INDUSTRIAL PERFORMANCE OF MgO-C REFRACTORIES WITH DIFFERENT TYPE OF BINDERS USED IN ELECTRIC ARC FURNACES

摘要

Carbon-containing basic refractories have been widely used in metallurgical industry because of their excellent slag attack resistance and thermal shock resistance. Magnesia-carbon products are mainly composed by magnesia clinker, carbonaceous source, antioxidants and by an organic binder. In spite of many studies devoted to the search of new binders for carbon-based refractories, phenolic resins and pitch are still the most common binders used in MgO-C bricks.Considering that carbon containing refractories undoubtedly will be very important for many years to come, this paper compares industrial results between two kinds of MgO-C bricks. Products from various suppliers and different binder, pitch and resin bonded, were applied as working lining of 200TM-electric arc furnaces. Materials with 10-13.5% C were tested and characterization techniques of the as-received products include: thermal expansion, average grain size of magnesia clinker, and optical microscopy. Industrial evaluation was exerted for 16 consecutive months and the procedure included the appraisal of the number of heats, refractory specific consumption (kg per ton of steel) and wear rates of each type of MgO-C linings. Average operating life of EAF with MgO-C pitch-bonded lining was 441 heats, while MgO-C resin-bonded bricks produced 215 heats. Additionally, wear rates for pitch-bonded refractory material were lower than that of resin-bonded. It was concluded that, under evaluated operating conditions, pitch-bonded bricks had better performance than MgO-C resin-bonded refractory.