The use of chromium in refractories is important in metallurgical applications. 'Chrome ore' and 'chromite' are terms used synonymously in the refractory industry. There are three grades of chrome ores for industrial usage. These are (i) metallurgical, (ii) refractory, and (iii) chemical. Only the refractory grade ore is used for …
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It is shown that fusion-cast chromium-bearing refractories KhPL-85 and KhMG are as corrosion-resistant as chromium-oxide-based ceramic refractories in melts …
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It is shown that melted and cast chromespinelid refractory KhPL-85 developed, containing 80% Cr2O3 with respect to corrosion resistance in molten glass …
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The Zambales ophiolite is the major source of chromite ore in the Philippines. The chromitites are concordant cumulates and are associated with distinct chromitite-bearing sequences within the mantle peridotites. Refractory and metallurgical chromite deposits are spatially separated and related to different lithologic associations, which crystallized from …
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Table 2 shows the chemical composition of the unused high chromia refractory. The main components were chromium, alumina, and zirconia with traces of other oxides. The specific sampling locations and photographs of the used high chromia refractory brick were shown in Fig. 1. The macro-crack parallel to the corroded surface …
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Chromium oxide (Cr2O3), sometimes referred to as chromia, is a specialist material commonly used as one of the chief alloying elements in certain aluminium oxide (Al2O3) and zirconium dioxide (ZrO2) ceramics, imparting greater dynamic performance in challenging high-temperature processes. Saint-Gobain Performance Ceramics & …
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assemblies, electrode blocks, doghouse corner refractory blocks and arches) can be upgraded with bonded Alumina - Chrome - Silica refractories for the remaining lining of …
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The most used lining refractory material in the metallurgy of copper is chromium-magnesite refractory. Magnesia, magnesia-spinel (MgO*Al 2 O 3), and dolomite (MgO*CaO) refractories are also used in copper metallurgy, but generally speaking, the resistance of chromite-magnesia refractories is superior to all other said …
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Chromium Corundum Series. Application. Using in unshaped refractory materials, castable materials, ramming materials, etc, also can be used as abrasive materials and tools raw materials, mainly for non-ferrous smelting industry, the petrochemical industry, glass industry, steel industry and a variety of high-temperature furnace. Typical Index
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The high-temperature Crushing strength of refractory materials is shown in Figure 1-10. As the temperature rises, the strength of most refractory products increases, among which fireclay refractory and high-alumina refractory are particularly significant, reaching the maximum at 1000-1200°C. 2. High-temperature Rupture Strength
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chromium refractories. Furthermore, Cr 6+ contaminates the air in the production of refractories that contain chromium. Thus, in melting periclase-chromite the Cr 6+ content in the gas phase reaches 1.7 mg/m 3 (170 MPC). As a temporary measure it is neces- sary to build a more effective system of controlling Cr 6+, consisting of scrubbers ...
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Fig 5 Thermal conductivity of refractory bricks. In refractory structures built of insulating firebricks or very other porous refractories, the type of furnace atmosphere can have a very appreciable effect on heat loss through the refractory walls. This is especially true for atmospheres with a high content of hydrogen.
