag of the molten slag layer.

Abstract: This reduction processing apparatus for a steel-making slag that continuously performs reduction processing to a hot steel-making slag by using an electric furnace includes: a slag-supplying container that charges the hot steel-making slag into the electric furnace; an electrode that is provided at the electric furnace and heats a molten slag layer on a molten iron produced by reducing the hot steel-making slag; an auxiliary-raw-material supplying unit that supplies an auxiliary-raw-material including a reducing agent to the molten slag layer; and a tilting unit that tilts the slag-supplying container and adjusts a charging amount of the hot steel-making slag to the electric furnace.

Abstract: This slag-supplying container of an electric furnace for reduction processing of steel-making slag includes: a container body that causes hot steel-making slag to flow to the electric furnace; a slag discharging portion connected with an electric-furnace-side slag-supplying port; a slag receiving portion that receives the hot steel-making slag supplied; a lid that opens and closes the slag receiving portion; an exhausting portion that discharges exhaust gas from the electric furnace; and, a tilting unit that tilts the container body to adjust the amount of inflow of the hot steel-making slag to the electric-furnace-side slag-supplying port.

Abstract: In order to preheat pieces of iron scrap of various sizes and shapes highly effectively while avoiding the fusion of the pieces of iron scrap, a rotary kiln type preheating furnace and a shaft type preheating furnace are arranged in parallel with each other in the front stage of a melting furnace in which iron scrap is melted, and preheated iron scrap is charged from both preheating furnaces into the melting furnace. A damper is provided between the shaft type preheating furnace and the melting furnace, so that exhaust gas discharged from the melting furnace is prevented from directly flowing into the shaft type preheating furnace and introduced into the rotary kiln type preheating furnace. Exhaust gas which has passed through the rotary kiln type preheating furnace is introduced into the shaft type preheating furnace preferably from an upper portion and discharged from a lower portion.

Abstract: A preheating and melting apparatus for scrap, for preheating and melting the scrap highly efficiently, includes a scrap melting furnace having a top blowing lance and an electric arc heater and a preheater for introducing an exhaust gas generated from the melting furnace and preheating the scrap. The scrap preheater is a shaft furnace and a rotary furnace is disposed at the bottom portion of the shaft furnace to continue the shaft furnace. The scrap discharged from the shaft furnace is transferred into the rotary furnace and it is then charged into the scrap melting furnace.