Development of waste-free technology for periclase-carbon refractory production

Results are provided for a study of product nonconformity during manufacture of periclase-carbon ladle refractories and refractory scrap as a potential raw material source. Optimum charge compositions are given with addition of secondary refractories and a production scheme for the manufacture of periclase-carbon refractory objects taking account of existing technology in the OOO Ogneupor magnesium-dolomite refractory workshop. Pilot batches of objects are produced for industrial tests, confirming a lack of deterioration in operating properties.     

Investigation of Taimyrsk graphites for producing periclase-carbon ladle refractories

Conclusions The investigations showed that Taimyrsk graphite corresponds in chemical composition to foundry and crucible graphite.The content of crystalline graphite equals 13.0–26.3%. The characteristics of periclase carbon goods based on foundry and Taimyrsk graphites correspond to the demands placed on ladle refractories. The wear factors of these products in the slag belt of the lining of 350-tonne steel ladles are on practically the same level.Taimyrsk graphites may be used for the production of periclase-carbon ladle refractories in place of crucible or foundry graphite.L. N. Kurlyandskaya (Urals Geology Planning Association) and L. Ya. Osipova (All-Union Institute of Refractories) took part in this research.Translated from Ogneupory, No. 1, pp. 15–17, January, 1991.     

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.     

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.     

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.     

Thermal Expansion of Magnesian Materials

Results for periclase-carbon materials with different proportion of the finely dispersed fraction tested for linear expansion at 20 – 1420°C under argon are reported. The composition of finely dispersed fraction (varying in proportion from 100% periclase to 100% alumomagnesian spinel) and the carbonization regime are factors that determine the thermal expansion of the materials studied. A hysteretic behavior of the linear expansion curves is established and shown to be related to sintering processes and volumetric phase transformations. The data obtained can be used to optimize the composition and heat treatment of periclase-carbon refractory materials.     

Slag resistance of periclase-carbon refractories based on modified phenol formaldehyde resin

Results are provided for a study of the slag resistance of periclase-carbon specimens based on modified phenol formaldehyde resin using different forms of filler, i.e., sintered and fuzed periclase. It is established that penetration of molten slag and its reaction with refractory is independent of the form of periclase filler. There is a reduction in slag penetration into refractory with introduction of modifying additions.     

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.     

Tests of refractory products of the magnohrom company at the novolipetsk metallurgical works JSC

The largest Yugoslavian producer of refractory materials Magnohrom — Kraljevo Company developed a program for manufacturing periclase-carbon products with an additive of molten periclase, corundum, and antioxidants in the early 1990s. Full-scale tests at the NLMK JSC (Novolipetsk Metallurgical Works) and the Izhorskie Zavody JSC have shown that the endurance of refractory products of Magnohrom — Kraljevo Company are at the level provided by the leader of European refractory production RADEX.     

Effect of surface‐treated graphites on the properties of carbon‐containing monolithic refractory materials—A comprehensive comparison

The performance of alumina‐ and magnesia‐based carbon‐containing refractory castables, suitable for different sectors of steel plants, has been compared. Natural flaky graphites have been modified by their surface treatment via sol‐gel route. The sustainability of graphite in oxidizing atmosphere was noticeably increased by this method with a synergistic possibility of pollution abatement. The hydrophilic nanocoatings of ceramic oxides derived by inorganic precursors reduced the water demand of the composite batch and simultaneously enhanced its oxidation resistance. The oxide coating compositions together with the precursor chemistry have been varied to substantiate their common beneficial features. Scanning electron microscopy (SEM), Raman spectroscopy, Differential thermal analysis (DTA), Thermogravimetry (TG), X‐ray diffraction, thermal conductivity, and zeta‐potential studies have been carried out to compare the influence of heat treatment on as‐received and surface‐modified graphites. The properties of refractory castables, namely, bulk density, apparent porosity, and cold crushing strength have been measured within wide temperature region (110–1500°C), to confirm the positive influence of nanoengineering on graphite surface. The sequence of important phase reactions during sintering of both the composite materials has been discussed. Finally the slag resistance behavior at aggressively fired condition has been investigated to corroborate the improved matrix characteristics due to coated graphites.     

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.     

Refractories for the Taphole of Converters

A range of refractory materials for the converter's taphole lining commercially available from the Kombinat Magnezit Joint-Stock Co. and major aspects of the processing technology are considered. The effective use of antioxidant additions is confirmed by thermal analysis. Results of operational tests of refractory materials are discussed. The advantages of an innovative design of the taphole unit composed of blocks of variable diameter and assembled on a metal template are emphasized. An economic feasibility analysis of the use of periclase-carbon taphole blocks is given. The newly designed refractory material are shown to conform with the requirements of modern converter technology.     

Composition and Fabrication of Magnesia Briquettes from Refractory Scrap for Repairing the Lining of Oxygen Converters

A technology for fabrication of refractory briquettes from spent periclase and periclase-carbon materials salvaged from decommissioned steel ladles has been developed. The briquettes can be used as a patching material to repair the worn refractory lining in oxygen converters. Tests of the patching briquettes were conducted at the MISW JSC with satisfactory results.__________Translated from Novye Ogneupory, No. 1, pp. 17 – 19, January, 2005.     

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.     

Properties of periclase-carbon refractories containing metal powders

Conclusions The effect of the metallic additives (Al, Cr, and FeSi) on the properties of unfired periclase-carbon products was studied. It was shown that their presence decreases the degree of oxidation of graphite without decreasing the strength properties of the refractory. When heat treating the periclase-carbon specimens up to 1000°C, the effectiveness of the additives decreases in the following order: Al, Cr, FeSi. At 1400°C, the effectiveness of all the additives is virtually identical.Translated from Ogneupory, No. 8, pp. 7–9, August, 1989.     

Periclase-Carbon Components for Use in the Refractory Lining of the Steel-Tapping Channel of a 370-Ton Converter

Tests of periclase-carbon blocks for the converter's steel-tapping channel available from the Kombinat Magnezit JSC were carried out in an oxygen-converter shop at the Magnitogorskii Metal-and-Steel Works JSC. The new refractory materials are shown to have a higher endurance as compared to the conventional periclase blocks, which made it possible to increase the operational efficiency of converters.     

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.     

GRAPHITE AS A REFRACTORY*

(1) Some properties of graphite are discussed and industrial applications as a refractory are enumerated. (2) Previous work on graphite, particularly during the World War on graphite crucibles, is reviewed. That work was directed toward finding substitutes for imported graphites and clays. Since peace-time conditions were restored the manufacturers have returned to foreign sources of raw materials and some reasons for this tendency are advanced (3) Analyses of several foreign and domestic graphites are tabulated (4) Reports are given on experiments on the thermal conductivity of clay-graphite bodies.; with the effect of varying percentages of graphite on the conductivity.     

Composite refractory protective coatings for carbon-graphite materials

Production examples are considered for improving the refractoriness of structural graphites and carbon-ceramic composite materials and constructions of them created on the basis of surface composite heat-resistant coatings based on molybdenum silicide and silicon carbide. The temperature limits for coating preparation and their operating capacity are determined. The structure of composite refractory coatings is studied by optical methods. The optimum limit for pyrolytic coatings is established. Translated from Novye Ogneupory, No. 10, pp. 45–50, October 2008.