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1. Introduction. Refractory materials are indispensable support materials for high-temperature industrial fields such as non-ferrous metals, steel and building materials [1].In particular, magnesia-chrome refractories have been widely used in various high-temperature industries due to their high refractoriness, high temperature strength, strong …
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Results are provided for preparation of fused cast chromium corundum refractories using a charge of waste lump baddeleyite-corundum refractories after service in glass-making furnaces. It is shown that fusion cast chromium corundum refractories, containing 41,2 and 62.1 % Cr2O3 and prepared from a charge using baddeleyite …
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However, the use of chromium-containing materials is today questioned because hexavalent chromium (Cr 6+) is classified as carcinogenic potential. The roadmap was established to substitute magnesia–chrome refractory by chromium-free material for the lining of RH vessels in Europe in 2005 as the best solution . Many studies started to …
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Based on the above reasons, magnesia-chromium refractories have the advantages of high high-temperature strength and good kiln-hanging performance, and are currently still widely used in the high-temperature firing zone of cement rotary kilns. In the steel industry, chromium-free environmentally friendly refractory materials can be used …
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Fused cast refractories are divided into six categories according to their chemical composition: (1) alumina silica series (Al 2 O 3 –SiO 2), mainly including fused cast mullite brick; (2) alumina silica zirconia series (Al 2 O 3 –SiO 2 –ZrO 2), including fused cast zirconia corundum series which have 15%, 33%, 36%, 41%, and other zirconia …
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Abstract – This paper examines the role of refractory-grade chromite in refractories. The chromite deposit at Verref's Marico Chrome mine is described. The refractory properties …
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Magnesium bricks are alkaline refractory materials made from sintered magnesia or fused magnesia as raw materials, which are press-molded and sintered.. Applications of Magnesium Bricks Magnesium bricks are …
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Refractories are non-metallic materials with chemical and physical qualities that allow them to be used in buildings or as components of systems that are subjected to temperatures …
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The valence state of chromium was studied using XPS analysis as the Cr(2p) fine structure spectra of the quenched samples S1 and S2 are shown in Fig. 3. A mathematical curve fitting program was applied to deconvolute the Cr 2p3/2 and Cr 2p1/2 photoelectron peaks, and the binding energies (BE) were compared with various …
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Rotary kiln containing refractory lining. ... Chromium ores were widely used as secondary minerals in magnesia brick, but disposal problems caused by hexavalent chromium rendered these products an unattractive option in most countries. ... In the mechanical stress category, brick crush-ing is the most common problem (Figure 3.7.8). The main ...
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As a kind of refractory material, the magnesia chrome refractory brick is made of magnesite and chromium concentrate as the main raw material, molded through high pressure and fired in the high temperature. Heat-resistance temperature, the maximum allowed environment temperature is 1700℃. It has features of high strength, high …
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3880 – Chromium Oxide 3720 – Alumina, Al2O3, pure sintered 3580 – Chromite, 38%, Cr2O3 3400 – Alumina, fused Bauxite 3400 – Silicon Carbide, 80-90% 3400 – Fireclay ... Refractories may be classified in a number of ways. From the chemical standpoint, refractory sub-stances, in common with matter in general, are of three classes ...
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A variety of chrome-free refractories, such as magnesia-alumina, magnesia-carbon, and alumino-silicate materials, 17−24 have been successfully developed and applied to iron metallurgy and ...
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A refractory lining refers to a protective layer behind the working lining in contact with furnace contents, encased in a metal shell. ... The chromium and the iron come from construction materials upstream of the combustion chamber and the ATR reactor. Often ruby deposition is seen in a narrow section in the upper part of the …
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Refractory metals also have high density and are chemically inert. Their high melting points give way to powder metallurgy as the choice for manufacturing different components.. A few of the most common applications for refractory metals include wire filaments, tools, chemical vessels within corrosive atmospheres and casting molds. With …
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With pleasure, we present this Special Issue of Materials, titled "Design, Manufacturing and Properties of Refractory Materials".Refractory materials are both economically and socially strategic materials as they enable the production of other crucial products, including steel, non-ferrous metals, cement clinker, lime, glass and many others.
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The oxidation states of chromium in solid state change with an increase in temperatures according to the following order: Cr(III)→Cr(VI)→Cr(III). Thus, spent Cr 2 O 3-containing refractory castables especially those used in the 700–1100 °C temperature range must be treated carefully before land filling.
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In this study, the microscopic properties of spent magnesia-chromium refractories before and after leaching were detected by SEM-EDS and BSE. In addition, the influence of conditions on magnesium leaching was studied by leaching kinetics test, and the kinetics of the leaching process was analyzed by statistical and graphical …
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Magnesia-chrome refractories act as a lining for electric furnaces when valuable metals are recovered from copper converter slags. However, the lifetime of …
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Engineering ceramics and refractory materials* In Smithells Metals Reference Book (Eighth Edition), 2004. 27.8 Design of refractory linings. A refractory lining usually comprises a safety or backup layer behind the working lining in contact with the furnace contents. The whole body is encased in a metal shell. The temperature gradients in the …
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11.5 Refractory Manufacturing 11.5.1 Process Description1-2 Refractories are materials that provide linings for high-temperature furnaces and other processing units. Refractories must be able to withstand physical wear, high temperatures (above ... chromium, iron, lead, mercury, magnesium, manganese, nickel, titanium, vanadium, and zinc also are
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Aluminum-Chromium refractories have very well high chemical stability and outstanding ... crush test with a 5 ton power was carried out by Universal Pressure Apparatus to evaluate the fracture
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