Yu. A. Polonskii

The enthalpy and specific heat of yttrium oxide at 1300–2100°K

ConclusionsThe temperature dependence of the enthalpy and heat capacity of Y2O3 over the range 1300–2100°K was determined by a combination of experimental and analytical methods. The equation obtained can be interpolated in a first approximation for the temperature range 298–1300°K.

Dependence of the dielectric properties, porosity, and apparent density of quartz ceramic on the phase of composition

ConclusionsIt has been established that there is a connection between the porosity, the apparent density, and the concentration of cristobalite and the dielectric constant of a quartz ceramic; this connection may be used to carry out on-line, nondestructive monitoring of quality.A reduction in porosity of the quartz ceramic associated with an increase in temperature is accompanied by an increase in the concentration of cristobalite. In the experimental quartz ceramic a significant amount of cristobalite (>5%) appears with a porosity <13%.

Technology of producing high-grade electroengineering periclase by melting in an induction furnace with a cold crucible

ConclusionsInduction melting of reactive MgO in a cold crucible in the Kristall-402 equipment makes it possible to produce a periclase with a mass fraction of MgO>99%. Noncontaminating crushing, sieving, and mixing together powders of a specified grain composition plus heat treatment at 1600°C in air ensures that the highest quality periclase in accordance with GOST 13236-73 is obtained. The combined heat treatment of the periclase and an addition of talc increases the electrical resistivity and the general resistivity to hydration.

Masses based on Arkalyk clay for guniting steel-teeming ladles

ConclusionsThe authors investigate the properties of gunite masses based on Arkalyk clays with regard to service conditions in steel-teeming ladles used in open-hearth manufacture of steel. The optimal composition of the mass is as follows: 90% chamotte, 10% clay, and 10% binder (above 100%). Industrial tests have been performed on a mass for guniting 230-ton steel-teeming ladles of the MMC. The durability of a gunite layer 30–35 mm thick is about 6 pourings. The results confirm that Arkalyk clay is a promising material for making gunite masses.

Guniting of the monolithic lining of steel-teeming ladles

ConclusionsThe authors have developed the principles of guniting the monolithic lining of steel-teeming ladles with semidry masses. Determination of the wetting of a vitrified siliceous monolithic lining with aqueous solutions of additives and suspensions of these solutions, plasticizing additives, and refractory filler has shown that a coating can be deposited onto the surface of a monolithic lining. Formation of a ceramic bond between the coating and the vitrified surface of a monolithic lining takes place at high temperatures (900°C or above). Masses of siliceous, aluminosilicate, and periclase-chromite compositions have been developed for guniting the monolithic lining of steel-teeming ladles.A procedure for guniting the monolithic lining of 180- and 350-ton steel-teeming ladles has been developed and tested. The best results have been obtained with use of gunite masses of periclase-chromite composition.

Checking the structure of fusion-cast baddeleyite-corundum BKCh products with the radio-wave method

ConclusionsOwing to the large dimensions and weight and also the high cost of BKCh articles, they should be quality controlled by nondestructive methods of the radiowave type. In the first case this method is useful for selecting BKCh articles for the most critical elements of the structure, e.g., the channel of tank furnaces.

Introducing “Orion” equipment for mechanized guncreting of steel ladles

ConclusionsIndustrial operation in steel factories of the “Orion” complex has shown the effectiveness of the plant and of mechanizing the guncreting of steel ladles. The average life of the lining in ladles was increased by 25–50%, the maximum life of 200-ton ladles at the Rustav factory having been brought to 52 heats. A reduction has been achieved in the specific consumption of ladle refractories equal to 1.7–3 kg/ton of steel. At Magnitogorsk they have increased the throughput capacity of steel melting bays by 3% with a reduction in the ladle stock of 11%.

Improving the efficiency of guniting steel-pouring ladles

ConclusionsHot guniting of steel-pouring ladles without cooling the lining enables us to reduce the time taken to prepare them for pouring, and creates conditions for repeated hot guniting within a ladle campaign. This will make it possible to increase the stability of the lining and to reduce the energy expended on drying the gunite layer.The efficiency of mechanized guniting can also be improved by differential use of gunites with rational compositions.

Kyanite compounds for guncreting the linings of steel ladles

ConclusionsA study was made of the properties of guncrete compounds based on kyanite suitable for service in steel ladles. The best properties were possessed by a compound containing 80% kyanite, 10% clay, and 10% binder.Industrial trials with the guncrete compounds were completed. The life of the new compounds is 20% longer than that of similar compounds based on Novoselitsk kaolin.

Making ladle products using North Onezhsk bauxites

ConclusionsIt was found that the North-Onezhsk bauxites are promising raw materials for the production of highly resistant ladle bricks.We developed and mastered a technology in the BKO conditions for making ladle brick using these bauxites containing up to 6% iron oxides.In the lining of the steel ladles made with the use of bauxite chamotte, the bricks wear out 30–40% less than with ordinary ladle brick produced by BKO and the Chasov Yarsk Combine.