Natural Graphites Used as Additions and Their Effect on the Performance of Carbon-Containing Refractories

Natural graphites as additions to periclase-carbon refractory materials are considered. The effect of ash components and natural graphites with different specific surface on the oxidizability, mechanical strength, and slag resistance of the refractory material are studied. Low-ash natural graphites with low specific surface are recommended for production of periclase-carbon refractories.     

Effect of carbon-containing additions on periclase-carbon refractory properties

Results are provided for a study of the effect of pitch additions of a different nature on binder properties and refractory material quality in the production of periclase-carbon refractories. The desirability is established of using coal-tar and petroleum pitches as a carbonizing agent for refractory material.     

Development of a Technology for Manufacture of Periclase-Carbon Refractories

A technology for manufacture of periclase-carbon refractories for the lining of steel-teeming ladles of oxygen-blowing converter is developed.     

Periclase-carbon refractories bonded with lignosulfonates and complex additives

Conclusions The use of refractory batches, in the production of periclase-carbon refractories developed by the Magnezit Combine, with the introduction of complex additives, a liquid constitutent in the form of liganosulfonate of improved quality helps to produce periclase-carbon refractories ensuring a high resistance in the high-wear zones of various furnaces in the metallurgical industries.Translated from Ogneupory, No.3, pp. 13–16, March, 1991.     

Fabrication Of Periclase-Carbon Refractories With An Antioxidant And Their Testing In A Lining Of A 370-ton Converter

Periclase-carbon refractories based on electrofused periclase with an additive of passivated aluminum have been tested in service in the top cone of a 370-ton converter of the Magnitogorsk Metallurgical Works. The lining with experimental refractories withstood 1501 heats whereas the endurance of commercial periclase-carbon refractories of grades PUPK-6 and PUPK-8 equals 1185–1416 heats. It was concluded that the periclase-carbon articles with an aluminum antioxidant have good prospects for lining converters.     

Towards Increasing Endurance of Carbon-Containing Refractories for Converter Steel-Making Technology

The many-years cooperation of the Magnitogorskii Metal-and-Steel Works Joint-Stock Co. and the Kombinat Magnezit Joint-Stock Co. has resulted in the development of advanced periclase-carbon refractories for converter linings with an endurance of 2536 heats (maximum 3388 heats), and for steel-teeming ladle linings — more than 60 heats. The refractory consumption rate is decreased by a factor of 3.7, with a corresponding decrease in the consumption of refractory per ton of steel.     

Antioxidants in carbon-bearing refractories

A study of boron-bearing additives to periclase-carbon refractories is described. The special features of their oxidation and phase formation in heating of periclase-carbon compositions are investigated. It is shown that some of them can be used successfully as an antioxidant component that improves the operational characteristics of periclase-carbon ceramics. It is shown that the imported antioxidant boron-2000 is analogous to amorphous-boron (95–85%) preparations, and the latter are recommended for the creation of domestic grades of thermally stable periclase-carbon refractories. Translated from Ogneupory i Tekhnicheskaya Keramika, No. 2, pp. 2–5, February, 2000.     

Use of unfired periclase-carbon refractories in parts of linings of 350-ton steel-teeming ladles

Workers of the Azovstal’Company have established the causes of the decrease in the endurance of slag-line areas of linings of 350-ton steel-teeming ladles. In 1995–1996 they conducted industrial tests and introduced a process for lining the slag areas of 350-ton teeming ladles with unfired periclase-carbon refractories. The mean service life of a lining of a 350-ton teeming ladle with a slag line made of periclase-carbon refractories amounts to 23 heats on the average without hot repairs of the slag line during the campaign. The wear of the periclase-carbon lining in the slag line is 3.6–4.3 mm per heat. The specific consumption of refractories and materials for a lining has been decreased by 0.6–0.8 kg per ton of converter steel. Such an operating capacity for the periclase-carbon refractories in slag lines is provided by the composition and structure of the refractories, which possess a high heat resistance and resist the effect of the molten metal and slag. Translated from Ogneupory i Tekhnicheskaya Keramika, No. 2, pp. 37–39, February, 1998.     

High-strength periclase-carbon refractories based on phenol-formaldehyde resin with modification of different batch components

The production of periclase-carbon refractories based on phenol-formaldehyde resin with modification of different batch components is considered, which ensures a compression strength of 70–122 MPa. The strength is increased by reinforcing the resite structure by polysiloxane bonds. The synthesis of SiC in the service of refractories contributes to increasing the slag resistance of the refractory by being an additional antioxidant. __________ Translated from Novye Ogneupory, No. 7, pp. 52–55, July, 2006.     

Thermal Stresses Generated in the Lining of a Steel Ladle

Conditions for the thermal regime of 25-ton steel ladles lined with periclase-carbon refractories are analyzed. The input data for numerical analysis are the temperatures at the inner surface of the lining measured experimentally. Temperature profiles over the cross-section of the hot layer of the lining are calculated and then used to determine thermal stresses in the refractory material. A conclusion is drawn that sharp temperature gradients during the heating-up should be avoided. The currently employed heating regimes generate thermal stresses that exceed the strength tolerance limits for refractory materials. __________ Translated from Novye Ogneupory, No. 10, pp. 84 – 87, August, 2005.     

