FOAMING SLAG AND SCRAP MELTING BEHAVIOR IN ELECTRIC ARC FURNACE - A NEW AND VERY PRECISE DETECTION METHOD WITH AUTOMATIC CARBON CONTROL

摘要

Foaming slag in electric arc furnaces is one of the topics that engage many steelwork operators around the world. Since the 80's a variety of methods, such as FFT analysis of the electric current or also directional microphone investigations, have not led to successful detection of the foaming slag height and nor, therefore, to complete automation of the electric arc furnace process. Therefore Siemens Industry Sector, Metals Technologies Division developed a new possibility to detect the level or at least the quality of foaming slag in the furnace. In different publications [1, 2, 3, 4] the topic of this special development was reported. In February 2005 research and development was launched to investigate detectability by means of structure-borne sound. Second step was to develop a control algorithm for the injection of carbon. The successful commissioning of the carbon control at the arc furnace No.1 of Lechstahlwerke GmbH led to further steps: The first results, details are explained later in the paper, are extremely good, so that an entirely full automated arc furnace operation seems to be possible in mid time range from the authors side of view. Siemens is setting up a research and development program for the next 3 years.