E. S. Borisovskii

Effect of the structural parameters of refractories on their slag impregnation in the units used for vacuum refining of steels

ConclusionsWe studied the effect of the specific features of the pore structure (porosity) and the wetting characteristics of the refractories on their depth of impregnation in the units used for vacuum refining of steels. The changes occurring in the pore space of the refractories during their service were examined. Minimum impregnation occurs in the materials having an insignificant content of the glass phase, a branched pore structure, and a large total volume of fine pores (in particular, pores measuring <1 μm in radius).

Effect of certain transition-metal oxides on the structure and properties of periclase-chromite refractories

ConclusionsThe solubility of the oxides of the transition metals in fused chromium spinellide decreases in the following order: iron oxide, manganese oxide, vanadium oxide, and titanium oxide. This series corresponds to the well known series [12] of increasing atomic volumes of the elements.When firing the periclase-chromite systems based on the chromium spinellides containing the oxides of the transition metals, the migration of these metals into periclase decreases in the following order: iron → manganese → vanadium.It was revealed that the addition of manganese oxide to iron-free chromium spinellide decreases its microhardness. However, in this case, the addition of manganese oxide does not affect the other properties of the specimens.

Fused periclase−chromite-base parts for steel ladle degassers

ConclusionsThe possibility of production of PKhP parts to TU 14-8-368-81 from a mixture of combined ground fused Periclase-chromite with the crust has been shown.These parts may on an equivalent basis replace standard PKhP parts produced from scarce fused periclase-chromite in the wall lining of a circulation degasser of Novolipetsk Metallurgical Combine. It is desirable to continue production of experimental lots of PKhP parts of a combined ground mixture of fused periclase-chromite with the crust and to test them in the zones of a circulation degasser lining with more severe service conditions (bottom, snorkel) and also to test them in batch and circulation type degassers for the purpose of studying the possibility of use of these refractories in place of standard PKhP parts.The introduction of PKhP parts of a combined ground mixture of fused periclase-chromite with the crust makes it possible to eliminate the costs of manual labor for separation of the crust from the fused periclase-chromite and for sorting of the block and to increase the yield of acceptable periclase-chromite for the production of PKhP parts by not less than 20%. To provide stable quality of such parts careful control of the chemical composition of the raw material of fused Periclase-chromite with the crust used for production of parts is necessary.

Effect of iron oxides on the service life of periclase-spinellide refractories

ConclusionsThe conducted tests showed that low-silica periclase-spinellide refractories having an excess iron content in the chromium-containing component are not suitable for use because of their rapid slag-induced chemical corrosion.In continuously operating metallurgical units where splitting of the lining due to the action of the slags is not a decisive factor, it is advisable to use refractories having the optimum content of iron oxides for the formation of a homogeneous spinellide matrix.In units operating cyclically under the most severe conditions (for example, in the ASEA-SKF type installations), the periclase-spinellide products in which the spinellide having the minimum content of iron oxides acts as a fused synthetic chromium-containing component are suitable since they exhibit the best high-temperature thermomechanical properties and stability.

Periclase-spinel products based on sintered materials for vacuum treatment of steel outside the furnace

ConclusionsA technology was developed for periclass-spinel, low-silica chrome-concentrate (SiO2 <1.5%) and sintered periclase (MgO 91–92%, SiO2 < 3%). As regards the resistance in the walls of the metal zone of circulation vacuum equipment, these refractories are not inferior to PKhP periclase-chromite goods made from fused materials.In the production of PShKh articles it is recommended that titanium additives be used to ensure sintering of the chrome-concentrate to a low porosity, and to stabilize the properties of goods made with it.It is desirable to make wider tests of these refractories in vacuum units of different types. The introduction of PShKh articles based on sintered materials in the walls instead of PKhP articles should reduce the consumption of scarce fused materials for vacuum treatment and cut the costs of the linings.

A corundum hydraulically hardening compound with addition of baddeleyite for steel ladle vacuum degassing vessels

ConclusionsA corundum hydraulically hardening compound with addition of baddeleyite has been developed. In comparison with standard production MKN corundum compound it makes it possible to prepare concretes with improced physicotechnical characteristics, to increase the wear resistance of nozzle outer linings of batch and circulating vacuum degassers operating in electric melt and converter shops, to reduce labor costs for intermediate repairs, and to decrease the consumption of materials. To obtain more representative data it is desirable to conduct broad production tests of the new compound.

Testing low-silica chromium concentrate in the production of refractories for treating steel outside the furnace

Essais de production de refractaires periclase-spinelle a partir de concentrats de chrome industriels. Etude des proprietes physicomecaniques et de la structure des produits obtenus

Microstructure and chemical composition of the phases of the fused low-silica chromite-periclase materials

In order to produce chromite (chrome)-periclase bearing refractories having a low silica content, one makes use of beneficiated concentrates of chromium ores or synthetic chromiumbearing materials [i, 2] Which require presintering or prior melting because of the fine dispersion of the products of benefieiation and synthesis. It was previously shown [3, 4] that fused materials can exhibit significant differences in the structure and that ferrochromium has a negative effect on the service properties of the products.

Corundum hydraulically hardening rammed compounds with a reduced grain size

ConclusionsThe production and use of rammed hydraulically hardening corundum compounds with different maximum grain sizes (from 1 to 7 mm) permits intermediate repairs of the linings of ladles of a steel ladle treatment unit, increasing their life.It is possible to determine the quantity of binder for obtaining the maximum strength by calculation by use of the coefficient of optimization, which is the portion of binder required per unit of specific surface of the mixture of filler grains. For the corundum hydraulically hardening compounds the optimum value of this coefficient is 0.8–1.2.

Mineral composition, structure, and properties of high-temperature strength high-purity periclase-spinelide refractories

ConclusionsA dense synthetic high-chrome spinelide with a low silica content was obtained.Based on this spinelide and high-purity materials, a method was developed for periclasespinelide refractories with a dense structure and high indices of heat resistance, strength, and volumetric stability at service temperatures. The refractories are intended for lining the slag belt of the vacuum ladle of a unit for vacuum treatment and refining of steel.