BR-112023015894-B1 - METHOD FOR MANUFACTURING IRON INGOT USING AN ELECTRIC FURNACE SUPPLIED WITH IMAGING APPARATUS

BR112023015894B1BR 112023015894 B1BR112023015894 B1BR 112023015894B1BR-112023015894-B1

Abstract

METHOD FOR PRODUCING CAST IRON USING AN ELECTRIC FURNACE INCLUDING VIDEO DEVICE. To reliably supply scrap iron into a melting chamber. A method is provided for manufacturing iron ingots using an electric furnace comprising a preheating chamber, a melting chamber, an extrusion machine supplied to the preheating chamber, and an imaging apparatus for observing the interior of the melting chamber. The method comprises an extrusion step for supplying scrap iron, which is preheated in the preheating chamber, to the melting chamber by the extrusion machine, and a melting step for obtaining iron ingots by melting the scrap iron, which is supplied to the melting chamber, with arc heat. The extrusion step controls a movement of the extrusion machine and/or a time interval for moving the extrusion machine based on visual information obtained from the imaging apparatus.

Inventors

Koichi Tsutsumi
Yoshihiro Miwa
Shohei NAGASHIMA
Goro Okuyama
Katsutoshi Endo
Shunichi Kawanami

Assignees

JFE STEEL CORPORATION

Dates

Publication Date: 20260310
Application Date: 20220127
Priority Date: 20210210

Claims (3)

1. Method for producing cast iron using an electric furnace (1) which includes a preheating chamber (3) and a melting chamber (2), wherein the electric furnace (1) further includes an extrusion machine (10) located in the preheating chamber (3) and the method comprises: an extrusion process, carried out in the preheating chamber (3), for supplying a source of solid pig iron (15) preheated in the preheating chamber (3) to the melting chamber (2) by the extrusion machine (10); a melting process, carried out in the melting chamber (2), for melting the solid pig iron source (15) supplied to the melting chamber (2) by arc heat to obtain cast iron (16), CHARACTERIZED in that in the extrusion process, one or both of a quantity of movement of the extrusion machine (10) and a time interval to move the extrusion machine (10) are controlled based on visual information obtained from a video device (30) of the electric furnace (1) configured to observe an interior of the melting chamber (2).
2. Cast iron production method according to claim 1, CHARACTERIZED in that in the extrusion process, one or both of the increase in momentum and the reduction of the time interval are carried out in the case where the visual information obtained from the video device (30) indicates that the solid pig iron source (15) is not supplied from the preheating chamber (3) to the melting chamber (2).
3. Method of producing cast iron, according to claim 1 or 2, CHARACTERIZED in that in the extrusion process, additionally, one or both of the increase in momentum and the reduction of the time interval are carried out in the case where an extrusion pressure of the extrusion machine (10) is 40 MPa or less.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method of producing cast iron from a solid pig iron source using an electric furnace including a video device. The present invention relates, in particular, to a method of producing cast iron capable of observing the supply state of a solid pig iron source from a preheating chamber to a melting chamber and, based on this visual information, controlling the supply conditions of the solid pig iron source to the melting chamber. BACKGROUND OF THE INVENTION [0002] In the production of cast iron using an electric furnace, a source of solid pig iron, such as scrap, is melted by the heat of the arc to obtain cast iron. There is, therefore, the problem of consuming a large amount of electrical energy to generate the heat of the arc. For example, the following methods are conventionally used to save electrical energy consumption in the electric furnace: a method of preheating a source of solid pig iron before melting by a burner using fossil fuel or similar; a method of preheating a source of solid pig iron before melting using high-temperature exhaust gas generated during the melting of a source of solid pig iron in the previous operation; and a method of blowing coke into a melting chamber as an auxiliary heat source. [0003] For example, JP H10-292990 A (PTL 1) discloses a technique in which, in an electric furnace where a preheating shaft and a melting chamber are directly connected, while continuously or intermittently supplying a solid pig iron source to the preheating shaft so as to maintain the state in which the solid pig iron source is present in the melting chamber and the preheating shaft continuously, the solid pig iron source in the melting chamber is arc melted. With the technique in PTL 1, the electric furnace, which does not require, in particular, a device to transport and supply the solid pig iron source to the melting chamber, is used to cause the solid pig iron source preheated by the high-temperature exhaust gas to melt into molten iron, thus efficiently melting the solid pig iron source. [0004] For example, JP 2018-70926 A (PTL 2) discloses an electric furnace operation control system including: an input unit that receives configuration items as operating conditions for electrorefining; and a controller that feeds the configuration items to a neural network to execute the electric furnace refining based on the estimated values of the operation result. [0005] For example, JP 2011-69606 A (PTL 3) discloses a method for producing molten metal by melting from an iron source using an arc melting line, including: a state change detection process for detecting a state change in a melting chamber when an arc discharge is generated; and a supply rate adjustment process for adjusting the supply rate from the iron source to the melting chamber based on the result of the detection in the state change detection process.LIST OF CITATIONSPATENT LITERATUREPTL 1: JP H10-292990 APTL 2: JP 2018-70926 APTL 3: JP 2011-69606 A SUMMARY (Technical Problem) [0006] However, our examination revealed the following: although the technique in PTL 1 is basically to continuously supply the solid pig iron source to the melting chamber while gradually melting the solid pig iron source by preheating and the self-weight of the solid pig iron source, in reality the supply of the solid pig iron source can stagnate on the way from the preheating shaft to the melting chamber. This occurs due to unintended situations, such as the solid pig iron source being overheated and jammed in large chunks, or gaps forming in the solid pig iron source column. Since the state of the solid pig iron source in the melting chamber cannot be directly observed with the technique in PTL 1, it is impossible to recognize such unintended situations during operation. Such irregular supply of the solid pig iron source also increases the electrical energy consumption in the electric furnace. [0007] The technique in PTL 2 is the electric furnace operation control system that builds a neural network reflecting a state near the electric furnace to allow an accurate estimate of the carbon concentration at the endpoint of the cast molten steel. However, the video data used is data from the solid pig iron source photographed in a scrap loading device, i.e., the solid pig iron source before being loaded into the electric furnace. Since the solid pig iron source differs in temperature between before and after being loaded into the electric furnace, and also because the solid pig iron source accumulates differently after being loaded into the electric furnace, this technique is insufficient for a stable supply of the solid pig iron source. Furthermore, although this technique involves carbon concentration at the endpoint and temperature control, it is insufficient for obtaining cast iron with high efficiency and low electrical energy consumption. [0008] The technique in PTL 3 involves adjusting the rate o