What is the process for slag removal and furnace repair in an intermediate-frequency melting furnace?
2022-05-09
The medium-frequency melting furnace boasts high productivity, with the melting cycle reduced to around 35 minutes. To maximize the furnace’s power output, it’s essential to remove slag as quickly as possible. However, using conventional methods like slag skimmers or manual slag removal proves inefficient—taking too long and creating poor working conditions. To address this issue, a new method has been introduced: tilting the furnace backward by 20–25° after each melt, allowing the slag to flow out through a slot at the rear top of the furnace body directly into a transport vehicle. This approach is not only fast and convenient but also significantly enhances operational efficiency. Additionally, medium-frequency melting furnaces require maintenance after each furnace campaign. To minimize downtime during the replacement of refractory lining materials, it’s crucial to employ mechanized solutions. Vibratory ramming machines and pusher systems have now become standard accessories for large and medium-sized melting furnaces. In particular, the furnace-lining pusher allows refractory materials to be ejected even before the lining has fully cooled, further cutting down furnace-repair time while simultaneously improving workplace safety and comfort.
The groundbreaking development of the medium-frequency melting furnace involves employing a single power system to supply two furnaces simultaneously, enabling continuous operation without production downtime. Practical experience has shown that the total effective power of induction melting furnaces is often underutilized throughout the entire melting process. Specifically, during activities like measuring molten iron temperature, sampling, slag removal, and tapping—especially during pouring—the power supply should either be reduced or temporarily disconnected. If the pouring process takes an extended period, the utilization rate drops to around 50%. To maintain the required production efficiency, the rated power of the power equipment would need to be approximately 118 times higher than the actual demand. To address this challenge, a dual-power system has been developed. In this setup, both the rectifier and the melting furnaces share the same set of capacitors for power supply. Each converter can be independently controlled, allowing the total effective power to be flexibly allocated between the two furnaces in any desired proportion. Beyond providing sufficient power for insulating one furnace at a time, the system’s surplus energy can also be directed toward melting the charge material in the other furnace. This innovative design enables simultaneous power delivery to both furnaces, completely eliminating the need for switching mechanisms or the installation of an additional power system. Moreover, the system eliminates the necessity of shifting power to the holding furnace during the melting process, ensuring that the critical pouring temperature is consistently maintained. As a result, the furnace seamlessly performs both melting and holding functions. And when one furnace requires maintenance, the power supply can be easily isolated from it, allowing the system to continue powering only the operational furnace—thus enhancing safety and operational reliability.
The medium-frequency melting furnace features a computer-controlled system, ensuring a high degree of automation. With its powerful output, the medium-frequency melting furnace boasts short melting cycles and a high superheat rate. Only by integrating a computer control system can the equipment’s full potential be realized, while simultaneously providing effective protection for both the plant and its operators. Currently, large-scale medium-frequency melting furnaces are already equipped with a relatively comprehensive computer-aided monitoring system. Its key functions include:
(1) When the molten iron in the furnace crucible reaches the preset temperature, ensure that the furnace power is automatically reduced;
(2) Monitor, measure, and control molten iron temperature;
(3) Provide an automatic sintering program for the new furnace lining;
(4) Determine the amounts of C, Si, and other alloying elements required to meet the molten iron specifications;
(5) It has an automatic cold-start device.
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2025-09-17