Recycling of Ladle Slag in the EAF: A Way to Improve Environmental Conditions and Reduce Variable Costs in the Steel Plants - The results of Stefana SpA (Italy)

摘要

Environment is becoming more and more a key issue for the Steel Industry. In areas like Europe, where the increasing variable cost of production and the cost of men power are reducing the profit, the additional cost of residues dumping can reduce to zero the result of the steel plant. Only Italian Electric Steel produces more than two million tons of slag per year and other various types of residues as spent refractory, fumes dust, mill scale, etc. The recycling of these by-products permits to achieve three important results: minimizing the exploitation of natural resources, reducing the amount of dumped material, but also the cost of EAF fluxes, something important for the steel production balance. In 2005 has been started up the second Italian industrial plant that permits to convert ladle furnace slag - so called white slag - and spent refractory into a final powder product that can be injected in its Electric Arc Furnace. The plant is located in the Ospitaletto Works of Stefana SpA, a Steel plant producing about one million tons per year of wire rods and beams. This industrial application shows the sustainability of this particular recycling procedure, cost and process-wise. Important benefits, moreover the reduced cost for slag dumping, is coming from the reduced amount of lime charged into the EAF. One of the key issues for the success of this plant has been the accurate study of the metallurgical characteristics of the LF Slag, the EAF Slag and their interaction with the recycled powder.