Functional carbonized refractories for the lining of steel ladles have been developed. Results of tests carried out on 400-ton steel ladles under industrial conditions are reported. The average durability of the refractory lining was 94.5 heats against rated value of 100 heats.A challenging problem in the technology of carbonized periclase refractories has been production of high-density components. 2 A major shortcoming of the carbonized periclase refractories is that, subjected to oxidation, they suffer decompaction (loss of density). The high density of material is achieved by the rational compounding (grain composition and the amount of bond added) under controlled conditions of the mix preparation, molding and heat-treatment regime. The carbonized periclase refractories are manufactured using advanced processing equipment: mixers that assure high quality of the mixes and presses operating at high molding pressure and mold degassing [1 -3]. Important features of carbonized refractories that control the carbon oxidation rate are the size and volume of open pores, spatial distribution of pores throughout the bulk of the refractory, gas permeability, and the contact compatibility of carbon particles with oxide materials and antioxidant additives [4].KAMK-5-grade carbonized alumomagnesian refractories for the working layer of the lining in the molten-metal zone, KPShK-8-grade carbonized periclase-spinel refractories for the lining of the transition zone, KPK-10-grade carbonized periclase refractories for the lining of the lower slag zone, and KPK-12-grade carbonized periclase refractories for the lining of the upper slag zone of the steel ladle have been developed (Fig. 1).Relevant specifications of the carbonized refractories are given in Table 1.Based on an optimized multifractional grain composition and introducing a carbon constituent (plasticized grains) [5], one can obtain a carbonized refractory with the predominant pore size not in excess of 5 mm. The pore sizes measured by mercury porosimetry are given in Table 2.The high-temperature bending strength for carbonized KPK-12, KPK-10, KPShK-8, and KAMK-5 refractories (sintered at 1000°C for 120 min and tested for bending in an oxidizing medium at 1300°C) is shown in Fig. 2.

Periclase-carbon linings made from objects supplied by OAO Borovichi Refractory Combine have been tested under operating conditions of converter workshop No. 2 at OAO NLMK in 2007 -2008 There is comparative analysis of linings and directions for improving refractory composition are determined.Specialists of OAO Novolipetsk Metallurgical Combine are devoting increased attention to the quality and reduction in cost of smelted steel. Intensification of production operations during the manufacture and processing of steel (argon blowing, chemical heating complicates the service conditions of refractory linings in metallurgical units: converters, steel-pouring ladles, electric furnaces, furnace ladle devices. The cost of refractory linings made from oxide-carbon refractories and operating in regimes of the intense action of high temperature, molten metals and slags, various gas atmospheres, mechanical loads, and also expenditure on repair and maintenance, contribute a considerable part of the cost of output. The service conditions for lining a converter in CW-2 of OAO NLMK are provided below:

Not many enterprises live such a long and fruitful live as the Borovichi Refractory Works (BRW). The plant has withstood many trials, including the hard times of the perestroika. The enterprise has overcome the difficulties and reached the position of a leader of the refractory industry of Russia. Today's successes are a result of the successful policy of the board of directors and of the management of the plant aimed at expanding and diversifying the production and creating conditions for creative labor of all workers.In the 19th century the Borovichi Refractory Works produced substitutes for bricks imported from Great Britain. Persistent effort aimed at advancing the existing processes and developing new ones has made it possible to bring to market articles that are in greater demand than imported ones. The task is solved successfully by the research department of the enterprise, i.e., the Center for Advancing the Processes and the Production (CAPP). The Center employs trained personnel (65 qualified workers of which 34 are engineers and 3 are candidates of engineering science) and appropriate domestic and imported equipment.The range of products of the BRW is renewed every year. In recent years the plant has started production of articles for continuous casting of steel, articles from low-cement refractory concretes, periclase-spinel refractors, refractory concretes, lightweight chamotte structural articles, large bocks for glass-melting furnaces, checker firebricks for glass-furnace regenerators, refractories for the aluminum industry, and bitstone. A complete set of refractories for continuous casting of steel produced by the BRW includes ladle (steel-teeming) nozzles, shuttle plates, header nozzles, tubes for protecting the metal jet from secondary oxidation in the region between the steel-teeming ladle and the tundish ladle of CCM, single-block stoppers, articles and mixes for control and working layers of the lining of tundish ladles, articles for organizing metal flows in tundish ladles, nonswirl nozzles, and immersion nozzles.Single-block stoppers. These articles are produced by a specially developed process and by a process similar to that used by the leading world producers. Depending on the operating conditions the stoppers have different configurations and differ in the material of the head part (corundum-graphite or periclase-carbon) and fastening (metallic nut, ceramic insert, thread inside the stopper, splint).Pipes for protecting metal jet. Pipes with corundum composition for protecting metal jet are produced using novel processes from powdered fused corundum of various fractions, graphite, and special additives that raise the heat resistance and wear resistance of the articles. Pipes of grade KGTU for ensuring the specified resistance of articles have a reinforced slag-line composition.Immersion nozzles. The nozzles have a corundum composition and are produced by novel methods ensuring heat resistance and wear resistance of the articles. Depending on the service conditions and design and on the...

The main areas of activity of OAO BKO (Open Joint Stock Corporation Borovich Refractory Combine) for the production and supply of sets of oxide-carbon refractory objects and subsidiary materials intended for the working layer of metallurgical units are considered. Results for the operation of the refractories supplied to metallurgical units, and prospects for joint work for increasing the operating life of linings are presented.Specialists of OAO BKO have developed and are constantly improving oxide-carbon refractories intended for lining steel-pouring ladles, converters, furnace-ladle units for extra-furnace processing of steel, and other metallurgical production units. The consumers of this production are numerous Russian metallurgical enterprises: OAO Severstal', OAO NLMK, OAO ChMK, OAO VTZ, OAO AvtoVaz, and many others. Since 2006 within the framework of a joint enterprise OAO BKO has produced oxide-carbon refractories in the PRC. The production capacity of the joint enterprise is about 30,000 tons per year. The Chinese shareholders also have their own plant for melting magnesite which is a favorable fact in the production of oxide-carbon refractories, since only periclase of the highest quality is used.The technology of oxide-carbon refractory production in the joint enterprise is determined by OAO BKO specialists in relation to service conditions in some consumer enterprise. Monitoring of quality is carried out in China by OAO BKO specialists.An increase the life of accident-free operation of linings is provided by a combination of technology with an increase in the technical property indices and the quality of the refractories used, continuous optimization of the lay-up design for the lining working layer providing the same life for all lining elements and uniform wear. The comprehensive solution of the problem for oxide-carbon refractories makes it possible to accomplish further improvement in physicochemical and operation properties of objects, to increase the life of the structural elements of refractory linings, and economic steel production. As a result of selecting the optimum grades for different areas of steel-pouring ladle linings, based on continuous engineering and monitoring operation of units, the life of the lining working layer supplied by OAO BKO satisfies the operating conditions of consumers, and provides guaranteed commitments.In a combined lay-up for lining the walls there is use of periclase-carbon objects grade PU-4AS and periclasespinel-carbon wall items grade PShU-45 and PShU-50, that are a new development of OAO BKO and serve as a replacement for the widely used corundum-periclase-carbon refractories. High-purity materials are used during the manufacture of objects: fuzed coarsely-crystalline periclase, fuzed aluminomagnesium spinel, fuzed corundum, coarse-flake graphite, combined antioxidizing addition Al met + Si and a combined organic binder. In preparation of the mix the polyfraction grain size composition of periclase and corundum is selected and introduced in an amount that i...

No abstract