Periclase-carbon composite refractories with a new complex binder

Abstract

We describe the development of the technology of periclase-carbon composite refractories with a new complex binder, which combines the properties of phenolic resins and coal-tar pitch. Theoretical analysis and the results of application in steel teeming ladle lining show that a combination of these thermoreactive and thermoplastic components in the new binder provides a more compact (denser) structure of the coke framework (residue) possessing increased resistance to oxidation. Articles made of the new composite refractory have been successfully tested in the lining of steel teeming ladles. The wear characteristics of new lining materials in steel ladles has been studied.The intensification of technological operations involved in the production and processing of steel complicates the conditions of operation of the refractory lining in metallurgical setups. The most material-consuming unit with respect to refractories is the steel teeming ladle. In Russia, the expenditures for steel-ladle refractories account for about 25% of the total cost of refractories in the entire cycle of metallurgical works. This circumstance explains increased attention devoted to the quality, reliability, and safety of lining in steel teeming ladles. Periclase-carbon composite refractories (PCRs) are widely used in the lining of modern steel teeming ladles [1 -6]. Table 1 summarizes the main factors of wear for PCRs used in various parts of lining of a steel teeming ladle [7].The degradation of teeming-ladle refractories takes place at high temperatures under the action of slag and gas phase and the moving liquid and solid media with mechanical and thermomechanical loads. The main factors leading to wear of the carbon-containing composite refractories are (i) oxidation of the carbonaceous component by the melted slag and hot gaseous medium in the metal zone and (ii) dissolution in the slag, corrosive wear, and cleavage in the slag zone.PCRs possess high corrosion resistance and thermal stability due to certain features of the graphite phase, namely, a small thermal expansion and low wetting by slag. A significant disadvantage of these materials, as well as of other carbon-containing composite refractories, is their loosening caused by oxidation of the carbonaceous component.The experience of commercial applications shows that the introduction of expensive antioxidants (increasing the cost of articles by 10 -40%) not always provides the necessary increase in the service life of modified refractories. Im-

Functionalized Cellular Carbon‐MgO Composites: From Interface Processing to Thermal Shock Resistant Low‐Carbon MgO‐C Refractories

“…Thus, investigating low-carbon-containing refractories (LCCRs) with increased service life, improved thermal shock resistivity and increased corrosion and oxidation resistivity represents one of the key development goals of the modern steel industry roadmap. [3][4][5][6] Although advanced processing and functionalization allow many refractory materials to be anti-oxidative and anticorrosive and hence offer many different ways to improve thermomechanical characteristics, processes for colloidal processing of coatings made from aqueous suspensions have already gained significant importance. These colloidal processing methodologies are not only restricted to dip coating or spray coating techniques, a number of which are described in the following.…”