Effect of antioxidants on the properties of unfired carbon-bearing refractories

The effect of antioxidants on the properties of periclase-carbon and aluminum-periclase-carbon refractories is considered. It is shown that the introduction of aluminum and crystalline silicon into the composition of the refractory mixture decreases the degree of burning-out of silicon in 3-h heat treatment at 1200°C. In addition, the thermoreactive binder based on a resorcinol oligomer used for the production of refractory specimens has a favorable effect on the preservation of carbon in the refractory due to the activation of the oxidation of the coke formed in polymerization of the oligomer. These factors should improve the slag-and metal-resistance of the refractory, its service parameters, and the quality of the final product.     

Improving Lining Resistance Using High-Magnesia Fluxes in the Converter Steelmaking Process

Tests carried out at the Severstal Joint-Stock Co. and Magnitogorskii Iron-and-Steel Works JSC showed that a lime-magnesia flux containing 30 – 35% MgO used in the converter steelmaking process produced a favorable effect on the refractory lining resistance. Compositions for high-magnesia granules (50 – 65% MgO) were developed, their properties characterized, and the rate of solution in the slag melt was determined. Using these granules in the converter process makes it possible to increase the service life of periclase-carbon refractories for converter linings.     

Operation of periclase-carbon converter linings in OAO Magnitogorsk Metallurgical combine

Under OAO Magnitogorsk Metallurgical Combine (MMK) oxygen-converter workshop conditions from 2006 to 2008 inclusively ten converter linings with the same construction were operated made from periclase-carbon objects produced by OOO Gruppa Magnezit, Over the two years of operation the life of linings increased from 43000 to 5500 melts, and in 2009 a life of more than 6000 melts was achieved. Results are provided for analysis of periclase-carbon refractory operation in converter linings and the effect of different melting parameters on the improvement of lining service life is demonstrated.     

Periclase-Carbon Refractories for Operation in the Mouth of a Converter Vessel

The performance of periclase-carbon refractories cemented with a phenolic bond that are intended for use in the lining of the cone section of the oxygen converter vessel has been studied by x-ray diffraction and petrography techniques. The results obtained provide a basis for further improvement of the oxygen converter technology and refractory fabrication.__________Translated from Novye Ogneupory, No. 2, pp. 23 – 25, February, 2005.Based on materials reported to the 8th Congress of Steelmakers (18 – 22 October, 2004, Nizhny Tagil, Russia).     

Processes of wear in periclase carbon articles in steel-casting ladles

Conclusions The wear resistance of periclase-carbon articles grade PUÉP-116 in the walls of steel ladles is 1.5–2 times greater than that of mullite-corundum refractories MKS-72.The feature of the phase inversion of periclase-carbon articles is the formation in the working zone of a dense, spinel-containing subzone which retards the wear of the refractory lining.The wear of periclase-carbon articles occurs through the gradual replacement of the periclase by the more fusible aluminosilicate compounds of the mellilite and merwinite type, and subsequent fusion of the rapidly slagged surface layer.Discussion: Problems with the Production and Use of Refractories for Lining Steel Casting Ladles [For the start of these discussions see No. 8, 1988 and for the continuation — Nos. 9–12, 1988, Nos. 1–3, 5, 7, 9, 11, 1989; and No. 2, 1990].Translated from Ogneupory, No. 3, pp. 3–5, March, 1990.     

Unfired periclase-carbon refractories with a thermoreactive polymer binder

Elevated environmental requirements necessitate the development of new binders with a high carbon residue, heat treatment of which does not result in emission of toxic or carcinogenic substances. Such binders should have adequate technological properties. It is shown that it is possible to use a thermoreactive polymer binder based on a resorcinol oligomer for production of periclase-carbon refractories. The binder is soluble in water and organic solvents and possesses a high carbon residue (> 60%). Specimens of periclase-carbon refractories with the suggested binder and 5–12% graphite exhibit good ceramic and mechanical properties. Translated from Ogneupory i Tekhnicheskaya Keramika, Nos. 1–2, pp. 19–24, January–February, 1999.     

Production of Periclase-Carbon Refractories at Semiluki Refractory Plant

The technology and commercial production of periclase-carbon articles with a regular grain composition from a raw material with unstable grain size are described. A comparative study of casting, elemental, and crucible graphite as the basic carbon component has shown that the best commercial properties are provided by the use of crucible graphite. Tests of periclase-carbon refractories without metallic aluminum and with various contents of aluminum have shown the possibility of a differentiated approach to the use of the antioxidant with allowance for the specific service conditions of the lining.     

PROPERTIES OF SILICA BRICK MANUFACTURED FROM SHARON CONGLOMERATE1

New developments in the field of silicate refractories include greatly improved refractoriness and a high development of desirable qualities in silica refractories manufactured from Sharon conglomerate. The nature of silica refractories in general is discussed and a résumé of materials utilized in the manufacture of silica brick in the United States is given. Several illustrations of this new refractory are included, as well as test data.     

我国耐火材料矿物资源状况与发展问题的讨论

介绍了我国耐火资源的现状和开发利用状况,包括我国耐火资源储量分析、耐火资源的行业配置、耐火矿物资源消耗状况以及耐火矿物资源利用情况。对合理利用耐火资源,走可持续发展道路提出建议;通过改进原料产品生产工艺,提高耐火矿物资源的利用效能;合理使用耐火材料,降低耐火资源的消耗。     

Increasing the Durability of the Lining of 385-Ton Steel-Teeming Ladles

Data on the durability of the lining of steel ladles in service at an MISW ISC oxygen-converter shop are reported. The best stability of the lining under severe operating conditions was achieved using periclase-carbon refractories (since 2000, available from an in-home manufacturer at the MISW). The highest lining durability is found in periclase-carbon components composed of fused periclase (with MgO content not less than 96%) and coarse-grained graphite (7 – 10%).