影响镁铬耐火材料抗粗铜侵蚀的因素

研究了温度、保温时间、粗铜的加入量和气氛等因素对镁铬耐火材料抗粗铜侵蚀性能的影响。结果表明 :随着侵蚀温度的升高 ,侵蚀保温时间的延长和粗铜加入量的增加 ,其渗透面积增大 ;气氛对粗铜渗透性影响较大 ,粗铜熔体中 [O]浓度越高 ,粗铜的渗透性越强。     

Periclase-forsterite refractories from silica magnesite

Conclusions Periclase-forsterite refractories from silica magnesite of Beloretsk deposits are endowed with excellent properties.The density of periclase-forsterite brick is subject to a wide range of changes depending on the grain distribution of the mixture, molding pressure, sintering temperatures and the introduction of additives. The effect of additives on the sintering of periclase-forsterite mixtures from silica magnesite has the same pattern as in the sintering of pure magnesium or regular magnesite. The most effective sintering additives are titanium and zirconium dioxides. Additions of ZrO₂ produces a higher refractoriness-under-load of periclase-forsterite brick.Periclase-forsterite brick is highly-resistant in regenerator checkers of open-hearth furnaces. This is caused by peculiar changes in its mineralogical structure which occur during service, i.e. recrystallization of periclase in top layers which brings about higher density instead of looseness as in forsterite refractories bonded with unite.The forming and the properties of periclase-forsterite refractories as they depend on such factors as basic raw material, manufacturing methods and phase composition need further studies and large-scale testing in order to determine the rational areas of application.     

Converter refractories from Satkinsk dolomitic magnesite

Conclusions Satkinsk dolomitic magnesite fired in a rotary kiln using a cycle employed for Styl'sk dolomite can be used to obtain sintered powder with an apparent density 3.15 g/cm³.Compared with the currently produced tarred dolomite-magnesite refractories, the tar-bonded converter refractories made on the basis of powder produced from dolomitic magnesite are characterized by higher densities, strength, and resistance to hydration.Thus, Satkinsk dolomitic magnesite which is hardly used at the present time is a promising raw material for producing converter refractories.Translated from Ogneupory, No. 8, pp. 15–20, August, 1971.     

Tarred magnesite refractories for oxygen converters

Conclusions A technology was developed for producing tarred magnesite refractories for lining steel converters. The average monthly life of the lining of the converters at the ZSMZ was increased to 624 heats (August 1970) with a maximum life of 662 heats.The tarred magnesite refractories based on MDPK-75 powder possess excellent resistance to hydration and have a high strength. Considering these facts and also in view of the high capacity of the refractories division of ZSMZ it is possible to transport tarred magnesite products over appreciable distances and to deliver them to converters in newly constructed factories.The outstanding feature of tarred magnesite refractories is their slight tendency to slagging, in connection with which the life of the tarred magnesite linings largely depends on the daily output of the converters. To reduce the consumption of refractories in each converter at the ZSMZ it is necessary to arrange more than 30 heats per day during the entire campaign period.Translated from Ogneupory, No. 1, pp. 4–9, January, 1971.     

Life of refractories made of Tal'skiy magnesite

Conclusions Magnesite brick made of Tal'skiy magnesite serves somewhat better than standard magnesite brick and can be used for lining open-hearth furnaces.Magnesite brick with the addition of scale and chrome-magnesite brick made from Tal'skiy magnesite serve just as well as the corresponding refractories from the Satka material, and can be used to line the walls of open-hearth furnaces.Magnesite-chrome brick made with Tal'skiy magnesite serves just as well as standard magnesite-chrome brick and can be used to line the roofs of open-hearth furnaces.Metallurgical powder made from Tal'skiy magnesite serves just as well as Satka magnesite powder and can be used both as a weld-on and as a servicing material for open-hearth furnace hearths.Tal'skiy magnesite of the experimental type is an industrial raw material for making high-grade magnesian refractories.     

Unfired magnesite refractories in resin phosphate bonding

Conclusions A process has been developed for producing unfired, dense, thermal-shock and slag-resistant magnesite refractories with a resin-phosphate binding.One feature of this process is the molding of the articles with an addition of orthophosphoric acid but without heating from a mass containing coarse (> 0.5 mm) magnesite grains and also fine magnesite grains (< 0.5 mm) coated with resin.Translated from Ogneupory, No. 7, pp. 56–58, July, 1979.     

Production of roof refractories using magnesite chromite clinker

Conclusions A method for producing roof products using magnesite-chromite clinker from caustic magnesite and Kimpersai chromite was developed and tested on an industrial scale. The dry method of producing the clinker from 20–25% chromite and 75–80% magnesite powder is the best.Roof refractories made with the use of magnesite-chromite clinker satisfy the requirements of GOST for all factors except spalling resistance.Translated from Ogneupory, No. 7, pp. 9–14, July, 1967.     

Making magnesite roof refractories with additions of fused spinel

Conclusions The Nikitov Dolomite Combine has produced an industrial batch of magnesite — spinel roof products containing fused spinel in the batch. The experimental refractories have very high quality factors.Testing of these products in the roof of a large open-hearth furnace with intensive oxygen blow in the bath showed that their resistance is 19% higher than the resistance of roofs made from periclase — spinel brick in identical furnaces at the Krivoi Rog Metallurgical Factory (with a simultaneous increase in output of 3.1%)Translated from Ogneupory, No. 4, pp. 1–6, April, 1971.     

Production and service-testing of refractories based on flotation-concentrated magnesite

Conclusions Flotation-concentrated magnesite and pure and concentrated chromite were used for producing high-temperature fired magnesite, magnesite-chromite, and periclase-spinel refractories which, compared with ordinary types, contained less silicates and, more direct bonds between the high-refractoriness minerals so that their refractoriness under a load and their thermal strength were higher.In the lining of 100-ton converters for steel, the durability of the experimental magnesite refractory produced from concentrated magnesite and tar-impregnated was 19% better than that of ordinary tarbonded magnesite brick.In the lining of the tuyere zone and of the zone above it in 20-ton and 30-ton converters for copper and nickel, the durability of the experimental magnesite-chromite and periclase-spinel refractories produced from concentrated magnesite and concentrated and pure chromite was 30–35% better than that of ordinary MKhS and PShS type refractories.Translated from Ogneupory, No. 1, pp. 11–15, January, 1976.     

Periglase-spinel refractories based on magnesite powder from caustic dust

Conclusions Periclase-spinel products in whose batch ordinary magnesite powder of fractions 3-1 mm is replaced with powder of the same fraction but obtained by burning caustic magnesite without sintering additives are satisfactory as regards all factors except thermal-shock resistance, and meet the requirements of GOST 10888-64.The resistance and wear of the experimental periclase-spinel products in the roof of an open-hearth furnace are about the same as for ordinary roof magnesite-chromite refractories.Translated from Ogneupory, No.5, pp. 12–13, May, 1970.     

High density magnesite — Chromite refractories from sinter-active bodies

Conclusions Using actively sintering bodies it is possible to make high-density magnesite-chromite products. There is typically a very low porosity and high strength at ordinary and high temperatures. The thermalshock resistance of these products in conditions of 1300°C air is the same as for industrial products MKhS and PShS. Compared with these, the high-density products have a higher deformation temperature and greater rigidity.Translated from Ogneupory, No. 1, pp. 32–37, January, 1972.