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perature in the filling is above that os the original firing, the processes of silica transformation into the higher-temperature modifications continue, and at the moment of formation they have imperfect structures and are easily subjected to reduction and breakdown.The maximum weight losses and the most rapid growths are shown by specimens fired with short soaks (10-25 h). This is connected both with ~he significant embrittlement of the structure and with the maximum imperfection of crystallization and modification inversions (in the specimens 15-35% of residual quartz is preserved, the cristobalite is in the form mainly of metastable structureless silica). The resistance of the dinas specimens to reduction rises with prolongation of the soaking during firing (Fig. 8).It should be mentioned that firing in a medium of solid reducer causes a certain reduction in the strength of the specimens with a simultaneous reduction in porosity. In this case the porosity is reduced more during firing in coke than in the earbon,whichapparently is explained by the effect of fluxes from the coke ash.Reduction firing markedly alters the mineral composition of the specimens: there is a big reduction in the quartz content (especially in underfired specimens, i.e., first heat-treated at 1360 ~ and 1400~ with a soak of 10-25 h); there is an increase in the amount of cristobalite, reaching 30-40% (sometimes 50%), and the eristobalite consists of laminar fl-form; there is an increase in the tridymite content (except for specimens fired at 1440~and also in the silicates, glass, iron oxides and sulfides, especially after reducing firing in coke. The residual content of SiO 2 in specimens after reducing fire in coke does not exceed 92.6% (with an original content of 93.8-95.2%), indicating absorption of elements from the coke ash. CONCLUSIONSA reduction in the maximum grain size of dinas batches and an increase in pressing force ensure high apparent density in the articles, which increases their resistance to the action of solid reducing agents.The optimum firing temperature for dinas refractories should be considered as 1400~ an increase or reduction in this by 40~ causes a fall in the resistance of the dinas to reduction, which is connected with the incompletion of the processes of crystallization (at 1360~ and excess embrittlement of the structure (at 1440~ Prolonging isothermal soaking of specimens during their first firing contributes to more complete mineral formation, growth and ordering of the crystals of the high-temperature modifications, which increases the material's resistance to the action of the reducing agents. The service conditions of rammed linings in the gutters of blast furnaces require the use of materials resistant to corrosive iron and slag. Use is made of carbon, silicon carbide, and high-alumina compounds [1][2][3].To cheek whether we can use silicon carbide and electrocorundum in compounds for gutter linings, the Magnitogorsk combine (MMK) made laboratory investigations of their corrosion by iron and slag. The...

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