Effect of alloying with rare earth metals on the recrystallization temperature and properties of aluminum and an alloy of the system Al-Cu-Mn

Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 4, pp. 40–43, April, 1990.     

Production of high-alumina cement clinker by fusion in an electric furnace

Conclusions The possibility of obtaining clinker from high-alumina cement by melting a mixture of lime and technical alumina in an electric-arc furnace at the Klyuchevsk Ferroalloy Plant has been shown.The high-alumina cement obtained from fused clinker is significantly better in its physicochemical properties than the cement produced on the basis of the lime-alumina slags from the ferroalloy industry.Translated from Ogneupory, No. 5, pp. 25–27, May, 1984.     

Production and use of periclase-chromite concrete parts for the linings of high temperature ladles

Conclusions A method has been developed for production of standard periclase-chromite concrete parts for the linings of high temperature ladles for teeming steel and ferroalloys. The parts have high strength and low porosity and are practically shrinkage-free.The life of periclase-chromite concrete parts in the steel teeming ladles of Chelyabinsk Metallurgical Plant is about four times greater than that of fireclay parts, in Red October Plant practically the same as that observed with the use of high alumina parts, and at Chelyabinsk Electrometallurgical Plant it was higher only in the upper portion of ladles in comparison with that obtained with the normally used fired periclase parts.During service in ladles the parts do not spall, become encrusted at a metal temperature of 1620 °C, do not become encrusted at 1790°C, and at 2200°C are eroded by slag.Translated from Ogneupory, No. 7, pp. 16–20, July, 1982.     

Volatilization of components from zirconia ceramics

Conclusions We investigated volatilization in isothermal conditions of solid solutions of oxides of calcium and yttrium in ZrO₂.The calcium oxide is intensely sublimited from the solid solution of zirconium dioxide, stabilized with CaO at 2000–2100°C. However, during soaking and rapid cooling, destabilization does not occur, even during sublimation of 70–75% CaO. With rise in temperature to 2400–2500°C and a 4 h soak, only 0.5% CaO is preserved in the solid solution, which leads to destabilization and conversion of a large part of the cubic form of ZrO₂ with calcium oxide by fusion, we note sublimation of part of the CaO, and the remaining quantity (3%) is adequate for complete conversion of the zirconia into the stable cubic form.Volatilization of the stabilizing additive occurs in the form of YO at substantially higher temperatures than volatilization of the calcium oxide from the solid solution of zirconium dioxide, stabilized with yttrium oxide. Simultaneously with this we note volatilization of zirconium dioxide in the form of ZrO and ZrO₂.For the use of zirconium dioxide at elevated service temperatures, we would recommend yttrium oxide as a stabilizing additive.Translated from Ogneupory, No. 1, pp. 49–52, January, 1968.     

Effectiveness and prospectives for making new refractories for heating units in mining-beneficiating combines

Conclusions The East Institute of Refractories (VostIO) has carried out research on the basis of which, taking into account foreign experience, they determined the best compositions for refractory concretes for use in calcination machines for the mining-beneficiation combines; they developed a production method and a repair procedure for linings made of concretes by guncreting.Data on the resistance of these concretes in the linings of OK-306 machines at the Northern Combine (GOK) and two OK-I-520 machines operated at the Mikhailovsk Combine since 1977 indicate that the concretes satisfy modern requirements.The approximate demand for guncrete-concretes recommended for calcination machines by 1985 will be about 25,000 tons. A large proportion of the concretes will be required primarily for conveyer machines and RPO units in which the replacement of presently imported materials by Soviet is now specified.The final decision on the matter of organizing the production of the new materials will be taken by the corresponding planning and economic committees after completion of industrial trials of the concretes in the firing zone of conveyerized and shaft furnaces and in the hearths of agglomeration machines.Translated from Ogneupory, No. 8, pp. 20–25, August, 1981.     

Adhesion of the coatings of receptacles and casting molds made of suspensions based on silica sols and vitreous silica

Conclusions It is shown that the adhesion of the coating made from suspensions based on silica sol and vitreous silica reaches 1 MPa; the adhesive strength of the coating increases with the concentration of SiO₂ in the silica sol; the temperature interval between 100 and 300°C is optimal for the formation of the coating.The electrical nature of the adhesion of the coating made from suspensions based on silica sol and vitreous silica has been discovered; the possibility of using dielectric measurements to monitor the forming of the adhesive join and of forecasting its strength has been established.The refractory coatings made from suspensions based on silica sol and vitreous silica have been tested and recommended for use at the Cherepovetsk Metallurgical Combine.Translated from Ogneupory, No. 2, pp. 47–50, February, 1986.